Using High-Field Magnetic Resonance Imaging to Estimate Distensibility of the Middle Cerebral Artery

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Background

Although cerebral arterial stiffness may be an important marker for cerebrovascular health, there is not yet a measurement that accurately reflects the distensibility of major intracranial arteries. Herein, we aim to noninvasively measure distension of the human middle cerebral artery (MCA).

Methods

Ten healthy volunteers (age: 30.3 ± 10.8 years) underwent ultra-high-field (7-tesla) MRI scanning. Time-of-flight angiography and phase-contrast flow imaging were used to locate the M1 segment of the MCA and to determine the occurrence of systole and diastole. High-resolution cross-sectional cardiac triggered T ₂-weighted images of the M1 segment of the MCA were acquired in systole and diastole.

Results

The average distension of the MCA area from diastole to systole was 2.58% (range: 0.08%-6.48%). There was no significant correlation between MCA distension and the pulsatility index, calculated from the phase-contrast flow velocity profiles.

Conclusion

These results lead to the first noninvasive image-based estimation of distensibility of the MCA (approx. 5.8 × 10 ^-4 mm Hg ^-1) and demonstrate that ultra-high-field MRI could be a promising tool for investigating distensibility of intracranial arteries in relation to cerebrovascular pathology.

Related collections

Most cited references 10

Record: found
Abstract: found
Article: not found

Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility--Reykjavik study.

Gary F Mitchell, Mark van Buchem, Sigurdur Sigurdsson … (2011)

Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing to structural brain lesions and cognitive impairment in the presence of high aortic stiffness remain unclear. We hypothesized that disproportionate stiffening of the proximal aorta as compared with the carotid arteries reduces wave reflection at this important interface and thereby facilitates transmission of excessive pulsatile energy into the cerebral microcirculation, leading to microvascular damage and impaired function. To assess this hypothesis, we evaluated carotid pressure and flow, carotid-femoral pulse wave velocity, brain magnetic resonance images and cognitive scores in participants in the community-based Age, Gene/Environment Susceptibility--Reykjavik study who had no history of stroke, transient ischaemic attack or dementia (n = 668, 378 females, 69-93 years of age). Aortic characteristic impedance was assessed in a random subset (n = 422) and the reflection coefficient at the aorta-carotid interface was computed. Carotid flow pulsatility index was negatively related to the aorta-carotid reflection coefficient (R = -0.66, P<0.001). Carotid pulse pressure, pulsatility index and carotid-femoral pulse wave velocity were each associated with increased risk for silent subcortical infarcts (hazard ratios of 1.62-1.71 per standard deviation, P<0.002). Carotid-femoral pulse wave velocity was associated with higher white matter hyperintensity volume (0.108 ± 0.045 SD/SD, P = 0.018). Pulsatility index was associated with lower whole brain (-0.127 ± 0.037 SD/SD, P<0.001), grey matter (-0.079 ± 0.038 SD/SD, P = 0.038) and white matter (-0.128 ± 0.039 SD/SD, P<0.001) volumes. Carotid-femoral pulse wave velocity (-0.095 ± 0.043 SD/SD, P = 0.028) and carotid pulse pressure (-0.114 ± 0.045 SD/SD, P = 0.013) were associated with lower memory scores. Pulsatility index was associated with lower memory scores (-0.165 ± 0.039 SD/SD, P<0.001), slower processing speed (-0.118 ± 0.033 SD/SD, P<0.001) and worse performance on tests assessing executive function (-0.155 ± 0.041 SD/SD, P<0.001). When magnetic resonance imaging measures (grey and white matter volumes, white matter hyperintensity volumes and prevalent subcortical infarcts) were included in cognitive models, haemodynamic associations were attenuated or no longer significant, consistent with the hypothesis that increased aortic stiffness and excessive flow pulsatility damage the microcirculation, leading to quantifiable tissue damage and reduced cognitive performance. Marked stiffening of the aorta is associated with reduced wave reflection at the interface between carotid and aorta, transmission of excessive flow pulsatility into the brain, microvascular structural brain damage and lower scores in various cognitive domains.

0 comments Cited 279 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Clinical applications of arterial stiffness; definitions and reference values.

Michael F O'Rourke, Jan Staessen, Charalambos Vlachopoulos … (2002)

Arterial stiffening is the most important cause of increasing systolic and pulse pressure, and for decreasing diastolic pressure beyond 40 years of age. Stiffening affects predominantly the aorta and proximal elastic arteries, and to a lesser degree the peripheral muscular arteries. While conceptually a Windkessel model is the simplest way to visualize the cushioning function of arteries, this is not useful clinically under changing conditions when effects of wave reflection become prominent. Many measures have been applied to quantify stiffness, but all are approximations only, on account of the nonhomogeneous structure of the arterial wall, its variability in different locations, at different levels of distending pressure, and with changes in smooth muscle tone. This article summarizes the methods and indices used to estimate arterial stiffness, and provides values from a survey of the literature, followed by recommendations of an international group of workers in the field who attended the First Consensus Conference on Arterial Stiffness, which was held in Paris during 2000, under the chairmanship of M.E. Safar and E.D. Frohlich.

