Diffuse Peripheral Zone T2 Hypointensity: When to Worry About Prostate Cancer.

Evaluate the accuracy of an obscured surgical capsule (OSC) for detecting diffuse prostate cancer (PCa) in the setting of diffusely T2 hypointense peripheral zones (PZs) on prostate magnetic resonance imaging. Axial T2-weighted sequences of prostate magnetic resonance imaging performed on July 1, 2015, to August 1, 2017, were blindly assessed for diffusely T2 hypointense PZs, OSC, and focal diffusion abnormalities by 2 radiologists. Diffuse PCa was defined by the presence of bilateral PCa on at least 4 contiguous biopsy cores involving 2/3 levels. Interobserver agreement and multivariate analysis were performed. Seven (10%) of 70 patients had diffuse PCa. There was weak interreader agreement for OSC (κ coefficient = 0.58). Obscured surgical capsule was 57% sensitive and 89% specific for the presence of diffuse PCa and was associated with it (odds ratio, 17.6; P = 0.0008). Multivariate logistic regression demonstrated that OSC was the only significant predictor for the presence of diffuse PCa. Obscured surgical capsule is a strong independent predictor for diffuse PCa in T2 hypointense PZs.