What question did this study set out to answer?

This research aims to determine the correlation between internal carotid artery stenosis and time-to-peak delay in cerebral blood flow among asymptomatic patients.

February 2, 2026

Relationship Between Degree of Stenosis and Time-To-Peak Delay in High Grade Asymptomatic Carotid Artery Disease

Key Points

This research aims to determine the correlation between internal carotid artery stenosis and time-to-peak delay in cerebral blood flow among asymptomatic patients.
Insonation of ICAs using a 7-10MHz probe for velocity measurements.
Standardized dynamic contrast perfusion imaging across multiple sites.
Calculation of TTP delay in hemispheres and regression analysis adjusting for risk variables.
Automated backwards model reduction in linear regressions.
End-diastolic velocity on the index side correlated significantly with time-to-peak delay (β=0.003, p=0.005).
Peak systolic velocity showed a similar correlation but was not significant (β=0.001, p=0.099).
Non-index side velocities did not correlate with TTP delay.

Abstract

Background: Cerebral hemodynamic impairment in patients with asymptomatic high-grade (>70%) internal carotid artery (ICA) stenosis is associated with risk of stroke and cognitive decline, but correlations between degree of stenosis and hemodynamic impairment are derived from small case series. Using baseline data from 242 participants in the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis–Hemodynamics (CREST-H) study, we hypothesized that degree of stenosis in the ICA would correlate with time-to-peak (TTP) delay in ipsilateral cerebral blood flow using MR/CT perfusion scans, adjusting for demographic and cardiovascular risk variables. Methods: From all participants, ICAs were insonated using a 7-10MHz probe for peak systolic velocity (PSV) and end diastolic velocity (EDV). Dynamic contrast perfusion imaging was standardized across 61 CREST-H sites, using standard sequential T2*-weighted perfusion imaging. CT perfusion used standard clinical protocols. TTP delay was calculated in the ipsilateral versus contralateral hemispheres. In cross-sectional analysis, linear regression used TTP delay as the outcome variable and PSV, EDV, and PSV ICA/CCA ratio (ICR) on the index and non-index side as primary predictor variables in 6 separate models, adjusting for covariates, followed by automated backward elimination model reduction. Results: Among 392 CREST-H participants, the 242 with complete data for all variables were included in the regression analysis (Age 70±7.6, 62%M). EDV on the index side correlated with TTP delay (β=0.003, p=0.005). PSV had a similar correlation but did not reach significance (β=0.001, p=0.099), nor did ICR (β=0.003, p=0.126). Non-index side PSV, EDV, and ICR showed no correlation with TTP delay (p=0.268, p=0.495, p=0.380 respectively). Circle of Willis completeness did not correlate with TTP. Conclusions: In this large cohort of patients with high-grade asymptomatic carotid stenosis, higher end-diastolic flow velocities correlated with greater TTP delays, supporting a definition of "hemodynamically significant stenosis." Our findings have implications for management of asymptomatic carotid stenosis which will be tested in the CREST-H study. Registration: Clinicaltrials.gov Identifier: NCT03192215

Relationship Between Degree of Stenosis and Time-To-Peak Delay in High Grade Asymptomatic Carotid Artery Disease

Key Points

Abstract

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