At the end of each explained answer, there is a number combination in parentheses. The first number identifies the reference source; the second number or set of numbers indicates the page or pages on which the relevant information can be found.
1. (C) The fetal calvarium is absent superior to the eyes. This finding is consistent with anencephaly. (1:19)
2. (B) The image shows a defect in the posterior cranial vault. Because brain tissue is herniated through the defect, this would be an occipital encephalocele. This fetus also demonstrates microcephaly caused by the large defect. (1:19)
3. (D) Equinovarus, or clubfoot, may be isolated or associated with other defects, most commonly neural tube defects. (2:363)
4. (A) The image represents a cystic hygroma. The multiple septations seen are characteristic of second-trimester cystic hygroma. The intact cranium differentiates it from an encephalocele. (2:992)
5. (A) Seventy-five percent of fetuses with cystic hygromas have a chromosomal abnormality, most commonly Turner’s syndrome. (2:56)
6. (C) The image is an example of a “lemon”-shaped skull. It is most commonly associated with spinal defects, but can be present with encephaloceles and in normal fetuses 1–2% of the time. (2:286)
7. (A) Abdominal ascites outlines the abdominal viscera. Ascites associated with meconium peritonitis may have particles of debris within it, and echogenic foci are often present in the fetal liver. Non-Immune hydrops must have two fluid collections or one fluid collection with anasarca. (2:470, 471)
8. (A) Bilateral pleural effusions and edema. (14:1460–1461)
9. (C) Alobar holoprosencephaly is characterized by a single ventricle, single choroid, and fused thalamus. (1:20)
10. (D) Cystic hygroma is associated with Turner’s syndrome, not trisomy 18. (3:499–502)
11. (C) Paternally derived triploidy is associated with a relatively normally grown fetus that has a proportionate head size. The placenta is large with multiple cystic spaces resembling a molar pregnancy. This accounts for 90% of triploidy. (2:850)
12. (F) Maternally derived triploidy is associated with a small placenta. The fetus has severe asymmetric growth restriction and oligohydramnios. (2:851; 3:506)
13. (A) Potter’s syndrome is associated with renal agenesis, oligohydramnios, pulmonary hypoplasia and malformation of the hands and feet. (20:1282)
14. (C) The embryo cardiac activity can be seen at 6 weeks gestation and on some occasion at 5 and half weeks with higher frequency transducers. The embryo heart rate at 6 weeks range from 112 to 136 bpm, which increases to a rate of 140 to 160 bpm at 9 weeks. A heart rate of less than 80 bpm is associated with pregnancy failure. (20:994; 14:1094)
15. (C) Krukenberg’s tumor is a malignant tumor of the ovary that metastasizes from a primary in the gastrointestinal tract. Meigs’ syndrome is a benign tumor of the ovaries associated with ascites and pleural effusion. (20:920; 943)
16. (D) Hydatidiform mole. This sonogram demonstrates multiple tiny cystic spaces representing vesicles. This gives a sonographic appearance of honeycomb or snowstorm appearance, which is characteristic of hydatidiform mole. (20:1012;14:1578)
17. (A) Talipes equinovarus or clubfoot is a developmental deformity in which the foot is inverted and planter flexed so that the metatarsal long axis is in the same plane as the tibia and fibula. The deformity affects the muscles and tendons of the foot. Clubfoot can also occur from restriction of movement due to oligohydramnios. (20:1309;14:1453)
18. (C) Seventy-five percent of twins are dizygotic. (1:27)
19. (D) The twin peak is formed when the placental tissue migrates between the chorionic layers. This is 94–100% predictive of dizygotic twins. (2:182, 183)
20. (D) Forty percent of conjoined twins are born stillborn. Fifty-six percent of conjoined twins are thoraco-omphalopagus, thoracopagus, and omphalopagus. Polyhydramnios is present 50% of the time. Commonly, there is one umbilical cord that may have an abnormal number of vessels and is shared by the conjoined fetuses. (1:29)
21. (A) Ninety percent of the time, the uterus tilts forward in anteverted position, meaning the uterus forms a 90° angle with the posterior vaginal wall. The uterus, however, may be in any of the following positions:
• Anteverted: The uterus tilts forward with a 90° angle to the posterior vaginal wall.
• Anteflexed: The uterine corpus is flexed anteriorly on the cervix, forming a sharp angle at the cervix.
• Retroverted: The uterus tilts backward without a sharp angle between the corpus and cervix.
• Retroflexed: The uterine corpus is flexed posteriorly on the cervix, forming a sharp angle at the cervix.
This sonogram demonstrate a retroverted uterus (2:531)
22. (E) Absence of cardiac motion. (Study Guide)
23. (E) Fluid in the endometrial cavity in a post-menopausal patient may be associated with cervical stenosis or malignancy. (14:544)
24. (B) Painless bright red blood is associated with placenta previa. (20:1149)
25. (E) The hippocampus is a horseshoe shaped paired structure located in the left and right brain hemisphere. It is not a midline structure. (10:853)
26. (B) The occurrence rate for thanatophoric dysplasia is 1/6000–1/17,000 births. Sonographic findings are polyhydramnios, severe rhizomelia, and micromelia with bowing. The thorax is bell-shaped, and the cranium is cloverleaf-shaped with hydrocephaly and frontal bossing. (1:28; 2:343)
27. (F) Heterozygous achondroplasia accounts for 80% of achondroplasias. It is the most common form of genetic skeletal dysplasia. It is often not identified before 26–27 weeks. (1:27)
28. (B) The outline of a septate uterus is relatively normal and contains two endometrial cavities separated by a thin fibrous septum. A bicornuate uterus contains two endometrial cavities, but there is a deep indentation on the fundal contour. (19:534–538)
29. (B) A meningocele is a spina bifida with herniation of the meninges only. (1:19)
30. (E) Normal cephalic presentation, with the fetal head close to the internal os of the cervix. The placenta is not identified in this image. (20:1148–1153)
31. (B) This is an image of an increased nuchal skinfold (> 6 mm). Nuchal fold measurements are obtained between 15 to 20 weeks gestation. Nuchal translucency is performed between 11 to 14 weeks gestation. Both nuchal fold and nuchal translucency are used for screening Down’s syndrome (14:1233–1234; 20:1027)
32. (E) This sonogram demonstrate an intrauterine contraceptive devices (IUD) that is eccentric in position. (20:915–916)
33. (C) The image represents a benign cystic teratoma (BCT). A differential for this mass could be an endometrioma. (1. Table 9–4)
34. (E) Normal left ovary with iliac vessels. (20:885)
35. (A) The cystic structure in the posterior aspect of the embryonic head represents the rhombencephalon. It is a normal structure seen between 7–9 weeks which later forms the fourth ventricle. (2:139: 14:1113)
36. (E) Subserosal fibroid. (20:903)
37. (E) The serum β-hCG normally decreases significantly after a dilation and curettage (D&C). An increase after the procedure is highly suggestive of an ectopic pregnancy. This image after a D&C is a transabdominal sagittal sonogram with a left unruptured ectopic pregnancy next to the left ovary. (14:1102, 1113)
38. (A) Serous cystadenomas are the most common ovarian neoplasm accounting for 20–25% of all benign ovarian neoplasms. They usually present as large, thin-walled, unilocular cystic masses that may contain thin echogenic septations. (14:566–568)
39. (C) Hydrops fetalis is an accumulation of fluid in body cavities and soft tissue. This image shows cystic hygroma with body anasarca. (14:1137)
40. (D) The abnormality is spina bifida of the lumbar spine. The differential may include a sacrococcygeal teratoma based on the image alone; however, this fetus had a positive lemon/banana sign. (1:19)
41. (E) The image is an increased nuchal translucency. It has an 80% positive predictive value for trisomy 21. If combined with the first trimester biochemistry, it has a 90% positive predictive value for trisomy 21. (1:30)
42. (E) An increased nuchal translucency is associated with specific chromosomal abnormalities, genetic syndromes, and structural defects. (1:30)
43. (B) The dilation of the proximal urethra gives the fetal bladder the classic “keyhole” appearance associated with posterior urethral valve obstruction. (1:25)
44. (E) Tetralogy of Fallot is comprised of a VSD, overriding aorta, pulmonary stenosis, and right ventricular hypertrophy. The hypertrophy is not always present, particularly in the early to midsecond trimester. This image shows the VSD and overriding aorta. (1:21)
45. (D) The stomach is located posterior to the fetal heart, which is deviated to the right side of the chest. The solid appearance on the left side of the thorax is consistent with the liver. (1:22)
46. (D) This image demonstrates a displaced and irregular shape cerebellum, which is curved like a banana and known as the “banana sign.” It is characterized by the inferior displacement of the cerebellum and has a strong association with spinal defects and Arnold–Chiari malformation. (2:73)
47. (B) The image is an example of an omphalocele. Atypically the bowel is herniated instead of the liver. Notice the membrane around the bowel and the umbilical cord inserting into the membrane. (1:23)
48. (D) The image is consistent with enlarged kidneys. Dysplastic kidneys would have multiple cysts. Infantile polycystic kidney disease is associated with large kidneys; however, they are echogenic and oligohydramnios is present. (2:543)
49. (B) The tongue can be seen protruding from the mouth, consistent with macroglossia. The chin, forehead, and profile are normal. (4:225)
50. (C) Beckwith–Wiedemann syndrome is a group of disorders including omphalocele, macroglossia, organomegaly, and hemihypertrophy (1:24)
51. (A) Multicystic, dysplastic kidneys have multiple cysts of various sizes. The cysts occur randomly and do not follow any pattern, as with dilated renal pyramids. The parenchyma is usually echogenic. (1:25)
52. (C) It has a variable prevalence, with Native American being the highest at 3.6/1000 births. (2:322)
53. (D) Three-dimensional imaging of the internal organs is termed volume imaging. Three-dimensional images of surface structures, such as the fetal face, is surface rendering. (1:1020)
54. (B) There is a limitation on what can be visualized by the human eye using medical imaging. A 7 to 10 MHz transvaginal transducer can depict a 5mm gestational sac as early as 4 weeks. (14:1081)
55. (B) Fetal echocardiogram can be done earlier than 18 weeks, but is dependent on maternal habitus. After 24 weeks, the fetal bones become denser and more calcified and begin to limit the sonographic windows that allow visualization of the cardiac structures. (2:378, 379)
56. (A) Three-dimensional imaging of surface structures, such as the fetal face, is termed surface rendering. (1:1020)
57. (D) Although duodenal atresia has been detected in the first trimester, the classic “double bubble” sign is not usually present until the late second and early third trimesters. (2:466)
58. (E) When the increased AFP is unexplained, it is thought to be because of an increased placental transfer of AFP. The placental dysfunction can occur with various placental abnormalities that may be associated with certain third trimester complications. (2:30)
59. (B) Cloacal exstrophy is characterized by an abdominal wall defect inferior to the umbilical cord insertion with exstrophy of a cloacal sac and a neural tube defect. It is associated with a markedly increased MSAFP Amniotic sheets and congenital diaphragmatic hernia do not increase MSAFP Smith–Lemli–Opitz syndrome is associated with a low level of maternal uE3 and normal MSAFP (2:29, 503)
60. (C) If AFP (<0.6 MoM), uE3 (<0.5 MoM), and hCG (<0.3 MoM) are all decreased, the triple screen will show an increased risk for trisomy 18. (2:29)
61. (D) Pulmonary hypoplasia can be assumed by the small thoracic circumference and anhydramnios, but underdeveloped fetal lungs are not visible by sonography. (1:25)
62. (A) Vein of Galen aneurysm is an AV malformation located posterior to the third ventricle in the midline of the brain. (1:21)
63. (A) Truncus arteriosus consists of one outflow tract overriding a VSD. The right ventricular outflow tract is absent. Differential diagnosis includes tetralogy of Fallot with pulmonary atresia. Identifying the pulmonary arteries branching from the main trunk would differentiate the defect. (4:390)
