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ANSWERS
CASE 61
Nonimmune Fetal Hydrops
1. A, B, C, and D
2. C
3. A
4. C
References
Jauniaux E: Diagnosis and management of early non-immune hydrops fetalis.
Prenat Diagn 1997; 17(13):1261-1268.
http://www.ncbi.nlm.nih.gov/pubmed/9509544 (Accessed on June 13, 2012.)
Santolaya J, Jaffe R, Warsof SL: Antenatal classication of hydrops fetalis.
Obstet Gynecol 1992; 79(2):256-259.
http://www.ncbi.nlm.nih.gov/pubmed/1731295 (Accessed on June 13, 2012.)
Cross-Reference
Ultrasound: The REQUISITES, 2nd ed, pp 414-415, 419-422.
Comment
Definition and Causes
Fetal hydrops (hydrops fetalis) is a condition of uid accumulation in the fetal pleural, peritoneal, and pericardial spaces;
skin edema; and placentomegaly (Figure A). At the present
time, isoimmunization related to blood group incompatibilities
of the mother and fetus has become a relatively rare cause,
and most cases are classied as nonimmune hydrops. There are
approximately 80 different causes of nonimmune hydrops. In
the rst trimester, hydrops is usually attributable to a chromosomal defect (e.g., trisomy 21, trisomy 18, trisomy 13, or Turner
syndrome) in which lymphatic obstruction causes hydrops.
Nonimmune Causes
Common causes of fetal hydrops include cardiac malformations and cardiac arrhythmias such as tachyarrhythmia (Figure
B), which can be intermittent and not appreciated on any one
examination. Other nonimmune causes include cystic hygroma
with diffuse lymphatic obstruction and any mass that obstructs
venous return to the heart. Teratomas, particularly sacrococcygeal, may lead to hydrops, which is believed to be caused by
high outow through the tumor. The high-output heart failure
associated with a vein of Galen arteriovenous malformation
or severe anemia is an additional cause. Finally, maternal-fetal
infection, such as the TORCH (toxoplasmosis, other infections, rubella, cytomegalovirus, herpes) group and parvovirus
can result in hydrops.
Ultrasound Detection
Early detection of fetal hydrops is often difcult. Some
authors believe that increased nuchal translucency is the rst
manifestation of uid accumulation owing to hydrops. This
can be detected by 9 weeks’ gestation, with a nuchal translucency greater than 3 mm. In cases with diagnosis during the
rst trimester, karyotypically normal fetuses have shown resolution of hydrops later in the gestation. However, the outcome
of these fetuses is still unfavorable. Before 20 weeks’ gestation,
the two most common indicators of fetal hydrops are generalized skin thickening and placental enlargement. Structural
anomalies account for many cases of hydrops diagnosed after
15 weeks’ gestation. The nding of structural anomalies is
important clinically because by the time uid is detected within
body cavities and marked skin thickening is noted, the fetus is
often signicantly compromised. Studies of fetuses at risk for
immune hydrops showed that the length of the liver (from the
dome of the right hemidiaphragm to the distal tip) increased
as the rst sign of impending hydrops in moderate to severe
cases. Whether this is a uniform nding has not been determined, and its use in nonimmune hydrops has not been fully
worked out.
Prognosis
At the present time, the outcome of a fetus with full-blown
ultrasound signs of fetal hydrops is generally poor, and mortality is greater than 70%.
126
CASE 62
A
B
C
History: Four patients present with uterine enlargement
and palpable uterine masses.
1. What should be included in the differential diagnoses based
on the images? (Choose all that apply.)
A. Adenomyosis
B. Uterine polyp
C. Lipoleiomyoma
D. Leiomyosarcoma
2. What generally accounts for the increased echogenicity in
the lipoleiomyoma in Figure C?
A. Hemorrhage
B. Calcications
C. Multiple, closely packed boundary interfaces of mul-
tiple tissue types
D. Necrosis
D
3. What is the incidence of uterine sarcoma?
A. 10% of all uterine malignancies
B. 1% to 3%
C. 30% to 40% of all uterine malignancies
D. 10% to 15% of all uterine malignancies
4. How is a leiomyosarcoma of the uterus distinguished from
a leiomyoma?
