CASE 2

Courtesy of Dr. Bakhsh Hospital, Jeddah, Saudi Arabia

34-year-old female with abdominal pain and fever

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CASE 2 ANSWER

Right Acute Pyelonephritis

The corticomedullary (yellow circle) and the excretory (red circle) phases show heterogeneous enhancement of an enlarged right kidney, with perinephritic fluid and fat stranding (arrows). The wedge-shaped hypodensities and striated appearance of the right renal parenchyma is typically more apparent on the excretory phase

Key Points

• Causes of a striated nephrogram include acute pyelonephritis, acute vascular obstruction, acute ureteric obstruction, and acute tubular necrosis.

• CT phases of a renal protocol: Early 'arterial' (15-20 sec post IV injection), corticomedullary 'angiographic' (30-40 sec post IV injection), nephrographic (80-120 sec post IV injection), and late 'delayed / excretory / urographic' (3-5 min post IV injection) phases.

• Striated nephrogram is best seen on nephrographic or delayed phases.

• Exclude renal or perirenal abscesses in cases of renal infections.