Presentation
Two day history of right sided abdominal pain. Tender all over right side of abdomen.
Patient Data
Reduced enhancement of the right kidney compared to the left with asymmetric right-sided, perinephric fat stranding. Distension of the right renal pelvicalyceal system and right ureter, but with no obstructing stones. Small volume of fluid and fat stranding along the course of the right ureter. In addition to distension of the pelvicalyceal system, there appears to be a small volume of fluid in the right renal pelvis. Normal appearances of the left kidney, left ureter, and urinary bladder.
Incidental findings of diffuse of hepatic steatosis and aortic calcification, but with no aneurysm formation.
Due to the small volume of fluid in the right renal pelvis, the patient was recalled for a delayed phase study, but without further administration of intravenous contrast.
Normal handling of the contrast by the left kidney.
On the right side, there is persistent and late enhancement of the renal parenchyma, and greater distension of the calyces and pelvis by the excreted contrast. There is some distension of the proximal right ureter, but once again, there is no radiodense filling defect. Contrast has also leaked from the region of the renal pelvis/pelviureteric junction into the surrounding tissues, indicating a small volume urinoma.
Case Discussion
Several important teaching points can be made from this case:
It was assumed the presentation was due to recent passage of a ureteric stone, although one was not seen on the initial CT.
The contrast enhanced appearances of the right kidney are typical of obstructive uropathy, with delayed enhancement.
The presence of a small volume of fluid in the region of the renal pelvis or proximal ureter, may be inferred to be due to a small volume urine leak, and can be confirmed by acquiring a delayed phase study.
There may be continued distension of a ureter and delayed handling of contrast excretion after a stone has passed, likely to be due to edema of the ureter caused by irritation during stone passage.
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