A. Size at initial presentation
B. Leiomyosarcomas are usually necrotic and large.
C. Leimyosarcomas are usually small with calcications.
D. Shape
127
ANSWERS
CASE 62
Uterine Masses
1. C and D
2. C
3. B
4. B
References
Rha SE, Byun JY, Jung SE, et al: CT and MRI of uterine sarcomas and their
mimickers. AJR Am J Roentgenol 2003;181(5):1369-1374.
http://www.ncbi.nlm.nih.gov/pubmed/14573436 (Accessed on June 13, 2012.)
Shah SH, Jagannathan JP, Krajewski K, et al: Uterine sarcomas: then and now.
AJR 2012; 199:213-223.
http://www.ncbi.nlm.nih.gov/pubmed/22733915 (Accessed on July 5, 2012.)
Wallach EE, Viahos NF: Uterine myomas: an overview of development,
clinical features, and management. Obstet Gynecol 2004; 104(2):393-406.
http://www.ncbi.nlm.nih.gov/pubmed/15292018 (Accessed on June 13, 2012.)
Cross-Reference
Ultrasound: The REQUISITES, 2nd ed, pp 546, 549-555.
Comment
Histologic Description of Uterine Myomas
The four uterine masses depicted in this case have different
histologic features. The mass depicted in Figure A is a typical
uterine leiomyoma, the most common solid pelvic tumor in
women. This rst example is of the type with a coarse heterogeneous echotexture, which, if large enough, often distorts
the endometrial stripe. The masses in Figure B are broids
with calcied rims. These benign masses of smooth muscle
are actually monoclonal proliferations of muscle cells. Uterine
leiomyomas have a genetic basis, and their growth is related to
genetic predisposition, hormonal inuences, and growth factors. They can be found in subserosal, myometrial, submucosal,
or intracavitary locations.
Ultrasound Imaging of Simple Leiomyomas
On ultrasound, a simple leiomyoma is hypoechoic and solid
with some attenuation of the sound beam. The echogenicity
may be heterogeneous owing to the presence of calcication, necrosis, hemorrhage, or hyalinization. It is important
to describe the relationship with the endometrial lining, and
follow-up studies are often performed to evaluate for a change
in size. Sonohysterography is an important adjunct to transvaginal ultrasound in symptomatic women with known myomas,
especially before surgical or medical therapy.
Ultrasound Imaging of Uterine Lipoleiomyomas
The mass in Figure C is a rare lipoleiomyoma. This benign
subtype of leiomyoma contains lipid. The presence of multiple, closely packed (multiple) boundary interfaces in the
tumor accounts for the homogeneous increased echogenicity
on ultrasound. It is important when imaging an exophytic lipoleiomyoma to be certain that the mass arises from the myometrium because this appearance is similar to the appearance of
an ovarian dermoid.
Ultrasound Imaging of Uterine Sarcomas
The fourth case is a uterine leiomyosarcoma (Figure D).
This entity accounts for just under 40% of uterine sarcomas.
The majority arise de novo, with less than 5% as malignant
transformation from an existing leiomyoma. This rare uterine malignancy usually manifests with extensive necrosis and
hemorrhage. It can be indistinguishable from a leiomyoma on
ultrasound and CT. A rapid increase in size of a leiomyoma
should raise concern regarding a leiomyosarcoma. In addition, leiomyosarcomas are usually necrotic and large. Leiomyosarcoma is the most common type of uterine myometrial
malignancy. The mixed mesodermal tumor is less common.
A characteristic ultrasound appearance of the mixed mesodermal tumor has been described. A heterogeneous myometrial
echotexture can be seen with hyperechoic areas and anechoic
areas, which may be large and irregularly shaped, scattered
throughout the myometrium. Although uterine sarcomas generally have the worst prognosis of uterine masses, a mixed
mesodermal tumor also has a very poor prognosis.
128
CASE 63
A
History: An asymptomatic patient in her third trimester
undergoes imaging.
1. What abnormality in this third-trimester pregnancy is
shown in the sagittal plane of the lower uterine segment in
all three images? (Choose all that apply.)
A. Bulging membranes
B. Incompetent cervix
C. Incompetent cervix with funneling
D. Prolapse of amniotic sac
2. What is cervical funneling?
A. Opening of the internal os
B. Opening of the external os
C. Elongation of the cervix
D. Foreshortening of the cervix
3. What is the best technique for measuring cervical length?
A. Transabdominal ultrasound
B. Transvaginal ultrasound
C. Digital examination
D. Transperineal ultrasound
4. Which of the following maneuvers is most reliable to dilate
a closed but incompetent cervix?
A. Standing
B. Coughing
C. Transfundal pressure
D. Valsalva
B
H = fetal head; B = urinary bladder.
