Structures that can be imaged and common indications include the following: Kidneys: For hydronephrosis, stones, and tumors Bladder: For bladder volumes (eg, postvoid volume, assessed immediately after voiding; in suspected urinary retention due to bladder outlet obstruction), diverticula, and stones Scrotum: For hydroceles, spermatoceles, testicular tumors, varicoceles, and (with Doppler blood flow measurement) for testicular torsion Prostate: To measure prostate volume (eg, to help assess benign prostatic hyperplasia or interpret prostate-specific antigen results) and to guide needle biopsy Penis: To help evaluate Peyronie disease; with Doppler, to assess blood flow (when evaluating erectile dysfunction) Urethra: To measure length and caliber of urethral strictures Computed Tomography Computed tomography provides a broad view of the urinary tract and surrounding structures.