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Updated: Aug 3, 2025
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Low cancer yield in PI-RADS 3 upgraded to 4 by dynamic contrast-enhanced MRI: is it time to reconsider scoring
Emanuele Messina1, Martina Pecoraro1, Ludovica Laschena1
1Department of Radiological Sciences, Oncology and Pathology, Sapienza University/Policlinico Umberto I, Viale del Policlinico 155, 00185, Rome, Italy.
Objectives:
To evaluate MRI diagnostic performance in detecting clinically significant prostate cancer (csPCa) in peripheral-zone PI-RADS 4 lesions, comparing those with clearly restricted diffusion (DWI-score 4), and those with equivocal diffusion pattern (DWI-score 3) and positive dynamic contrast-enhanced (DCE) MRI.
Methods:
This observational prospective study enrolled 389 men referred to MRI and, if positive (PI-RADS 3 with PSA-density [PSAD] ≥ 0.15 ng/mL/mL, 4 and 5), to MRI-directed biopsy. Lesions with DWI-score 3 and positive DCE were classified as "PI-RADS 3up," instead of PI-RADS 4. Univariable and multivariable analyses were implemented to determine features correlated to csPCa detection.
Results:
Prevalence of csPCa was 14.5% and 53.3% in PI-RADS categories 3up and 4, respectively (p < 0.001). MRI showed a sensitivity of 100.0%, specificity 40.9%, PPV 46.5%, NPV 100.0%, and accuracy 60.9% for csPCa detection. Modifying the threshold to consider MRI positive and to indicate biopsy (same as previously described, but PI-RADS 3up only when associated with elevated PSAD), the sensitivity changed to 93.9%, specificity 57.2%, PPV 53.0%, NPV 94.8%, and accuracy 69.7%. Age (p < 0.001), PSAD (p < 0.001), positive DWI (p < 0.001), and PI-RADS score (p = 0.04) resulted in independent predictors of csPCa.
Conclusions:
Most cases of PI-RADS 3up were false-positives, suggesting that upgrading peripheral lesions with DWI-score 3 to PI-RADS 4 because of positive DCE has a detrimental effect on MRI accuracy, decreasing the true prevalence of csPCa in the PI-RADS 4 category. PI-RADS 3up should not be upgraded and directed to biopsy only if associated with increased PSAD.
Key Points:
• As per PI-RADS v2.1 recommendations, in case of a peripheral zone lesion with equivocal diffusion-weighted imaging (DWI score 3), but positive dynamic contrast-enhanced (DCE) MRI, the overall PI-RADS score should be upgraded to 4. • The current PI-RADS recommendation of upgrading PI-RADS 3 lesions of the peripheral zone to PI-RADS 4 because of positive DCE decreased clinically significant prostate cancer detection rate in our series. • According to our results, the most accurate threshold for setting indication to prostate biopsy is PI-RADS 3 or PI-RADS 3 with positive DCE both associated with increased PSA density.
Insights
Upgrading PI-RADS 3 lesions with equivocal diffusion to PI-RADS 4 based on MRI alone decreases prostate cancer detection. Biopsy indication for PI-RADS 3 lesions should consider PSA density for improved accuracy.
Area of Science:
- Radiology
- Oncology
- Medical Imaging
Background:
- Prostate cancer detection relies on MRI, with PI-RADS scoring guiding biopsy decisions.
- Peripheral zone lesions with equivocal diffusion (DWI-score 3) and positive DCE are often upgraded to PI-RADS 4.
- This upgrade strategy's impact on clinically significant prostate cancer (csPCa) detection needs evaluation.
Purpose of the Study:
- To assess the diagnostic performance of MRI in detecting csPCa in peripheral-zone PI-RADS 4 lesions.
- To compare MRI performance for PI-RADS 4 lesions with restricted diffusion (DWI-score 4) versus those with equivocal diffusion (DWI-score 3) and positive DCE.
- To determine if upgrading PI-RADS 3 lesions to PI-RADS 4 based on DCE alone affects csPCa detection rates.
Main Methods:
- An observational prospective study included 389 men undergoing MRI and biopsy.
- Lesions with DWI-score 3 and positive DCE were categorized as "PI-RADS 3up" instead of PI-RADS 4.
- Univariable and multivariable analyses identified predictors of csPCa detection.
Main Results:
- The prevalence of csPCa was significantly higher in PI-RADS 4 (53.3%) compared to PI-RADS 3up (14.5%) lesions (p < 0.001).
- Initial MRI performance for csPCa detection showed 100.0% sensitivity and 40.9% specificity.
- Modifying the biopsy threshold to PI-RADS 3up only with elevated PSA density improved accuracy to 69.7% (sensitivity 93.9%, specificity 57.2%).
- Age, PSA density, positive DWI, and PI-RADS score were independent predictors of csPCa.
Conclusions:
- Upgrading PI-RADS 3 lesions with equivocal diffusion to PI-RADS 4 based solely on positive DCE negatively impacts MRI accuracy for csPCa detection.
- The PI-RADS v2.1 recommendation to upgrade these lesions may decrease the true prevalence of csPCa in the PI-RADS 4 category.
- Biopsy indication for PI-RADS 3up lesions should be reserved for cases with elevated PSA density, improving diagnostic precision.
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