Fig. 2

Axial images obtained in a 62-year-old patient with prostate-specific antigen (PSA) level of 8.1 ng/mL and normal digital rectal examination. Prostate multiparametric magnetic resonance imaging (a, T2-weighted image; b, apparent diffusion coefficient map; c, diffusion-weighted trace image obtained with b value of 2000 s/mm²; and d, dynamic contrast-enhanced image) showed a 13-mm linear lesion parallel to the capsule in the peripheral zone of the left base (a–d, arrowheads). Using PI-RADSv2 descriptors, 17 readers assigned to the lesion a T2-weighted imaging (T2WI) category of 2 (‘Linear, wedge-shaped or diffuse mild hypointensity, usually indistinct margin’), two readers a T2WI category of 3 (‘Heterogeneous signal intensity or non-circumscribed, rounded, moderate hypointensity’) and two readers a T2WI category of 4 (‘Circumscribed, homogeneous moderate hypointense focus/mass confined to prostate and < 1.5 cm in greatest dimension’). Two readers assigned a diffusion-weighted imaging (DWI) category of 2 (‘Indistinct hypointense on ADC ‘), fifteen readers a DWI category of 3 (‘Focal mildly/moderately hypointense on ADC and isointense/mildly hyperintense on high b value DWI’) and three readers a DWI category of 4 (‘Focal markedly hypointense on ADC and markedly hyperintense on high b value DWI < 1.5 cm on axial images’). Seventeen readers judged the lesion as positive at dynamic contrast-enhanced (DCE) imaging (‘Focal, AND earlier than or contemporaneously with enhancement of adjacent tissues, AND corresponds to suspicious findings on T2WI and/or DWI’), and four readers judged it as negative (‘No early enhancement, OR diffuse enhancement not corresponding to a focal finding on T2W and/or DWI, OR focal enhancement corresponding to a lesion demonstrating features of BPH on T2W’). The final PI-RADSv2 score was 2 for three readers, 3 for four readers and 4 for fourteen readers. Using PI-RADSv2.1 descriptors, the assignment of T2WI categories was the same as with PI-RADSv2 since the descriptors are identical. Fifteen readers assigned a DWI category of 2 (‘Linear/wedge-shaped hypointense on ADC and/or linear/wedge-shaped hyperintense on high b value DWI’), four readers a diffusion category of 3 (‘Focal (discrete and different from the background) hypointense on ADC and/or focal hyperintense on high b value DWI; may be markedly hypointense on ADC or markedly hyperintense on high b value DWI but not both’) and two readers a DWI category of 4 (‘Focal markedly hypointense on ADC and markedly hyperintense on high b value DWI < 1.5 cm on axial images’). Sixteen readers judged the lesion as positive at DCE imaging (‘Focal, AND earlier than or contemporaneously with enhancement of adjacent tissues, AND corresponds to suspicious findings on T2W and/or DWI’) and five as negative (‘No early or contemporaneous enhancement, OR diffuse multifocal enhancement NOT corresponding to a focal finding on T2W and/or DWI, OR focal enhancement corresponding to a lesion demonstrating features of BPH on T2W, including features of extruded BPH in the PZ). The final PI-RADSv2.1 score was 2 for sixteen readers, 3 for one reader and 4 for four readers. Systematic and targeted biopsy showed normal prostate tissue, with mild inflammation in the left base. Fifty-six months later, the patient had a PSA level of 6 ng/ml and had not undergone another prostate biopsy.