WFUMB Liver Ultrasound Fusion Imaging Technical Review and Position Statement: Focus on CT/MRI-Based Fusion.
Authors
Affiliations (21)
Affiliations (21)
- Department of Gastroenterology and Hepatology, Elias Emergency University Hospital, Bucharest, Romania; Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania. Electronic address: [email protected].
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
- Department of Gastroenterology and Hepatology, "Victor Babeș" University of Medicine and Pharmacy, Timișoara, Romania.
- Department of Diagnostics and Public Health, Radiology Section / Institute of Radiology, University of Verona, Verona, Italy.
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania; 3rd Medical Department, "Prof. Dr. O. Fodor" Regional Institute of Gastroenterology and Hepatology, Cluj-Napoca, Romania.
- Department of General Internal Medicine, Kliniken Hirslanden Beau Site, Salem and Permanence, Bern, Switzerland.
- Brandenburg Institute for Clinical Ultrasound, Medical University Brandenburg Theodor Fontane, Neuruppin, Germany; Department of Internal Medicine, Krankenhaus Märkisch-Oderland, Strausberg, Germany.
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA.
- Department of Radiology, Interdisciplinary Ultrasound Center, LMU University Hospital, Munich, Germany.
- Department of Radiology, Northeastern Ohio Medical University/Southwoods Imaging, Youngstown, OH, USA.
- Department for Visceral Surgery and Medicine, Division of Hepatology, Inselspital/Bern University Hospital, University of Bern, Bern, Switzerland.
- Department of Diagnostics and Public Health, Radiology Section / Institute of Radiology, University of Verona, Verona, Italy; Department of Radiology, Ospedale Civile Maggiore, Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy.
- Department of Gastroenterology and Hepatology, Elias Emergency University Hospital, Bucharest, Romania; Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
- Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania; Department of Oncology, Fundeni Clinical Institute, Bucharest, Romania.
- Department of Gastroenterology and Hepatology, Elias Emergency University Hospital, Bucharest, Romania.
- Klinik Für Radiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany.
- Medical Department 2, Caritas Krankenhaus, Bad Mergentheim, Germany.
- Faculty of Life and Medical Sciences/Doshisha Medical Ultrasound Research Center, Doshisha University, Kyoto, Japan.
- Department of Gastroenterology, Wakayama Medical University Hospital, Wakayama, Japan.
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China.
- Copenhagen Academy for Medical Education and Simulation, University of Copenhagen and the Capital Region of Denmark, Copenhagen, Denmark.
Abstract
Ultrasound fusion imaging is a hybrid technique that combines real-time ultrasonography (US) with pre-acquired computed tomography (CT) or magnetic resonance imaging (MRI), using electromagnetic (EM) tracking to enable precise spatial correlation between modalities. This technology is increasingly used for liver imaging and interventions, especially when conventional B-mode US fails to provide adequate lesion visualization. The aim of this technical review and position statement is to evaluate the technical accuracy (target registration errors) and lesion visibility of ultrasound fusion imaging based on published evidence and expert consensus. This manuscript was designed as the technical component of a two-part World Federation for Ultrasound in Medicine and Biology (WFUMB) position statement. A systematic review was conducted using a PICO framework focused on two core questions: (i) to evaluate EM-tracked fusion target registration errors (PICO T1), and (ii) whether fusion improves visibility of lesions in difficult-to-image liver lesions (PICO T2). Literature from January 2012 to January 2025 was searched across PubMed, Scopus, Embase, and IEEE Xplore, with manual citation tracking and AI-assisted query generation. Eligible studies included research on US/CEUS fusion with CT/MRI, reporting technical accuracy and lesion conspicuity. The technical accuracy of fusion imaging was consistently high, with target registration errors (TRE) of ∼1-3 mm in ideal phantom settings and ∼4-14 mm in clinical studies. Automatic registration methods were faster and similarly accurate as manual registration, possibly reducing operator dependence. Fusion imaging improved the detectability of lesions not visible (occult) on conventional B-mode US, increasing the diagnostic yield and enabling successful interventions (e.g., ablation) in up to 90%-95% of cases. Safety profiles across studies were favorable, with major complication rates generally below 2%. Furthermore, fusion imaging might prove especially beneficial for treating tumors in difficult locations (e.g., caudate lobe, peribiliary lesions). Ultrasound fusion imaging significantly enhances the spatial accuracy of liver interventions by aligning real-time US with CT/MRI datasets. It improves interventional procedures guidance and maintains a low complication profile as compared to conventional US alone. Advancements in artificial intelligence (AI) and augmented reality (AR) are expected to further optimize image co-registration workflows and clinical outcomes. This technical review supports the broader adoption of fusion imaging as a key tool in liver imaging and intervention.