Figure 5b. Renal mycotic aneurysm in a 33-year-old male IV drug user with endocarditis who presented with hematuria and clot retention. US showed an aneurysm in the upper pole of the right kidney. (a) Coronal reformatted image from contrast-enhanced CT (window level = 40 HU, window width = 500 HU) shows an intrarenal aneurysm (black arrows) arising from an upper pole renal artery (white arrows). No enhancement of the renal parenchyma is seen surrounding the aneurysm; there is low-attenuation material extending into the renal pelvis and upper ureter (arrowheads), a finding that represents blood. (b) Selective conventional arteriogram shows a jet of contrast material (arrow) entering the aneurysm. (c) Image obtained later in the angiographic series shows incomplete opacification of the aneurysm (arrowheads) due to the presence of thrombosis. The aneurysm was successfully treated with coil embolization followed by nephrectomy.