64. (D) The most predictive sonographic findings are the overriding aorta and VSD. If the VSD is perimembranous, it will not appear on the four-chamber view. The right ventricle may appear larger than the left, but this is not a consistent finding and is dependent of the degree of pulmonary stenosis. Differential diagnosis would include truncus arteriosus. (4:426)
65. (A) Congenital cystic adenomatoid malformation (CCAM) is divided into three subsets; macro, medium, and microcystic. Survival rate combines all types and sizes and is 75–80%. Studies have shown that CCAM regresses 55–69% of the time. (2:439–441)
66. (F) Congenital diaphragmatic hernia is left sided 75–90% of the time. Prognosis is poor, particularly if the liver is herniated into the chest. Five to fifteen percent of congenital diaphragmatic hernias are associated with chromosomal abnormalities, commonly trisomy 18. (2:433–438)
67. (D) Ninety percent of esophageal atresia have a tracheoesophageal fistula. This allows amniotic fluid to reach the stomach, but at a slower rate. The stomach will be visualized, but may be smaller than usual. Polyhydramnios occurs in the mid to late second trimester. The VACTERL complex is: vertebral anomalies, anal atresia, cardiac abnormalities, tracheoesophageal atresia, renal anomalies, and limb anomalies. At least three of the anomalies listed must be present to diagnosis the VACTERL condition. (2:103, 460)
68. (A) Trisomy 21 is associated with a decreased MSAFP and an increased hCG. (5:71)
69. (C) The uterosacral ligament is the distal portion of the cardinal ligament. It anchors the cervix and is responsible for uterine orientation. (1:5)
70. (B) Both the suspensory and broad ligaments are folds of peritoneum. (1:5)
71. (A) The piriformis muscles lie more posteriorly and are ovoid and symmetrical. (16:292)
72. (A) The most dependent portion is the pouch of Douglas, or the posterior cul-de-sac. It is located posterior to the cervix and anterior to the rectum. (1:6)
73. (C) The posterior cul-de-sac (pouch of Douglas) is located posterior to the uterus. The anterior cul-de-sac (vesicouterine pouch) is located anterior to the uterus. The prevesical space (retropubic space) is anterior to the bladder. They form the peritoneal spaces of the pelvic cavity. (1:6)
74. (G) Transvaginal probes need to be pre-cleaned with soap and water as well as soaked in a disinfecting solution and covered by a disposable probe cover. The probes should be cleaned after each examination. (1:4)
75. (D) An invasive mole and a hydatidiform mole are excessive trophoblastic proliferation. Unlike the hydatidiform mole, chorioadenoma destruens is malignant and invades into the myometrium. (3:734)
76. (E) Paternally derived trisomy 13 presents with a large placenta sometimes termed a partial mole. Less commonly, a dizygotic pregnancy may occur. One fetus results from normal fertilization of one egg and a complete molar pregnancy results from the fertilization of the other egg. In those cases, it is possible for the hydatidiform mole to advance to choriocarcinoma. (3:734)
77. (C) The ovum enters the fallopian tube at the fimbriated ends. It courses to the ampulla where fertilization occurs 24–36 hours after ovulation. (6:211, 212)
78. (B) Methotrexate (MTX) is a folic acid antagonist used as a medical treatment for a unruptured ectopic pregnancy. The recommended candidates for medical treatment are; hemodynamically stable, hCG of less than 5,000 mIU/mL, no fetal cardiac activity and the ectopic mass size should be less than 4 cm. The is the current recommendation at the time of writing. Previously the recommended was a serum beta hCG of less than 10,000 mIU/mL(24:25)
79. (E) This patient most-likely had a ruptured ectopic pregnancy. Medical treatment is the first option if the patient is hemodynamically stable and with an unruptured pregnancy. However, this patient stated that she had a syncope episode followed by a salpingectomy in which case a ruptured ectopic pregnancy is most-likely. (14:1102–1113)
80. (B) Intrauterine fetal demise (IUFD) is defined as an absence of fetal heart tones after 20 weeks. A blighted ovum does not have an embryo (anembryonic pregnancy). Missed abortion is a demise embryo that has not aborted in the first trimester. A fetus can be in a resting mode without movement but demonstrate a fetal heart tone. (1:14)
81. (E) Dysgerminoma is a malignant tumor. (14:570)
82. (B) Dermoid cysts are more common in younger women and they have a variable sonographic appearance ranging from completely anechoic to hyperechoic. (14:569, 570)
83. (A) Normal adult ovarian size is 3 × 2 × 2 cm. (17:104)
84. (B) The first finding is a gestational sac, however ectopic pregnancies may also present with a pseudo-sac. A yolk sac is the earliest definitive sonographic sign of an intrauterine pregnancy. (6:198)
85. (B) The detection rate is 65%, but may vary among patients depending on the maternal habitus, fetal position, AFV, ultrasound scanner, and expertise of the sonog-rapher and physician. (6:325)
86. (D) The detection rate is 85%, but may vary among patients depending on the maternal habitus, fetal position, AFV, ultrasound scanner, and expertise of the sonog-rapher and physician. (6:325)
87. (D) Distal acoustic shadowing is associated with a solid mass. (6:124)
88. (C) Theca lutein cysts are present in 18–37% of hydatidiform moles. (20:1153)
89. (A) The crown rump length (CRL) is the most accurate because fetal growth is very uniform and is rarely affected by pathological disorders. The choices C and D are based on human memory of the maternal LMP, which assumes ovulation on day 14. (3:138)
90. (A) Fetal growth in the first trimester is very uniform, thus allowing for accurate dating if the total of three crown rump length (CRL) measurements are taking and then averaged. (1.Table 9–6)
91. (B) Fetal growth is starting to show variation and multiple parameters are used to calculate the EDC. Both of these factors allow for an increased range of error. (1:Table 9–6)
92. (C) Fetal growth is showing a moderate amount of variation, which allows for an increasing range of error. (1.Table 9–6)
93. (D) Fetal growth has a large amount of variation in the third trimester and obtaining the images for EFW can be challenging depending on fetal position and size. This allows for the largest range of error in the pregnancy. (1:Table 9–6)
94. (B) The hCG doubles in approximately 48 hours until 10 weeks or a minimum of 66 percent in 48 hours. (6:195)
95. (A) Twin pregnancy is associated with an elevated hCG. (6:225)
96. (D) The internal component of an endometrioma is typically blood from bleeding ectopic endometrial tissue during menstruation. Differential diagnosis may include a dermoid tumor; however, most women tend to be asymptomatic with dermoids. (Table 9–4)
97. (C) Nagele’s rule is: (1) identify the LMP, (2) add 7 days, (3) subtract 3 months, and (4) add one year. (1:397)
98. (D) Krubenberg tumor is a metastatic adenocarcinoma of the ovary. The stomach is the primary site in most cases. The mass is usually bilateral. (14:571–572)
99. (B) Cystadenomas may have thin septations. Cystadeno-carcinomas may contain thickened septations. (14:566)
100. (A) Sertoli–Leydig cell tumor is an androblastoma and Brenner’s cell tumor is a transitional cell tumor. Chocolate cyst is another name for endometrioma. Stein-Leventhal syndrome is a subgroup of a more encompassing disease called polycystic ovarian syndrome (PCOS). (1: Table 9–9, 3, 4)
101. (C) The etiology of hydatidiform mole is fertilization of an ovum without any active chromosomal material. (7:357)
102. (D) Blood flow direction and velocity is characteristics of color Doppler imaging. (1:1–2)
103. (A) The extra-embryonic peripheral cells of the blastocyst. The trophoblast forms these cells, which form the wall of the blastocyst. (7:357)
104. (D) At the time of ovulation, a dominant follicle grows to approximately 20 to 25 mm. (15:404)
105. (A) Leiomyomas are present in 20–30% of the female population, with a higher percentage in black women. (14:538)
106. (A) Acute or chronic pelvic inflammatory disease (PID) is most commonly caused by gonorrhea or chlamydia. If left untreated, the infection can progress to a tubo-ovarian abscess, where pus is surrounded by tubal and ovarian tissue. (16:399)
107. (B) Mucinous cystadenocarcinomas when ruptures are associated with pseudomyxoma peritonei. All the other choices are related to dermoid cyst. (20:937–939)
108. (C) Normal endometrial lining in postmenopausal women not on hormone replacement therapy should be less than 3 mm. Endometrial thickness of less than 3 mm is associated with low risk of endometrial disease. (14:543)
109. (B) Women on tamoxifen for treatment or prevention of breast cancer and women on estrogen therapy are known to have thickened endometrium. An endometrial thickness of 5 mm is taken as the cutoff normal range for women on hormone replacement therapy (HRT). (2:841)
110. (C) In the proliferative phase, the lining is thick, but the internal component is hypoechoic. This allows for the echogenic polyp to be seen. In the secretory phase, the entire endometrial lining is echogenic and will mask a polyp. (1:10)
111. (D) LMP refers to the first day of menses. (1:11)
112. (A) The differential diagnoses that may mimic hydatidiform moles are missed abortions, cystic degenerative leiomyomas, blighted ovum, and incomplete abortion. Endometriosis is endometrial tissue outside of the endometrial lining. (20:1012)
113. (D) 80%. (7:424)
114. (A) The cervix is the most inferior portion of the uterus and invaginates into the vagina. Moving superiorly, the next section is the isthmus beginning at the internal os. The body, or corpus, of the uterus is the largest section of the uterus. The most superior portion is the fundus. (1:4)
115. (B) The outer layer is the serosal, or peritoneal layer. The large muscular middle layer is the myometrium, and the inner layer is the endometrium. (1:4–5)
116–118. (B) (D) (A) In a sagittal plane, the ovaries can be identified as a hypoechoic structure containing small anechoic follicles that undergo cyclic changes. The landmarks for the ovaries include the anechoic internal iliac vessels posteriorly The ureters when visualized are tubular anechoic structures. As they enter the pelvis, they course along the psoas muscles, between the ovaries and internal iliac vessels and enter the urinary bladder posteriorly. (18:180, 283–285)
119. (C) A nulliparous uterus is 7 × 5 × 4 cm. Multiparous increases the normal size by more than 1 cm per dimension. A post-menopausal uterus becomes atrophic and decreases in size. (14:532)
120. (A) The aqueduct of Sylvius (cerebral aqueduct) is a narrow channel that connects the 3rd ventricle to the 4th ventricle. (20:1224)
121. (B) Congenital abnormalities result from improper fusion of the mullerian (paramesonephric) ducts. (14:534)
122. (A) The proliferative phases are days 5–9 post-menstruation. (1:8)
123. (C) The periovulatory, or late proliferative, phase is days 10–14 post-menstruation. (1:8)
124. (D) The secretory phase is day 15–28 post-menstruation. The echogenicity is a result of edema of the functional zone of the endometrium. (1:8)
125. (D) Symptoms of endometriosis caused by adhesions include dysmenorrhea, low back pain, dyspareunia (painful sexual intercourse), irregular bleeding and infertility (2:868)
126. (A) Endometriosis is defined as the presence of endometrial glands in stroma outside of the uterine cavity. The endometrial tissue commonly involves structures within the pelvis, ovaries and broad ligament. However, endometrial ectopic tissue can be found in the abdomen, thorax or brain. (14:522; 21–517–528)
127. (D) Dermoid tumors are most commonly located superior to the uterine fundus. (7:436)
128. (A) A fetus greater than the 90th percentile for estimated fetal weight is termed large for gestational age (LGA). A fetus greater than 4,000 g is macrosomic. (3:544; 2:215)
129. (B) LGA refers to a fetus measuring greater than the 90th percentile for gestational age. (3:544; 2:215)
130. (D) All of the above. Identification of a macrosomic fetus can alert the obstetrician to watch for complications of macrosomia during delivery. (2:215)
131. (A) Cystic Hygroma is associated with polyhydramnios (Study Guide)
132. (E) Other causes for an increased fundal height include incorrect dates, and molar pregnancy. (2:215; 6:465)
133. (A) Although the other features, such as oligohydramnios, do often coexist and interact with IUGR, the diagnosis of IUGR is a fetus < 10% for gestational age. (2:206)
