Multi-reader evaluation of different image quality scoring systems in prostate MRI.

OBJECTIVES

To evaluate different image quality scoring systems in the assessment of factors limiting diagnostic accuracy of prostate MRI.

METHODS

This retrospective IRB-approved study included 281 patients undergoing prostate MRI prior to biopsy. Four readers (2 experienced, 2 novice) independently reviewed all MRI examinations (n = 295) and assigned scores for subjective image quality (1-5; 1:poor, 5:excellent), the PI-QUAL and the PSHS scoring system. The original PI-RADS scores were extracted from the report and transperineal template saturation biopsy served as histopathological reference.

RESULTS

Inter-reader agreement was found to be good, with PSHS showing highest agreement (kappa: 0.65). The PSHS scoring system performed well assessing the influence of image quality on sensitivity of MR for clinically-significant cancer for the experienced readers using a PI-RADS score cut-off ≥ 3/≥4, as did the PI-QUAL scoring system with a PI-RADS cut-off ≥ 4. For the less experienced radiologist, this was true for PSHS (clinically-significant and all cancers) and PI-QUAL scores (clinically-significant cancers) for a PI-RADS score ≥ 3. PSHS scores were positively associated with the detection of clinically-significant cancer based on a PI-RADS cut-off ≥ 4, OR 1.86 (95 % CI 1.22-2.82), and had the highest Somers' D.

CONCLUSIONS

The PSHS scoring system performed well in assessing the effect of image quality on detection rates, as did the PI-QUAL system. Since both systems focus on different aspects of image quality, their incorporation into prostate MRI reports could further enhance standardization and allow for a reliable assessment of image quality as a potential confounder in prostate MRI.