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."