Micro-Ultrasound Prostate Cancer Archives

High Resolution Micro-Ultrasound: Going Beyond MRI

by Laurence Klotz, MD, FRCSC | Jul 2024

Laurence Klotz, MD, FRCSC, illustrates the value of high resolution micro-ultrasound over that of multiparametric MRI (mpMRI) in prostate cancer staging and diagnosis. He begins by reviewing the history, strengths, and limitations of mpMRI, and he presents his own history with high resolution micro-ultrasound.

Dr. Klotz then explains the differences between high resolution micro-ultrasound and conventional ultrasound. He compares the sensitivity, precision, and accuracy of high resolution micro-ultrasound against those of mpMRI and conventional ultrasound.

Dr. Klotz concludes by examining the efficacy of combining mpMRI and high resolution micro-ultrasound for prostate cancer diagnosis and staging. He presents data from ongoing trials supporting the use of high resolution micro-ultrasound as a complement to mpMRI.

OPTIMUM Trial – Current and Emerging Evidence Supporting 29MHz High- Precision, Real-Time Micro-Ultrasound

by Preston C. Sprenkle, MD | Apr 2023

Preston C. Sprenkle, MD, discusses the OPTIMUM trial examining micro-ultrasound, MRI fusion, and the combination of these in prostate cancer diagnosis.

ExactVu™ Micro-Ultrasound for Diagnosis of Prostate Cancer

by Priya N. Werahera, PhD | Apr 2022

Priya N. Werahera, PhD, Research Associate Professor in the Departments of Pathology and Bioengineering at the University of Colorado Anschutz Medical Campus, discusses the advantages of using the ExactVu micro-ultrasound platform to diagnose prostate cancer. First, he considers whether MRI imaging can be considered standard of care, arguing that it cannot be seen as such since many cancers are MRI-invisible, it is not cost effective, the technology remains in evolution, and there is high interobserver variability among radiologists. Dr. Werahera then turns to micro-ultrasound, explaining that the new ExactVu system is a 29 MHz machine which provides real-time imaging of prostate cancer lesions, has a high resolution of 70 microns, and can provide both lateral and axial resolution. He cites a meta-analysis which shows that micro-ultrasound is a relatively convenient and cost-effective method of real-time imaging which is highly sensitive in detecting clinically significant prostate cancer. Dr. Werahera then discusses a study at the University of Colorado comparing micro-ultrasound lesions vs. histopathology data of mapping biopsy which found that PRIMUS scores 4-5 have 100% sensitivity at the patient-level and 80% sensitivity at lesion-level for diagnosis of ≥ Gleason Grade 2 prostate cancer lesions. There were 2 undiagnosed Gleason Grade 2 lesions, both of which were small and located anteriorly. Dr. Werahera concludes that ExactVu micro-ultrasound has the potential to improve current imaging standards since it has comparable screening performance to MRI and comparable biopsy performance to MRI fusion, while also allowing for easier, more effective micro-ultrasound/MRI fusion. He also notes that ExactVu micro-ultrasound may enable widespread focal therapy due to its high accuracy in finding satellite lesions and lesion boundaries.

Considerations to Improve Screening for Prostate Cancer

by Gerald L. Andriole, Jr., MD | Dec 2021

Gerald L. Andriole, Jr., MD, outgoing Robert K. Royce Distinguished Professor and Chief of Urologic Surgery at Barnes-Jewish Hospital, the Siteman Cancer Center, and Washington University School of Medicine in St. Louis, Missouri, and incoming Director of Urology in the National Capital Region at the Brady Urologic Institute at Johns Hopkins University, reviews current guidelines for prostate cancer screening and considers how screening can be improved. After an introduction from E. David Crawford, Editor-in-Chief of Grand Rounds in Urology and Professor of Urology at the University of California, San Diego, Dr. Andriole summarizes the AUA, EAU, and NCCN prostate cancer screening guidelines, highlighting the NCCN’s recommendation that men get an early-in-life PSA test to obtain a baseline, and interrogating the validity of the age cut-offs for testing in the AUA and EAU guidelines. He then proposes a series of concepts to improve screening, starting with recommendations on how to better identify which men are at above average risk. Dr. Andriole particularly emphasizes the utility of polygenomic risk scores, which have a high negative predictive value and can focus attention on which patients need to be further screened. He suggests that another key way to improve screening is to reduce confusion about the PSA test among patients and primary care providers by setting a cut-point of 1-1.5 as a threshold for referral to a urologist. Dr. Andriole then considers how to identify patients with clinically-significant prostate cancer earlier, focusing on the need for better biopsies. He also notes the importance of reducing unnecessary repeat and initial biopsies and suggests potentially using biomarkers, MRI, and PSMA-PET to decide whether a biopsy is necessary. After concluding his talk, Dr. Andriole further discusses polygenic risk score, the pros and cons of multiparametric MRI, the benefits of micro-ultrasound, transrectal versus transperineal biopsy, and the future of screening with Dr. Crawford.

