Rectal preparation significantly improves prostate imaging quality: Assessment of the PI-QUAL score with visual grading characteristics

Abstract

To investigate the effects of a rectal preparation regimen, that consisted of a rectal cleansing enema and an endorectal gel filling protocol, on prostate imaging quality (PI-QUAL). Methods: Multiparametric MRI (mpMRI) was performed in 150 consecutive patients divided into two groups of 75 patients. One group received a rectal preparation with a cleansing enema and endorectal gel filling (median age 65.3 years, median PSA level 6 ng/ml). The other patient group did not receive such a preparation (median age 64 years, median PSA level 6 ng/ml). Two uroradiologists independently rated general image quality and lesion visibility on diffusion-weighted imaging (DWI), T2-weighted (T2w), and dynamic contrast-enhanced (DCE) images using a five-point ordinal scale. In addition, two uroradiologists assigned PI-QUAL scores, using the dedicated scoring sheet. Data sets were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/ area under the curve (AUC) analysis. Results: VGC revealed significantly better general image quality for DWI (AUC R1 0.708 (0.628-0.779 CI, p < 0.001; AUC R2 0.687 (0.606-0.760 CI, p < 0.001) and lesion visibility for both readers (AUC R1 0.729 (0.607-0.831 CI, p < 0.001); AUC R2 0.714 (0.590-0.818CI, p < 0.001) in the preparation group. For T2w imaging, rectal preparation resulted in significantly better lesion visibility for both readers (R1 0.663 (0.537-0.774 CI, p = 0.014; R2 0.663 (0.537-0.774 CI, p = 0.014)). Averaged PI-QUAL scores were significantly improved with rectal preparation (AUC R3/R4 0.667, CI 0.581-0.754, p < 0.001). Conclusion: Rectal preparation significantly improved prostate imaging quality (PI-QUAL) and lesion visibility. Hence, a rectal preparation regimen consisting of a rectal cleansing enema and an endorectal gel filling could be considered.

Impact of PI-QUAL on PI-RADS and cancer yield in an MRI-TRUS fusion biopsy population

“…Our analysis also showed only moderate agreement for the PI-QUAL score, inter-as well as intra-individually. This is in line with initial studies [12,16,17]. Here, individual differences in the interpretation of the respective, rather subjective, criteria might become apparent.…”

“…As all patients underwent MRI-TRUS and systematic transrectal prostate biopsy, histologic verification for each predefined region was available. Referring to the results by Obuchowski et al [33], our study is considered a Level 4 study ("ROI level requiring correct location of lesion") with higher reliability compared to the previously published results on a per-patient level with or without the correct location of the lesion, i.e., Level 1 [16] and Level 2 [12,17] studies.…”

“…responded to this need and recently presented PI-QUAL, an important approach to standardized reporting of image quality in mpMRI of the prostate [13]. The initial evaluation studies highlight the importance of quality assessment, but, however, also outline some weaknesses of the new PI-QUAL [12,16,17]. The main point is that a standardized image quality score such as PI-QUAL is only meaningful and serves its purpose if the score has an impact on the diagnostic performance in the detection of clinically significant prostate cancer (ISUP ≥ 2).…”

“…One possible factor might be the varying image quality due to different technical parameters [8,9], as well as patient-related characteristics (e.g. motion or rectal air artefacts) [10][11][12]. To date, the PI-RADS lexicon v2.1 includes a statement on the minimally acceptable technical standards for mpMRI of the prostate, but neither the adherence to those standards nor the final image quality and corresponding diagnostic confidence, has yet been reported in a uniform and standardized way.…”

Developments in proton MR spectroscopic imaging of prostate cancer

“…A recent post-processing approach to restore field inhomogeneity effects in prostate MRSI is over-discretized reconstruction, which appears to improve lipid signal contamination [ 115 ]. Finally, a practical step to improve the B 0 inhomogeneity is the preparation of the rectum with a cleansing enema and an endorectal gel filling [ 116 ].…”