Amide Proton Transfer MR Imaging of Prostate Cancer: A Preliminary Study

Purpose: To evaluate the capability of amide proton transfer (AFT) MR imaging for detection of prostate cancer that typically shows a higher tumor cell proliferation rate and cellular density leading to an MRI-detectable overall elevated mobile protein level in higher grade tumors. Materials and Methods: Twelve patients with biopsy-proven prostate cancer were imaged on a 3 Testa MR imaging system before prostatectomy. APT-MR images were acquired by means of a single-slice single-shot turbo spin echo sequence with a saturation prepulse preparation using 33 different frequency offsets (-8 to 8 ppm, interval 0.5 ppm). For quantification we used the APT ratio (APTR) based on the asymmetry of the magnetization transfer ratio at 3.5 ppm in respect to the water signal. Tumor and peripheral zone benign regions of interest (ROIs) were delineated based on whole mount pathology slides after prostatectomy. Results: APTR in prostate cancer ROIs was 5.8% +/- 3.2%, significantly higher than that in the peripheral zone benign regions (0.3% +/- 3.2%, P = 0.002). Conclusion: APT-MR imaging is feasible in prostate cancer detection and has the potential to discriminate between cancer and noncancer tissues.