ACR Inservice Recall

1. Section II – Genitourinary Tract Radiology
Figure 1A
Figure 1B
51. A 32-year-old male transplant patient presents with elevated creatinine. You are shown color (Figure 1A) and
pulsed Doppler (Figure 1B) ultrasound images. Which one of the following is the MOST likely diagnosis?
A. Acute rejection
B. Acute tubular necrosis
C. Arterio-venous fistula
D. Pseudoaneurysm
E. Renal artery stenosis
Diagnostic In-Training Exam 2003 1

2. Section II – Genitourinary Tract Radiology
Question #51
Findings: The Color Doppler image demonstrates a vascular cavity with inflow, outflow, and spectral broadening.
On pulsed Doppler, this area has a low resistance arterial/venous waveform.
Rationales:
A) Incorrect. In normal transplant kidneys, the resistive index (RI=peak systolic velocity minus diastolic velocity/
peak systolic velocity) is usually 0.7 and below. In rejection, RI’s tend to be elevated, usually above 0.8.
Elevated RI’s are not specific, and can be seen with acute tubular necrosis. In this case, the Doppler waveform
demonstrates increased diastolic velocity, therefore, the RI is low. This would be unusual for rejection.
B) Incorrect. See the rationale for 1A. The Doppler waveforms for rejection and ATN may be indistinguishable.
C) Correct. AV fistulas are usually the result of graft biopsies, as was the situation in this case. At Doppler
interrogation, they demonstrate increased velocity with low resistance, and spectral broadening.
D) Incorrect. Graft pseudoaneurysms are also usually a result of biopsies. They are characterized by to-and-fro flow
by color and pulsed Doppler.
E) Incorrect. Stenosis of the graft anastomosis is characterized by a high velocity jet (>2.0 m/s in many cases) at the
area of narrowing, and distal dampening. This is manifested as a tardus parvus waveform (prolonged
acceleration time), and spectral broadening
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3. Section II – Genitourinary Tract Radiology
Figure 2
52. A 19-year-old woman is involved in a high speed motor vehicle accident. You are shown a contrast enhanced
CT scan (Figure 2). Which one of the following is the MOST likely diagnosis?
A. Renal contusions
B. Contrast reaction
C. Hypotension
D. Renal arterial injuries
E. Ureteral transections
Diagnostic In-Training Exam 2003 3

4. Section II – Genitourinary Tract Radiology
Question #52
Findings: Non-enhancement of both kidneys after blunt abdominal trauma with blood in the perirenal and
pararenal spaces.
Rationales:
A) Incorrect. Renal contusions are characterized by small intrarenal hematomas and areas of decreased function
due to edema and increased intrarenal pressure. In this case, both kidneys demonstrate a global lack of any
function.
B) Incorrect. Contrast reactions resulting in hypotension demonstrate a persistent nephrogram on delayed images.
In this case, there is no appreciable uptake of contrast material into either kidney.
C) Incorrect. This would appear similar to B
D) Correct. This is a typical appearance for a bilateral renal arterial injury, most of which are caused by a tear in
the intima of the renal artery with subsequent thrombosis. Most cases of renal arterial injury are unilateral.
There is essentially no enhancement of either kidney after the administration of intravenous contrast material.
In some cases, particularly when the diagnosis is delayed, rim enhancement of peripheral cortex from capsular
collaterals can be seen.
E) Incorrect. Ureteral transection can be diagnosed by CT when extravasation of contrast material from the ureter
is seen on delayed images.
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5. Section II – Genitourinary Tract Radiology
Figure 3
53. You are shown a single image from an intravenous contrast-enhanced CT of the pelvis (Figure 3) on a 61-
year-old man with a history of prostate cancer. Which one of the following is the MOST likely diagnosis?
A. Uretero-vesical junction calculus
B. Transitional cell carcinoma of the bladder
C. Simple ureterocele
D. Ectopic ureterocele
E. Malakoplakia
Diagnostic In-Training Exam 2003 5

6. Section II – Genitourinary Tract Radiology
Question #53
Findings: This CT image with intravenous contrast material demonstrates a bulbous, contrast filled structure
originating from the uretero-vesical junction and protruding into the bladder.
Rationales:
A) Incorrect. Ureteropelvic junction obstructions occur at the renal pelvis, proximal ureter junction, clearly more
proximally than in this case. On contrast enhanced delayed CT scans, a dilated renal pelvis and renal collecting
system is characteristic. Less contrast material would be expected to be seen in the ipsilateral ureter due to the
proximal obstruction.
B) Incorrect. Transitional cell carcinoma of the bladder typically appears as an irregular urothelial-based filling
defect. In this case, the ureterocele is very smooth, and no filling defect is seen within the contrast filled
ureterocele lumen.
C) Correct. This is a typical appearance for a simple ureterocele. Important features of this diagnosis include a
thin-walled contrast filled cavity, and a smooth ovoid appearance.
D) Incorrect. Ectopic ureteroceles tend to occur in more inferior and medial locations than simple ureteroceles. By
comparing the position of the ureterocele to the contralateral ureteral orifice, it is apparent that this ureterocele
originates in the expected position as the uretero-vesical junction, and is thus most likely to be a simple
ureterocele.
E) Incorrect. Malakoplakia is an unusual condition of the urinary tract associated with urinary tract infection, and
characterized by the presence of soft raised plaques, usually in the urinary bladder. These are indistinguishable
from other causes of bladder masses, and a tissue diagnosis is usually necessary
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7. Section II – Genitourinary Tract Radiology
Figure 4
54. A 15-year-old African-American girl with sickle cell trait presents with gross hematuria (Figure 4). What is
the MOST likely diagnosis?
A. Lymphoma
B. Medullary renal carcinoma
C. Renal cell carcinoma
D. Global renal infarct
E. Acute pyelonephritis
Diagnostic In-Training Exam 2003 7

