Model-based blood flow quantification from DSA: quantitative evaluation on patient data and comparison with TCCD

Purpose: To support intra-interventional decisions on diagnosis and treatment of cerebrovascular diseases, a method providing quantitative information about the blood flow in the vascular system is proposed. Method: This method combines rotational angiography to extract the 3D vessel geometry and digital subtraction angiography (DSA) to obtain the flow observations. A physical model of blood flow and contrast agent transport is used to predict the propagation of the contrast agent through the vascular system. In an iterative approach, the model parameters, including the volumetric blood flow rate, are adapted until the prediction matches the observations from the DSA. The flow estimation method was applied to patient data: For 24 patients, the volumetric blood flow rate was determined from angiographic images and for 17 patients, results were compared with transcranial color coded Doppler (TCCD) measurements. Results: The agreement of the x-ray based flow estimates with TCCD was reasonable (bias ΔM = 3%, correlation ρ = 0.76) and reproducibility was clearly better than the reproducibility of the acquired TCCD measurements. Conclusion: Overall we conclude that it is feasible to model the contrast agent transport in patients and to utilize the flow model to quantify their blood flow with angiographic means.