High-Resolution MRI of Excised Human Prostate Specimens Acquired with 9.4T in Detection and Identification of Cancers: Validation of a Technique

Purpose: To evaluate feasibility of high-resolution, high-field ex vivo prostate magnetic resonance imaging (MRI) as an aid to guide pathologists examination and develop in vivo MRI methods. Materials and Methods: Unfixed excised prostatectomy specimens (n = 9) were obtained and imaged immediately after radical prostatectomy under an Institutional Review Board-approved protocol. High-resolution T2-weighted (T2W) MRI of specimens were acquired with a Bruker 9.4 T scanner to correlate with whole-mount histology. Additionally, T2 and apparent diffusion coefficient (ADC) maps were generated. Results: By visual inspection of the nine prostate specimens imaged, high-resolution T2W MRI showed improved anatomical detail compared to published low-resolution images acquired at 4 T as published by other investigators. Benign prostatic hyperplasia, adenocarcinomas, curvilinear duct architecture distortion due to adenocarcinomas, and normal radial duct distribution were readily identified. T2 was approximate to 10 msec longer (P < 0.03) and the ADC was approximate to 1.4 times larger (P < 0.002) in the normal peripheral zone compared to the peripheral zone with prostate cancer. Conclusion: Differences in T2 and ADC between benign and malignant tissue are consistent with in vivo data. High-resolution, high-field MRI has the potential to improve the detection and identification of prostate structures. The protocols and techniques developed in this study could augment routine pathological analysis of surgical specimens and guide treatment of prostate cancer patients.