C
129
ANSWERS
CASE 63
Incompetent Cervix
1. B and C
2. A
3. B
4. C
References
Fox NS, Rebarber A, Roman AS, et al: Association between second-trimester
cervical length and spontaneous preterm birth in twin pregnancies. J Ultra-
sound Med 2010; 29(12):1733-1739.
http://www.ncbi.nlm.nih.gov/pubmed/21098845 (Accessed on June 13, 2012.)
Gomez R, Galasso M, Romero R, et al: Ultrasonographic examination of the
uterine cervix is better than cervical digital examination as a predictor of
the likelihood of premature delivery in patients with preterm labor and
intact membranes. Am J Obstet Gynecol 1994; 171(4):956-964.
http://www.ncbi.nlm.nih.gov/pubmed/7943109 (Accessed on June 13, 2012.)
Hertzberg BS, Livingston E, DeLong DM, et al: Ultrasonographic evaluation
of the cervix: transperineal versus endovaginal imaging. J Ultrasound Med
2001; 20(10):1071-1078; quiz 1080.
http://www.ncbi.nlm.nih.gov/pubmed/11587014 (Accessed on June 13, 2012.)
Cross-Reference
Ultrasound: The REQUISITES, 2nd ed, pp 327, 502-509.
Comment
General Dimensions of the Cervix
Cervical shortening is associated with preterm delivery.
Although many observers believe that a cervical length between
2.5 and 3 cm is the lower limit of normal, there is a continuum.
A normal cervical length is 3 cm or more, 2 to 3 cm is borderline normal, and less than 2 cm is denitely abnormal (Figures
A and B). Cervical length is most strongly associated with preterm birth close to the end of the second trimester.
Ultrasound of the Lower Uterine Segment
The lower uterine segment can be imaged using a transabdominal, translabial, or transvaginal technique. Distention of
the urinary bladder compresses the lower uterine segment,
which can create the false appearance of a long cervix and the
false appearance of a funneled cervix (dilation of the internal
os). Translabial and transvaginal techniques are more accurate
when performed with an empty urinary bladder. Transvaginal
scanning with an empty bladder is the most consistently accurate technique to evaluate the cervix (Figures A and C). The
vaginal probe is inserted into the anterior fornix of the vagina,
withdrawn slightly, and then advanced only enough to obtain
a clear image. This action decreases the pressure on the cervix, which can articially increase the length. Results of one
large study showed that endovaginal images were frequently
superior to transperineal ones. Transperineal measurements
of cervical length can be signicantly shorter than endovaginal measurements, especially before 20 weeks’ gestation; short
cervical lengths on transperineal ultrasound measured before
20 weeks’ gestation should be conrmed by endovaginal
ultrasound.
Ultrasound Imaging of Funneling
Ultrasound is more accurate than digital examination for the
detection of funneling. The degree of dilation of the internal
os, which denes incompetence, has been quoted as greater
than 3 to 6 mm. Cervical incompetence, painless dilatation of
the cervix, is a common cause of pregnancy failure in the second trimester. The length of the funnel has prognostic value.
V-shaped funneling has been shown to be more predictive of
preterm delivery than U-shaped funneling. In addition to cervical shortening, a change in cervical length between examinations (particularly a change of ≥6 mm) has a small association
with preterm labor. A study of patients with multiple gestations with short cervical lengths determined that cerclage as
indicated by ultrasound was not associated with a lower incidence of spontaneous preterm delivery compared with conservative management.
130
CASE 64
A
History: A patient in the late second trimester undergoes
ultrasound imaging, and axial images of the fetal brain are
obtained.
1. What should be included in the differential diagnosis of the
intracranial fetal mass? (Choose all that apply.)
A. Enlarged choroid plexus
B. Neoplasm
C. Intracranial hemorrhage
D. Hydrocephalus
2. When are most intracranial fetal hemorrhages detected on
ultrasound?
A. During the rst month of gestation
B. By 8 weeks’ gestation
C. After 23 weeks’ gestation
D. At term
B
3. What is the most common cause of fetal intracranial hemorrhage in the third trimester?
A. Direct maternal abdominal trauma
B. Maternal hypertension
C. Maternal diabetes
D. Maternal hypotension
4. What is the difference in prognosis if fetal hemorrhage
occurs intraventricularly versus intraparenchymally?
A. The prognosis is poor with isolated intraventricular
hemorrhage.
