Multiparametric MR can identify high grade prostatic intraepithelial neoplasia (HGPIN) lesions and predict future detection of prostate cancer in men with a negative initial prostate biopsy.

Purpose This study aims to determine the pre-biopsy diffusion-weighted imaging (DWI) and magnetic resonance spectroscopic imaging (MRSI) characteristics of patients with high-grade prostatic intraepithelial neoplasia (HGPIN) and perform follow-up studies in these patients to assess the clinical implications. Materials and methods One hundred sixteen men with prostate specific antigen between 4 and 10 ng/ml underwent pre-biopsy MR examinations. Nine of them had HGPIN lesions without concomitant prostate cancer (PCa) on biopsy. Apparent diffusion coefficient (ADC) and metabolite ratio [Citrate/(Choline + Creatine)] were calculated and these 9 patients were followed to determine the clinical outcomes. Results Mean ADC for HGPIN foci was 1.01 ± 0.16 × 10 − 3 mm 2 /s while for the normal peripheral zone it was 1.69 ± 0.25 × 10 − 3 mm 2 /s (p < 0.005). Mean metabolite ratio for voxels in the HGPIN region of initial biopsy was 0.24 ± 0.16 while for the normal peripheral zone the value was 2.66 ± 1.57 (p < 0.005). Four of 5 patients who were available for follow-up were detected to have prostate cancer on repeat biopsy. No significant change in metabolite ratio and PSA was observed while ADC showed further reduction on follow-up. Conclusion HGPIN foci have ADC and metabolite ratio values similar to adenocarcinoma prostate, indicating that such patients have a high likelihood of developing cancer. DWI may help identify such men who may be candidates for close follow-up. [ABSTRACT FROM AUTHOR]