3D Diffusion-Prepared FLASH for Prostate MRI Near Metallic Implants

Motivation: Diffusion weighted imaging (DWI) is critical for prostate MRI, but echo planar imaging (EPI) DWI suffers from severe distortion in patients with hip implants or excessive bowel gas, often rendering images unusable. Goal(s): To develop 3D DWI of the prostate with minimal distortion from nearby metal. Approach: We compared a diffusion prepared, phase-navigated, fast low-angle shot (FLASH) readout sequence to EPI DWI to assess image quality, distortion correction and diffusion contrast. Results: Phantom experiments demonstrate the reduced FOV, distortion correction and ADC accuracy. Images in human subjects avoid the severe signal loss and distortion of EPI DWI in the subject with metal. Impact: We showed that 3D diffusion-prepared FLASH enables DWI where EPI often fails near hip replacements. Increased robustness of prostate imaging protocols to the presence of metal and/or bowel gas may obviate the need for contrast injection in these patients.