Extrarenal uptake of Tc-99m-DTPA in a case of retroperitoneal abscess causing spurious data in renal function assessment.

The author reports CT of the abdomen and quantitative analysis of renal scintigraphy that was spuriously assessed due to unwanted extrarenal uptake. The patient had a retroperitoneal abscess that was related to fistula from the right kidney. Renal scintigraphy was performed to assess split renal function as a preoperative evaluation for nephrectomy. The computer generated differential function did not appear to coincide with the visual analysis. This discrepancy was believed due to extrarenal uptake from the area of the retroperitoneal abscess.