Reducing Acquisition Time of Diffusion Weighted MR Imaging of the Rectum with Simultaneous Multi-Slice Acquisition: A Reader Study.

RATIONALE AND OBJECTIVES:To assess the acquisition time and image quality of simultaneous multislice-accelerated diffusion-weighted imaging (SMS-DWI) versus conventional DWI (C-DWI) of the rectum. MATERIALS AND METHODS:In patients scheduled for a magnetic resonance imaging of the rectum, both SMS-DWI and C-DWI were performed on a 3T whole body magnetic resonance scanner. Image quality of the DWI sequences was reviewed by two independent radiologists who were blinded to the method of imaging using a five-point Likert scale: (score ranging from 1 (non-diagnostic) to 5 (excellent). The mean scores of SMS-DWI versus C-DWI were compared for the individual readers using a nonparametric test (Wilcoxon signed ranks). RESULTS:The SMS-DWI protocol acquisition time was 4:08 min vs. 7:24 min per patient, which led to a reduction of 44.1% for the C-DWI protocol, both excluding time for sequence specific adjustments (shimming). No statistical differences between the conventional-, and SMS- diffusion weighted images were seen for both readers. Mean overall image quality of the SMS-DWI TRACE images was 3.5 (SD: 1.3) and 3.3 (SD: 1.0) for reader 1 and reader 2, respectively. Mean overall image quality of the C-DWI TRACE images was 3.4 (SD: 1.3) and 3.2 (SD: 1.1) for reader 1 and reader 2, respectively. CONCLUSION:Optimized SMS-DWI compared to C-DWI in imaging of the rectum showed similar image quality while a significant acquisition time reduction was achieved.