In prostatic transition zone lesions (PI-RADS v2.1): which subgroup should be biopsied?

The study aimed to compare the diagnostic performance of T2-weighted imaging (T2WI) score 3 transition zone (TZ) lesions between Prostate Imaging and Reporting Data System (PI-RADS) v2.1 and modified PI-RADS v2.1-B. Among TZ lesions (n = 78), 47 (60.0%) had T2WI score of 3, and 16 of the 47 (34.0%) were malignant. The rate of malignancy was 8.8% in PI-RADS category 3A, 100% in PI-RADS category 3B, and 100% in PI-RADS category 4. The apparent diffusion coefficient value of PI-RADS category 3B (0.934 ± 0.158 × 10−3 mm2/s) showed significant difference with that of PI-RADS category 3A (1.098 ± 0.146 × 10−3 mm2/s) but none with PI-RADS category 4 (0.821 ± 0.091 × 10−3 mm2/s). There was no significant difference in the sensitivity and negative predictive value of PI-RADS v2.1 and PI-RADS v2.1-B. Specificity and positive predictive value of modified PI-RADS v2.1-B were much higher than those of PI-RADS v2.1 for both readers (p < .001). The area under the receiver operating characteristic curve tended to be higher with PI-RADS v2.1-B than with PI-RADS v2.1. Biopsy for PI-RADS 3B lesion is necessary due to its superior malignancy potential than that of PI-RADS 3A lesion.