Added value of MR spectroscopy to combined T2-weighted and diffusion weighted MRI in prostatic lesions characterization

Abstract

Background: Recently, multiparametric magnetic resonance imaging has been extensively used for early detection and localization of clinically significant prostate cancer. Magnetic resonance spectroscopy provides chemical information about metabolites in normal and abnormal tissues. It isn ’ t widely used in routine imaging of prostatic lesions. Objectives: to evaluate the diagnostic benefit from adding MRS to combined T2WI and DWI (bi-parametric MRI) in prostatic lesions diagnosis. Patients and Methods : This prospective study included MRI prostate of 128 adult male obtained by using 1.5 Tesla machine. They were presented by clinically suspected prostatic lesions and elevated PSA level (> 4 ng/dl). MRI protocol included T1WI, T2WI, DWI and MRS. Diagnostic accuracy of bi-parametric MRI was compared with that of MRS alone and that after adding MRS to T2WI and DWI using the histopathological diagnosis as the standard of reference. Results : 68 (53%) patients were histopathologically diagnosed with malignant prostatic lesions and 60 (47%) patients with benign lesions. Combined MRS with bi-parametric MRI had the highest diagnostic accuracy of 96.8% with sensitivity, specificity, PPV, and NPV of 100%, 93.3%, 94.4%, and 100% respectively compared with those of bi-parametric MRI; 71.9 % accuracy, 76.5% sensitivity, 66.7 % specificity, 72.2% PPV and 71.4% NPV and MRS that had 90.6 % accuracy, 100% sensitivity, 80 % specificity, 85% PPV and 100% NPV. Conclusion: Adding MRS to T2WI and DWI is a promising diagnostic tool for better detection and characterization of different malignant and benign prostatic lesions compared to bi-parametric MRI.