Lead author Dr. Staude leader Chan Kyo Kim studied 27 patients who had increased levels of prostate specific antigen, or PSA, after being treated with high-intensity focused ultrasonic ablation. Eighteen of these patients had local tumor progression seen at biopsy.

Dynamic contrast-enhanced-MRI and diffusion weighted imaging had about a 72 percent accuracy rate in determining which patients needed additional treatment because they had residual or recurrent cancer, Kim said.

The study, published in the American Journal of Roentgenology, found that diffusion weighted imaging had fewer false positives than Dynamic contrast-enhanced-MRI, but dynamic contrast-enhanced-MRI had fewer false negatives.

"After high-intensity focused ultrasonic ablation, the normal anatomy of the prostate gland is completely lost or deformed making it difficult to distinguish benign tissue from cancer," Kim said in a statement. "The two imaging studies together, which can be done in about seven minutes, can overcome that challenge."