title: Does a cleansing enema improve image quality of 3T surface coil multiparametric prostate MRI?
abstract: OBJECTIVE
  To assesses the utility of a preparatory enema in the interpretation of prostate multiparametric (MP) magnetic resonance imaging (MRI).
  
  
  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 T2 -weighted (T2 W), trace b 1000 mm(2) /sec echo-planar (EPI) and apparent-diffusion coefficient (ADC) and assessed for motion/blur on T2 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 T2 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 T2 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 T2 . 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).
  
  
  CONCLUSIONS
  In this study the use of a preparatory enema did not improve image quality or reduce artifact in prostate MP-MRI.
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Lim
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Jeff
authors.initials: J
authors.lastname: Quon
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Matt
authors.initials: M
authors.lastname: McInnes
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Wael M
authors.initials: WM
authors.lastname: Shabana
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Khodary
authors.affiliation: Ottawa Hospital, University of Ottawa, Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors.forename: Nicola
authors.initials: N
authors.lastname: Schieda
mesh_terms: D000368:Aged; D016477:Artifacts; D003287:Contrast Media; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D004578:Electron Spin Resonance Spectroscopy; D004733:Enema; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009038:Motion; D060787:Neoplasm Grading; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D011871:Radiology
chemical_list: D003287:Contrast Media
keywords: diffusion weighted imaging; dynamic contrast enhancement; enema; magnetic resonance imaging; multiparametric; prostate