Measuring arterial tortuosity in the cerebrovascular system using Time-of-Flight MRI

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Vascular Biology

Background:

• The Circle of Willis (CW) is vital for brain blood supply, with increased vessel tortuosity linked to cerebrovascular disease progression.
• Accurate tortuosity measurement from MR TOF images is challenging due to segmentation noise and sparsity.
• Existing methods struggle with precise curvature estimation for reliable tortuosity metrics.

Purpose of the Study:

• To develop and validate an open-source pipeline for robustly estimating internal carotid artery (ICA) tortuosity from MR TOF data.
• To introduce novel curvature-based tortuosity metrics with an indicator of spline fit quality.
• To assess the pipeline's ability to capture tortuosity under noise and correlate it with clinical markers.

Main Methods:

• Developed an end-to-end pipeline utilizing unit-speed spline fitting for precise curvature estimation.
• Generated curvature-based tortuosity metrics for the ICA, incorporating a spline fit quality indicator.
• Validated the method with theoretical data and applied it to MR TOF images from 22 participants.

Main Results:

• The developed metrics accurately capture tortuosity even with significant image noise.
• The pipeline successfully discriminates between different types of abnormal arterial coiling.
• ICA tortuosity measures showed a positive correlation with participant age and carotid artery intima-media thickness.

Conclusions:

• The novel pipeline provides reliable tortuosity measures from MR TOF images, crucial for assessing cerebrovascular disease burden.
• This method has significant translational potential for clinical applications in estimating cerebrovascular disease.
• Open-source availability facilitates wider adoption and further research in the field.