High Resolution Micro Ultrasound: Can It Replace MRI?

How to cite: Klotz L. High Resolution Micro Ultrasound: Can It Replace MRI? Grand Rounds in Urology. February, 2026. Accessed Oct 2026. https://grandroundsinurology.com/high-resolution-micro-ultrasound-can-it-replace-mri/

Summary

Laurence Klotz, MD, FRCSC, Professor of Surgery, University of Toronto, and Sunnybrook Chair of Prostate Cancer Research, Sunnybrook Health Sciences Centre, Ontario, Canada, evaluates whether high-resolution micro-ultrasound can replace magnetic resonance imaging (MRI) in prostate cancer diagnosis.

Dr. Klotz presents high-resolution micro-ultrasound as an imaging modality for prostate cancer detection and its potential to replace or complement multiparametric MRI. He explains that MRI has transformed prostate cancer diagnostics by enabling targeted biopsy, but remains limited by cost, access, interpretation variability, and inability to detect small lesions reliably.

Dr. Klotz describes the technical advantages of micro-ultrasound, which operates at 29 MHz compared to conventional ultrasound frequencies, enabling resolution down to approximately 70 microns. This allows visualization of ductal architecture and real-time identification of suspicious lesions during biopsy. The technology integrates imaging and biopsy into a single session, eliminating the need for fusion targeting.

He reviews early comparative studies demonstrating similar sensitivity and specificity between micro-ultrasound and MRI for detecting clinically significant prostate cancer. The OPTIMUM randomized trial provides higher-quality evidence, showing non-inferiority of micro-ultrasound compared with MRI-guided biopsy. Detection rates for grade group 2 or higher cancers were comparable across imaging strategies, with similar performance in targeted biopsy alone.

Dr. Klotz highlights that concordance between modalities is high, but each identifies a small subset of lesions missed by the other, supporting a complementary role. Micro-ultrasound may also help clarify indeterminate MRI findings and improve correlation with tumor volume.

He emphasizes practical advantages, including reduced cost, accessibility, and shorter learning curve, as well as improved patient experience through transperineal biopsy techniques and enhanced analgesia. Micro-ultrasound enables a single-visit diagnostic pathway with targeted biopsy and minimal reliance on systematic sampling.

Dr. Klotz emphasizes that micro-ultrasound is non-inferior to MRI for detecting clinically significant prostate cancer and may serve as a primary imaging modality in selected settings, while remaining complementary to MRI in others.

The International Prostate Cancer Update (IPCU), is a multi-day, CME-accredited conference focused on new developments in prostate cancer treatment, diagnosis, and prevention. IPCU 36 featured lectures, interactive discussions, panel roundtables, debates, and case reports. This conference is led by expert physicians and is designed for urologists, medical oncologists, radiation oncologists, and other healthcare professionals involved in the diagnosis and treatment of prostate cancer.

The goal of this educational program is to equip healthcare professionals involved in the diagnosis and treatment of prostate cancer with the up-to-date clinical knowledge and tools they need to best treat their patients. The program will discuss the treatment of prostate cancer from diagnosis to treating advanced and metastatic disease. The conference aims to give physicians exposure to a comprehensive review of treating prostate cancer patients and to give them a chance to discuss the issues with peers and experts.