Prostate Ca imaging method may surpass standard MRI

A novel imaging technique may prove more effective than current magnetic resonance imaging approaches for localizing prostate tumors, researchers say.

A novel imaging technique may prove more effective than current magnetic resonance imaging (MRI) approaches for localizing prostate tumors, researchers say.

Study authors from the University of California, San Diego School of Medicine and UCLA say the technique, called restriction spectrum imaging-MRI or RSI-MRI, also may have significant implications for how patients with prostate cancer are ultimately treated.

“This new approach is a more reliable imaging technique for localizing tumors. It provides a better target for biopsies, especially for smaller tumors,” first author Rebecca Rakow-Penner, MD, PhD, of UC San Diego, said in a news release from that institution.

“Doctors at UC San Diego and UCLA now have a noninvasive imaging method to more accurately assess the local extent of the tumor and possibly predict the grade of the tumor, which can help them more precisely and effectively determine appropriate treatment,” added David S. Karow, MD, PhD, also of UC San Diego and the study’s corresponding author.

The RSI-MRI technique, described in the group’s paper in Prostate Cancer and Prostatic Disease (Jan. 6, 2015), corrects for magnetic field distortions and focuses upon water diffusion within tumor cells. By doing both, the ability of imaging to accurately plot a tumor’s location is increased and there is a more refined sense of the tumor’s extent, said co-author Nathan White, PhD, of UC San Diego, who is co-inventor of the RSI-MRI technique.

In the proof of principle study, researchers compared the efficacy of RSI-MRI with standard MRI for detecting extraprostatic extension among 28 prostate cancer patients who underwent both imaging techniques prior to radical prostatectomy, including 10 with histologically proven pT3 disease. Twenty-seven patients were evaluated. Standard MRI correctly identified extraprostatic extension in two of the nine pT3 patients (22%), while RSI-MRI identified extraprostatic extension in eight of nine patients (89%). RSI-MRI correctly identified pT2 disease in the remaining 18 patients, the researchers reported.

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In a related paper to be published in the journal Frontiers in Oncology, the same team of researchers reported that RSI-MRI appears to predict tumor grade. Higher grade tumors correlate with higher restricted water volume in the cancer cells’ large nuclei.

“If by imaging we could predict the tumor grade,” added co-author Robert Reiter, MD, of UCLA, “we may be able to spare some patients from prostate resection and monitor their cancer with imaging.”