Estimation of bolus dispersion effects in perfusion MRI using image-based computational fluid dynamics

Area of Science:

• Medical Imaging
• Neuroscience
• Biophysics

Background:

• Bolus tracking MRI is crucial for acute stroke investigation and perfusion measurement.
• Steno-occlusive disease can cause bolus dispersion, leading to significant errors in cerebral blood flow (CBF) quantification.
• The exact vascular transport function characterizing bolus dispersion remains unknown.

Purpose of the Study:

• To present a novel method for quantifying bolus dispersion errors in perfusion measurements.
• To evaluate the accuracy of existing simple vascular models using the new methodology.
• To assess the impact of stenosis on bolus dispersion and CBF quantification.

Main Methods:

• Construction of patient-specific models using anatomical and physiological MR data.
• Computation of arterial blood flow and contrast agent bolus transport via finite element analysis.
• Testing the methodology on MR data from normal subjects and patients with carotid artery stenosis.

Main Results:

• Estimated CBF errors ranged from 15% to 20%.
• Stenosis presence did not consistently correlate with increased bolus dispersion.
• Both geometrical and physiological factors influence the degree of bolus dispersion.

Conclusions:

• The developed method enhances understanding of dispersion-related errors in perfusion imaging.
• It aids in assessing and validating vascular models for CBF quantification.
• It supports the development of new methods to correct dispersion errors in stroke assessment.