ACR Inservice Recall

1. Section XII – Ultrasound
Figure 1A
Figure 1B
Figure 1C
501. A 22-year-old pregnant female presents for routine dating examination. You are shown sonographic
images through the fetal abdomen (Figure 1A) and the fetal pelvis (Figures 1B and 1C). Which one of
the following is the MOST likely diagnosis?
A. Multicystic dysplastic kidney
B. Posterior urethral valves
C. Ureteropelvic junction obstruction
D. Mesoblastic nephroma
E. Autosomal recessive polycystic disease
Diagnostic In-Training Exam 2002 1

2. Section XII – Ultrasound
Question #501
Findings: Bilateral hydronephrosis, megacystis, and a dilated posterior urethra (“keyhole”) in a male fetus.
Rationales:
A) Incorrect. The multicystic dysplastic kidney contains multiple cysts of various sizes that are not connected but
replace essentially all renal parenchyma. The kidney is usually large but can be normal sized. Multicystic
dysplastic kidney is usually a unilateral process with a good prognosis. Bilateral multicystic dysplastic kidney is
uniformly fatal because of the nonfunctional status of the affected kidneys. In bilateral multicystic dysplastic
kidney, there is often oligohydramnios and there should be no fluid in the bladder. These features differ from
those in the test case.
B) Correct. Posterior urethral valves obstruct the prostatic urethra in the male fetus, resulting in a dilated proximal
urethra and bladder. Most affected fetuses have sonographically evident hydroureteronephrosis, secondary to
reflux or obstruction. In some cases, the kidneys are small or echogenic or contain cysts, all of which are signs of
cystic renal dysplasia. Moderate to severe oligohydramnios is common. The features of posterior urethral valves
are present in the test case.
C) Incorrect. Ureteropelvic junction (UPJ) obstruction is the most common congenital urinary tract anomaly.
Sonographically, the diagnosis is suggested by the presence of a dilated renal pelvis and calyces in the setting of a
non-dilated ureter and a normal bladder. The degree of pelvicaliectasis and parenchymal thinning is variable.
The bilateral hydronephrosis, megacystis and dilated posterior urethra do not favor UPJ obstruction.
D) Incorrect. Mesoblastic nephroma, (also termed fetal renal hamartoma) is a common renal mass in infants under
1 year of age. The common presenting sign is a painless abdominal mass. Microscopically, mesoblastic
nephroma contains intersecting bundles of spindle cells, dysplastic tubules, and islands of cartilage. The
sonographic features are usually those of a large, echogenic mass with a homogeneous echopattern or
heterogeneous echotexture related to areas of necrosis or hemorrhage. Occasionally concentric hypo- and
hyperechoic rings surround the mass.
E) Incorrect. The typical sonographic features of prenatally detected autosomal recessive (infantile) disease are
bilateral, markedly enlarged, and echogenic kidneys, associated with oligohydramnios and a small bladder.
These features are substantially different from those in the test case. The abnormal renal enlargement and
echogenicity arise from dilatation of renal tubules, creating a multiplicity of sonic interfaces. The cystic tubules
are usually too small to resolve as discrete cysts.
Citations:
Callen. Ultrasonography in Obstetrics and Gynecology. 4th ed. WB Saunders Co., Philadelphia, PA. 2000.
2 American College of Radiology

3. Section XII – Ultrasound
Figure 2A
Figure 2B
502. A 27-year-old pregnant woman presents at 19 weeks gestation with size greater than dates. You are shown two
sonograms through the fetal cranium (Figure 2A, coronal; Figure 2B, axial). Which one of the following is the
MOST likely diagnosis?
A. Hydrocephalus
B. Hydranencaphaly
C. Holoprosencephaly
D. Porencephaly
E. Anencephaly
Diagnostic In-Training Exam 2002 3

