title: Technical recommendations for the use of carotid duplex ultrasound for the assessment of extracranial blood flow.
abstract: Duplex ultrasound is an evolving technology that allows the assessment of volumetric blood flow in the carotid and vertebral arteries during a range of interventions along the spectrum of health and chronic disease. Duplex ultrasound can provide high-resolution diameter and velocity information in real-time and is noninvasive with minimal risks or contraindications. However, this ultrasound approach is a specialized technique requiring intensive training and stringent control of multiple complex settings; results are highly operator-dependent, and analysis approaches are inconsistent. Importantly, therefore, methodological differences can invalidate comparisons between different imaging modalities and studies; such methodological errors have potential to discredit study findings completely. The task of this review is to provide the first comprehensive, user-friendly technical guideline for the application of duplex ultrasound in measuring extracranial blood flow in human research. An update on recent developments in the use of edge-detection software for offline analysis is highlighted, and suggestions for future directions in this field are provided. These recommendations are presented in an attempt to standardize measurements across research groups and, hence, ultimately to improve the accuracy and reproducibility of measuring extracranial blood flow both within subjects and between groups.
authors.affiliation: Department of Surgical Sciences, University of Otago, Dunedin, New Zealand; School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand; and kate.thomas@otago.ac.nz.
authors.forename: Kate N
authors.initials: KN
authors.lastname: Thomas
authors.affiliation: Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada.
authors.forename: Nia C S
authors.initials: NC
authors.lastname: Lewis
authors.affiliation: Department of Surgical Sciences, University of Otago, Dunedin, New Zealand;
authors.forename: Brigid G
authors.initials: BG
authors.lastname: Hill
authors.affiliation: Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada.
authors.forename: Philip N
authors.initials: PN
authors.lastname: Ainslie
mesh_terms: D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000502:physiology; D002560:Cerebrovascular Circulation; D004452:Echocardiography; D006801:Humans; D012039:Regional Blood Flow / Q000502:physiology*; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods*; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000502:physiology
keywords: carotid artery; cerebral blood flow measurement; cerebral hemodynamics; transcranial Doppler; ultrasound