Korean J Radiol.  2019 Feb;20(2):225-235. 10.3348/kjr.2018.0320.

Usefulness of Virtual Expiratory CT Images to Compensate for Respiratory Liver Motion in Ultrasound/CT Image Fusion: A Prospective Study in Patients with Focal Hepatic Lesions

  • 1Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. leeminwoo0@gmail.com
  • 2Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
  • 3Medical Imaging R&D Group, Health & Medical Equipment Business, Samsung Electronics Co., Ltd., Seoul, Korea.
  • 4Biostatics and Clinical Epidemiology Center, Samsung Medical Center, Seoul, Korea.


To assess whether virtual expiratory (VE)-computed tomography (CT)/ultrasound (US) fusion imaging is more effective than conventional inspiratory (CI)-CT/US fusion imaging for hepatic interventional procedures.
This prospective study was approved by the Institutional Review Board, and informed consent was obtained from each patient. In total, 62 patients with focal hepatic lesions referred for hepatic interventional procedures were enrolled. VE-CT images were generated from CI-CT images to reduce the effects of respiration-induced liver motion. The two types of CT images were fused with real-time US images for each patient. The operators scored the visual similarity with the liver anatomy upon initial image fusion and the summative usability of complete image fusion using the respective five-point scales. The time required for complete image fusion and the number of point locks used were also compared.
In comparison with CI-CT/US fusion imaging, VE-CT/US fusion imaging showed significantly higher visual similarity with the liver anatomy on the initial image fusion (mean score, 3.9 vs. 1.7; p < 0.001) and higher summative usability for complete image fusion (mean score, 4.0 vs. 1.9; p < 0.001). The required time (mean, 11.1 seconds vs. 22.5 seconds; p < 0.001) and the number of point locks (mean, 1.6 vs. 3.0; p < 0.001) needed for complete image fusion using VE-CT/US fusion imaging were significantly lower than those needed for CI-CT/US fusion imaging.
VE-CT/US fusion imaging is more effective than CI-CT/US fusion imaging for hepatic interventional procedures.


Ultrasonography; Computed tomography; Fusion imaging; Liver; Respiration
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