PROSTATIC CRYOSURGERY - USE OF MR-IMAGING IN EVALUATION OF SUCCESS AND TECHNICAL MODIFICATIONS

PURPOSE: To evaluate the usefulness of contrast material-enhanced magn etic resonance (MR) imaging in objective assessment of prostatic cryos urgery and the role of MR imaging in the modification of prostatic cry osurgical technique. MATERIALS AND METHODS: Thirty-eight consecutive p atients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enha ncement before cryosurgery and unenhanced and gadolinium-enhanced MR i maging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging finding s were correlated with those from transrectal ultrasound-directed pros tatic staging biopsy. RESULTS: Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-e nhanced images. With progressive modification of cryosurgical techniqu e, complete cryoablation of the prostate was achieved in the latter ni ne of the 38 patients. When cryoablation was considered complete accor ding to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor. CONCLUSION: Gad olinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging f indings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.