Fig. 1

A 38-year-old woman was admitted to the emergency department because of acute right flank pain and severe macroscopic haematuria. Medical history revealed right-sided nephrolithiasis for which she had undergone three sessions of extracorporeal shock wave lithotripsy in the past. Laboratory investigation revealed moderate anaemia and normal renal function. Renal US ruled out hydronephrosis and neoplasia (not shown). A small (10-mm) residual stone fragment detected in a single calyx was not considered responsible for the haematuria. No ureteral stones were detected with a non-contrast CT scan. Diagnostic cystoscopy was within normal limits except for bleeding from the right ureteric orifice. Diagnostic right-sided semi-rigid ureteroscopy excluded any gross ureteral pathology.a-d MR imaging of the abdomen showed a small low-signal-intensity lesion in the upper lobe of the right kidney on T2-w TSE images (a). The lesion was not obvious on plain T1-w images. The 3D T1 gradient echo MR angiography showed early filling of a 1.5-cm lesion (b, arrow) located in the subcortical parenchyma (c) with early venous drainage directly to the inferior vena cava (d, arrow). Findings were more conspicuous on the original thin-slice-thickness images rather than the MIP reconstructions. These findings were consistent with RAVM