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

The purpose of this study was to evaluate the ability of MR imaging with an endorectal coil (el-MRI) to predict the local pathological stage of prosta tic carcinoma prior to radical prostatectomy. Thirty-one consecutive patien ts (median age 61 years, range 40-71 years) with clinically localised prost ate cancer were assessed preoperatively by endorectal MRI (at 1.0 T). The p ulse sequences consisted of fast spin-echo axial and coronal T2-weighted im ages and inversion recovery with two echoes for axial fat suppressed images . The assessment of tumour stage and measurement of tumour dimension by erM RI were compared with the corresponding findings on whole-mount step sectio ns 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). Ca psular penetration was detected by erMRI with a sensitivity of 0.71 and spe cificity of 0.47, whereas the sensitivity for SVI detection was 0.71 and th e specificity 0.83. Endorectal MRI for staging clinically localised prostat ic carcinoma gives a good prediction of invasion of the seminal vesicles bu t is unreliable in predicting capsular penetration.