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

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 T₂-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.

Most small cerebral cortical veins demonstrate significant flow pulsatility: a human phase contrast MRI study at 7T

“…This could bias PI measurements. Changes in cross-sectional area across the cardiac cycle have been observed in the middle cerebral artery (Warnert et al, 2016), but to best of our knowledge have not been reported in the small cortical veins and arteries studied here. Cortical veins may be expected to show a smaller change in cross sectional area than cortical arteries (Lee et al, 2001;Kim et al, 2007;Pike, 2009, 2010;Wesolowski et al, 2019).…”

Regulation of cerebral blood flow and metabolism during exercise

“…ß74%) was stable throughout exercise. In summary, the difficulties to date in identifying the role of neurogenic control on the cerebrovascular response to exercise are twofold, as follows: (i) because of the potential for changes in middle cerebral artery diameter, interpretation of neurogenic control quantified using only MCAv may underestimate the CBF response (Coverdale et al 2014;Verbree et al 2014Verbree et al , 2017Warnet et al 2016); and (ii) the lack of a cerebral specific sympathetic antagonist or agonist makes it difficult to separate the systemic (i.e. perfusion pressure) factors from the local neural influences.…”

“…, ; Warnet et al . ); and (ii) the lack of a cerebral specific sympathetic antagonist or agonist makes it difficult to separate the systemic (i.e. perfusion pressure) factors from the local neural influences.…”

Arterial stiffness, cognitive impairment and dementia: confounding factor or real risk?

“…In humans, two recent studies in healthy volunteers described non‐invasive imaging methods to study cerebral artery compliance (Warnert et al . , ), a finding of great promise to elucidate the contribution of systemic stiffness in large arteries on the stiffness of cerebral arteries.…”

“…Although arterial stiffness is increased in this model, confounding factors such as narrowing of carotid lumen or increased peripheral inflammation may explain this compensatory effect. In humans, two recent studies in healthy volunteers described non-invasive imaging methods to study cerebral artery compliance (Warnert et al 2015(Warnert et al , 2016, a finding of great promise to elucidate the contribution of systemic stiffness in large arteries on the stiffness of cerebral arteries.…”