0 comments Cited 202 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Increased cerebral arterial pulsatility in patients with leukoaraiosis: arterial stiffness enhances transmission of aortic pulsatility.

Michela Simoni, Sara Mazzucco, Wilhelm Kuker … (2012)

Arterial stiffening reduces damping of the arterial waveform and hence increases pulsatility of cerebral blood flow, potentially damaging small vessels. In the absence of previous studies in patients with recent transient ischemic attack or stroke, we determined the associations between leukoaraiosis and aortic and middle cerebral artery stiffness and pulsatility. Patients were recruited from the Oxford Vascular Study within 6 weeks of a transient ischemic attack or minor stroke. Leukoaraiosis was categorized on MRI by 2 independent observers with the Fazekas and age-related white matter change scales. Middle cerebral artery (MCA) stiffness (transit time) and pulsatility (Gosling's index: MCA-PI) were measured with transcranial ultrasound and aortic pulse wave velocity and aortic systolic, diastolic, and pulse pressure with applanation tonometry (Sphygmocor). In 100 patients, MCA-PI was significantly greater in patients with leukoaraiosis (0.91 versus 0.73, P<0.0001). Severity of leukoaraiosis was associated with MCA-PI and aortic pulse wave velocity (Fazekas: χ(2)=0.39, MCA-PI P=0.01, aortic pulse wave velocity P=0.06; age-related white matter change: χ(2)=0.38, MCA-PI P=0.015; aortic pulse wave velocity P=0.026) for periventricular and deep white matter lesions independent of aortic systolic blood pressure, diastolic blood pressure, and pulse pressure and MCA transit time with MCA-PI independent of age. In a multivariate model (r(2)=0.68, P<0.0001), MCA-PI was independently associated with aortic pulse wave velocity (P=0.016) and aortic pulse pressure (P<0.0001) and inversely associated with aortic diastolic blood pressure (P<0.0001) and MCA transit time (P=0.001). MCA pulsatility was the strongest physiological correlate of leukoaraiosis, independent of age, and was dependent on aortic diastolic blood pressure and pulse pressure and aortic and MCA stiffness, supporting the hypothesis that large artery stiffening results in increased arterial pulsatility with transmission to the cerebral small vessels resulting in leukoaraiosis.

0 comments Cited 126 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Journal

Journal ID (nlm-ta): Neurodegener Dis

Journal ID (iso-abbrev): Neurodegener Dis

Journal ID (publisher-id): NDD

Title: Neuro-Degenerative Diseases

Publisher: S. Karger AG (Allschwilerstrasse 10, P.O. Box · Postfach · Case postale, CH–4009, Basel, Switzerland · Schweiz · Suisse, Phone: +41 61 306 11 11, Fax: +41 61 306 12 34, karger@karger.ch )

ISSN (Print): 1660-2854

ISSN (Electronic): 1660-2862

Publication date (Print): September 2016

Publication date (Electronic): 23 July 2016

Publication date PMC-release: 23 July 2016

Volume: 16

Issue: 5-6

Pages: 407-410

Affiliations

[1] ^aCardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, UK

[2] ^bDepartment of Clinical Neurological Sciences, University of Western Ontario, London, Ont., Canada

[3] ^cC.J. Gorter Center for High-Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands

Author notes

*Richard G. Wise, Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Maindy Road, Cardiff CF24 4HQ (UK), E-Mail wiserg@ 123456cardiff.ac.uk

Article

Publisher ID: ndd-0016-0407

DOI: 10.1159/000446397

PMC ID: 5322578

PubMed ID: 27449212

SO-VID: a2c2f8fd-1a7b-446d-a298-cf4c5f6a808b

License:

This article is licensed under the Creative Commons Attribution 4.0 International License (CC BY) (http://www.karger.com/Services/OpenAccessLicense). Usage, derivative works and distribution are permitted provided that proper credit is given to the author and the original publisher.

History

Date received : 21 January 2016

Date revision received : 23 April 2016

Page count

Figures: 2, References: 12, Pages: 4

Comments

Comment on this article

scite_

Cited by 10

See all cited by

Most referenced authors 108

See all reference authors

Using High-Field Magnetic Resonance Imaging to Estimate Distensibility of the Middle Cerebral Artery

Read this article at

Abstract

Background

Methods

Results

Conclusion

Related collections

Karger: Neurology and Neuroscience

Most cited references 10

Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility--Reykjavik study.

Clinical applications of arterial stiffness; definitions and reference values.

Increased cerebral arterial pulsatility in patients with leukoaraiosis: arterial stiffness enhances transmission of aortic pulsatility.

Author and article information

Journal

Affiliations

Author notes

Article

History

Page count

Categories

Comments

Comment on this article

Similar content 256

Cited by 10

Most referenced authors 108