Measurement of blood-brain barrier permeability in acute ischemic stroke using standard first-pass perfusion CT data.

Background And Purpose: Increased blood-brain barrier permeability is believed to be associated with complications following acute ischemic stroke and with infarct expansion. Measurement of blood-brain barrier permeability requires a delayed image acquisition methodology, which prolongs examination time, increasing the likelihood of movement artefacts and radiation dose. Existing quantitative methods overestimate blood-brain barrier permeability when early phase CT perfusion data are used. The purpose of this study is to develop a method that yields the correct blood-brain barrier permeability value using first-pass perfusion CT data.

Methods: We acquired 43 CT perfusion datasets, comprising experimental (n = 30) and validation subject groups (n = 13). The Gjedde-Patlak method was used to estimate blood-brain barrier permeability using first-pass (30-60 s after contrast administration) and delayed phase (30-200 s) data. In the experimental group, linear regression was used to obtain a function predicting first-pass blood-brain barrier permeability estimates from delayed phase estimates in each stroke compartment. The reliability of prediction with this function was then tested using data from the validation group.

Results: The predicted delayed phase blood-brain barrier permeability was strongly correlated with the measured delayed phase value (r = 0.67 and 0.6 for experimental and validation group respectively; p < 0.01). Predicted and measured delayed phase blood-brain barrier permeability in each stroke compartment were not significantly different in both experimental and validation groups.

Conclusion: We have developed a method of estimating blood-brain barrier permeability using first-pass perfusion CT data. This predictive method allows reliable blood-brain barrier permeability estimation within standard acquisition time, minimizing the likelihood of motion artefacts thereby improving image quality and reducing radiation dose.