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Updated: Aug 12, 2025
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Improving the understanding of PI-RADS in practice: characters of PI-RADS 4 and 5 lesions with negative biopsy
Yu-Hao Wang1, Chao Liang1, Fei-Peng Zhu2
1Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Abstract:
The Prostate Imaging Reporting and Data System (PI-RADS) has good ability to identify the nature of lesions on prostate magnetic resonance imaging (MRI). However, some lesions are still reported as PI-RADS 4 and 5 but are biopsy-proven benign. Herein, we aimed to summarize the reasons for the negative prostate biopsy of patients who were assessed as PI-RADS 4 and 5 by biparameter MRI. We retrospectively sorted out the prostate MRI, treatment, and follow-up results of patients who underwent a biparameter MRI examination of the prostate in The First Affiliated Hospital of Nanjing Medical University (Nanjing, China) from August 2019 to June 2021 with PI-RADS 4 and 5 but a negative biopsy. We focused on reviewing the MRI characteristics. A total of 467 patients underwent transperineal prostate biopsy. Among them, biopsy pathology of 93 cases were negative. After follow-up, 90 patients were ruled out of prostate cancer. Among the 90 cases, 40 were considered to be overestimated PI-RADS after review. A total of 22 cases were transition zone (TZ) lesions with regular appearance and clear boundaries, and 3 cases were symmetrical lesions. Among 15 cases, the TZ nodules penetrated the peripheral zone (PZ) and were mistaken for the origin of PZ. A total of 17 cases of lesions were difficult to distinguish from prostate cancer. Among them, 5 cases were granulomatous inflammation (1 case of prostate tuberculosis). A total of 33 cases were ambiguous lesions, whose performance was between PI-RADS 3 and 4. In summary, the reasons for "false-positive MRI diagnosis" included PI-RADS overestimation, ambiguous images giving higher PI-RADS, diseases that were really difficult to distinguish, and missed lesion in the initial biopsy; and the first two accounted for the most.
Insights
High PI-RADS scores on prostate MRI do not always mean cancer. This study found reasons for benign biopsies in PI-RADS 4 and 5 lesions, including overestimation and ambiguous imaging findings.
Area of Science:
- Radiology
- Urology
- Oncology
Background:
- The Prostate Imaging Reporting and Data System (PI-RADS) is used to assess prostate MRI findings.
- Some lesions categorized as PI-RADS 4 and 5 are found to be benign after biopsy, leading to unnecessary procedures.
Purpose of the Study:
- To identify reasons for negative prostate biopsies in patients with PI-RADS 4 and 5 lesions on biparametric MRI.
- To analyze MRI characteristics associated with false-positive PI-RADS assessments.
Main Methods:
- Retrospective review of prostate MRI, biopsy, and follow-up data from 467 patients with PI-RADS 4-5 lesions.
- Focus on analyzing MRI characteristics of 90 patients with initially negative biopsies who were later confirmed as cancer-free.
- Detailed review of 40 cases with PI-RADS overestimation, transition zone lesions, and ambiguous findings.
Main Results:
- Of 93 patients with negative biopsies, 90 were confirmed cancer-free after follow-up.
- PI-RADS overestimation (40 cases) and ambiguous imaging (33 cases) were primary reasons for false positives.
- Other causes included transition zone lesions mimicking peripheral zone cancers (15 cases) and difficult-to-distinguish inflammatory conditions (17 cases).
Conclusions:
- Reasons for false-positive PI-RADS 4-5 diagnoses include PI-RADS overestimation, ambiguous imaging, difficult-to-distinguish benign conditions, and missed lesions during biopsy.
- PI-RADS overestimation and ambiguous imaging are the most common contributors to false-positive MRI diagnoses.
- Further refinement of PI-RADS interpretation criteria may reduce unnecessary biopsies.
