Diagnostic Performance of High-Resolution Micro-Ultrasound and Conventional Ultrasound in MRI-Ultrasound Fusion Biopsy for Clinically Significant Prostate Cancer Detection
Ghazal Khajir, MD, Lindsey Webb, BSME, Soum Lokeshwar, MD, Taira Anderson, BS, Michael S. Leapman, MD, Preston C. Sprenkle, MD, Joseph F. Renzulli, MD
Yale school of medicine, New Haven, CT, USA
BACKGROUND: Significant improvements in imaging resolution and quality with micro-ultrasound (microUS) compared with conventional ultrasound may improve the diagnostic accuracy of prostate biopsy. The aim of this study was to evaluate the diagnostic outcomes of MRI-ultrasound fusion targeted biopsy in detecting clinically significant prostate cancer using either microUS technology or conventional ultrasound. METHODS: We performed a retrospective analysis of 429 patients who received ExactVu microUS-guided biopsy at a single institution from October 2021 through January 2023. Targeted biopsies (TB) were taken from multiparametric MRI targets (Prostate Imaging-Reporting and Data System [PI-RADS] ≥2), followed by a 12-core systematic biopsy (SB). We also included a matched group of 470 men based on the PI-RADS score and biopsy status who underwent MRI-conventional US fusion biopsy using the Artemis device at the same institution between January 2017 and May 2022. The proportion of cancers detection (any cancer and grade group (GG) ≥2) by TB was compared between MRI-microUS fusion biopsy and (MRI-conventional US fusion biopsy groups. RESULTS: The overall incidence of GG≥2 cancer was similar between MRI-microUS fusion biopsy and MRI-conventional US fusion biopsy groups (53.6% vs 55.3%, p>0.05). In patients undergoing MRI-microUS fusion biopsy, detection of any cancer in SB was greater than TB (69.2% vs 57.1%, p<0.001), while GG≥2 detection was similar between SB and TB (44.9% vs 40.5%, p=0.06, Table 1). Moreover, detection of any cancer and GG ≥2 using TB were lower in MRI-microUS fusion biopsy group compared with those in MRI-conventional US fusion biopsy group (any cancer: 57.1% vs 71.9%, p<0.001; GG ≥2: 40.5% vs 49.7%, p=0.005, Table 1). On multivariate analysis, age (OR 1.05, p<0.001), biopsy-naïve status vs. prior negative biopsy (OR 0.25, p<0.001) and vs. active surveillance (OR 0.61, p=0.009), PSA density (OR 2.29 per 0.1 unit increase, p<0.001), and PI-RADS score 4 vs. 3 (OR 5.11, p<0.001) and 5 vs. 3 (OR 9.67, p<0.001) were significant predictors in the detection of GG ≥2 (Table 2). However, MRI-US fusion method (microUS or conventional US) was not associated with the detection of GG ≥2 (p>0.05). CONCLUSIONS: Among patients undergoing MRI-US fusion targeted biopsy, microUS-guided targeted biopsy of MRI regions of interest yielded lower cancer detection compared with MRI-conventional US fusion biopsy. Nevertheless, both MRI-microUS and MRI-conventional US fusion biopsy groups were comparable in terms of overall cancer detection on combined systematic and fusion targeted biopsy. We await the results of the OPTIMUM randomized trial to clarify the relationship between microUS and conventional US fusion biopsy. 
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