This paper describes a computer-aided diagnosis method for targeted prostate biopsies within the peripheral zone in T2-Weighted MRI. We subdivided the peripheral zone into four regions and compare each sub region's grey level histogram with malignant and normal histogram models, and use specific metrics to estimate the presence of abnormality. The initial evaluation based on 200 MRI slices taken from 40 different patients and we achieved 87% correct classification rate with 89% and 86% sensitivity and specificity, respectively. The main contribution of this paper is a novel approach of Computer Aided Diagnosis which is using grey level histograms analysis between sub regions. In clinical point of view, the developed method could assist clinicians to perform targeted biopsies which are better than the random ones which are currently used.