134. (B) An increased HC/AC ratio is the result of redistribution of fetal blood away from the bowel and directed to the fetal head. (3:522)
135. (D) All of the above. IUGR may be found in chromosomal abnormalities, infection early in pregnancy, and placental insufficiency. (2:207)
136. (D) The abdominal circumference (AC) is the single most sensitive indicator for IUGR. (20:1076)
137. (A) Doppler ultrasound has shown that in fetus with asymmetric IUGR, vascular resistant increases in the umbilical artery and decreases in the middle cerebral artery. (20:1081)
138. (C) The diastolic notch is normal before 26 weeks and is related to trophoblastic invasion. (2:685)
139. (E) Hematometrocolpos is an accumulation of secretions and blood due to an obstruction at the level of the vagina. The vagina and endometrial cavity become distended with echogenic material. If scanned prior to puberty, the secretions appear anechoic. (14:544)
140. (D) Patients receiving ovulation induction or follicle-stimulating hormones for assisted reproduction are at risk for OHSS. (2:866)
141. (B) Endometrial carcinoma is the most common gynecologic malignancy in North America with 75–80% occurring in post-menopausal women. There is a strong association for patients on hormone replacement therapy. The endometrium has a heterogeneous echo texture with irregular or poorly defined borders. Cystic changes in the endometrium are also seen in patients with endometrial hyperplasia and polyps. Endometriosis is ectopic endometrial tissue outside the uterus. (14:548)
142. (A) The sonographic appearance of the iliopsoas muscles are hypoechoic, bilateral mass-like structures with a bright central echo. In a transverse plane, the paired muscles are located on the anterolateral aspect of the urinary bladder. (18:274)
143. (C) Pseudo-gestational sac is seen in 20% of ectopic pregnancy. It does not have an embryo or a yolk sac. It does not grow with the same incline as a real gestational sac. (20:1006)
144. (C) Endometrial polyps can present either as a focal homogeneously echogenic or complex lesion within the endometrial cavity. They may contain one or more small cysts. (17:293)
145. (D) Given the clinical history, an endometrioma is the most likely diagnosis. The characteristic appearance is an adnexal cyst filled with homogeneously low-level echoes. This has been referred to as the “ground glass” appearance. Endometriomas are also referred to as chocolate cysts. They may also present as cysts with fine septations or similar to a hemorrhagic cyst. The may contain fluid-fluid levels. (17:313)
146. (B) Fibroids (myomas, leiomyomas) are common occurring benign tumors of the uterus. This subserosal myoma can be seen projecting from the serosal surface of the uterus. (17:284)
147. (A) Hemorrhagic cysts have a variable sonographic appearance dependent on the amount of hemorrhage and the time of the hemorrhage relative to the examination. Acute hemorrhagic cysts are generally hyperechoic and may mimic a solid mass. Diffuse low-level internal echoes are more commonly see in endometriosis. The more complex pattern of the mass represents clot hemo-lysis. Serous cystadenocarcinoma most frequently occurs in perimenopausal and postmenopausal women. (14:557; 566)
148. (D) Polycystic ovaries present with a more echogenic center with small anechoic immature follicles lining the periphery. (16:289)
149. (A) Patients with polycystic ovarian syndrome (Stein-Leventhal syndrome) usually present with amenorrhea, infertility, hirsutism and with multiple small immature follicles of the ovaries. Ovarian agenesis is an imperfect development or absent of the ovaries. (16:289)
150. (A) The typical sonographic appearance is that of a tubular or ovoid cystic structure. Visible folds, which appear echogenic, may be seen. (14:560, 572, 573)
151. (B) Adenomyosis results when endometrial glands invade the myometrium and may be diffuse or localized. These glands respond to hormone stimulation. There are various sonographic characteristics. The sonographic characteristics in this image include small cysts within the myometrium and enlargement of the posterior myometrium. Note the eccentrically situated endometrial cavity. (17:287-289)
152. (A) Tamoxifen has an estrogenic effect on the uterus. Patients treated with tamoxifen are at an increased risk for endometrial hyperplasia, endometrial carcinoma, and endometrial polyps. (14:549)
153. (B) Nabothian cysts, also referred to as inclusion cysts, are commonly seen in the cervix. They can be multiple and vary in size and may contain internal echoes due to hemorrhage or infection. (14:551)
154. (D) Tubo-ovarian abscess (TOA) usually results from chronic pelvic inflammatory disease. Patients usually have a history of a sexually transmitted disease. It is a progressive process and as the infection worsens, peri-ovarian adhesions may form resulting in fusion of inflamed dilated tubes and ovaries (tubo-ovarian complex). With progression of the disease, a TOA may form and appear as a complex multiloculated masses with septations, irregular borders, internal echoes, and posterior acoustic enhancement. (14:572, 573)
155. (D) The urinary bladder should be distended to the point where it covers the entire fundus of the uterus. The distended bladder provides an acoustic window to view pelvic organs. It also serves as a reference standard for evaluating cystic structures. (14:529)
156. (D) Reverberation artifact occurs when the ultrasound beam bounces between two or more interfaces in a repetitious fashion. This is commonly seen on the anterior aspect of the urinary bladder due to reverberation between the fascial planes of the abdominal wall and the transducer and appears as echoes within the urinary bladder. (16:631, 632)
157. (B) The central nervous center that regulates fetal tone functions first at 7.5–8.5 weeks. (2:663)
158. (A) The central nervous center that regulates body movements starts functioning at 9 weeks. (2:663)
159. (C) The central nervous center that regulates fetal breathing starts at 21 weeks. (2:663)
160. (D) The central nervous center for fetal heart rate reactivity functions by the end of the second trimester or beginning of the third trimester. (2:663)
161. (A) Meigs’ syndrome is define as a triad of a benign ovarian fibroma, ascites, and pleural effusion with the effusion is most frequently on the right. (2:882)
162. (D) Biophysical profile (PPP) is a test used to evaluate fetal well-being using a scoring system. This involves a combination of ultrasound and non-stress test with five variables. Each of these five variables is given a score of 0 or 2, depending if the specific criteria are met. (14:1513)
163. (B) Fetal breathing must last at least 30 seconds in a 30-minute time period in order to score a 2 in the biophysical profile. (2:663)
164. (A) In response to hypoxia, the fetus reroutes blood to the brain in a brain-sparing effort. The middle cerebral artery is normally of higher resistance, but it will decrease to compensate for the increased blood flow and brain-sparing effort. (2:690, 691)
165. (D) Cervical phase of an impending abortion. The uterus has an hourglass appearance because the cervix is dilated to the size of the fundus. Heavy vaginal bleeding and lower abdominal cramping are clinical sign and symptoms of an abortion in progress. The pain is due to uterine contraction. (14:1092)
166. (B) The amniotic fluid is produced by the fetal kidneys, umbilical cord, fetal skin, and lungs. The removal of the fluid is by the gastrointestinal tract, lungs, and umbilical cord. The maximum amniotic fluid volume peaks at approximately 33 weeks and then begins to decline. The fetus starts swallowing the amniotic fluid at 12 weeks of gestation. (20:1169)
167. (D) Pelvic inflammatory disease (PID) is an ascending infection. The most common causes of PID are chlamydia and gonorrhea. Other bacterial causes are Actinomyces israelii, mycoplasma, and tuberculosis. The disease causes inflammation of the pelvic organs as it ascends, causing occlusion of the fallopian tubes and thereby resulting in infertility. Genital herpes is a viral sexually transmitted disease that causes blisters on the genitals. The virus travels to the nerve cells and remains in the body for life. (20:947)
168. (A) The adnexa is any accessory part, organ, structures, or mass that is located lateral to the uterus. The fallopian tubes, ovaries, broad ligaments, ovarian cyst, and ovarian artery are all adnexal. The urinary bladder, uterus, and vagina are midline structures and are not adnexal structures. (20:873)
169. (A) The single deepest pocket (SDP) is a vertical dimension of the largest pocket of amniotic fluid. Measurements of less then 2 cm are suggestive of oligohydramnios. (2:642)
170. (D) All four quadrants are added and compared to an expected amniotic fluid volume for that fetus’ gestational age. The normal range extends from 2.5% to 97.5%. (8:1168)
171. (C) Nonspecific signs of fetal death are double contour of the fetal head caused by scalp edema, absence of the falx cerebri because of liquefaction of the brain, echoes in the amniotic fluid because of fragmentation of the fetal skin, and a decrease in biparietal diameter measurements because of collapse of the cranial sutures after death. No fetal heart movement is a specific sign of fetal death. (7:429)
172. (A) Scalp edema can be seen 2–3 days, or 48–72 hours, after fetal death. (7:429)
173. (C) The decidua of early intrauterine pregnancy is divided into decidua basalis, decidua parietalis (vera), and decidua capsularis. This marked hypertrophic change in the endometrium occurs no matter where the pregnancy is located. The uterine mucosa responds by a decidual reaction caused by hormonal stimuli. However, when an ectopic pregnancy occurs, the uterine decidua responds by a cast-off called a decidual cast. This should not be confused with the normal decidua in an early pregnancy. (7:431)
174. (B) Nabothian cyst is located in the cervix. Gartner’s duct cysts and Bartholin cysts are vaginal masses. Hematocolpos is also a vaginal mass in which the vagina is filled with menstrual blood. (14:550)
175. (E) All of the above. The functions of the yolk sac are: nutrition transfer of nutrients to the embryo; hemopoiesis-blood cell development; and development of sex cells that later become spermatogonia or oogonia. (7:431)
176. (B) The yolk sac reduces in size as pregnancy advances. However, it may persist throughout pregnancy and continue to persist into adulthood. In about 2% of adults, the proximal intra-abdominal part of the yolk sac is presented as a diverticulum of the ilium, called Meckel’s diverticulum. (7:431)
177. (C) The yolk sac is located adjacent to the embryonic plate in early pregnancy and is located within the chorionic cavity. (2:113)
178. (B) The yolk sac may be visible as early as 5 weeks on transvaginal ultrasound, and 6 weeks on transabdominal ultrasound. (20:788)
179. (C) Zygote. (7:433)
180. (B) Cleavage. (7:433)
181. (A) Morula. (7:433)
182. (D) Blastocyst. (7:433)
183. (D) The most common abnormal conditions associated with oligohydramnios are (1) fetal demise, (2) renal agenesis, (3) intrauterine growth restriction, (4) premature rupture of membranes, (5) post-date pregnancy, and (6) posterior urethral valve syndrome. The mnemonic DRIPPP serves as a key for memorizing the six conditions most commonly associated with oligohydramnios. Urethral stenosis is associated with polyhydramnios. (20:1174)
184. (B) As the pregnancy advances, the placenta becomes less resistive. This allows for more blood and oxygen to reach the growing fetus. (2:687)
185. (A) An increasing S/D ratio of the umbilical cord is a sign of vascular resistance within the placenta, which ultimately leads to a decrease in oxygen to the fetus. (2:268)
186. (D) Vasa previa is condition in which the umbilical cord is the presenting part. This condition may also be associated with succenturiate placenta or a velamentous cord insertion. The rare condition has an increase risk of hemorrhage and cord compression. (20:1093)
187. (A) The incidence of placenta previa at term is 0.5–1%, with 90% of previa bleeding before 38 weeks. Clinically the patient may present with painless vaginal bleeding. (9:403:20;1148)
188. (B) Pseudogestational sac is a decidual cast (fluid) located in the uterine cavity that may mimic the sonographic appearance of an intrauterine pregnancy and is seen in approximately 20% of ectopic pregnancies. A pseudogestational sac does not contain an embryo or yolk sac and does not have an incline in growth size. (20:999)
