RESUMO
PURPOSE: To evaluate the effect of enema and dietary restrictions on prostate MR image quality metrics and to assess inter-reader agreement for these metrics. METHODS: This retrospective study included 195 men divided into groups based on their compliance with preparation instructions before prostate MRI (Enemaâ¯+â¯Diet, nâ¯=â¯98; Enema, nâ¯=â¯42; Diet, nâ¯=â¯35; Control [no compliance], nâ¯=â¯20). Four readers independently assessed six image quality metrics on a 5-point scale. Between-group comparisons were made using Wilcoxon rank sum test. Inter-reader agreement was calculated using Fleiss' kappa. RESULTS: Compared with the Control group, image quality with respect to rectal stool/gas, distortion of diffusion-weighted images, overall image quality, and confidence in assessment was higher in the Enemaâ¯+â¯Diet, Enema, and Diet groups (p⯠<â¯0.05 for all comparisons). The Enemaâ¯+â¯Diet and Enema groups had significantly higher scores than the Diet group for rectal stool/gas (p < 0.001 and 0.005, respectively). The Enemaâ¯+â¯Diet and Diet groups had higher scores than the Control group for rectal peristalsis (pâ¯=â¯0.027 and 0.009, respectively), but there were no significant differences in motion artifacts on T2-weighted images. Agreement among readers was fair, with kappa values ranging from 0.25 to 0.37. CONCLUSION: Enema and dietary restriction can improve the quality of prostate MRI by decreasing rectal distension and distortion of diffusion-weighted images and by increasing reader confidence in image assessment. Inter-reader agreement using subjective criteria for analysis of MRI quality is fair.