Fig. 1. Type 1 NCP.

A. Schematic diagram showing the compression of the LRV in the narrow space between the AA and SMA. B, C. Type 1 compression of the LRV in a 33-year-old female with proteinuria. Greyscale (B) and color Doppler US (C) images show a tightly compressed LRV (arrow) between the AA (a) and SMA (s) and a dilated proximal LRV (asterisk). Note the bright-colored jetting of blood flow (arrowheads) from the aortomesenteric LRV. Supplementary video 1 is a video-clip of color Doppler US (C). AA = abdominal aorta, IVC = inferior vena cava, LRV = left renal vein, NCP = nutcracker phenomenon, SMA = superior mesenteric artery, US = ultrasound