Computed tomography and transrectal ultrasound in the diagnosis of prostatic disease--a comparative study.

Computed tomography (CT) and transrectal ultrasound were performed in 88 patients with clinically and histologically proven prostatic disease. An ultrasound diagnosis of prostatic cancer was suggested in 49 of 54 patients with proven disease, whereas CT identified only 21 of those patients. There were no specific features of confined prostatic malignancy on CT and the most reliable feature of an unconfined tumour was infiltration of the posterior aspect of the bladder base. It was not possible on ultrasound to differentiate between prostatic inflammatory disease and a confined carcinoma but ultrasound was accurate in detecting defects in the prostatic capsule, the hallmark of unconfined prostatic malignancy.