189. (A) The yolk sac is located in the chorionic cavity between the amnion and chorionic sac. It measures 5 mm to 6 mm. The yolk sac shrinks as pregnancy advances. It should not be measured in the CRL. (7:427)
190. (A) The umbilical cord normally consists of two arteries and one vein. (1:17)
191. (E) Open tube defect, anencephaly, and cephalocele are part of the neural tube defect spectrum. (1:19)
192. (B) Herniation of meninges alone is termed a meningocele. (1:19)
193. (A) To calculate the gestational age using the rule of thumb, first convert 28 mm to centimeters by moving the decimal point one space to the left; 28 mm is now 2.8 cm. Then add 6.5 to the CRL to estimate the gestational age, which in this case is 9.3 weeks (7:Table 8–4)
194. (D) The “lemon” refers to the narrowing of the parietal bones giving the appearance of a lemon-shaped cranium in the axial view. (1:19)
195. (C) The “banana” refers to the displacement of the cerebellum inferiorly into the upper cervical canal. On transverse view, the cerebellum is small and resembles a banana. (1:19)
196. (D) 95% of the time. (1:19)
197. (E) The lemon sign is found in 1–2% of normal fetuses. (2:286)
198. (D) There is no contraindication to scanning a placenta previa transvaginally, and it provides the most accurate diagnosis. Transabdominal scanning may give a false-positive caused by a full maternal bladder compressing the internal os or an inadequate view of the internal os. (2:591)
199. (B) If the placenta is greater than 2 cm from the internal os, a vaginal delivery is considered safe. (2:591)
200. (B) The normally positioned heart should be rotated approximately 45° with the apex pointed to the left. (2:384)
201. (C) The horizontal position of the fetal heart is largely due to a large liver size. (7:432)
202. (B) Non-Immune hydrops is defined by the absence of detectible circulating antibiotic against red blood cells (RBCs) in the mother. Before the discovery of RhoGAM (anti-D immunoglobulin, most cases of hydrops were immune, which causes a hemolytic disorder known as erythroblastosis fetalis. (14:1459)
203. (C) 75% of cephaloceles are occipital. (1:19)
204. (A) In the absence of a spinal defect, if the lateral ventricles measure greater than 10 mm in the atrium of the occipital horn, it is commonly associated with an obstruction of the ventricular system. (14:1242)
205. (C) RhoGAM Rh (D) immune globulin is made from human plasma. The drug is an injection given intramuscularly to prevent hemolytic disease of the newborn. It is given at 28 weeks of pregnancy and another dose within 72 hours after childbirth if the child has Rh-positive blood. RhoGAM is not given to Rh-positive mothers with bleeding episodes. (20:1087)
206. (E) Congenital hydrocephaly is an X-linked abnormality, with the expression in males and the females being carriers. It is able to be detected through DNA testing. (1:19)
207. (D) TORCH represents a group of infections (toxoplas-mosis, others, rubella, cytomegalovirus, and herpes simplex (HSV), which can cross the placenta barrier and cause microcephaly, ventriculomegaly, and calcifications. (14:1262)
208. (A) Cervical ectopic pregnancy is close to the vagina with the external os of the cervix positioned in the vagina; with rupture, the bleeding is external. When ruptured, all of the others results in hemoperitoneum. (21:441)
209. (A) Transvaginal sonogram demonstrates a gestational sac implanted in the lower uterine segment in the scar of a previous caesarian section. Note the close proximity of the ectopic sac to the posterior urinary bladder wall. There is prominent vascularity at the implantation site, and the multiple small cystic structures are multiple nabothian cyst. (14:1109)
210. (D) The arrow points to the vitelline duct, also known as omphalomesenteric duct or yolk stalk. (14:1080)
211. (E) The normal placement of an intrauterine device (IUD) is in the uterine cavity. Ultrasound can demonstrate malposition of an IUD. This IUD is seen in the cervix with double parallel echogenic lines (entrance-exit reflections). (14:550)
212. (D) The cisterna magna is enlarged if the measurement is greater than 11 mm. The normal cisterna magna measures 3–11 mm, with an average size 5–6 mm. (20:1027)
213. (A) A true Dandy–Walker malformation is associated with agenesis of the cerebellar vermis with communication to the fourth ventricle. A Dandy–Walker malformation variant is described as having some degree of cerebellar vermis agenesis, but not complete agenesis. An arachnoid cyst will push the cerebellum superiorly without splaying the cerebellum. (2:292)
214. (C) An arachnoid cyst will not cause splaying of the cerebellum and the cerebellar vermis will be intact. (2:292)
215. (A) Dandy–Walker malformation is associated with other midline defects including agenesis of the corpus callosum and cephaloceles, as well as holoprosencephaly, clefting, and cardiac defects. Dandy–Walker malformation has a 50–70% risk of associated abnormalities. (2:292)
216. (B) Clomiphene citrate (Clomid) is one of the first-line drugs used for ovulation induction. Folic acid is a B vitamin helpful in preventing neural tube defects. Metho-trexate is a drug used in treating rheumatoid arthritis and ectopic pregnancy. (20:963)
217. (E) Subnormal intelligence is reported in 40–70% of cases. Morbidity rates are 24% but are improving with increased anesthesia and surgical techniques. (2:295)
218. (D) The most common cause of hypotelorism is holoprosencephaly. Hypotelorism is found in many different syndromes and chromosomal abnormalities and is strongly associated with abnormalities of the brain. (2:309; 4:223)
219. (B) Cyclopia—absent nose with protrusion of tissue at level of eye sockets; hypotelorism—close set orbits; cebocephaly—single nostril nose; and cleft lip/palate are all abnormal facial findings strongly associated with holoprosencephaly. (2:309–311)
220. (C) Thirty to fifty percent of fetuses with holoprosencephaly have chromosomal abnormalities, the most common being trisomy 13. (4:119)
221. (A) The most common cause of hypertelorism is a defect that prevents the migration of the eyes to their normal position. An anterior cephalocele is the most common blockage of that migration. (2:311)
222. (E) Teratomas can occur in many different locations. The most common region is sacrococcygeal accounting for 50% of fetal teratomas. The second most common location is orofacial (including intracranial) and cervical, accounting for 5% of fetal teratomas. (2:31 7)
223. (B) Maternal Graves’ disease and Hashimoto thyroiditis produce antibodies that cross the placenta and may affect fetal thyroid production. (2:318)
224. (C) Macroglossia is present in 97.5% of Beckwith-Wiedemann syndrome. (2:320)
225. (B) The arrow points to the cerebellum. (20:585)
226. (D) Other findings of Beckwith-Wiedemann syndrome include omphalocele, organomegaly, hemi-hypertrophy, and hypoglycemia. Macroglossia is present in 97% of Beckwith-Wiedemann syndrome. (1:24)
227. (B) Of the isolated cleft lip and palate cases, 40% are unilateral cleft lip and palate, 29% are unilateral cleft lip, 27% are bilateral cleft lip and palate, and 5% are bilateral cleft lip. (2:324)
228. (B) The arrow is pointing to the choroid plexus. (20:999)
229. (C) Medial cleft lip is associated with a spectrum of mid-line defects, the most common being holoprosencephaly. (2:314)
230. (D) Pierre Robin syndrome, trisomy 18, and campomelic dysplasia are all associated with micrognathia and polyhydramnios. Micrognathia commonly causes difficulty swallowing resulting in polyhydramnios. (2:56, 327, 352)
231. (E) Sonograms A and B demonstrate disorganized echoes in the lower uterine segment, suggestive of incomplete abortion (retained products). No intrauterine pregnancy or free-fluid is seen. The patient’s complaint of lower abdominal cramping is a common clinical symptom in spontaneous abortion due to uterine contractions. The serum β-hCG has decreased greater than half in 48 hours, which is also suggestive of abortion. (14:577; 21:403)
232. (F) Absence of the fetal nasal bone is associated with trisomy 21 (Down’s syndrome). The sonographer should look for other associated physical features: small ears, protruding tongue, spinal and heart defects, and increased nuchal fold. (2:327; 14:1135; 20:1116)
233. (G) Focal myometrial contraction is physiologic and should disappear within 20–30 minutes. (16:450)
234. (C) Development of the corpus callosum occurs between 12 and 18 weeks; therefore, visualization is not possible less than 18 weeks. (2:290)
235. (D) The “teardrop” appearance (enlargement of the atria and occipital horns and lateral displacement of the anterior horns) is present 90% of the time. (2:290; 6:255)
236. (C) Hydranencephaly exists when the cerebral hemispheres are replaced by fluid. The brain stem is usually spared. Causes are thought to be infection or obstruction of the internal carotid artery. (2:297)
237. (D) Microcephaly has been described as an HC between –2 and –3 standard deviations (SD) of the mean. (2:298)
238. (D) A vein of Galen aneurysm is a type of arteriovenous (AV) malformation. Agenesis of the corpus callosum, third ventricular dilation, and an arachnoid cyst are cystic midline lesions, but they will not have the high, turbulent blood flow of an AV malformation. (2:301)
239. (B) Isolated choroid plexus cyst has a small risk for trisomy 18. If other abnormalities are identified along with the choroid plexus cyst, the risk for trisomy 18 increases. (2:301)
240. (E) Cigarette smoking is known to affect the ciliary action in the nasopharynx, respiratory tract, and the fallopian tubes. Bilateral tubal ligation also is a risk factor. Chlamydia trachomatis and PID are among the most common risk factors. Herpes genitalis is a viral STD infection that causes painful lesions on the skin and hides within the nerve cells. Herpes virus is not known to cause PID or a risk factor for ectopic pregnancy. (21:434)
241. (C) The image should also show the cavum septi pellucidi, cerebellum and cisterna magna. The measurements should be taken from the outer edge of the cranium to the outer edge of the skin. The skin fold should be less than 5 mm. (6:245)
242. (D) The ovaries are normally located in the ovarian fossa, medial to the external iliac vessels, and anterior to the internal iliac vessels and ureter. (20:865)
243. (A) Inclusion cyst is when fluid produced by the ovaries is not absorbed and becomes trapped between the adhesions. This occurs more frequently in patients with a history of previous surgery or pelvic inflammatory disease. (14:507)
244. (A) A cephalic index of more than 85 describes an increased BPD when compared to a shorter OFD. The head has a rounded appearance on ultrasound. (6:244)
245. (B) Dolichocephaly is a long, narrow head with a small biparietal diameter when compared with a longer OFD. (6:381)
246. (B) Sterile procedure requires a sterile field. A sterile gel is required. (7:322–324)
247. (D) Oil-based lubricants such as petroleum jell, cold creams, baby oil, or mineral oils should be avoided because they cause deterioration of the latex, resulting in breakage. (7:323)
248. (D) Dolichocephaly is associated with breech fetuses and oligohydramnios. (2:991)
249. (F) Brachycephaly with a flat occiput is a feature of trisomy 21. Brachycephaly may also be present with a spina bifida due to ventricular enlargement. Most commonly, brachycephaly is a normal variant. (4:1009)
250. (C) The head is larger than the abdomen at 12–24 weeks. (7:434)
251. (B) At 32–36 weeks, the head and body are about the same size. (7:434)
252. (A) After 36 weeks, the abdomen is larger than the head. (7:434)
253. (B) The scanning plane is too high. When performing a biparietal diameter (BPD) measurement, the fetal head should be ovoid and the measurement obtained at the level of the thalami and cavum septum pellucidum. (7:440)
254. (D) The fluid within a cystic hygroma is lymphatic fluid from an obstructed lymph system. (6:263)
255. (A) A cystic hygroma occurs when the jugular lymph sacs fail to communicate with the venous system. The obstructed lymphatic fluid fills the sacs and forms the cystic hygroma. (6:263)
256. (E) The uterus is frequently larger for dates. (21:998)
257. (C) The cervical region. (7:426)
258. (E) C and D. Cystic hygromas are associated with elevated MSAFP and Turner’s syndrome. (7:365)
259. (F) The sonographic appearance of hydatidiform mole are multiple, snowstorm, Swiss cheese, honeycomb, vesicular sonographic texture. (14:1577)
260–269. See Fig. 7–103.
270–272. See Fig. 7–104.
273–281. See Fig. 7–105.
