MR imaging of the penis

The signal intensity of the corpora cavernosa of the penis at magnetic reso nance (MR) imaging may vary from that of the corpus spongiosum; this differ ence is dependent on the rate of blood flow within the cavernous spaces tha t constitute the corporal bodies. Also visible at MR imaging are the layers of fibrous tissue that envelop the corporal bodies, the deep arteries and veins, subcutaneous connective tissue, tunica dartos, epidermis, and urethr a. While the iliac, pudendal, perineal, and common penile arteries can be e valuated with three-dimensional MR angiography, the smaller end arteries of the penis have not yet been reliably demonstrated. MR imaging may be used to detect and stage penile and urethral cancers, identify and characterize benign penile masses, evaluate arteriogenic impotence, identify penile frac tures, evaluate penile prostheses, localize periurethral abscesses, and ide ntify plaques of Peyronie disease. With its direct multiplanar imaging capa bilities, superb soft-tissue contrast, and excellent spatial resolution, hi gh-field surface coil MR imaging can show the soft-tissue and vascular anat omy of the penis, as well as the appearance of many penile diseases.