How to improve image quality of DWI of the prostate-enema or catheter preparation?

Objectives To compare the impact of laxative enema preparation versus air/gas suction through a small catheter on image quality of prostate DWI. Methods In this single-center study, 200 consecutive patients (100 in each arm) with either enema or catheter preparation were retrospectively included. Two blinded readers independently assessed aspects of image quality on 5-point Likert scales. Scores were compared between groups and the influence of confounding factors evaluated using multivariable logistic regression. Prostate diameters were compared on DWI and T-2-weighted imaging using intraclass correlation coefficients. Results Image quality was significantly higher in the enema group regarding the severity of susceptibility-related artifacts (reader 1: 0.34 +/- 0.77 vs. 1.73 +/- 1.34, reader 2: 0.38 +/- 0.86 vs. 1.76 +/- 1.39), the differentiability of the anatomy (reader 1: 3.36 +/- 1.05 vs. 2.08 +/- 1.31, reader 2: 3.37 +/- 1.05 vs. 2.09 +/- 1.35), and the overall image quality (reader 1: 3.66 +/- 0.77 vs. 2.26 +/- 1.33, Reader 2: 3.59 +/- 0.87 vs. 2.23 +/- 1.38) with almost perfect inter-observer agreement (kappa = 0.92-0.95). In the enema group, rectal distention was significantly lower and strongly correlated with the severity of artifacts (reader 1: rho = 0.79, reader 2: rho = 0.73). Furthermore, there were significantly fewer substantial image distortions, with odds ratios of 0.051 and 0.084 for the two readers which coincided with a higher agreement of the prostate diameters in the phase-encoding direction (0.96 vs. 0.89). Conclusions Enema preparation is superior to catheter preparation and yields substantial improvements in image quality.

Automated summary

The study found that enema preparation is superior to catheter preparation for prostate DWI imaging, significantly improving image quality by reducing susceptibility-related artifacts and image distortions.