282. (C) The foramen ovale allows for oxygenated blood to pass from the right atrium to the left atrium. (6:323)
283. (B) The ductus arteriosus allows for approximately 70% of the blood to bypass the nonfunctioning lungs. (6:323)
284. (C) It is a destructive process that obliterates the cerebral cortex. The brainstem is usually spared. Other causes include infection and intrauterine strangulation. (3:385)
285. (E) Alobar holoprosencephaly and severe hydrocephaly may sonographically present similar to hydranencephaly. Lobar holoprosencephaly sonographically presents with an interhemispheric fissure anterior and posterior, thus being excluded in the differential. (2:299)
286. (D) Hemivertebrae is easiest to view in the sagittal plane of view because the other vertebrae may be used as a reference of normal. It is visible in the other planes of view also, but requires more meticulous scanning. (3:456)
287. (D) Arnold–Chiari malformation is most commonly associated with myelomeningocele and hydrocephaly. (2:73)
288. (C) Microcephaly is a result of a large portion of the brain tissue being herniated out of the cranium. (1:19)
289. (A) Semilobar holoprosencephaly is a single anterior ventricle with partial separation of the posterior cerebellar hemispheres. (1:20)
290. (A) The most likely diagnosis would be alobar holoprosencephaly. Differential diagnosis would include hydranencephaly and hydrocephaly. Hydranencephaly would not show any cerebral cortex and only brainstem would be spared. Hydrocephaly would show a bi-lobed thalamus with a dilated third ventricle. (1:20)
291. (C) Hydranencephaly will present with no visible cerebral cortex. The differential includes alobar holoprosencephaly (fused thalamus) and severe hydrocephaly (bilobed thalamus with dilated third ventricle). (1:20)
292. (B) It may be possible to diagnose anencephaly as early as 12 weeks, but it should be definitely diagnosed by 14 weeks. (1:19)
293. (D) Acrania is theorized to be the first trimester finding of anencephaly. With prolonged exposure to the amniotic fluid, the abnormal brain tissue is eroded, and the second trimester finding of anencephaly is appreciated. (3:379, 380)
294. (4) The last number stands for the number of living children. (1:3)
295. (2) The number of preterm births is the second number after parity. (1:3)
296. (7) G refers to the gravida or number of pregnancies. (1:3)
297. (1) The third number after parity represents the number of abortions (spontaneous and elective). (1:3)
298. (3) The first number after parity represents the number of full term pregnancies. (1:3)
299. (A) The number of pregnancies is listed after gravida (G). The first number after parity (P) is the number of full term pregnancies (3), the second number is the number of preterm pregnancies (one set of twins, single pregnancy, and one preterm fetal death >20 weeks = 2), the third number is the number of abortions (1), and the final number is the number of living children (5). (1:3)
300. (A) Benign penetration and growth of endometrial glands and stroma into the myometrium. (21:898)
301. (A) AFP is produced by the fetus. An abnormal concentration occurs whenever there is an abnormal opening in the fetus allowing an increased amount of the protein in the amniotic fluid. (2:25)
302. (B) Using the rule of thumb, subtract 6.5 from 8, which equals 1.5 cm. (7:Table 8–4)
303. (C) After 12 weeks, the fetus has a curvilinear shape making it technically more difficult to obtain accurate linear measurement. (21:995)
304. (C) Multiple parameters help to increase the accuracy of estimated fetal weight. (3:146)
305. (C) Only the shaft of the femur should be measured in femur length, excluding the femoral neck and other epiphyseal calcification centers. (7:442)
306. (C) Of the cases with polyhydramnios, 60% are idiopathic, 20% are structural, and 20% are maternal insulin dependent diabetes mellitus. (1:16)
307. (F) Polyhydramnios has many causes that may include increased urine production or decreased fetal swallowing. (1:29; 2:348, 651)
308. (C) Amnion begins to fuse with the chorion at 12 weeks and is routinely complete by 14–16 weeks. (2:124)
309. (B) Hematopoiesis, or red blood cell production, is done by the fetus and by the yolk sac in early pregnancy. The placenta is responsible for the exchange of nutrients, oxygen, and waste. The placenta also acts as a barrier although some medication can cross through the placenta. (1:16)
310. (E) Maternal hypertension is seen in approximately 50% of cases of severe abruption. Other causes are cocaine abuse, trauma, fibroids, short cord, and placenta previa. Focal myometrial contraction is physiologic and temporary and is least likely to cause abruption. (21:1152)
311. (B) Placental abruption is defined as premature separation of the placenta after 20 weeks of gestation. If the placenta premature separate before 20 weeks, it is called spontaneous abortion. (2:612 :20;1152)
312. (D) The hypoechoic region behind the placenta should measure 1–2 cm in thickness. Any increase in thickness of this area should alert the sonographer to a possible hematoma. (2:611)
313. (C) Implantation sites at risk for placenta accreta are uterine scars, submucosal fibroids, lower uterine segment, rudimentary horn, and uterine cornua. (2:613, 614)
314. (A) Placenta accreta may be divided into (1) placenta accreta—placental attachment to the myometrium without invasion, (2) placenta increta—invasion of placenta into the myometrium and (3) placenta percreta—invasion of placenta through the uterus and into other organs. (1:17)
315. (D) Chorioangioma is a vascular mass arising from chorionic tissue and is similar to a hemangioma. (2:612)
316. (A) Wharton’s jelly is a mucoid connective tissue that surrounds the umbilical vein and artery. (6:440)
317. (A) A true cord cyst is attributable to allantoic duct remnants and is thought to be more common in the first trimester. (2:621; 3:212)
318. (D) A velamentous cord insertion is associated with IUGR, particularly in monochorionic twins. (2:620)
319. (C) An eccentric cord insertion is considered a normal variant and is of no clinical significance. (3:206; 2:620)
320. (B) Atrial and ventricular septal defects are the most common defects accounting for 26% of the cardiac abnormalities. (1:21)
321. (A) Generally, the left side of the heart perfuses the fetal cranium. (7:449)
322. (B) Generally, the right side of the heart perfuses the systemic circulation of the fetus. (7:449)
323. (B) The ratio of the heart circumference to the thoracic circumference should be 30–50%. (2:384)
324. (E) This condition is called situs inversus (partial or total), dextrocardia and heterotaxy syndrome. Along with dextrocardia, there may be significant intracardiac anomalies, anomalies of the great vessels, an interrupted inferior vena cava, an anomalous venous return system, asplenia or polysplenia, and possible heterotaxy of the abdominal organs depending on whether it is complete or partial. (4:385)
325. (C) 50% of trisomy 21 cases have a cardiac defect, with the majority being atrioventricular canal defects. (2:45)
326. (C) This view allows for visualization of the right ventricular outflow tract, the left ventricular outflow tract and the crossing of the outflow tracts. (2:385)
327. (E) Other structures to evaluate include atrial sizes, foramen ovale, coronary vessels, and thickness of the ventricular walls, cardiac orientation, and size. (2:385)
328. (B) The banana sign is an abnormal flattening of the cerebellum giving it a banana shape. The normal cerebellum should have a dumbbell shape. The banana and lemon signs are both associated with spina bifida. (20:1072)
329. (C) The treatment for ectopic pregnancy depends on whether the ectopic pregnancy is ruptured or unruptured and if the patient is hemodynamically stable. This patient stated she had a ruptured ectopic pregnancy and fainted. Fainting is not a good sign with an ectopic pregnancy; this indicates a temporary loss of consciousness possibly secondary to blood loss from ruptured ectopic pregnancy. A salpingectomy via laparotomy is most likely this patient’s previous surgery. Methotrexate is a drug given for unruptured ectopic pregnancies that are hemodynamically stable. (21:452)
330. (A) Coarctation of the Aorta is a narrowing of the aorta, usually near the ductus arteriosus. It may be very difficult to image depending on the degree of stenosis. Often diagnosis relies on the ventricular discrepancy indicating that a stenosis is present. (4:366)
331. (A) Eighty percent of congenital diaphragmatic hernia is left sided. (14:1304)
332. (E) Whenever the heart is deviated with the correct apex orientation, the sonographer should consider a thoracic mass. (2:429, 433, 440; 6:290)
333. (A) It is important to identify the location of the fetal liver. If the liver is intrathoracic, the prognosis for survival is 43%. If the liver is intra-abdominal, the prognosis is 80% survival. (1:22)
334. (D) Although chromosomal abnormalities and associated anomalies are prevalent in congenital diaphragmatic hernia, the significant factor in mortality is pulmonary hypoplasia. (1:22)
335. (D) If the liver is intrathoracic, the survival rate is 43%, if the liver is intra-abdominal, the survival rate is 80%. (1:22)
336. (C) CCAM accounts for 75–80% of congenital lung malformations with over 95% of those being unilateral. (2:439)
337. (C) Macrocystic is defined as multiple large cysts measuring 2–10 cm. (1:22)
338. (B) Type II cysts are less than 2 cm, but still visible. (1:22)
339. (A) Sonographically, these appear as a solid, homogenous, echogenic lung mass. (1:22)
340. (D) Dysgerminoma is the most common type of malignant germ cell tumor and is associated with elevation of alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG). (21:931)
341. (B) The most common appearance detected prenatally is a well-circumscribed echogenic mass in the left lower lung base. (2:441)
342. (D) Methotrexate is a folic acid antagonist. It inhibits DNA synthesis and kills the rapidly dividing trophoblastic cells. The drug is a medical treatment for ectopic pregnancy and has a protocol for safe and effective use. The patient must be clinically stable, the ectopic should not be ruptured, the serum β-hCG should be less than 5,000 mIU/mL, and the ectopic sac should be less than 3.5 cm. (14:1112; 21:455)
343. (D) There are five types of TE fistulas. They make up 90% of the cases of esophageal atresia. (2:460)
344. (C) Regardless of the presence of a TE fistula, 80% of fetuses derive polyhydramnios by the third trimester. (2:457)
345. (B) Esophageal atresia is a very strong marker for trisomy 18. (2:4547)
346. (B) Amniotic fluid fills the stomach and duodenum proximal to the site of obstruction. The ultrasound appearance resembles a “double bubble.” (2:466)
347. (D) Thirty-three percent will have spinal defects, 36% will have cardiac defects. (2:466)
348. (A) Thirty percent of fetuses with duodenal atresia have trisomy 21. (2:466)
349. (C) The bowel begins to herniate at 7 weeks and becomes most visible at 9–10 weeks on ultrasound. The bowel then returns to the abdomen by the end of the twelfth week. (22:248)
350. (B) Pseudo-gestational sac is seen in approximately 20% of ectopic pregnancies. It is anechoic and is the result of sloughing decidua. This is not a true gestational sac; therefore, it does not contain an embryo or yolk sac. It also does not have the normal incline of growth of 1 mm/day like a true gestational sac. (14:1105; 20:1005)
351. (C) The sign/symptoms of ectopic pregnancy vary depending on whether the pregnancy is ruptured or unruptured. A symptom of unruptured ectopic pregnancy is unilateral pain that increases in its intensity with time. After rupture, the symptoms change due to hemoperitoneum, which is associated with generalized abdominal pain, rebound tenderness, fainting, tachycardia, hypotension, and right shoulder pain due to blood that irritates the diaphragmatic nerves. (4:474)
352. (C) Gastroschisis is rarely associated with chromosomal or non-gastrointestinal disorders and has an excellent survival rate. (2:492)
353. (D) When the bowel perforates, meconium enters the peritoneal space. A membrane forms that seals off the intestine at the site of the perforation. The meconium that entered the peritoneum may cause calcium deposits. Other findings are polyhydramnios, ascites with echogenic debris, and bowel dilation. (2:470, 471)
354. (E) All of the above. They may all cause a complication in gastroschisis and should be monitored with ultrasound throughout the pregnancy. (2:497)
355. (A) Although left-sided gastroschisis have been reported, it is typically to the right of the umbilical cord. (4:473, 474)
356. (C) The physiological hernia is the outpouching of the umbilical cord due to small and large bowel as they rotate around the superior mesenteric artery (SMA). It occurs at the beginning of the seventh week and is a normal migration of the midgut into the umbilical cord. This migration occurs because there is not enough room in the abdomen for the rapidly growing midgut. The midgut returns to the abdomen at about the tenth week. The fetal liver does not migrate in the umbilical cord. (22:248)
357. (D) This sonogram demonstrates an early intrauterine pregnancy with a small embryo in a retroverted uterus. Although this patient presented with clinical symptoms of an ectopic, her pregnancy is in situ confirmed by this sonogram. (14:1102)
358. (B) Small omphaloceles may be mistaken for a cord hematoma. If the defect at the base of the cord insertion is more than 7 mm, it is most likely an omphalocele. (4:484)
359. (C) Omphaloceles are not associated with teratogens, such as maternal smoking. (4:484)
360. (B) Ectopia cordis results from underdevelopment or agenesis of the fetal sternum. It is rarely isolated and is most commonly part of the pentalogy of Cantrell. (4:467)
361. (D) Pentalogy of Cantrell involves defects of the lower sternum, diaphragm, diaphragmatic pericardium, abdominal wall, and intracardiac defects. It is associated with trisomy 13 and trisomy 18. (2:501; 4:493)
362. (F) Beckwith–Wiedemann syndrome is due to a dysfunction of the placenta excreting increased levels of growth hormone. This causes organomegaly, macroglossia, omphalocele, hemi hypertrophy, and cardiac abnormalities. (2:501)
363. (B) Cloacal exstrophy is believed to arise from irregular development of the cloacal membrane. Neural tube defects are present 50% of the time. (2:508)
364. (C) Limb–body wall complex (LBWC) is the most severe abdominal wall defect with the entire ventral wall disrupted. If the umbilical cord is visualized at all, it is very short and severe scoliosis is present. (2:508; 4:453–455, 762)
365. (C) Amniotic band syndrome is a rupture of the amnion early in pregnancy. That rupture allows bands of amniotic tissue to float freely in the amniotic fluid. If these bands come in contact with the fetus, they can cause strictures, amputations, and adhesions to the band itself. Amniotic sheets, also known as uterine synechiae, are caused by scars or adhesions in the uterus. The amnion and chorion grow around the synechiae and form a thick membrane with two layers of amnion and chorion on either side of the membrane. It is attached to the uterus at both ends and does not impede the fetus in any way. (2:502–504,511; 4:762–766)
