title: Evaluation of the carotid artery stenosis based on minimization of mechanical energy loss of the blood flow.
abstract: BACKGROUND
  Internal carotid artery stenosis requires an accurate risk assessment for the prevention of stroke. Although the internal carotid artery area stenosis ratio at the common carotid artery bifurcation can be used as one of the diagnostic methods of internal carotid artery stenosis, the accuracy of results would still depend on the measurement techniques. The purpose of this study is to propose a novel method to estimate the effect of internal carotid artery stenosis on the blood flow based on the concept of minimization of energy loss.
  
  
  METHODS
  Eight internal carotid arteries from different medical centers were diagnosed as stenosed internal carotid arteries, as plaques were found at different locations on the vessel. A computational fluid dynamics solver was developed based on an open-source code (OpenFOAM) to test the flow ratio and energy loss of those stenosed internal carotid arteries. For comparison, a healthy internal carotid artery and an idealized internal carotid artery model have also been tested and compared with stenosed internal carotid artery in terms of flow ratio and energy loss.
  
  
  RESULTS
  We found that at a given common carotid artery bifurcation, there must be a certain flow distribution in the internal carotid artery and external carotid artery, for which the total energy loss at the bifurcation is at a minimum; for a given common carotid artery flow rate, an irregular shaped plaque at the bifurcation constantly resulted in a large value of minimization of energy loss. Thus, minimization of energy loss can be used as an indicator for the estimation of internal carotid artery stenosis.
authors.affiliation: 1 Division of Neurosurgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Sheau Fung
authors.initials: SF
authors.lastname: Sia
authors.affiliation: 2 Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Xihai
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 2 Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: 3 Medical Center, Tsinghua University, Beijing, China.|4 Australian School of Advanced Medicine (ASAM), Macquarie University, Sydney, NSW, Australia.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: 5 Monash Medical Centre, Melbourne, VIC, Australia.
authors.forename: Winston
authors.initials: W
authors.lastname: Chong
authors.affiliation: 2 Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Le
authors.initials: L
authors.lastname: He
authors.affiliation: 2 Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D008955:Models, Cardiovascular; D012039:Regional Blood Flow
keywords: Internal carotid artery stenosis; computational fluid dynamics; energy loss; internal carotid artery flow ratio; minimization of energy loss