Description:
<jats:p><jats:italic>Purpose</jats:italic>. To evaluate the ESUR scoring system (PI-RADS) for multiparametric MRI of the prostate in clinical routine and to define a reliable way to generate an overall PI-RADS score.<jats:italic>Methods</jats:italic>. Retrospective analysis of all patients with a history of negative prebiopsies, who underwent 3 Tesla multiparametric MRI from October 2011 to April 2013 (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>143</mml:mn></mml:math>): PI-RADS scores for each single modality were defined. To generate the overall PI-RADS score, an algorithm based approach summing up each single-modality score to a sum-score was compared to a more subjective approach, weighting the single modalities dependent on the radiologist’s impression. Because of ongoing cancer suspicion 73 patients underwent targeted mpMRI-ultrasound image fusion rebiopsy. For this group thresholds for tumor incidences and malignancy were calculated.<jats:italic>Results</jats:italic>. 39 (53%) out of 73 targeted rebiopsies were cancer positive. The PI-RADS score correlated well with tumor incidence (AUC of 0.86, 95% CI 0.78 to 0.94) and malignancy (AUC 0.84, 95% CI 0.68 to 0.99). Regarding the sum-score a threshold of ≥10 turned out to be reliable for cancer detection (sensitivity 90%, specificity 62%) and for ≥13 for indicating higher malignancy (Gleason<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mo>≥</mml:mo><mml:mn>4</mml:mn><mml:mo>+</mml:mo><mml:mn>3</mml:mn></mml:math>) (sensitivity 80%, specificity 86%). To generate the overall PI-RADS score, the use of an algorithm based approach was more reliable than that of the approach based on the radiologist’s impression.<jats:italic>Conclusion</jats:italic>. The presented scoring system correlates well with tumor incidence and malignancy. To generate the overall PI-RADS score, it seems to be advisable to use an algorithm based instead of a subjective approach.</jats:p>