Hemodynamic Assessment of Carotid Artery Stenosis Using 4D Flow MRI: Complementary Insights Beyond Morphological
Yuki Kanazawa1, Chika Tatsugae2, Tosiaki Miyati3
1Department of Medical Imaging Physics, Faculty of Life Sciences, Kumamoto University, Japan (Y.K.); Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan (Y.K., M.H.).
Insights
Four-dimensional flow MRI (4D flow MRI) can assess hemodynamic parameters like peak velocity in carotid artery stenosis. Peak velocity is a predictor of significant stenosis, offering insights beyond traditional imaging alone.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
- Hemodynamics
Background:
- Carotid artery stenosis severity is typically graded by morphology.
- Morphological grading may not fully capture the local hemodynamic burden.
Purpose of the Study:
- Investigate associations between 4D flow MRI hemodynamic parameters and carotid artery stenosis severity.
- Evaluate the diagnostic performance of these parameters.
- Explore morphology-related hemodynamic variations.
Main Methods:
- 65 patients with carotid artery stenosis underwent 4D flow MRI and TOF-MRA.
- Stenosis rate calculated using NASCET criteria.
- Hemodynamic parameters (peak velocity, WSS, flow volume) extracted.
- Correlation, logistic regression, and ROC analyses performed.
Main Results:
- Peak velocity correlated positively with stenosis rate.
- Peak velocity independently predicted significant stenosis (NASCET ≥50%).
- Combined model achieved moderate diagnostic performance (AUC ≈ 0.72).
- Morphology-based analysis showed qualitative flow differences but no significant quantitative hemodynamic variations.
Conclusions:
- 4D flow MRI-derived peak velocity provides information on local flow acceleration missed by morphology alone.
- Morphology-based grading may not fully reflect the local hemodynamic burden in carotid artery stenosis.
Rationale And Objectives:
To investigate the association between hemodynamic parameters derived from four-dimensional flow magnetic resonance imaging (4D flow MRI) and carotid artery stenosis severity, to evaluate their diagnostic performance, and to perform an exploratory assessment of morphology-related hemodynamic variation.
Material And Methods:
A total of 65 patients with carotid artery stenosis underwent 4D flow MRI and time-of-flight MR angiography (TOF-MRA). Stenosis rate was calculated using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria. Hemodynamic parameters including peak velocity, average wall shear stress (WSS), and total forward flow volume were extracted at the most stenotic segment. Associations with stenosis rate were evaluated using Spearman correlation. Multivariable logistic regression and receiver operating characteristic (ROC) analyses were performed to assess predictive performance. Supplementary exploratory analyses examined the relationship between morphology-based classification and hemodynamic parameters.
Results:
Peak velocity showed a weak positive correlation with stenosis rate, whereas average WSS and total forward flow volume showed weak or negligible correlations. In multivariable analysis, peak velocity was identified as an independent predictor of significant stenosis (NASCET ≥50%). ROC analysis demonstrated moderate diagnostic performance, with the combined model achieving the highest area under the curve (AUC ≈ 0.72). Exploratory morphology-based analyses showed qualitative differences in flow patterns, but no significant quantitative differences in the evaluated hemodynamic parameters across morphological groups.
Conclusion:
4D flow MRI-derived hemodynamic parameters, particularly peak velocity, may provide information on local flow acceleration that is not fully captured by morphology-based stenosis grading alone. The findings also suggest that morphology-based grading alone may not fully reflect local hemodynamic burden.
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