CHICAGO--Because of its high cost and lack of universal availability, magnetic resonance imaging (MRI) has not been a prominent tool in the initial evaluation of prostate cancer. However, MRI is proving to be a highly accurate method of identifying local recurrence of prostate cancer after radical prostatec-tomy, Jeffrey M. Silverman, MD, said at the Radiological Society of North America (RSNA) annual meeting.
Using endorectal surface coil MR imaging, Dr. Silverman and his colleagues at Cedars-Sinai Medical Center, Los Angeles, prospectively analyzed 41 men who had undergone radical prostatectomy an average of 26 months previously.
Thirty-five men had clinical suspicion of recurrent prostate cancer because of an elevated PSA level or the presence of a nodule or induration on digital rectal examination. Six men served as controls because they had no signs of recurrence.
The men had four MRI sequences--a sagittal series of fat-saturated T2-weighted fast spin echo images, fat-saturated axial T2-weighted fast spin echo images, fat-saturated axial T1-weighted images, and fat-saturated axial T1-weighted images after gadolinium enhancement.
All 31 men who were suspected of having recurrent cancer because of higher than usual PSA levels exhibited a prostate bed soft tissue nodule on MRI. The nodules were isointense compared to skeletal muscle on T1-weighted images, hyperintense on T2-weighted images, and all were obviously enhanced after gadolinium administration, he said.
Four men with a palpable nodule or induration detected at digital rectal examination but stable PSA levels had fibrosis, and, in every case, MR imaging revealed no abnormality. The six men who had no clinical evidence of recurrent prostate cancer also had unremarkable MR scans.
The sensitivity and specificity of endorectal surface coil MRI detection of local recurrence was 100% in the study. Dr. Silverman concluded, therefore, that "endorectal surface coil MR imaging is a useful tool for men who have undergone radical prostatectomy and are suspected of having local recurrence of disease."