Gleason Grade Linked to Signal Intensity Ratio on MRI
Imaging method may allow non-invasive assessment of prostate cancer aggressiveness
THURSDAY, Dec. 20 (HealthDay News) -- MRI may offer a non-invasive method for helping evaluate the aggressiveness of prostate cancer, according to research published in the January issue of Radiology.
Liang Wang, M.D., Ph.D., of Memorial Sloan-Kettering Cancer Center in New York City, and colleagues analyzed data from 74 men who underwent endorectal MRI and radical prostatectomy, followed by whole-mount step-section histopathologic evaluation.
The investigators found that on corrected and uncorrected T2-weighted MR images, the Gleason grade of prostate cancer is significantly correlated with the tumor-muscle signal intensity ratio. Lower tumor-muscle signal intensity ratios were associated with higher Gleason grades. In addition, on T2-weighted MR images, tumor-muscle signal intensity ratios were lower in transition zone tumors than peripheral zone tumors.
"The mechanism underlying our findings is not entirely clear to us. We speculate that the lower signal intensity values in more aggressive tumors may be caused by a higher cellular density. Schiebler et al demonstrated that the signal intensity of prostate lesions on T2-weighted MR images is associated with lesion cellularity, as well as presence and amount of fluid contents, collagen, and fibromuscular stroma. The reason that the signal intensity values of tumors of the same grade are lower for those in the transition zone than for those in the peripheral zone could be related to the underlying histologic differences between transition zone and peripheral zone tumors," the authors write.