Background and purpose: Since the detection of localized prostate cancer is increasing

it's important to distinguish from benign lesions like prostatitis. This study aimed to compare diffusion weighted imaging with apparent diffusion coefficients in differential diagnosis of localized prostate cancer on 3.0T MR. Methods: Sixtynine cases with localized prostate cancer proved by pathology

43 in perpheral zone (PZ) and 26 in central gland (CG)

33 with prostatitis

and 37 with benign prostatic hyperplasia (BPH) were analyzed. The signal noise ratio (SNR) and apparent diffusion coefficient (ADC) value of lesions were measured

and a semiquantitative grading of DW image was performed. The diagnostic accuracy of both methods was evaluated by ROC. Results: 45 cancer foci and 36 prostatitis lesions in PZ

27 cancer foci and 42 BPH lesions in CG were included. The sensitivity and specificity for ADC value to distinguish cancer from begin lesions in PZ and CG were 88.9% and 86.1%、81.5% and 73.8% respectively. The diagnostic accuracy of ADC value was higher than DWI semiquantitative grading and SNR (P0.05). Conclusion: ADC value yielded a higher accuracy in differential diagnosis of localized prostate cancer on 3.0T MR

thus it’s recommended as a major index for diagnosis.