4. Section XII – Ultrasound
Question #502
Findings: A coronal sonogram of the fetal head shows a single monoventricle and fused midline thalami. There is
no evidence of the formation of distinct lateral ventricles. No falx or other midline structure is identified. A thin
rim of surrounding brain parenchyma is present. These findings are most consistent with diagnosis of alobar
holoprosencephaly.
Rationales:
A) Incorrect. Hydrocephalus is a term used to describe dilatation of the ventricular system. The cerebral cortex is
present but can be markedly thinned in fetuses with very severe hydrocephalus. The falx and other midline
structures are normal. The frontal horns of the lateral ventricles are separated and the thalami are normal rather
than fused, as seen in fetuses with holoprosencephaly. The absence of distinct lateral ventricles and the apparent
fusion of the thalami make hydrocephalus an unlikely diagnosis.
B) Incorrect. Hydranencephaly is characterized by complete or near complete absence of the cerebral hemispheres,
which are replaced with cerebrospinal fluid (CSF) contained within intact meninges. Occasionally, a minute
amount of cerebral cortex is preserved, but is usually not detectable by sonography. Thus, in hydranencephalic
fetuses, sonography of the fetal head demonstrates no cortical mantle. There is variable development of the falx.
The finding of an irregular cortical mantle in the fetus in the test case eliminates hydranencephaly as a
diagnostic possibility. In addition, hydranencephaly is extremely rare, and the few reported cases have been
primarily in the third trimester.
C) Correct. Holoprosencephaly represents a continuum of anomalous development. The most severe form is alobar
holoprosencephaly, in which no cleavage of the prosencephalon has occurred. The brain is small and lacks a
normal ventricular system. A monoventricular cavity is present; the thalami are fused and the third ventricle is
absent. The test case is an example of alobar holoprosencephaly. An intermediate form of holoprosencephaly is
termed semilobar holoprosencephaly. A monoventricular cavity with rudimentary occipital horns is present, and
the thalamus and basal ganglia are totally or partially fused. In the least severe type, lobar holoprosencephaly,
the two hemispheres and lateral ventricles are separated. The frontal horns are hypoplastic, but the remainder of
the ventricular system develops nearly normally. The basal ganglia and thalami are usually separated. A strong
association with aneuploidy has been demonstrated. Prenatal ultrasound can identify the vast majority of
affected fetuses before the time of viability.
D) Incorrect. Porencephaly refers to a CSF-filled cyst or cavity within the brain, which many communicate with the
ventricular system. The cystic space is thought to be the consequence of a vascular, traumatic, or infectious
destructive process that focally damages the parenchyma. The prenatal sonographic findings of porencephaly
include a cystic space in the brain parenchyma and a normally formed ventricular system, although
hydrocephalus may be present. The falx and infratentorial structures are normal. Porencephaly is an unlikely
diagnosis in the test case because of the abnormal ventricular system shown in the test images.
E) Incorrect. Anencephaly results from a failure of the rostral neuropore to close and is distinguished by absence of
the cerebral hemispheres and accompanying cranium. In this case, a normal calvarium is demonstrated which
excludes the diagnosis. The diagnosis is usually made in utero. Imaging studies are rarely needed postnatally.
Citations:
Diagnostic ultrasound of fetal anomalies: Text and Atlas. Nyberg DA, Mahoney BS, Pretorius DH. Yearbook Medical Publishers,
1990.
4 American College of Radiology

5. Section XII – Ultrasound
Figure 3A
Figure 3B
503. A 29-year-old otherwise healthy male with acute renal failure following successful completion of a marathon
on a hot day. You are shown two longitudinal images (Figure 3A and Figure 3B) through the right hepatorenal
fossa. Which one of the following is the MOST likely diagnosis?
A. Hemorrhagic renal cyst
B. Angiomyolipoma
C. Renal cell carcinoma
D. Adrenal metastases
E. Myelolipoma
Diagnostic In-Training Exam 2002 5