366. (D) If a mother is Rh–, she will produce antibodies against an Rh+ fetus. The mother’s antibodies will perceive the fetal blood as foreign and attack the fetal red blood cells resulting in erythroblastosis fetalis. (9:413)
367. (D) RhoGAM is an anti-D immune globulin used in preventing Rh immunization. Folic acid is a vitamin B used in preventing neural tube defect and Clomid is an infertility drug. The drug methotrexate is a chemotherapy drug and used for other medical conditions such as ectopic pregnancy and rheumatoid arthritis. (20:1087)
368. (B) This condition will cause immune hydrops in the fetus. (9:413)
369. (C) A blighted ovum is also known as anembryonic pregnancy. Sonographically, this is a large gestational sac that does not contain a yolk sac or an embryo. A missed abortion is defined as a dead embryo. Both blighted ovum and missed abortion are fail pregnancies. The difference is a blighted ovum is without an embryo and missed abortion is with an embryo but does not have heart activity. (20:1011)
370. (E) Findings of heart failure include pericardial effusions, decreased contractility, increased ventricular thickness, abnormal umbilical cord, and middle cerebral artery Doppler. (2:567; 3:276; 6:492)
371. (D) Fetal hydrops is defined as two sites of fluid accumulation or one site of fluid accumulation and fetal ascites. (2:551)
372. (D) The cardiac ventricular walls will thicken and contractility decreases. This causes the cardiac output to decrease. This may lead to acidosis, increased hematocrit, and increased neonatal morbidity. (3:339)
373. (D) The list of causes for non-immune hydrops fetalis (NIHF) is more than 120 conditions, some of which are rare. Major causes are: cardiac arrhythmias and tumors, abnormal chromosomes, cardiac failure, anemia, arteriovenous shunts, mediastinal compression, metabolic disease, fetal infection, fetal tumors, congenital fetal defects, and placental defects. (1:24)
374. (A) In situ is defined as follows: in the correct place or position. The correct placement of an IUD is in the uterine cavity and the IUD string is placed in the vagina. The IUD string cannot be seen on ultrasound. Eccentric denotes “away from the center” and is a descriptive term for an IUD not in the correct position. Today’s IUDs are made of flexible plastic with or without copper. When in situ, the IUD sonographically appears as high-amplitude linear echoes with a distal acoustic shadow. (14:550)
375. (A) Fitz–Hugh–Curtis syndrome is inflammation of the liver capsule and diaphragm secondary to bacterial spread, from the pelvis to the right upper quadrant. These findings are seen in cases of pelvic inflammatory disease. (14:2002)
376. (F) Partial situs inversus, divided into asplenia and polysplenia, has a 40% incidence of anomalies. They include complex heart disease, absent gallbladder, interrupted inferior vena cava with an azygous venous return and splenic abnormalities. (2:480; 6:274)
377. (B) A ureteropelvic junction (UPJ) obstruction is an obstruction at the junction of the ureter and renal pelvis. Therefore, the fetal urine is obstructed within the kidney causing hydronephrosis, but not hydroureter. As long as the contralateral kidney is functioning normally, the amniotic fluid should remain normal. (1:25)
378. (A) A ureterovesical junction (UVJ) obstruction is an obstruction at the junction of the ureter and fetal bladder. It is associated with ureter anomalies, such as duplication and abnormal insertion sites. There is often an ureterocele caused by the abnormal insertion of the ureter. Hydroureter and mild hydronephrosis are commonly present. (1:25; 2:527)
379. (E) The ureters is about 1 to 2 mm in diameter and not normally visible on ultrasound. (20:1045;14:1396)
380. (C) The trigone is located at the inferior portion of the posterior bladder wall. (16:194, 195)
381. (E) Spontaneous abortion is characterized by lower abdominal cramping and vaginal bleeding due to uterine contraction. When the abortion is complete, the contractions and vaginal bleeding stop. The serum β-hCG will usually decrease greater than half in 48 hours. Sonographically, the uterus will be free of any retain products. (2:529)
382. (A) Complete posterior urethral valves (PUV) obstruction does not allow for any fetal urination; therefore, severe oligohydramnios occurs. (2:535)
383. (A) Potter’s facies is characterized by low set ears, flat nose and chin. Potters syndrome is predominately a male disorder and is associated with bilateral renal agenesis, oligohydramnios, and clubfoot. Small mouth with protruding tongue and small ears are facial features of Down’s syndrome (2:536)
384. (D) The primary cause of neonatal death in posterior urethral valves (PUV) syndrome is pulmonary hypoplasia, although the other entities are also serious complications. (1:25)
385. (C) In cases of renal agenesis, particularly after 16 weeks, anhydramnios is present. (2:537)
386. (B) A normal fetal bladder should empty every 30–45 minutes. (6:281)
387. (C) Ovarian torsion can cause internal bleeding but not related to vaginal bleeding. All the others given choices are associated with abnormal vaginal bleeding. Hyper-thyroidism and hypothyroidism can also cause abnormal vaginal bleeding. (21:1025–1039)
388. (D) Three pairs of kidneys form in successive stages: pronephros, mesonephros, and metanephros, with metanephros remaining as the functioning kidney. (10:687)
389. (B) The urinary system develops closely with the uterine development. Twenty to thirty percent of patients with uterine anomalies also have renal ectopia or agenesis. (2:828)
390. (B) Multicystic dysplastic kidney disease is caused by a first trimester obstruction. The kidney is nonfunctioning with ureteral atresia. (2:541)
391. (A) In cases of a unilateral nonfunctioning kidney, the contralateral kidney will often enlarge to compensate. The unilateral kidney usually provides enough function to be sufficient for the individual. (2:5440)
392. (B) The risk to the fetus in an autosomal dominant disease with one parent affected is 50%. (2:542)
393. (B) Autosomal dominant polycystic kidney disease does not typically cause renal disease prenatally therefore the amniotic fluid is normal. The kidneys may appear large and echogenic. Autosomal recessive polycystic kidney disease does affect renal function and is associated with oligohydramnios. Meckel’s syndrome is associated with encephaloceles and post-axial polydactyly. (2:545)
394. (B) Although kidneys grow throughout gestation, the ratio of kidneys to abdomen remains constant at 0.27–0.30. (2:519)
395. (C) Unless the kidney is echogenic or obstructed, the anechoic cysts in the periphery represent normal renal pyramids. (3:518, 534)
396. (B) Fetal urine production begins at 12 weeks, but the fetal kidneys do not produce the majority of the fetal urine until 16 weeks. (2:517; 6:296)
397. (E) Ectopic pregnancy is defined as any pregnancy outside of the endometrial cavity. Although approximately 90% of ectopic pregnancies occur in the fallopian tube, it can occur in other locations such as the abdomen and ovaries. Ectopic pregnancy can occur in the uterus such as a cervical or a hysterotomy scar from a previous cesarean section. (21:439:14:1109)
398. (D) Although this is somewhat debated, many sources quote a number from 4 to 6 mm as the upper limit of normal in the second trimester. (2:520; 3:496)
399. (B) Grade 0—no dilation. (2:521)
400. (C) Grade I—renal pelvic dilation with or without infundibula visible. (2:521)
401. (E) Grade II—renal pelvic dilation with calices visible. (2:521)
402. (A) Grade III—renal pelvis and calices dilated. (2:521)
403. (D) Grade IV—renal pelvis and calices dilated with parenchymal thinning. (2:521)
404. (C) Because of its vascularity, the fetus may experience heart failure and polyhydramnios. On ultrasound, a congenital mesoblastic nephroma will resemble a Wilms’ tumor. (2:548)
405. (A) A neuroblastoma appears as a suprarenal mass and should be considered when a mass is identified superior to the kidney. Nephroblastoma (Wilms’ tumor) is a malignant renal tumor that effect children. (2:549)
406. (C) Nephroblastoma, also known as Wilm’s tumor, is a malignant renal tumor that sonographically appears similar to a mesoblastic nephroma. (4:880, 881)
407–409. (B) Rectus abdominis. (A) Obturator internus. (C) Pir-iformis. In a transverse plane, the rectus abdominis muscles appear as low-level hypoechoic echoes on the most midline anterior portion of the abdomina-pelvic wall. The obturator internus muscles are posterior and medial to the iliopsoas muscles and appear as thin, bilinear, low-level echoes on the posterolateral aspect of the urinary bladder. The piriformis muscles are bilateral hypoechoic structures seen posterior to the uterus and anterior to the sacrum. (18:275, 276)
410. (D) The levator ani muscles make up the pelvic diaphragm and are easily visualized in a transabdominal transverse plane. These bilateral muscles appear hypoechoic and are seen medial to the obturator internus muscles and posterior to the cervix and vagina. (18:275)
411. (C) A change in head shape, such as brachycephaly or dolicocephaly, affects accurate measurement in predicting gestational age. The degree to which fetal head shape affects BPD can be estimated with the formula: CI = BPD/OFD × 100. (7:438)
412. (A) Ovarian tumors account for 50–81% of torsion. Hyperstimulated ovaries produce large cysts that may get a torsion but less common than ovarian tumors. (2:872)
413. (E) The ovary has a dual blood supply: the ovarian and uterine arteries. The ovarian arteries originate from the aorta just below the renal vessels, with each coursing into the retroperitoneal space. It enters the broad ligament and then enters through the hilum of the ovary. The left ovarian vein drains into the left renal vein. The right ovarian vein connects directly into the inferior vena cava. The uterine artery arises from the anterior division of the hypogastric (internal iliac artery). (20:52; 21:866)
414. (D) Hyperstimulated ovaries produce large cysts that may be torsed, as well as cause fullness and nausea to the patient. Rarely, more severe complications can occur because of the shift in fluid resulting in ascites and effusions. (2:866)
415. (F) The presentation of ovarian torsion varies, depending on the duration and degree of vascular compromise. Ovarian torsion is twisting of the ovary and its vessels resulting in occlusion of its blood supply. Approximately 95% of cases are associated with an adnexal mass. Although torsion of a normal ovary can occur, this is more frequent in children than adults. Doppler ultrasound is very helpful in confirming the presence of blood flow. However, on rare occasions, ultrasound may demonstrate bilateral flow in a patient who has an ovarian torsion. This is due to twisting and untwisting of the ovary. The clinical symptoms of unilateral pain with nausea and vomiting are usually present even in a false-positive sonogram. Ovarian torsion does not occur if the ovaries and fallopian tubes are removed. (14:562, 563; 20:931; 21:507)
416. (A) Endometrial cancer is one of the most common gynecologic malignancies, after cervical cancer. Post-menopausal bleeding is an early sign. Abdominal/pelvic ascites, intra-abdominal mass, and pelvic pain are late signs. Most cancers are painless in early stages. (21:873)
417. (B) Fibroids are estrogen dependent and commonly increase in pregnancy and decrease post-menopausally. The only sonographic difference between a leiomyoma and a leiomyosarcoma is a rapid increase in growth. (2:841)
418. (A) On sonography, a leiomyoma and a leiomyosarcoma appear the same. Clinically, the only difference is a rapid increase in growth in postmenopausal women. (2:841)
419. (C) The fetal lung is isoechoic to the fetal liver in the second trimester. (2:634)
420. (A) Although the lung increases in echogenicity throughout the pregnancy, researchers have not been able to correlate the increase with lung maturity. (2:634; 6:272)
421. (E) Visualization of the femoral epiphyseal plate is seen on fetuses with a gestational age greater than 33 weeks with 95% accuracy. (2:632)
422. (A) Polydactyly may be isolated or occur as part of a syndrome. The extra digit may have a bone or may be soft tissue only. Postaxial refers to the ulnar aspect of the hand. (2:362)
423. (B) Polydactyly may be isolated or occur as part of a syndrome. The extra digit may have a bone or be soft tissue only. Preaxial refers to the radial aspect of the hand. (2:362)
424. (B) Discordance in dichorionic/diamniotic twins is more acceptable because of their different genetic makeup, provided that the smaller twin is not less than the 10th percentile in EFW. In monochorionic twins, EFW should be concordant and not differ by more than 20%. (2:184)
425. (A) Supine hypotensive syndrome is due to obstruction by the gravid uterus on the inferior vena cava, resulting in decreased venous return to the heart. The patient should be turned on the left side and the symptoms will disappear. Sitting up will also help. (7:362)
426. (C) Twin fetal discordance is determined by subtracting the largest twin from the smallest twin and dividing by the largest twin. This number is multiplied by 100 to determine the percentage. (2:184)
427. (D) Frank breech is described as the buttocks descending first with the thighs and legs extending upward along the anterior fetal trunk. (7:445)
428. (C) Complete breech is described as the buttocks descending first with the knees flexed, and the fetus sitting cross-legged. (7:445)
429. (A) A footling breech is when one or both feet are prolapsed into the lower uterine segment. (7:445)
430. (B) Ectopic pregnancy in the interstitial (cornual) region of the fallopian tube increases the risk for maternal mobility or mortality. This is due to its location giving the ectopic more room to grow. It ruptures at a larger size with a close proximity to the uterine artery, making this type of ectopic most potentially life-threatening. (20:1009; 21:433)
431. (B) XY karyotype indicates a male fetus. XX karyotype indicates a female fetus. Down’s syndrome is labeled 47,+21, and Turner’s syndrome in labeled 45X. (2:20, 21)
432. (D) HIPAA, is a federal laws, which forbid healthcare workers from giving out patient information without consent, even to other family members. Sonographers must comply with this legislation. If the sonographer is not compliant, he or she can face up to $250,000 in fines and/or jail time up to 10 years. (23:77)
433. (C) The fetus (regardless of the body part), as well as the sac, closest to the internal os is labeled fetus A. (6:467)
434. (A) The fetus would be lying on its right side, with left side closest to the maternal abdominal wall. (7:432)
435. (A) The fetus would be laying on its right side, with the left side closest to the maternal abdominal wall. (7:432)
436. (A) The fetus would be laying on its right side, with the left side closest to the maternal abdominal wall. (7:432)
437. (C) Placental lakes are areas of fibrin under the chorion, on the fetal side of the placenta. They carry no clinical significance. (2:603)
438. (D) Hypertension and maternal smoking can cause the placenta to undergo early maturation. Smoking can cause an increase in calcifications in the placenta. Unfortunately, placenta maturation has not proved to be a reliable tool in assessing placental function or fetal well-being. (2:604)
