Differentiating clinically significant prostate cancer from clinically insignificant prostate cancer using qualitative and semi-quantitative indices of dynamic contrast-enhanced MRI

Purpose: To investigate the utility of qualitative and semi-quantitative evaluation of DCE-MRI for detecting clinically significant prostate cancer (csPC).

Methods: This retrospective study analyzed 307 lesions in 231 patients who underwent 3.0T MRI. Experienced radiologists assessed PI-RADS v 2.1 assessment category, qualitative contrast enhancement (QCE), contrast enhancement pattern (CEP: type 1, 2, 3), tumor contrast ratio, and tumor size of PC lesions in consensus. Mean and 0-10th-percentile ADC value of the lesion (ADC_mean and ADC_0-10) were calculated. Specimens obtained from MRI-ultrasound fusion-guided prostate biopsy were used as the pathological reference standard.

Results: In assessment of tumor aggressiveness, PI-RADS assessment category, QCE, tumor size, and ratio of CEP 2 + 3 were significantly higher in PC with Gleason score (GS) ≥ 3 + 4 (n = 256) than in PC with GS = 6 (n = 51) (P ≤ 0.001). Tumor ADC_mean and tumor ADC_0-10 were comparable between PC with GS ≥ 3 + 4 and PC with GS = 6 (P = 0.164 to 0.504). Regarding diagnostic performance of csPC in 45 PI-RADS 3 transition zone lesions, only ratio of CEP 2 + 3 was significantly higher in PC with GS ≥ 3 + 4 (n = 31) than in PC with GS = 6 (n = 14) (P = 0.008).

Conclusion: Qualitative DCE-MRI indices may contribute to PC aggressiveness and improve detection of csPC in PI-RADS assessment category 3 lesions.