Urologic Perspective on the Clinical Utility of and Emerging Data on Micro-Ultrasound

by Rafael Sanchez-Salas, MD | Dec 2021

In part 2 of a 2-part series on micro-ultrasound for prostate cancer imaging, Rafael Sanchez-Salas, MD, Associate Professor of Urology at McGill University in Montreal, Quebec, reviews data on micro-ultrasound (microUS) from a urologic perspective, comparing it to MRI in order to evaluate its clinical utility. He explains that there is more and more data suggesting microUS’s superiority to multiparametric (mp)MRI in screening and the benefits of using it in addition to MRI in clinically significant prostate cancer (csPCa). Dr. Sanchez-Salas discusses microUS’s comparable detection rates to mpMRI as shown by a balanced forest plot with ratios ranging between .94 and 1.05 and its ability to help 23% of patients avoid biopsy with no cases of missed csPCa. He then looks at a study testing a proposed protocol for assessing risk based on microUS which showed a much higher sensitivity than mpMRI in microUS of 87.5% vs. 55-61% but lower specificity of 80% vs. 87-88%. Dr. Sanchez-Salas states that there are still several questions to be answered about microUS’s utility on its own, during active surveillance, for focal therapy, and for bladder cancer staging. He concludes with a discussion of the OPTIMUM trial, which will conclude in spring of 2023 and which is meant to provide level-1 evidence regarding the use of microUS in prostate biopsy.

Radiologic Perspective on the Clinical Utility of and Emerging Data on Micro-Ultrasound

by Sangeet Ghai, MD, FRCR | Dec 2021

In part 1 of a 2-part series on micro-ultrasound for prostate cancer imaging, Sangeet Ghai, MD, FRCR, Deputy Chief of Research and Associate Professor in the Joint Department of Medical Imaging (JDMI) at the University of Toronto in Ontario, Canada, considers micro-ultrasound and data evaluating its ability to produce better results than conventional imaging from a radiologic perspective. He explains that micro-ultrasound is a system that functions on a higher frequency than conventional options and uses the PRIMUS protocol, a prostate risk identification system similar to PIRADS. Dr. Ghai states that micro-ultrasound has been shown to increase detection rates by 12%, have sensitivity as high as 91%, and find cancer that was missed by MRI. He also discusses data comparing micro-ultrasound to other imaging modalities that shows that micro-ultrasound can find 1.05 times as much grade group 2 and higher disease as multiparametric MRI and has a 14.6% higher detection rate than robotic elastic fusion. Dr. Ghai concludes by reviewing data looking at micro-ultrasound visibility of MRI lesions and real-time targeting showing that 90% of MRI lesions were visible on micro-ultrasound and that 61% of those harbored clinically significant prostate cancer (csPCa) on targeted biopsy, that 43% of MRI lesions were retrospectively visible on TRUS and that 58% of those harbored csPCa, and that 24% of micro-ultrasound lesions with normal MRI were positive for csPCa.

The OPTIMUM Trial: 29 MHz Micro-Ultrasound vs. MRI in Diagnosis of Prostate Cancer

by Gerald L. Andriole, Jr., MD | Nov 2021

Gerald L. Andriole, Jr., MD, Robert K. Royce Distinguished Professor and Chief of Urologic Surgery at Barnes-Jewish Hospital, the Siteman Cancer Center, and Washington University School of Medicine in St. Louis, Missouri, introduces the OPTIMUM trial comparing high-resolution 29 MHz micro-ultrasound to MRI in the diagnosis of prostate cancer. After an introduction by E. David Crawford, MD, Professor of Urology at the University of California, San Diego, and Editor-in-Chief of Grand Rounds in Urology, Dr. Andriole explains that micro-ultrasound is a novel ultrasound-based system operating at 29 MHz that results in a 300 percent improvement in resolution compared to conventional ultrasound. He explains that micro-ultrasound can be used for transrectal or transperineal biopsy, with or without MRI. Dr. Andriole also notes that, like MRI with PI-RADS, micro-ultrasound has its own prostate risk identification using micro-ultrasound (PRI-MUS) classification system and works with all the skills urologists already have. He observes that several small studies have found superior or comparable sensitivity and/or clinically-significant prostate cancer detection with micro-ultrasound as compared to MRI, but that level 1 evidence is lacking. Dr. Andriole explains that the OPTIMUM trial, a 3-arm randomized controlled trial, is intended to fill in that gap and provide better evidence regarding micro-ultrasound’s efficacy. He describes the design of the trial, noting that 1200 biopsy-naïve subjects will be randomized to micro-ultrasound-only biopsy, MRI/micro-ultrasound “FusionVu” biopsy, and MRI/ultrasound biopsy with conventional fusion system, and that the trial is set to begin in winter 2021 and finish by spring 2023. The discussion concludes with a question and answer session in which Drs. Crawford and Andriole discuss which fusion platforms will be used, the price of micro-ultrasound, other potential applications for micro-ultrasound, and more.

Accuracy of ExactVu™ Micro-Ultrasound for Diagnosis of Prostate Cancer

by Priya N. Werahera, PhD | Aug 2020

Priya N. Werahera, PhD, Research Assistant Professor in the Departments of Pathology and Bioengineering at the University of Colorado Anschutz Medical Campus, shares results from a study that compared ExactVu™ Micro-Ultrasound’s accuracy with that of mapping biopsy’s. He specifies that although more studies are needed to confirm these positive findings, this study has shown that the PRIMUS scoring system (similar to PIRADS) is consistent, and that there is potential clinical utility thanks to ExactVu’s™ ability to deliver real-time diagnoses and be used with or without MRI.