439. (D) Triploidy from the paternal component, presents with a large cystic placenta. (2:599; 6:421)
440. (D) Maternal hypertension can cause a restrictive flow in the uterine vessels, which in turn, may decrease the placental perfusion. (2:599; 6:421)
441. (D) Gestational diabetes mellitus is a cause for macrosomia because of the increased maternal blood sugars. (2:215)
442. (B) Although it is important to make sure the exam room and the transducer are sterilized prior to any procedure. The informed consent is most imperative prior to the procedure. An informed consent is an agreement by the patient to undergo a specific medical intervention. This agreement includes risks, benefits, and alternatives to the procedure. The form should be signed by the patient and physician and include a witness. The patient must be of legal age and mentally competent. (22:181)
443. (A) Caudal regression syndrome is associated with insulin-dependent diabetes mellitus in up to 16% of the cases. It is thought to occur with poor glucose control in the first trimester. Findings include sacral agenesis, spinal, and lower limb abnormalities, femoral hypoplasia, gastrointestinal and genitourinary abnormalities. (2:364–366)
444. (B) Adult tissue is more tolerant of temperature increases than embryo tissue or ossifying fetal bones. (24:306–334)
445. (A) Duplex pulse Doppler studies (pulse-wave Doppler with real time) are of significantly higher output intensities than power Doppler or fetal Doppler monitor. (24:306–334)
446. (E) The phenotype for Turner’s syndrome is 45X, indicating only one single X, or female, chromosome. (2:21)
447. (A) The ALARA principle (as low as reasonably achievable) employs keeping the power output as low as possible and increasing the receiver gain in order to change the quality of the image. This principle also employs reducing the scanning time in order to minimize the patient’s ultrasound exposure. (24:322)
448. (E) Caudal regression syndrome and cardiac defects are first-trimester insults and a risk of occurrence increases with increasing blood sugar levels in the first trimester. Shoulder dystocia can occur with delivery of macrosomic fetuses. (3:544)
449. (D) Depending on the fetal gestational age, lung maturity amniocentesis may be performed to assure lung maturation before delivery. In cases of complete PROM, often there is not an adequate sample of amniotic fluid available for maturity testing. (2:628)
450. (D) Although an increased amniotic fluid volume is associated with macrosomia, it is not a direct assessment of macrosomia. (3:544)
451. (D) CVS and PUBS may be performed provided the placenta or umbilical cord is accessible. If the fetal bladder is full, as in cases of PUV syndrome, fetal urine may be tested for karyotype. (2:32)
452. (E) Amniocentesis is a prenatal test to analyze the amniotic fluid. It can be used to detect multiple potential abnormalities such as Down’s syndrome, cystic fibrosis, sickle cell disease, neural tube detect, and fetal lungs maturity. It also can be used to test the level of fetal bilirubin, infection, and for a limited amount of short-limb syndromes. However, amniocentesis is not useful in detecting cleft palate or cleft lips. (2:33, 566; 14:1602–1604)
453. (C) Hypertension can affect the vascular bed of the placenta resulting in intrauterine growth retardation. (2:214)
454. (A) Excessive maternal smoking has been linked to accelerated maturation of the placenta. It is not predictive, however, in actual placenta perfusion to the fetus. (6:420)
455. (C) BBOW, bulging bag of water, refers to the amniotic membrane bulging into the vagina. (13:156)
456. (D) PROM, premature rupture of membranes, is the rupture of membranes before 37 weeks. (2:588)
457. (F) All of the above. Overdistension of the urinary bladder can result in serious diagnostic error. Overdistension of the urinary bladder may result in closure of an incompetent cervix due to bladder compression on the cervix; placenta previa caused by bladder compression on the lower uterine segment; closure of the gestational sac caused by bladder compression that causes both sides of the sac walls to meet resulting in a loss of the anechoic center or a change in sac shape (distortion); nonvisualization of the internal iliac vein because of displacement. (7:432)
458. (C) Ovulation occurs approximately 14 days after the first day of the last menstrual period. (2:105)
459. (C) Gravida is a woman who is pregnant. (7:435)
460. (A) Multipara is a woman who has given birth two or more times. (7:435)
461. (D) Nullipara is a woman who has never given birth to a viable infant. (7:435)
462. (H) Primipara is woman who has given birth one time to a viable infant, regardless of whether the child was living at birth and regardless of whether the birth was single or multiple. (7:435)
463. (B) Nulligravida is a woman who has never been pregnant. (7:435)
464. (E) Primigravida is a woman who is pregnant for the first time. (7:435)
465. (F) Multigravida is a woman who has been pregnant several times. (7:435)
466. (G) Para is the number of pregnancies that have continued to viability. (7:435)
467. (I) Trimester is a 3-month period during gestation. (7:435)
468. (D) The puerperium period begins with the expulsion of the placenta and continues until maternal physiology and anatomy return to a prepregnancy level, approximately 6–8 weeks. (6:533)
469. (B) Sonographic assessment of the maternal kidneys and bowel would not be considered a gynecological sonogram. (6:533)
470. (A) When the transducer is in direct contact with the patient, it exposes the patient to the greatest risk of electrical shock from a cracked transducer. Water and metals are conductors of electricity. (24:330)
471. (D) The ovaries are least likely to be seen on a postpartum pelvic sonogram. This may be because of extrapelvic position of the ovaries caused by the large uterus. (7:438)
472. (A) At approximately 20–22 weeks of gestation, the fundus of the gravid uterus is at the level of the umbilicus, and at 12 weeks of gestation, it is at the symphysis pubic. This is known as fundal height. (7:347)
473. (E) Hemorrhage, thromboembolism, and infection are the most common complications during the postpartum period. Placenta previa is an antepartum complication. (7:438)
474. (E) Ascites is an abnormal accumulation of fluid in the abdominal (peritoneal) cavity. There are multiple causes, heart failure, nephrotic syndrome pancreatitis, cancer alcoholic hepatitis, and tuberculosis. Fibroid uterus is a benign tumor and generally does not cause ascites. (16:133)
475. (D) 25% of fetuses are breech at 28 weeks, 7% at 32 weeks, and 3–4% at term. (9:451)
476. (B) Malignant ascites is characterized by loculated intra-peritoneal fluid collection with loops of bowel adherent to the abdominal wall. (16:143)
477. (C) VBAC is a commonly used abbreviation for vaginal birth after cesarean section. (12:370)
478. (B) The normal anatomical site for implantation of pregnancy is the endometrial (uterine) cavity, and the normal location for fertilization of the ovum is the ampullary region of the fallopian tube. (20:984)
479. (D) Placenta previa is the implantation of the placenta in the lower uterine segment. (7:438)
480. (A) Placenta accreta is the abnormal adherence of part or the all of placenta to the uterine wall. (7:439)
481. (C) Placenta succenturiata is an accessory lobe of placenta. (7:439)
482. (B) Abruptio placentae is the premature separation of the placenta after 20 weeks of gestation. (7:439)
483. (E) Placenta increta is the abnormal adherence of part or all of the placenta in which the chorionic villi invade the myometrium. (7:439)
484. (F) Placenta percreta is the abnormal adherence of part or all of the placenta in which the chorionic villi invade the uterine wall. (7:439)
485. (A) The fetal component of the placenta. (7:447)
486. (B) The maternal component of the placenta. (7:447)
487. (A) Sonographic fetal HELLP findings include IUGR, oligohydramnios, and possible signs of fetal distress (poor BPP, abnormal UC Doppler’s, for example). Clinically, HELLP is an acronym for hemolysis, elevated liver enzyme, and low platelet count. It is a variant of preeclampsia but can occur on its own. (2:86)
488. (A) The kidneys should be scanned to look for hydronephrosis. An enlarged fibroid greater than 14 cm in size can compress the distal ureter and cause hydronephrosis. These findings can also be due to the gravid uterus in pregnancy. A pseudohydronephrosis can occur with overdistended urinary bladder but disappears after post-void. (20:331)
489. (B) The primary infection that cause varicella-zoster virus (VZV) result from chicken pox. Herpes zoster, also known as shingles results from reactivation of varicella-zoster virus (VZV). (3:676)
490. (D) Cytomegalovirus (CMV) is the most common intrauterine congenital fetal viral infection. The maternal risk of transmission to the fetus is 40–50%, regardless of gestational age. (2:567)
491. (A) The secondary yolk sac is located in the chorionic cavity (extraembryonic coelom). The primitive yolk sac is not seen on ultrasound. The yolk sac contains vitelline fluid and has many functions including transfer of nutrients and development of blood (hematopoiesis). At approximately 12 weeks, the amnion and chorion begin to fuse and the yolk is no longer seen. (20:988, 989; 22:130, 131)
492. (D) Hematocolpos is blood in the vagina and is caused more commonly by imperforate hymen. Cervical stenosis is an acquired condition with obstruction at the cervical os, which can also result in hematometra but is less common. Hematometrocolpos is blood in the vagina and uterus. (14:544)
493. (D) In the case of IUGR, the fetus will direct more blood flow to the brain. This will lower the PI and S/D ratio of the middle cerebral artery (MCA). More recently, multiple studies have been conducted showing that the peak velocity of the MCA is a good predictor of fetal anemia. The peak velocity is measured and plotted of a curve to determine whether the fetus is in need of a fetal blood transfusion because of fetal anemia. (2:689, 690; 11:13)
494. (C) Leiomyomas (fibroids) are benign tumors of the muscle of the uterus, which are stimulated by estrogen. After menopause, the fibroid normally decreased in size due to the decrease in estrogen. An increase in size of fibroids after menopause is suggestive of leiomyosarcoma. (20:902–905)
495. (D) Multiple fluid-filled spaces in the uterine cavity with markedly elevated serum β-hCG are highly suggestive of hydatidiform mole, which is characterized by hydropic villi. The most common cyst associated with hydatidiform mole is theca lutein cyst, which is located on the ovary. Corpus lutein cyst is associated with an intrauterine pregnancy. Pseudo-gestational sac is associated with an ectopic pregnancy. (14:1576)
496. (D) Sex cord-stromal tumors include fibroma, thecoma, granulosa cell, and androblastoma (Sertoli-Leydig cell). They appear hypoechoic to echogenic with a mixed heterogeneous pattern and appear similar to each other on ultrasound. (2:874, 877)
497. (C) Endometriomas have a variety of sonographic appearances. Hemorrhagic cyst and ovarian abscesses is known to mimic its appearances. (2:868–869)
498. (A) A hydrosalpinx may initially look like a cystic mass with septations. On closer examination, the septations are not complete. The sonographer is able to follow the connection of the cystic spaces. This assumes that the structure is tubular and communicates as with hydrosalpinx. (2:870)
499. (E) A paraovarian, or mesonephric cyst originates from the mesonephric duct. A paraovarian cyst may form, regardless of uterine or ovarian status. Ovarian tissue does occasionally remain after an oophorectomy, especially if adhesions were present. The remaining ovarian tissue can still function and produce a cyst. It is called ovarian remnant syndrome and should be considered with any cystic mass identified in a post-oophorectomy patient. Peritoneal inclusion cyst is sometimes seen after oophorectomy due to fluid trapped between the adhesions. (2:867, 868)
500. (C) Hydatid cyst of Morgagni also known as a paratubal cyst is the most common paramesonephric cyst. It measures 2–10 mm and appears similar to ovarian cysts. (2:868;21:492)
501. (A) D1 × D2 × D3 × 0.523. (14:554)
502. (D) The image is a Dandy–Walker malformation. The cerebellum is splayed, and the vermis is absent. There is communication with the fourth ventricle. (1:20)
503. (C) Before puberty, the uterus is approximately 3 cm in length. (16:281)
504. (C) Cystic teratomas (dermoids) more frequently occur in females 10–30 years of age. They have a variable sonographic appearance. They can be cystic to complex, highly echogenic, and can contain echogenic foci with posterior shadowing. Fluid may be noted on the peripheral aspect of the mass. (16:298, 299)
505. (D) The vagina courses from the cervix to the external genitalia between the bladder and the rectum. It appears as a collapsed hypoechoic tubular structure with a highly reflective central echo representing the interface between the anterior and posterior walls of the vagina. The uterus forms a 90° angle with the posterior vaginal wall. (14:551)
506. (C) The endocervical canal extends from the internal os, which is approximately at the level of the isthmus where it joins the endocervical canal, to the external os, which projects into the vagina. (18:259)
507–510. (B) Fundus; (C) Corpus (body); (D) Isthmus; (A) Cervix. The uterus has four components. The fundus is the widest and most superior segment. The corpus (body), which is the largest segment, is continuous with the fundus. There is a normal constrictor where the cervical segment starts, which is called the isthmus. The cervix is cylindrical in shape and projects into the vagina. (18:259)
511. (B) Fluid can accumulate in several potential spaces in the pelvis. The pouch of Douglas (posterior cul-de-sac, rectouterine pouch) is situated posterior to the uterus and anterior to the wall of the rectum. The space of Retzius is between the symphysis pubis and the anterior wall of the urinary bladder. The anterior cul-de-sac (vesicouterine pouch) is situated between the uterus and the posterior wall of the urinary bladder. Morrison’s pouch is located in the abdomen between the right lobe of the liver and the right kidney. (18:257)
512. (E) Synechiae are adhesions that occur within the uterus due to a mechanical trauma. In Asherman’s syndrome, there are so many adhesions that the uterine cavity is completely closed. Adenomyosis is characterized by invasion of the endometrium into the myometrium. This condition is usually asymptomatic but may also present with uterine bleeding, pain, and infertility. Other possible causes of infertility include intracavity endometrial masses, submucosal myomas, endometrial polyps, and polycystic ovarian syndrome. (19:1085–1101)
513. (B) The sonographic appearance and thickness of the endometrium change cyclically with the menstrual cycle. During the secretory phase (days 15–28), the functional zone of the endometrium reaches its full thickness and becomes edematous. The sonographic appearance is more echogenic when compared to the adjacent myometrium and measures 7–14 mm. (18:278, 279)
514. (F) The hypothalamus secretes gonadotropin-releasing hormone (GnRH). Oxytocin is secreted by the posterior pituitary gland. (18:265, 266).
