[Non-invasive imaging diagnosis of left renal vein compression causing hematuria. Part 2. CT].

Left renal veins of 77 patients were examined by computed tomography (CT) to evaluate its usefulness in determining the left renal vein compression which is causing renal bleeding. From CT image, left renal vein compression was observed in 6 (86%) of the 7 cases which had been classified as idiopathic renal bleeding, in 9 (21%) of the 42 cases which had urinary tract diseases causing hematuria, and in 3 (11%) of the 28 cases which did not have hematuria. In 15 of the 18 cases of left renal vein compression, left renal vein was compressed between the superior mesenteric artery and the abdominal aorta, showing so-called nutcracker phenomenon. In the remaining 3 cases, however, the superior mesenteric artery provided sharp delineation from the abdominal aorta. The superior mesenteric artery and the abdominal aorta made the mean angle of 35.5 degree in patients with normal left renal vein, the mean angle of 45.4 degrees in those with left renal vein compression without nutcracker phenomenon, and the mean angle of 11.9 degrees in those with nutcracker phenomenon. CT was superior to ultrasonography, in revealing left renal vein compression.