To evaluate whether periprostatic fat volume and periprostatic fat ratio as determined by multiparametric magnetic resonance imaging (mpMRI) correlate with the presence of high-grade prostate cancer.

A total of 295 consecutive patients (median age: 64, range: 38-84) underwent mpMRI of the prostate gland between August 2013 and February 2015. All patients underwent a 3 Tesla mpMRI. Using DynaCAD (Invivo, Gainesville, FL), we calculated the prostate volume and volume of the periprostatic fat seen on mpMRI. The periprostatic fat ratio was calculated using the formula periprostatic fat volume/prostate volume.

A higher periprostatic fat volume (P < .001) and a higher periprostatic fat ratio (P < .001) were significantly associated with a higher Gleason score. Periprostatic fat ratio is a better predictor of higher Gleason score compared with periprostatic fat volume (P < .001). There was no correlation observed between periprostatic fat ratio and prostate-specific antigen (median: 7.34, range: 0.36-59.7, P = .274), age (median: 64, range: 38-84, P = .665), or body mass index (median: 28.33, range: 17.99-45.44, P = .310). Patients with a higher periprostatic fat ratio were more likely to undergo intervention for prostate cancer.

A higher periprostatic fat ratio is significantly associated with a higher Gleason score. Periprostatic fat ratio is a better predictor of higher Gleason score compared with periprostatic fat volume and may be an important risk factor in diagnosing patients with higher grade prostate cancer.