6. Section XII – Ultrasound
Question #503
Findings: Images demonstrate a 4.5 cm homogeneously hyperechoic suprarenal solid mass.
Rationales:
A) Incorrect. This mass is solid and hyperechoic in appearance. In contrast, a hemorrhagic renal cyst would arise in
the renal parenchyma. It may appear echogenic but it should have through transmission.
B) Incorrect. Angiomyolipomas are benign renal tumors composed of varying proportions of adipose tissue, smooth
muscle cells, and blood vessels. Although the sonographic findings in this patient are similar to those of an
angiomyolipoma, the suprarenal location of the mass excludes the diagnosis of angiomyolipoma.
C) Incorrect. Renal cell carcinomas are typically hypoechoic, although up to 30% of renal cell carcinomas under
3 cm in size may be hyperechoic. Again, however, the suprarenal appearance of this mass, and its homogeneous
hyperechoic nature make renal cell carcinoma unlikely.
D) Incorrect. Metastases to the adrenal are common, but this young patient has no other known malignancy. In
addition, metastases are typically hypoechoic, not hyperechoic as in the test patient.
E) Correct. Myelolipomas are rare, benign, non hyperfunctioning adrenal tumors composed of varying
proportions of fat and bone marrow elements. If enough fat is present (as in this case), these tumors are
typically seen as an echogenic mass in the adrenal bed.
Citations:
Rumack CM, Wilson SR, Charboneau JW. Diagnostic ultrasound, 2nd ed. Mosby . St. Louis, MO, 1998.
6 American College of Radiology

7. Section XII – Ultrasound
Figure 4A
Figure 4B
504. A 30-year-old female presents with pain in the iliac fossa five days after renal transplant. You are shown gray
scale (Figure 4A) and pulsed Doppler (Figure 4B) sonograms of the transplant. Which one of the following is
the MOST likely diagnosis?
A. Renal vein thrombosis
B. Cyclosporine toxicity
C. Hyperacute rejection
D. Renal artery spasm
E. Post transplant lymphoproliferative disorder
Diagnostic In-Training Exam 2002 7

8. Section XII – Ultrasound
Question #504
Findings: Grayscale image demonstrates mild nephromegaly at 14.1 cm. The spectral display of Doppler shifts
shows reversal of diastolic flow. This means that intrarenal resistance to arterial inflow has increased. When there
is very high resistance to inflow, systolic Doppler curves are also reduced to narrow, short, vertical spikes. This was
confirmed in all segments of the kidney and no detectable renal venous signal was obtainable.
Rationales:
A) Correct. Acute renal vein thrombosis (RVT) is a rare complication of renal transplantation (<1% of renal
transplant patients) and results in high intrarenal impedance and reduced arterial inflow, especially diastolic.
Doppler imaging reveals absent renal venous flow with reversed diastolic arterial flow. Grayscale imaging often
demonstrates a swollen kidney.
B) Incorrect. Cyclosporine is an integral part of immunosuppressive therapy for renal transplantation. It exhibits
an inhibitory effect on antigen-reactive T lymphocytes. Therapy with cyclosporine can result in damage to the
renal tubules. Clinical signs include oliguria, fever, and hypertension. Cyclosporine induced nephropathy does
not usually cause an abnormal grayscale appearance. The arterioles are usually spared, and so diastolic flow is
not reduced or reversed. Occasionally an elevated RI can be seen occasionally, presumably, because of intrarenal
edema or spasm of arcuate arteries. Although the resistive indices are elevated they do not typically result in
reversed diastolic arterial flow. The reversal of diastolic flow makes the diagnosis of cyclosporine toxicity
unlikely in the test patient.
C) Incorrect. Hyperacute rejection is mediated by preexisting humoral antibodies and occurs during or within
hours of surgery. This form of rejection occurs in recipients who have been sensitized by previous blood
transfusions, pregnancies, or a previous graft. Resistive indices can be elevated and diastolic flow reversal can
occur in hyperacute rejection. However, hyperacute rejection is an unlikely diagnosis in the test case because
of the onset of symptoms 5 days after transplantation..
D) Incorrect. Pulsed Doppler examination shows arterial Doppler shifts arising from within the allograft. This
means that the renal arteries are patent. Spasm of the renal arteries would dampen or completely obliterate
Doppler signals arising from intrarenal arteries.
E) Incorrect. Renal transplant recipients, particularly those treated with cyclosporine, are at increased risk for the
development of post-transplant lymphoproliferative disorder (PTLD) and lymphoma. Allograft involvement
by PTLD or lymphoma causes either an iso- or hypoechoic mass or diffuse cortical thickening, which are not
seen in the tests case. Moreover, one would not expect PTLD to develop within five days.
Citations:
Rumack CM, Wilson SR, Charboneau JW. Diagnostic ultrasound, 2nd ed. Mosby . St. Louis, MO, 1998.
8 American College of Radiology

