Diagnostic performance of apparent diffusion coefficient values in differentiating benign from malignant lesions in prostate PI-RADS v2.1 category 1 "nodules in nodule".

OBJECTIVES

To explore the associations between the apparent diffusion coefficient (ADC) values of prostate PI-RADS v2.1 category 1 "nodules in nodule" and their pathological characteristics.

METHODS

We retrospectively analyzed the prostate images from 226 male patients who underwent biopsy following MRI from January 2019 to December 2024. Two radiologists evaluated the PI-RADS v2.1 categories of identified nodules, measured the ADC values of the prostate nodules in a double-blind manner, and analyzed the associations between these values and the pathological characteristics of the nodules via independent sample t tests or Mann-Whitney U test.

RESULTS

The ADC values of PI-RADS v2.1 category 1 "nodules in nodule" pathologically confirmed as clinically significant prostate cancer (csPCa) were lower than those of benign prostate hyperplasia (BPH) ((unit in ×10 mm/s)TZ: 0.739 ± 0.15 versus 0.984 ± 0.24; PZ: 0.719 ± 0.17 versus 1.036 ± 0.21, p < 0.001). The AUCs were 0.799 (TZ) with a cutoff of 0.835 × 10mm/s, and 0.873(PZ) with a cutoff of 0.795 × 10mm/s, respectively. The total prostate-specific antigen (tPSA), free/t PSA, PSA density (PSAD), and prostate gland volume (PGV) differed significantly between patients with PI-RADS v2.1 "nodules in nodule" that were pathologically confirmed as csPCa and patients with BPH (all p < 0.05).

CONCLUSION

In patients with PI-RADS v2.1 category 1 "nodules in nodule", when the ADC values are less than 0.835 × 10mm/s in the TZ, the PI-RADS v2.1 score of the nodule can be upgraded to 3.