TECHNICAL DEVELOPMENT Does a Cleansing Enema Improve Image Quality of 3T Surface Coil Multiparametric Prostate MRI? Christopher Lim, BMBS, Jeff Quon, MD, Matt McInnes, MD, Wael M. Shabana, MD, PhD, Mohamed El-Khodary, MD, and Nicola Schieda, MD* Purpose: To assesses the utility of a preparatory enema in the interpretation of prostate multiparametric (MP) magnetic resonance imaging (MRI). Materials and Methods: Under a waiver from the Institutional Review Board (IRB), 32 patients without bowel prepara- tion and 28 patients who underwent a self-administered enema were imaged consecutively with 3T MP-MRI over 6 months. Two blinded radiologists independently assessed image quality on T 2 -weighted (T 2 W), trace b 1000 mm 2 /sec echo-planar (EPI) and apparent-diffusion coefficient (ADC) and assessed for motion/blur on T 2 W and distortion/blur on EPI and ADC. Radiologists also quantified rectal stool and gas. A third blinded radiologist generated contrast curves from dynamic contrast-enhanced (DCE) data at six locations and measured the number of corrupted data points, defined as >10% aberrant signal intensity change. Subjective scores were compared using Wilcoxon sign rank test. Rec- tal contents were correlated to artifact using Spearman correlation. Contrast curves were evaluated with independent t- tests. Results: There was no difference in image quality on T 2 W(P 5 0.66–0.74), EPI (P 5 0.13–0.36) or ADC (P 5 0.49–0.59). There was less rectal stool in the enema group (P 5 0.004) and amount of stool correlated with motion artifact on T 2 W (r 5 0.23, P 5 0.02); however, there was no difference in motion artifact between groups (P 5 0.47–0.94). Only a minority of patients in the non-enema group had moderate or large amounts of stool (16%) and none of these patients had severe or extensive artifact on T 2 . There was less rectal gas in the enema group (P 5 0.002); however, amount of gas did not correlate with distortion artifact on EPI or ADC (P 5 0.17–0.41) and there was no difference in blur (P 5 0.41– 0.91) or distortion (P 5 0.31–0.99) on EPI or ADC between groups. There was no difference in corrupted data points on DCE (P 5 0.46). Conclusion: In this study the use of a preparatory enema did not improve image quality or reduce artifact in prostate MP-MRI. J. MAGN. RESON. IMAGING 2014;00:000–000. M ultiparametric (MP) magnetic resonance imaging (MRI), which includes diffusion-weighted imaging (DWI), dynamic contrast enhancement (DCE), and/or MR spectroscopy, is the standard for prostate imaging. 1–3 With advances in technology, multichannel surface coil imaging of the prostate at 3T is now considered an acceptable alterna- tive to endorectal coil imaging. No difference in local stag- ing accuracy has been demonstrated with surface compared to endorectal coil imaging at 3T. 4–7 More recently, studies have demonstrated similar accuracy for the detection of dominant tumor foci in the prostate gland using surface and endorectal coil imaging at 3T. 8–10 Surface coil imaging offers several advantages over endorectal coil imaging including: reductions in cost, examination time, and, per- haps most important, patient discomfort. This results in improved patient tolerance. 1,11 MP-MRI image quality may be dependent on artifacts related to the adjacent rectum. This is mainly evident on functional imaging sequences. For example, the presence of gas in bowel and at the lung bases has been shown to nega- tively impact echo-planar (EPI) diffusion-weighted images (DWI) and the derived apparent diffusion coefficient (ADC) map in the abdomen and, artifacts on EPI are worse at 3T. 12–14 Similarly, motion artifact from the rectum could View this article online at wileyonlinelibrary.com. DOI: 10.1002/jmri.24833 Received Jun 17, 2014, Accepted for publication Dec 8, 2014. *Address reprint requests to: N.S, Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, 1053 Carling Ave., Ottawa, Ontario, Canada, K1Y 4E9. E-mail: nschieda@toh.on.ca Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada V C 2014 Wiley Periodicals, Inc. 1