Comparison of approaches for surface vessel diameter and pulsatility quantification.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Medical Imaging

Background:

• Cerebral blood vessels dynamically change diameter.
• Quantifying these changes is crucial for understanding physiological and pathological states.
• Intravital microscopy images are commonly used for vessel diameter analysis.

Purpose of the Study:

• To compare the accuracy of three image-based algorithms for measuring cerebral blood vessel diameter: cross section threshold (CST), full width at half maximum (FWHM), and find image edges (FIE).
• To introduce and validate a novel method for quantifying vessel pulsation amplitude using the interquartile range (IQR).

Main Methods:

• Comparison of CST, FWHM, and FIE algorithms using synthetic data with varying noise-to-signal ratios (NSR) and brightness gradients.
• Evaluation of a new IQR-based method for pulsation amplitude quantification against the existing phase averaging (PA) method.

Main Results:

• Under low NSR (0.07), average errors were FIE: 3.7%, CST: 2.4%, and FWHM: 0.2%.
• FIE demonstrated superior accuracy in images with higher NSR and brightness gradients.
• The IQR method for pulsation amplitude was found to be as accurate as PA.
• FWHM requires modification to maintain accuracy with increased NSR.

Conclusions:

• FIE is optimal for measuring relative diameter changes and average diameter in the presence of noise and artifacts.
• FWHM is best suited for precise average diameter measurements in clean images.
• The IQR method offers a reliable alternative for quantifying vessel pulsation amplitude.