Arterial spin labelling-based evaluation of cerebrovascular reserve impairment using a mathematical convolution model

Motivation: Modelled CVR response to acetazolamide in affected regions resembles the effects of dispersion compared to unaffected regions and thus can be mathematically described as a convolution with a flow dampening function (FDF). Goal(s): To formalise the derivation of the FDF and to assess clinical potential. Approach: Formalisation of the FDF was based on the convolution theorem. Analysis of simulation data and in-vivo ASL-based measurements were performed. Absolute area under the FDF was calculated. Results: The shape of the FDF followed a predictable pattern. Correlation analysis showed moderate to high correlations between absolute area and CVR and time to maximum blood flow augmentation, respectively. Impact: Flow dampening functions in conjunction with modelling of the cerebrovascular response after acetazolamide injection may be used as a clinical surrogate in patients with moyamoya disease. Further studies are warranted analysing longitudinal datasets and normal material.