9. Section XII – Ultrasound
Figure 5A
Figure 5B
505. A 25-year-old female with a palpable right adnexal mass on routine physical examination. You are shown
longitudinal (Figure 5A) and transverse (Figure 5B) endovaginal images of the right ovary. Which one of the
following is the MOST likely diagnosis?
A. Endometrioma
B. Cystadenocarcinoma
C. Tubo-ovarian abscess
D. Dermoid
E. Hydatid of Morgagni
Diagnostic In-Training Exam 2002 9

10. Section XII – Ultrasound
Question #505
Findings: A 4 cm predominantly cystic mass with a heterogeneous echotexture (reticulated mesh-like appearance)
arises from and is partially marginated by the right ovary.
Rationales:
A) Incorrect. Endometriomas most often appear as cystic masses containing homogeneous hypoechoic low level
echoes or debris and having irregular walls. If there is a large amount of bleeding of the endometrial tissue
during the menstrual cycle, endometriomas can appear very echogenic. A solid endometrioma is usually
homogeneous with medium-level echoes. Patients are asymptomatic or have dysmenorrhagia, dyspareunia, or
infertility. In the test case, the finding of a heterogeneous mass and the presenting symptoms would be very
unusual for an endometrioma.
B) Incorrect. Cystadenocarcinoma is typically found in patients over the age of 40. The lack of septations and
papillary projections also makes this diagnosis less than likely.
C) Incorrect. Tubo-ovarian abscess tends to be an irregular, cystic lesion associated with inflammatory changes
elsewhere in the pelvis. It is typically homogeneous and usually contains debris. A dilated fallopian tube is also
common. Since pelvic inflammatory disease is a bilateral process, the contralateral adnexum is also abnormal
Finally, patients are asymptomatic and have pelvic pain and vaginal discharge. None of these findings is present
in the test images, and therefore, the diagnosis of tubo-ovarian abscess would be very unlikely.
D) Correct. Dermoids (mature cystic teratomas) may have a very variable appearance ranging from completely
anechoic to completely hyperechoic. However, a cystic mass with an echogenic mural module (dermoid plug),
a highly echogenic mass with ill-defined acoustic shadowing (“tip of the iceberg”), bony and odontoid elements,
a fat-fluid or hair-fluid level, or finally, as in this case, a “dermoid mesh” are considered to be relatively specific.
Complications of dermoids include torsion, rupture resulting in chemical peritonitis (rupture occurs in
approximately 1% of cases), and malignant transformation (approximately 2% of cases in older women).
E) Incorrect. Part of the cranial end of the paramesonephric duct may persist as a vesicular appendage to the uterine
tube, the hydatid of Morgagni. Sonographically these are small, unilocular, thin-walled cysts, an appearance
that does not fit this case.
Citations:
Callen. Ultrasound in Obstetrics & Gynecology, 4th ed. WB Saunders, Philadelphia, PA.
10 American College of Radiology