Association of volume of self-directed versus assigned interpretive work with diagnostic performance of radiologists: an observational study

OBJECTIVES: To understand the sources of variability in diagnostic performance among experienced radiologists. DESIGN: All prostate MRI examinations performed between 2016 and 2018 were retrospectively reviewed. SETTING: University hospital in Japan. PARTICIPANTS: Data derived from 334 pathology-proven cases (male, mean age: 70 years; range: 35–90 years) that were interpreted by 10 experienced radiologists were subjected to the analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: Diagnostic performance measures of the radiologists were compared with candidate factors, including interpretive volume of prostate MRIs, volume of self-directed and assigned total annual interpretive work, and years of experience. The potential influence of fatigue was also evaluated by examining the effect of the report’s issue time. RESULTS: There were 186 prostate cancer cases. Performance was based on accuracy, sensitivity and specificity (86%, 85% and 84%, respectively). While performance was not correlated with the volume of prostate MRIs, per se (ρ=–0.15, p=0.69; ρ=–0.01, p=0.99; ρ=–0.33, p=0.36) or the total MRIs assigned for each radiologist (p>0.6) or years of experience (p>0.4), all measures were strongly correlated with voluntary work represented by the interpretive volume of abdominal CTs (r=0.79, p<0.01; r=0.80, p<0.01; r=0.64, p=0.048). The performance did not differ based on the issue time of the report (morning, afternoon and evening) (χ(2)(2)=3.65, p=0.16). CONCLUSIONS: Greater autonomy, represented as enhanced self-directed interpretive work, was most significantly correlated with the performance of prostate MRI interpretation. The lack of a correlation between the performance and assigned volume confirms the complexity of human learning. Together, these findings support the hypothesis that successful promotion of internal drivers could have a pervasive positive impact on improving diagnostic performance.