Evaluation of PI-RADS v2.1 Categories 3–5 Lesions Using Amide Proton Transfer Imaging

Overview

This study assessed the utility of amide proton transfer weighted imaging (APTWI) combined with apparent diffusion coefficient (ADC) and prostate-specific antigen density (PSAD) in evaluating the risk of clinically significant prostate cancer (csPC) in PI-RADS v2.1 category 3–5 lesions. The findings suggest that APTWI parameters correlate with Gleason Score and may improve risk stratification beyond conventional multiparametric MRI sequences.

Background

Prostate cancer (PCa) is a common malignancy in men with increasing incidence and mortality. The Gleason Score (GS) is used to grade tumor aggressiveness, guiding treatment decisions. Multiparametric MRI with PI-RADS v2.1 scoring aids in non-invasive detection and risk assessment but has limitations due to high false positive rates, especially in category 3–5 lesions. Amide proton transfer weighted imaging (APTWI) offers metabolic information by detecting intracellular protein changes, potentially improving the accuracy of PCa risk evaluation.

Data Highlights

Key Findings

• APTWI parameters (APTmax, APTmean, APTmin) were quantitatively measured using asymmetric magnetization transfer rate at 3.5 ppm.
• APTWI combined with ADC and PSAD improved risk stratification of PI-RADS v2.1 category 3–5 lesions for clinically significant prostate cancer.
• APTWI parameters showed correlation with Gleason Score, indicating potential to predict tumor aggressiveness.
• Multiparametric MRI alone has a high false positive rate for csPC, especially in PI-RADS 3 lesions; APTWI may reduce unnecessary biopsies and treatments.
• ROI selection was carefully standardized to avoid necrosis, calcification, hemorrhage, and volume effects, ensuring measurement accuracy.

Clinical Implications

Incorporating APTWI into the multiparametric MRI protocol may enhance the non-invasive assessment of prostate lesions, particularly in PI-RADS categories 3–5, by providing metabolic information that correlates with tumor aggressiveness. This could lead to better identification of patients requiring aggressive treatment and reduce unnecessary interventions in those with benign or indolent lesions.

Conclusion

APTWI combined with ADC and PSAD offers a promising approach to improve the evaluation and risk assessment of PI-RADS v2.1 category 3–5 prostate lesions, correlating with Gleason Score and potentially enhancing early diagnosis and treatment planning for prostate cancer.

References

1. NCCN Guidelines 2023 -- Prostate Cancer Early Detection and Treatment
2. PI-RADS v2.1 Committee 2019 -- Prostate Imaging Reporting and Data System
3. Zhou et al. 2023 -- Amide Proton Transfer Imaging in Prostate Cancer