Bolus delay and dispersion in perfusion MRI: implications for tissue predictor models in stroke

Area of Science:

• Neuroimaging
• Radiology
• Stroke Imaging

Background:

• Dynamic-susceptibility contrast (DSC)-MRI is crucial for acute stroke assessment, generating perfusion maps via arterial input function (AIF) deconvolution.
• Commonly, AIF is measured in major arteries, introducing potential perfusion errors due to bolus delay and dispersion.
• Existing methods often address delay but inadequately correct for dispersion, a significant source of error.

Purpose of the Study:

• To assess the relationship between bolus delay and dispersion in DSC-MRI.
• To evaluate the reliability of estimating dispersion from bolus delay in acute stroke patients.
• To quantify the impact of uncorrected dispersion on perfusion measurements.

Main Methods:

• Analysis of DSC-MRI data from acute stroke patients.
• Calculation and comparison of various bolus delay metrics.
• Assessment of the correlation between bolus delay and dispersion.
• Evaluation of the magnitude of perfusion errors caused by dispersion.

Main Results:

• A significant correlation was found between one definition of bolus delay and dispersion.
• Estimating dispersion based on bolus delay proved unreliable.
• Observed dispersion levels in many patients were substantial enough to cause significant perfusion errors.

Conclusions:

• Bolus delay and dispersion in DSC-MRI are linked but not predictably.
• Uncorrected dispersion significantly impacts perfusion map accuracy in acute stroke.
• Accurate quantification of dispersion is critical for reliable stroke assessment and management.