8. Section II – Genitourinary Tract Radiology
Question #54
Findings: This single contrast enhanced CT section shows a heterogeneous mass in the central right kidney causing
enlargement of the kidney, but sparing the cortex. There is periaortic adenopathy, which displaces the inferior vena
cava anteriorly.
Rationales:
A) Incorrect. Renal involvement by lymphoma is more often associated with non-Hodgkin’s lymphoma than with
Hodgkin’s disease and it is commonly bilateral. Most patients are asymptomatic and the lesion is detected on a
follow-up CT. The common CT appearance of renal lymphoma is that of multiple soft-tissue nodules. Other
patterns include direct invasion from adjacent lymph nodes, a solitary mass, and nephromegaly due to diffuse
parenchymal infiltration. Intrarenal lymphoma is hypo attenuating relative to the surrounding renal parenchyma
and shows minimal enhancement. Secondary findings such as splenomegaly and widespread lymphadenopathy
are common. Although lymphoma could be an explanation for the renal mass in this patient, the clinical history
makes this not the best diagnosis..
B) Correct. Renal medullary carcinoma is usually found in your black patients with sickle cell trait. This is an
aggressive neoplasm with a relentlessly progressive course. Spread, as evidenced by adenopathy in this case, is
typical when the tumor is first diagnosed. The tumor arises in the region of the renal medulla and often expands
centrally and enlarges the kidney.
C) Incorrect. Renal cell carcinoma can certainly look like this, and if the clinical setting were in an elderly patient,
would be a likely diagnosis, as would transitional cell carcinoma extending from the collecting system into the
renal parenchyma.
D) Incorrect. In acute global infarction, the kidney is of normal size and lacks contrast enhancement. The
unenhanced parenchyma usually appears homogeneous. A faint rim of cortical (i.e., a cortical rim sign) due to
perfusion by capsular collateral vessels may be seen. Although the peripheral enhancement in this case could be
seen in global infarction, the renal enlargement argues against the diagnosis.
E) Incorrect. Acute pyelonephritis, if fulminant, could conceivably be this diffuse, though it would be extremely
unusual to see this degree of adenopathy. Again, the presenting symptoms do not support the diagnosis of
infection.
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9. Section II – Genitourinary Tract Radiology
Figure 5
55. A 60-year-old man presented with suspect aortic injury but a normal aortic arch arteriogram. You are shown
an unenhanced CT scan obtained 48 hours later (Figure 5). What is the MOST likely diagnosis?
A. Renal vein thrombosis
B. Arterial occlusion
C. Pyelonephritis
D. Renal neoplasm
E. Acute tubular necrosis
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10. Section II – Genitourinary Tract Radiology
Question #55
Findings: CT scan is performed without IV contrast and thus, there is no contrast in aorta and hepatic vessels.
However, contrast enhancement is demonstrated within kidneys, which has pattern of corticomedullary phase
enhancement. Although this appearance can normally be seen when scanning within 70 seconds of start of the
contrast bolus, it would not be expected to persist 48 hours after contrast administration. The CT findings are
therefore consistent with bilateral renal failure.
Rationales:
A) Incorrect. CT findings of renal vein thrombosis include renal enlargement (usually unilateral), a prolonged
corticomedullary phase of enhancement, and impaired contrast excretion because of edema resulting from the
obstructed venous drainage. Renal vein thrombosis could theoretically result in the pattern seen in this patient
but bilateral disease is extremely rare. A more likely cause of bilateral renal failure with a corticomedullary
pattern of enhancement is acute tubular necrosis.
B) Incorrect. Acute arterial occlusion may be a global or segmental event. In acute global infarction, the kidney is
of normal size and lacks contrast enhancement, although a faint rim of cortical enhancement (i.e., a cortical
rim sign) may be seen because of perfusion by capsular collateral vessels. Segmental infarction appears as a
peripheral, wedge-shaped, or triangular area of diminished enhancement. Bilateral arterial occlusion would not
result in corticomedullary enhancement.
C) Incorrect. Acute pyelonephritis is a bacterial infection of the kidney. Typically, it has a patchy distribution, but
in severe cases, the entire kidney can be involved. Contrast-enhanced CT scans usually demonstrate ill-defined,
wedge-shaped zones of diminished attenuation. Contrast enhancement may be seen in areas of inflammation
on scans obtained several hours after contrast administration, but enhancing parenchyma would not be
expected 48 hours after contrast administration. In addition, pyelonephritis would be an unlikely cause of
symmetric bilateral renal failure.
D) Incorrect. Renal neoplasm would be an unlikely cause of symmetric bilateral renal failure.
E) Correct. Acute tubular necrosis refers to a nephrotoxic or ischemic injury to the renal tubules accompanied by
clinical manifestations of acute renal failure. It is the most common cause of acute renal failure and often results
in a persistent corticomedullary phase of renal enhancement sometime lasting for days. Acute tubular necrosis
is the best answer.
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