Indexing Cerebrovascular Health Using Transcranial Doppler Ultrasound

Rashid Afkhami; Rachel Wong; Saadallah Ramadan; Frederick Rohan Walker; Sarah Johnson

doi:10.1016/j.ultrasmedbio.2020.12.022

Indexing Cerebrovascular Health Using Transcranial Doppler Ultrasound

Ultrasound Med Biol. 2021 Apr;47(4):919-927. doi: 10.1016/j.ultrasmedbio.2020.12.022. Epub 2021 Jan 22.

Authors

Rashid Afkhami¹, Rachel Wong², Saadallah Ramadan³, Frederick Rohan Walker², Sarah Johnson⁴

Affiliations

¹ School of Electrical Engineering & Computing, University of Newcastle, Callaghan, New South Wales, Australia. Electronic address: rashid.afkhami@newcastle.edu.au.
² School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.
³ School of Health Science, University of Newcastle, Callaghan, New South Wales, Australia.
⁴ School of Electrical Engineering & Computing, University of Newcastle, Callaghan, New South Wales, Australia.

PMID: 33494950
DOI: 10.1016/j.ultrasmedbio.2020.12.022

Abstract

Transcranial Doppler (TCD) blood flow velocity has been extensively used in biomedical research as it provides a cost-effective and relatively simple approach to assess changes in cerebral blood flow dynamics and track cerebrovascular health status. In this article we introduce a new TCD-based timing index, TI_TCD, as an indicator of vascular stiffening and vascular health. We investigate the correlations of the new index and the existing indices, namely the pulsatility index and the augmentation index, with age, cardiorespiratory fitness (CRF) and magnetic resonance imaging (MRI) blood flow pulsatility index (PI_MRI). Notably, the new index showed stronger correlations with CRF (r = -0.79) and PI_MRI (r = 0.53) compared with the augmentation index (r = -0.65 with CRF and no significant correlation with PI_MRI) and the pulsatility index (no significant correlations with CRF or PI_MRI), and a similar correlation with age as the augmentation index. The clearer relationship of the proposed timing index with vascular aging factors underlines its utility as an early indicator of vascular stiffening.

Keywords: Aging; Augmentation index; Blood flow velocity; Pulsatility index; Transcranial Doppler; Wave reflection.

MeSH terms

Adult
Age Factors
Aged
Blood Flow Velocity
Cardiorespiratory Fitness / physiology
Cerebrovascular Circulation*
Female
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Ultrasonography, Doppler, Transcranial*
Vascular Stiffness / physiology*