Detecting aorto-ureteric fistula by 99mTc-Labeled Red Blood Cell SPECT

A 68-year-old male, known case of abdominal aortic dissection and recent aortic stent insertion, presented with gross hematuria. The urologists suspected aoro-ureteric fistula and performed open surgery (ureterolysis). Tc-99m labeled red blood cell (99mTc-RBC) scintigraphy was ordered to confirm the diagnosis and localize the possible aorto-ureteric fisula, Considering sustained gross hematuria and ongoing anemia, and the fact that the patient had some degrees of renal insufficiency consequently not a candidate for contrast Computed Tomography (CT) angiography, a 99mTc-RBC blood pool study was requested instead. The dynamic planar images showed a zone of abnormal radiotracer accumulation in the left side of the aorta, which remained till the end of study. SPECT images revealed a left aorto-ureteric fistula approximately 8cm above the aortic bifurcation.