Does the Internal Carotid Artery Attenuate Blood‐Flow Pulsatility in Small Vessel Disease? A 7 T <scp>4D</scp>‐Flow <scp>MRI</scp> Study
Rick J. van Tuijl, Ynte M. Ruigrok, Lennart J. Geurts, Irene C. van der Schaaf, Geert Jan Biessels, Gabriël J.E. Rinkel, Birgitta K. Velthuis, Jaco J.M. Zwanenburg
Abstract
BACKGROUND: Increased cerebral blood-flow pulsatility is associated with cerebral small vessel disease (cSVD). Reduced pulsatility attenuation over the internal carotid artery (ICA) could be a contributing factor to the development of cSVD and could be associated with intracranial ICA calcification (iICAC). PURPOSE: To compare pulsatility, pulsatility attenuation, and distensibility along the ICA between patients with cSVD and controls and to assess the association between iICAC and pulsatility and distensibility. STUDY TYPE: Retrospective, explorative cross-sectional study. SUBJECTS: A total of 17 patients with cSVD, manifested as lacunar infarcts or deep intracerebral hemorrhage, and 17 age- and sex-matched controls. FIELD STRENGTH/SEQUENCE: Three-dimensional (3D) T1-weighted gradient echo imaging and 4D phase-contrast (PC) MRI with a 3D time-resolved velocity encoded gradient echo sequence at 7 T. ASSESSMENT: Blood-flow velocity pulsatility index (vPI) and arterial distensibility were calculated for seven ICA segments (C1-C7). iICAC presence and volume were determined from available brain CT scans (acquired as part of standard clinical care) in patients with cSVD. STATISTICAL TESTS: Independent t-tests and linear mixed models. The threshold for statistically significance was P < 0.05 (two tailed). RESULTS: The cSVD group showed significantly higher ICA vPI and significantly lower distensibility compared to controls. Controls showed significant attenuation of vPI over the carotid siphon (-4.9% ± 3.6%). In contrast, patients with cSVD showed no attenuation, but a significant increase of vPI (+6.5% ± 3.1%). iICAC presence and volume correlated positively with vPI (r = 0.578) in patients with cSVD and negatively with distensibility (r = -0.386). CONCLUSION: Decreased distensibility and reduced pulsatility attenuation are associated with increased iICAC and may contribute to cSVD. Confirmation in a larger prospective study is required. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.