Does a cleansing enema improve image quality of 3T surface coil multiparametric prostate MRI?

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 preparation 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. Rectal 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 = 0.66–0.74), EPI ( P = 0.13–0.36) or ADC ( P = 0.49–0.59). There was less rectal stool in the enema group ( P = 0.004) and amount of stool correlated with motion artifact on T 2 W ( r = 0.23, P = 0.02); however, there was no difference in motion artifact between groups ( P = 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 = 0.002); however, amount of gas did not correlate with distortion artifact on EPI or ADC ( P = 0.17–0.41) and there was no difference in blur ( P = 0.41–0.91) or distortion ( P = 0.31–0.99) on EPI or ADC between groups. There was no difference in corrupted data points on DCE ( P = 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 2015;42:689–697.