Differences in PI-RADS Classification of Prostate Cancer Based on mpMRI Scans Taken 6 Weeks Apart

Area of Science:

• Radiology and Urology
• Oncology
• Medical Imaging

Background:

• Prostate cancer diagnosis relies on multiparametric magnetic resonance imaging (mpMRI) and the Prostate Imaging Reporting and Data System (PI-RADS).
• Consistency in PI-RADS scoring is crucial for accurate lesion identification and subsequent biopsy planning.
• Variability in imaging protocols or time intervals between scans may affect diagnostic reliability.

Purpose of the Study:

• To assess the consistency of Prostate Imaging Reporting and Data System (PI-RADS) lesion identification in prostate cancer.
• To evaluate the impact of a 6-week interval between two multiparametric magnetic resonance imaging (mpMRI) scans on biopsy results.
• To analyze the correlation between PI-RADS scores and histological findings in a high-volume tertiary care setting.

Main Methods:

• Retrospective analysis of real-world data from 111 patients undergoing two prostate mpMRI scans between 2018-2022.
• Scans were performed at different institutions with a median interval of 42 days.
• MRI-fused biopsy was conducted 7 days after the second MRI.

Main Results:

• PI-RADS V and IV were the most common classifications for index lesions on in-house MRI (33.3% and 49.5%, respectively).
• Cancer detection rates varied significantly by PI-RADS score, with PI-RADS V showing the highest detection rate (91.9%).
• Malignant histology was found in 64.9% of targeted lesions and 57.7% of randomized biopsies; the biopsy plan was adjusted for 51.4% of patients.

Conclusions:

• The 6-week interval between sequential prostate MRI scans did not significantly compromise the quality or reliability of biopsy results.
• PI-RADS classification remains a key factor in predicting cancer detection rates.
• Consistent lesion identification and accurate biopsy planning are achievable even with a moderate time gap between imaging studies.