Micro-ultrasound-guided prostate biopsy: a narrative review of evidence compared with the magnetic resonance imaging pathway

Prebiopsy magnetic resonance imaging (MRI) has reshaped the diagnosis of prostate cancer, but its performance depends on scanner quality, radiologist experience, and the method used to register images with real-time ultrasound, and access remains uneven. Micro-ultrasound (MUS) operates at 29 MHz and allows suspicious areas to be graded and sampled within a single session. This narrative review aims to assess what the comparative literature currently supports and what it does not, drawing on currently available randomized, prospective, and pathology-correlated studies. In the only randomized comparison to date, targeted plus systematic biopsy detected Grade Group 2 or higher cancer in 47.1% of men assigned to MUS and 42.6% assigned to MRI fusion (difference, 3.52 percentage points; 95% confidence interval, −3.95 to 10.92), meeting the prespecified noninferiority margin among men who proceeded to biopsy. Paired and observational studies report broadly similar targeted detection, but concordance between the modalities is incomplete, and each identifies a small number of significant cancers missed by the other. Systematic cores continue to yield additional Grade Group 2 or higher cancers in several larger cohorts. The available evidence therefore concerns biopsy guidance rather than the earlier decision of whom to biopsy, and questions of triage, biopsy avoidance, omission of systematic sampling, surveillance, and reproducibility outside experienced centers remain open. MUS is best regarded as an alternative guidance method in selected settings and a complementary real-time tool where MRI is available.