Performance of post-ablation MRI using PI-RADS scoring in detecting residual prostate cancer after HIFU: a single center experience

Jamil Almohtasib, Lucia Elting, Ignacio San Francisco, Ra’ad Al-Faouri, Agustin Perez-Londoño, Andrew Wagner, Boris Gershman, Peter Chang, Aria F. Olumi^*
Division of Urologic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, USA
* Corresponding Author: Aria F. Olumi. Email: email
(This article belongs to the Special Issue: Non-Radical Treatment for Prostate Cancer: A New Approach)

Canadian Journal of Urology https://doi.org/10.32604/cju.2026.078095

Received 24 December 2025; Accepted 11 May 2026; Published online 18 June 2026

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Abstract

Background: Follow-up after High-Intensity Focused Ultrasound (HIFU) for prostate cancer lacks standardization, particularly regarding the role and accuracy of imaging and biopsy. Therefore, this study aimed to evaluate the diagnostic performance of multiparametric magnetic resonance imaging (mpMRI) following HIFU therapy for intermediate-risk prostate cancer. Methods: Patients with biopsy-proven, intermediate-risk, localized prostate cancer were offered HIFU therapy. Prior to treatment, patients underwent template prostate biopsy, prostate MRI and genomic testing (OncotypeDX). Baseline International Prostate Symptom Score, Prostate-specific antigen, and Prostate Imaging-Reporting and Data System (PI-RADS) scores were recorded. Clinically significant prostate cancer (csPCa) was defined as a Gleason grade group ≥ 2. Follow-up included post-treatment MRI and biopsy one year after HIFU. Results: We treated 67 men, median PSA decreased from 6.0 (Interquartile range 4.5–7.8) ng/mL to 2.5 (1.2–4.0) ng/mL at first follow-up (p < 0.01). Post-HIFU MRI and biopsy were performed in 32 (47.8%) and 28 (41.8%) men, respectively. Among patients who had an MRI, 13 (40.6%) had positive findings (PI-RADS ≥ 3 lesions) and 19 (59.4%) did not. Of the 13 positive MRIs, 12 patients underwent biopsy, and 4 had csPCa, resulting in a positive predictive value of 33.3%. Among the 19 negative MRIs, 16 underwent biopsy and 12 had no csPCa with a NPV of 75.0%. Overall, 15 out of 28 (53.6%) men had evidence of prostate cancer on biopsy, with 8 out of 28 (28.6%) with csPCa. In the field, recurrence of PCa and csPCa was seen in 10 (35.7%) and 5 (17.9%) patients, respectively. There was no significant difference in pre- and post-HIFU IPSS scores (p = 0.221). Conclusions: In this cohort of men with intermediate-risk localized PCa treated with HIFU, MRI using PI-RADS scoring alone showed modest performance; it missed both in and out of field recurrence csPCa. Findings support the need for routine protocolized biopsy post-HIFU regardless of MRI findings.