Global impairment of brachial, carotid, and aortic vascular function in young smokers
Direct quantification by high-resolution magnetic resonance imaging
Frank Wiesmann, MD*,
Steffen E. Petersen, MD,
Paul M. Leeson, MD,
Jane M. Francis, DCR,
Matthew D. Robson, PhD,
Qian Wang, MD,
Robin Choudhury, MD,
Keith M. Channon, MD, FRCP and
Stefan Neubauer, MD, FRCP
University of Oxford Centre for Clinical Magnetic Resonance Research, Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
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Figure 1 Magnetic resonance imaging (MRI) of brachial artery reactivity to hyperemia. (a) Set up for brachial artery imaging in the magnetic resonance scanner with a pressure cuff on the forearm distal to the imaging site (curved arrow) and a surface coil placed above the elbow region for optimal magnetic resonance signal detection (straight arrow). (b to d) High-resolution MRIs aligned perpendicular to the brachial artery (arrows). (b) Baseline conditions (scale bar = 3 mm). Note the increase in brachial artery cross-section area (c) 1 min after cuff release (representing flow-mediated dilation) and (d) 3 min after GTN application (endothelium-independent relaxation).
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Figure 2 (a) Coronal-sagittal oblique scout image aligned with the aortic arch and descending aorta for assessment of distances between measurement points. Distance evaluation between the ascending aorta (AA) and proximal descending aorta (PDA) was performed by a series of short straight connected lines along the aortic luminal midline in the curved aortic arch, because the software did not allow for curved measurements. Distance between PDA and distal descending aorta (DDA) was assessed by a single-line measurement. Panels (b) and (c) show the corresponding TrueFISP images in transverse orientation.
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Figure 3 Magnetic resonance imaging (MRI) of central vascular compliance. Vessel wall tracings in transverse CINE TrueFISP MRIs acquired at the level of the pulmonary artery (PA) bifurcation revealing cross-section through the ascending (AA) and proximal descending aorta (PDA) at (a) diastole and (b) systole. (c and d) The MRIs of the right common carotid artery (CCA) acquired at diastole and systole. Note the increase in vessel cross-sections at systole (solid ellipse in b and d) in comparison with corresponding diastolic cross-sections (dotted ellipse in b and d). All images are cropped for display purposes (scale bar = 10 mm). EJV = external jugular vein; IJV = internal jugular vein; SCM = sternocleidomastoid muscle; SCV = superior vena cava.
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Figure 4 Relative cross-sectional area changes induced by (a) hyperemia (flow-mediated dilation [FMD] representing endothelium-dependent relaxation) and by (b) GTN (endothelium-independent relaxation) in 10 smokers and 12 nonsmokers. Solid bars = smokers; open bars = controls. *p < 0.05.
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Figure 5 Comparison of vascular distensibility between young smokers and control subjects quantified by magnetic resonance imaging at (a) different sites of the aorta, (b) in the common carotid artery, and (c) in the brachial artery. AA = ascending aorta; BA = brachial artery; CCA = common carotid artery; DDA = distal descending aorta; PDA = proximal descending aorta. Solid bars = smokers; open bars = controls. *p < 0.05.
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