Quantitative cerebrovascular 4D flow MRI at rest and during hypercapnia challenge

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• 作者：J. Mikhail Kellawan^a ; ^{kellawan@wisc.edu" class="auth_mail" title="E-mail the corresponding author} ; ^{mikhailkellawan@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; John W. Harrell^a ; ^{john.harrell@drake.edu" class="auth_mail" title="E-mail the corresponding author} ; Eric M. Schrauben^b ; ^{schrauben@wisc.edu" class="auth_mail" title="E-mail the corresponding author} ; Carson A. Hoffman^b ; ^{cahoffman@wisc.edu" class="auth_mail" title="E-mail the corresponding author} ; Alejandro Roldan-Alzate^c ; ^{roldan@wisc.edu" class="auth_mail" title="E-mail the corresponding author} ; William G. Schrage^a ; ^{wschrage@education.wisc.edu" class="auth_mail" title="E-mail the corresponding author} ; Oliver Wieben^b ; ^c ; ^{owieben@wisc.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：CBF ; cerebral blood flow ; PC VIPR ; four-dimensional (4D) phase contrast vastly-undersampled isotropic projection reconstruction (PC VIPR) ; TCD ; transcranial Doppler ultrasound ; MCA ; middle cerebral artery ; ACA ; anterior cerebral artery ; VA ; vertebral artery ; ICA ; internal carotid artery ; PETCO2 ; end-tidal CO2 ; HR ; heart rate ; MAP ; mean arterial pressure ; SaO2 ; arterial saturation
• 刊名：Magnetic Resonance Imaging
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：34
• 期：4
• 页码：422-428
• 全文大小：1632 K

文摘

Non-invasive measurement of cerebral blood flow (CBF) in humans is fraught with technologic, anatomic, and accessibility issues, which has hindered multi-vessel hemodynamic analysis of the cranial vasculature. Recent developments in cardiovascular MRI have allowed for the measurement of cine velocity vector fields over large imaging volumes in a single acquisition with 4D flow MRI. The purpose of this study was to develop an imaging protocol to simultaneously measure pulsatile flow in the circle of Willis as well as the carotid and vertebrate arteries at rest and during increased CO₂ (hypercapnia).

Methods

8 healthy adults (3 women, 26 ± 0.4 years) completed this study. Heart rate (pulse oximetry), arterial oxygen saturation (pulse oximetry), blood pressure (MAP, sphygmomanometry), and end-tidal CO₂ (capnograph) were measured at rest (baseline) and during hypercapnia. Hypercapnia was induced via breathing a mixed gas of 3% CO₂ and 21% O₂ (balance N₂) in the MR magnet. CBF and vessel cross-sectional area were quantified in 11 arteries using a 4D flow MRI scan, lasting 5–6 min with a radially undersampled acquisition and an isotropic spatial resolution of 0.7 mm.

Results

Baseline total CBF was 665 ± 54 ml • min^− 1. Hypercapnia increased total CBF 9 ± 3% to 721 ± 61 ml • min^− 1. Hypercapnic increases in CBF ranged from 7 to 36% by artery, with the largest increases in the left anterior cerebral artery. Increases in artery cross-sectional area were observed in basilar and vertebral arteries.

Conclusion

4D flow MRI methods are sensitive enough to detect non-uniform changes in CBF and cross-sectional area to a mild yet clinically relevant CO₂ stimulus. 4D flow MRI is a non-invasive reliable tool providing high spatio-temporal resolution in clinically feasible scan times without contrast agent. This approach can be used to interrogate regional cerebrovascular control in health and disease.