MRI with an endorectal coil for staging of clinically localised prostate cancer prior to radical prostatectomy

Abstract.

The purpose of this study was to evaluate the ability of MR imaging with an endorectal coil (erMRI) to predict the local pathological stage of prostatic carcinoma prior to radical prostatectomy. Thirty-one consecutive patients (median age 61 years, range 40–71 years) with clinically localised prostate cancer were assessed preoperatively by endorectal MRI (at 1.0 T). The pulse sequences consisted of fast spin-echo axial and coronal T2-weighted images and inversion recovery with two echoes for axial fat-suppressed images. The assessment of tumour stage and measurement of tumour dimension by erMRI were compared with the corresponding findings on whole-mount step sections of the surgical specimens. Postoperatively, 14 of the 31 patients (45 %) were found to have extracapsular extension, 7 with capsular penetration (CP) only, and 7 had a combination of CP and seminal vesicle invasion (SVI). Capsular penetration was detected by erMRI with a sensitivity of 0.71 and specificity of 0.47, whereas the sensitivity for SVI detection was 0.71 and the specificity 0.83. Endorectal MRI for staging clinically localised prostatic carcinoma gives a good prediction of invasion of the seminal vesicles but is unreliable in predicting capsular penetration.