Identification of the periprostatic venous plexus by MR imaging

T2-weighted images (spin echo 2,000/60) show a high signal intensity rim around the prostate. Our investigations show that this rim is not part of the pelvic fat; it has T1 and T2 relaxation times similar to heparinized blood; it demonstrates little inflow effect; and after an intravenous injection of Gd-diethylenetriamine pentaacetic acid, its signal intensity increases. We conclude that this rim is the periprostatic venous plexus.