Effects of the addition of quantitative apparent diffusion coefficient data on the diagnostic performance of the PI-RADS v2 scoring system to detect clinically significant prostate cancer.

To evaluate the impact of the addition of quantitative apparent diffusion coefficient (ADC) data into the diagnostic performance of the Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) scoring system to predict clinically significant prostate cancer (CSPCa).

We retrospectively included 91 consecutive patients who underwent prostate multiparametric magnetic resonance imaging (mp-MRI) and histopathological evaluation. Mp-MRI images were reported by the PI-RADSv2 scoring system and patients were divided into groups considering the likelihood of CSPCa. ADC value and ratio were obtained. Findings were correlated with histopathological data.

CSPCa was found in 41.8% of cases (n = 38). PI-RADSv2 score 3-5 yielded a sensitivity of 97.4% (95% confidence intervals 86.5-99.5), a specificity of 50.9% (37.9-63.9), and AUC of 0.74 (0.67-0.81) to predict CSPCa. ADC value < 750 µm2/s and an ADC ratio < 0.62 were the most accurate thresholds for differentiation of CSPCa, with AUC of 0.81 and 0.76, respectively. Combined PI-RADSv2 score 3-5 and ADC value < 750 µm2/s yielded a specificity of 84.9 (72.9-92.2), sensitivity of 70.3 (54.2-82.5), and AUC of 0.77 (0.68-0.86). Combined PI-RADSv2 score 3-5 and ADC ratio < 0.62 yielded a specificity of 86.5 (74.7-93.3), sensitivity of was 64.9 (48.8-78.2), and AUC of 0.75 (0.66-0.84).

Quantitative ADC data might not be beneficial to be used routinely in mp-MR imaging as criteria to detect clinically significant lesions due to the reduced sensitivity. Instead, when prostate lesions present a PI-RADSv2 score ≥ 3, additional quantitative ADC criteria can be helpful to increase the PI-RADS score specificity.

World journal of urology. 2019 Jun 07 [Epub ahead of print]

Marcia Oliveira Moraes, Diego H H Roman, Josenel Copetti, Francisco de S Santos, Alexandre Agra, Jorge A P Noronha, Gustavo Carvalhal, Eurico J Dornelles Neto, Matheus Zanon, Matteo Baldisserotto, Bruno Hochhegger

Department of Radiology, Pontificia Universidade Católica Do Rio Grande Do Sul, Av. Ipiranga, 6681, Porto Alegre, 90619900, Brazil., Department of Radiology, Pontificia Universidade Católica Do Rio Grande Do Sul, Av. Ipiranga, 6681, Porto Alegre, 90619900, Brazil. ., Department of Diagnostic Methods, Federal University of Health Sciences of Porto Alegre, R. Sarmento Leite, 245, Porto Alegre, 90050170, Brazil.