Clinical study of model-based blood flow quantification on cerebrovascular data

Diagnosis and treatment decisions of cerebrovascular diseases are currently based on structural information like the endovascular lumen. In future, clinical diagnosis will increasingly be based on functional information which gives direct information about the physiological parameters and, hence, is a direct measure for the severity of the pathology. In this context, an important functional quantity is the volumetric blood flow over time. The proposed flow quantification method uses contrasted X-ray images from cerebrovascular interventions and a model of contrast agent dispersion to estimate the flow parameters from the spatial and temporal development of the contrast agent concentration through the vascular system. To evaluate the model-based blood flow quantification under realistic circumstances, dedicated cerebrovascular data has been acquired during clinical interventions. To this aim, a clinical protocol for this novel procedure has been defined and optimized. For the verification of the measured flow results ultrasound Doppler measurements have been performed acting as ground truth. The clinical data available so far indicates the ability of the proposed flow model to explain the in-vivo transport of contrast agent in blood. The flow quantification results show good correspondence of flow waveform and mean volumetric flow rate with the accomplished ultrasound measurements before angiography. Hence, the method has the potential to give sufficiently accurate, quantitative flow estimates for clinical practice and to be an alternative to ultrasound Doppler.