Use of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer.

A total of 111 patients with clinically localized prostate cancer (stage A or B) underwent endorectal surface coil magnetic resonance imaging (MRI) for preoperative staging of the disease. Of the patients 43 with advanced disease on endorectal surface coil MRI (33 with stage C and 10 with stage D disease) received alternative therapy, as did 21 with stage B disease on MRI. The overall staging accuracy for the remaining 47 patients was 68%, with a 74% accuracy rate in staging advanced disease and a 91% accuracy rate for depiction of seminal vesicle involvement. Failure to recognize microscopic extracapsular disease was responsible for the majority of staging inaccuracies in this highly select group of patients. Endorectal surface coil MRI provides extremely high resolution images of the prostate and periprostatic structures, and is an exciting new modality for local staging of prostatic carcinoma.