B. The prognosis is poor with parenchymal hemorrhage.
C. The prognosis is worse with intraventricular hemor-
rhage than with subdural hemorrhage.
D. The difference depends on the age of the bleed.
131
ANSWERS
CASE 64
Intracranial Hemorrhage
1. A, B, and C
2. C
3. A
4. B
References
Brown MA, Sirlin CB, Farahmand N, et al: Screening sonography in
pregnant patients with blunt abdominal trauma. J Ultrasound Med 2005;
24(2):175-181.
http://www.ncbi.nlm.nih.gov/pubmed/15661948 (Accessed on June 13, 2012.)
Ghi T, Simonazzi G, Perolo A, et al: Outcome of antenatally diagnosed
intracranial hemorrhage: case series and review of the literature. Ultrasound
Obstet Gynecol 2003; 22(2):108-109.
http://www.ncbi.nlm.nih.gov/pubmed/12905503 (Accessed on June 13, 2012.)
Vergani P, Strobelt N, Locatelli A, et al: Clinical signicance of fetal intracra-
nial hemorrhage. Am J Obstet Gynecol 1996; 175(3 Pt 1):536-543.
http://www.ncbi.nlm.nih.gov/pubmed/8928712 (Accessed on June 13, 2012.)
Cross-Reference
Ultrasound: The REQUISITES, 2nd ed, p 399.
Comment
Definition and Etiology of Fetal Intracranial
Hemorrhage
Fetal hemorrhage is included in the differential diagnosis of an
intracranial fetal mass. In neonates, changes in cerebral blood
pressure and perinatal asphyxia contribute to the development
of cerebral hemorrhage. However, in the fetus, the intracerebral pressure is regulated and protected from uctuations in
the maternal blood pressure, which suggests that an alternative
pathophysiology might be associated with a cerebral hemorrhage. The most common cause is secondary to direct maternal abdominal trauma in the third trimester. Ultrasound is an
effective screening modality to determine the sequelae of the
trauma. Most hemorrhages are detected after 23 weeks’ gestation and are possibly related to the fact that the germinal
matrix vascular connections to subependymal venous networks develop after 20 weeks.
Locations
Prenatal cerebral hemorrhage can occur in the ventricle (see
arrowheads in Figure A), parenchyma (see arrows in Figures A
and B), or subdural or subarachnoid space. The prognosis is
poor with subdural and parenchymal hemorrhages but better
in cases of isolated intraventricular hemorrhage. The prognosis
is worse with higher degrees of ventricular dilation (>15 mm).
Imaging Features
On ultrasound, hemorrhage appears as a hyperechoic (either
homogeneous or heterogeneous) mass. Intraventricular hemorrhage may manifest as an irregular, enlarged choroid plexus.
The ventricular diameter and any parenchymal abnormality
must be evaluated and closely followed. Fetal intracranial hemorrhage is generally accurately identied and categorized by
prenatal ultrasound. MRI may be helpful in characterization
and delineation of the hemorrhage.
132
CASE 65
A
C
B
History: A patient who has had three prior cesarean sec-
tions now presents with vaginal bleeding in the second trimester and undergoes a follow-up ultrasound scan.
1. What should be included in the differential diagnosis for
Figures A and B? (Choose all that apply.)
A. Myometrial contraction
B. Placenta previa
C. Placenta accreta
D. Uterine broid
E. Abruptio placentae
2. Which of the following is the least sensitive gray-scale criterion in diagnosing placenta accreta?
A. Loss of the retroplacental sonolucency zone
B. Irregularity of the retroplacental sonolucent zone
C. Abnormal placental lacunae
D. Thinning or disruption of the hyperechoic uterine
serosa–bladder interface
3. Concerning color Doppler criteria of abruptio placentae,
which of the following would be the least sensitive sign?
A. Markedly dilated vessels over the peripheral subplacen-
tal zone
B. Intraplacental hypervascularity in vascular spaces
D
C. Diffuse lacunar ow pattern
D. Hypervascularity of the uterine serosa–bladder interface
4. Which of the following would not be considered therapy for
placenta accreta?
A. Prophylactic balloon occlusion of the hypogastric or
common iliac arteries
B. Cesarean section at term
C. Ureteric stent placement with surgery
D. Hysterectomy after cesarean section delivery
133
ANSWERS
CASE 65
Placenta Accreta
1. A, B, C, D, and E
2. D
3. A
4. B
References
Lim PS, Greenberg M, Edelson MI, et al: Utility of ultrasound and MRI in
prenatal diagnosis of placenta accreta: a pilot study. AJR Am J Roentgenol
2011; 197(6):1506-1513.
http://www.ncbi.nlm.nih.gov/pubmed/22109309 (Accessed on June 13, 2012.)