515. (A) A waveform with decreased diastolic flow would indicate a high-resistance pattern resulting in an increased RI. (19:1078, 1079)
516. (B) Fibromas are benign tumors of the ovary. When this tumor is associated with pleural effusion and ascites, it is referred to as Meigs’ syndrome. (14:571)
517. (B) Parity refers to the number of viable offspring, climacteric is a term for menopause, and Mittelschmerz refers to the middle pain preceding ovulation. Puberty is physical development after which sexual reproduction first becomes possible. (2:841, 861; 19:260)
518. (E) Bowel can have a variable echogenic appearance depending on the internal contents. (16:51)
519. (E) Cervical stenosis frequently involves the internal os and may cause secondary obstruction to the uterine cavity but not the vaginal cavity. This may result from radiation therapy, neoplasia, and infection. The characteristic appearance is a dilated, fluid-filled endometrial cavity. Internal echoes may be visualized due to debris or clot. (2:836, 827; 14:1998, 1999)
520. (D) Women who have not given birth (nulliparous) have a 2% lifetime risk. (19:1004, 1005)
521. (C) In vitro fertilization (IVF) and embryo transfer are used in patients with absent or significantly diseased tubes. Gamete intrafallopian tube transfer (GIFT) and zygote intrafallopian tube transfer (ZIFT) both involve transferring sperm and ova directly into the fallopian tube. (19:1048, 1049)
522. (C) The sonographic appearance and thickness of the endometrium change cyclically with the menstrual cycle. In the proliferative phase (days 5–14), the endometrium starts to thicken (4–8 mm) and appears linear and hypoechoic relative to the adjacent myometrium. During the menstrual phase (days 1–4), the endometrium is thin with a bright central echo representing the interface between the two endometrial layers. (18:278, 279)
523. (C) A bicornuate uterus has 2 widely separated endometrial cavities and there is an indentation on the fundal contour. (14:537)
524. (A) Congenital uterine anomalies are associated with an increased incidence of spontaneous abortions. (14:534)
525. (B) A pelvic (ectopic) kidney occurs during embryologic development, and the kidney fails to ascend into the abdomen. The kidney is usually small and abnormally rotated. The normal echogenic renal sinus can be noted. (14:328)
526. (D) The iliopsoas muscles together with the rectus abdominis muscles and transverse abdominis muscles are located within the false pelvis. (18:253)
527. (C) The infundibulopelvic ligaments together with the ovarian ligaments provide support to the ovaries and help maintain their position in the adnexal region. (18:255)
528. (D) Sonohysterography involves the insertion of normal saline into the uterine cavity to visualize the endometrium. (20:1134, 1135)
529. (B) Serous cystadenocarcinoma accounts for 40–50% of all malignant ovarian neoplasms. Sonographically, they usually appear as large multilocular complex cystic masses with papillary projections arising from the walls. They may contain thickened septa and echogenic solid material. The walls may be thickened. The greater the amount of internal solid material or irregular septa, the more likely tumors are malignant. The presence of ascites may indicate tumor extension beyond its capsule. (14:566; 19:906)
530. (E) Under normal circumstances, transvaginal ultrasound are performed with verbal consent only. However, patients who are mentally incompetent, drug impaired, or unconscious are not in the capacity to consent. In most cases, these patients require an administrative informed consent, court order consent, or informed consent from a healthcare proxy or family member. If a patient who is coherent refuses a procedure that is performed without her consent even if the procedure is warranted to save her life, the sonographer could be liable for assault and battery. An implied consent, which is used when an unconscious patient is at risk or if an emergency exists, cannot be utilized in non-emergency situations. An emergency is defined as a situation wherein the procedure is immediately or imminently necessary and any delay occasioned by an attempt to obtain consent would reasonably jeopardize life. (23:180, 181)
531. (E) Although 3D ultrasound DVD may be a kind gesture to family bonding. The Food and Drug Administration and other professional medical organizations discourage the use of ultrasound for non-medical reasons. Sonograms should be requested by a physician with just medical cause. (23:194)
532. (C) Pseudocyesis (false pregnancy) is a condition in which a non-pregnant woman believes that she is pregnant. This patient will sometimes give convincing stories of pregnancy. The patient may actually exhibit morning sickness, breast enlargement, and cessation of menstruation. However, in pseudocyesis, there is no physical, sonographic, or laboratory evidence of pregnancy. In missed abortion, ectopic, and abdominal pregnancy, the pregnancy test result is positive and will have some sonographic evidence. In fetal demise, the serum β-hCG is positive for several weeks depending on the gestational age at the time of death. (25:32)
533. (A) Precocious puberty is premature onset of secondary sexual characteristics before 8 years for girls and before 9 for boys. When a child’s gender is in question at birth due to its atypical appearance, it is referred to as ambiguous genitalia. (20:656; 21:271–278)
534. (D) Precocious puberty and ambiguous genitalia are the most commonly requested pediatric ultrasound. Accidental ingestion of foreign body is very common but best demonstrated by x-ray. Vaginal foreign body is less requested. Fibroids uterus are rarely seen before puberty. (21:268–275)
535. (A) The gold standard for predicting fetal lungs maturity is lecithin-sphingomyelin ratio from the amniotic fluid. Ultrasound cannot predict fetal lung maturity, however, some sonographic findings increase the likelihood. (25:969)
536. (B) An infection acquired via a medical instrument or a medical procedure is called iatrogenic. An infection contracted while under medical care is called nosocomial. (23:108)
537. (E) Retained products of conception (RPOC). This transvaginal sonogram demonstrates disorganize echoes in the uterine cavity after a dilation and curettage, which is highly suggestive of RPOC. The serum β-hCG is positive after an abortion or after a normal delivery and can remain positive for several weeks depending on the gestational age. (14:1578)
538. (A) The scan should be obtained with the fetus in the sagittal section with a neutral position of the fetal head. (28:90)
539. (A) Nuchal fold measurements are preformed in the second trimester and are measured from the outer edge of the occipital bone to the outer margin of the skin. (26:1)
540. (E) Thickened nuchal translucency is associated with cystic hygroma, nuchal edema, aneuploidy, and congenital heart disease. The most common syndromes associated with thickened translucency are Turner’s and Down’s syndromes. Rhombencephalon (hindbrain) is a normal brain vesicle seen in the early developing embryo. (26:1; 27:26)
541. (D) The optimal time to assess measurements for nuchal translucency is between 11 to 14 weeks. (26:1)
542. (E) Nuchal translucency thickness increases with crown-rump-length (CRL). The measurements increase from 1.2 mm at 11 weeks to 3 mm at 14 weeks. (26:1; 28:90)
543. (D) Mesenchymal edema is a term used to describe excessive enlarged nuchal translucency in association with cystic hygroma. (26:1)
References
1. Krebs C. Appleton & Lange’s Review for the ultrasonography Examination. 3rd ed. New York: Appleton & Lange; 2001.
2. Callen PW Ultrasonography in Obstetrics and Gynecology. 4th ed. Philadelphia: WB Saunders; 2000.
3. Fleischer A, Manning F, Jeanty P, Romero R. Sonography in Obstetrics and Gynecology: Principles and Practice. 5th ed. Stanford, CT: Appleton & Lange; 1996.
4. Bianchi DW, Cromblelholme TM, D’Alton ME. Fetalogy: Diagnosis and Management of the Fetal Patient. New York: McGraw-Hill; 2000.
5. Nyberg D, Mahony B, Pretorius D. Diagnostic Ultrasound of Fetal Anomalies. St. Louis, MO: Mosby-Year Book; 1990.
6. Berman MC, Cohen HL. Obstetrics and Gynecology. 2nd ed. Philadelphia: Lippincott; 1997.
7. Odwin CS, Dubinsky T, Fleischer AC. Appleton & Lange’s Review for the Ultrasonography Examination. 2nd ed. Norwalk, CT:
Appleton & Lange; 1993.
8. Moore TR, Cayle JE. The amniotic fluid index in normal human pregnancy. Am J Obstet Gynecol. 1990; 162:1168–1173.
9. Zuspan F, Quilligan E, Blumenfeld M. Handbook of Obstetrics, Gynecology, and Primary Care. St. Louis, MO: Mosby-Year Book; 1998.
10. Tortora GJ, Derrickson B: Principles of Anatomy and Physiology. 11th ed. New York: John Wiley & Sons, Inc; 2006.
11. Mari G et al. Proceedings SMFM. Miami Beach, FL; January 2000.
12. Gabbe S, Niebyl J, Simpson JL. Obstetrics: Normal and Problem Pregnancies. New York: Churchill Livingstone; 1996.
13. Thomas C. Taber’s Cyclopedic Medical Dictionary. Philadelphia: FA. Davis; 1982.
14. Rumack C et al. Diagnostic Ultrasound. 3rd ed. St. Louis, MO: Elsevier Mosby; 2005.
15. Schmidt G. Differential Diagnosis in Ultrasound Imaging. Stuttgart, Germany: Thieme; 2006.
16. Sanders R et al. Clinical Sonography A Practical Guide. 4th ed. Maryland: Lippincott, Williams & Wilkins; 2007.
17. Doubilet P et al. Atlas of Ultrasound in Obstetrics and Gynecology: A Multimedia Reference. Philadelphia, PA: Lippincott, Williams & Wilkins; 2003.
18. Curry RA et al. Sonography: Introduction to Normal Structure and Function. 2nd ed. St. Louis, MO: Saunders; 2004.
19. Fleischer AC et al. Sonography in Obstetrics and Gynecology: Principles and Practice. 6th ed. New York: McGraw-Hill; 2001.
20. Hangen-Ansert S. Textbook of Diagnostic Ultrasonography. 6th ed. St. Louis, MO: Mosby; 2006.
21. Mishell DR, Stenchever MA, Droegemueller W, et al. Comprehensive Gynecology. 3rd ed. St. Louis, MO: Mosby-Year Book, Inc; 1997.
22. Moore KL, Persaud TVN. The Developing Human: Clinically Oriented Embryology. 5th ed. Philadelphia, PA: 1993.
23. Craig M. Essentials of Sonography and Patient Care. 2nd ed. St. Louis, MO; 1993.
24. Kremkau FW. Diagnostic Ultrasound: Principles and Instruments. 6th ed. St. Louis, MO; 2006.
25. Cunningham G, MacDonald, Grant NF, et al. Williams Obstetrics. 20th ed. New York: Appleton & Lange; 1997.
26. Simpson LL, Levine D, et al. First Trimester Cystic Hygroma and Enlarged Nuchal Translucency. Waltham, MA: Up to Date; 2010.
27. Bianchi DW, Crombleholme TM, et al. Fetology Diagnosis and Management of Fetal Patient. New York, NY: McGraw-Hill; 2000.
28. Goldberg BB, Mc Gaham JP Atlas of Ultrasound Measurements. Elsevier Health Sciences; 2006.
29. Thilaganathan B, Sairam S, Michailidis G, et al. First trimester nuchal translucency: effective routine screening for Down’s syndrome. Br J Radiol. 1999;72.
30. Lipscomb GH. Medical Therapy for ectopic pregnancy. Semin Reprod Med Memphis. TN; 25:93. 2007.