Shih JC, Palacios Jaraquemada JM, Su YN, et al: Role of three-dimensional
power Doppler in the antenatal diagnosis of placenta accreta: comparison
with gray-scale and color Doppler techniques. Ultrasound Obstet Gynecol
2009; 33(2):193-203.
http://www.ncbi.nlm.nih.gov/pubmed/19173239 (Accessed on June 13, 2012.)
Cross-Reference
Ultrasound: The REQUISITES, 2nd ed, p 495.
Comment
Differential Diagnosis
The differential diagnosis includes placenta previa. Whenever
placenta previa is present, one always should consider placenta
accreta, especially if there is a history of cesarean section.
Other considerations are transient myometrial contraction or
overdistention of the urinary bladder leading to a false diagnosis of placenta previa. A mass in the lower uterine segment
such as a broid or retroplacental hemorrhage should be
considered. The most likely diagnosis in this case is placenta
accreta.
Ultrasound Findings
Placenta accreta is a general term to encompass all forms of
placenta accreta, increta, and percreta. In placenta accreta, the
chorionic villi implant in the myometrium. In placenta increta,
the chorionic villi invade the myometrium walls. In the most
severe form of placenta percreta, the chorionic villi penetrate through the myometrium. These ndings often occur in
patients with recurrent cesarean sections with placenta previa. Numerous ultrasound ndings have been described with
placenta accreta (Figures A to C), including complete loss of
the regularity of the retroplacental sonolucency zone (Figure A), thinning of the hypoechoic uterine serosa–bladder
interface (Figure A), presence of exophytic masses invading
the urinary bladder (Figure C), and a thickened placenta with
abnormal lacunae. Color Doppler criteria include the presence of color Doppler signal within the focal lacunae and
the presence of sonolucent vascular lakes with turbulence
ow in the placenta. Hypervascularity of the uterine serosa–
bladder interface (Figure B) occurs when abnormal vessels
penetrate from the placenta through the myometrium (Figure
C). MRI is also useful to identify the tortuous deep vessels
in the placenta, and abnormal dark bands, on T2-weighted
images, within the placenta are thought to represent infarcts
(Figure D).
Prognosis and Management
Recognition of the various forms of placenta accreta is very
important because this condition is associated with severe
maternal morbidity and mortality. Massive hemorrhage
occurs if the placenta invades deep into the myometrium
and it cannot be separated. Placenta accreta is managed with
cesarean section delivery of the fetus followed by hysterectomy. Ureteral stents are often placed to avoid injury of the
ureters during hysterectomy. Balloon occlusion of the uterine arteries is needed to prevent blood loss. Adequate blood
replacement should be available for the patient during the
surgery.
134
CASE 66
History: A patient undergoes ultrasound in the mid second
trimester of pregnancy, and an image of the fetal abdomen is
obtained.
1. What should be included in the differential diagnosis?
(Choose all that apply.)
A. Duodenal atresia
B. Jejunal atresia
C. Ileal atresia
D. Bilateral hydronephrosis and hydroureter
E. Meconium ileus
2. Which of the following statements concerning small bowel
obstruction is false?
A. Volvulus can be an etiology of small bowel obstruction.
B. Polyhydramnios is usually associated with small bowel
atresia during the third trimester.
C. Polyhydramnios is more likely to occur with distal small
bowel obstruction.
D. In utero small bowel obstruction is most commonly due
to small bowel atresia.
3. Which of the following statements concerning small bowel
obstruction is not true?
A. Jejunal obstruction and ileal obstruction occur with
approximately the same incidence.
B. Extraintestinal anomalies are common with small bowel
atresia.
C. Bowel abnormalities associated with small bowel atresia
include malrotation of the small bowel.
D. Gastroschisis is associated with small bowel atresia.
4. Which of the following statements concerning the prognosis and management of small bowel obstruction is false?
A. Premature delivery may occur with increasing degree of
polyhydramnios with small bowel obstruction.
B. Low birth weight is often associated with small bowel
obstruction.
C. Ileal atresia is more frequently associated with prema-
ture delivery than with jejunal atresia.
D. Small bowel obstruction associated with meconium peri-
tonitis has an increased rate of mortality in newborns.
135