Quantification of Blood Flow from Rotational Angiography

Abstract

Abstract. For assessment of cerebrovascular diseases, it is beneficial to obtain three-dimensional (3D) information on vessel morphology and hemodynamics. Rotational angiography is routinely used to determine the 3D geometry and we propose a method to exploit the same acquisition to determine the blood flow waveform and the mean volumetric flow rate. The method uses a model of contrast agent dispersion to determine the flow parameters from the spatial and temporal development of the contrast agent concentration, represented by a flow map. Furthermore, it also overcomes artifacts due to the rotation of the c-arm using a newly introduced reliability map. The method was validated on images from a computer simulation and from a phantom experiment. With a mean error of 11.0% for the mean volumetric flow rate and 15.3% for the blood flow waveform from the phantom experiments, we conclude that the method has the potential to give quantitative estimates of blood flow parameters during cerebrovascular interventions.

The influence of contrast agent injection on physiological flow in the circle of Willis

“…Furthermore, the effects of the presence of the catheter and its cross-sectional positioning in the artery on the local velocity fields [45] are assumed to have a negligible effect on the flow and pressure waveforms throughout the arterial tree. The shape of the injection rate used here differs from that used in literature, e.g., exponential decay [16]. However, the time-constant involved in the response to injection is small and the m-factor at a certain location is independent of the injection rate, i.e., the mfactor converges to its stable value within a heartbeat regardless the acceleration.…”

“…This fraction is referred to as the m-factor [16]. Therefore, the flow during injection q D at time t and location in the arterial tree x is described by…”

“…For the cerebral circulation, several in vivo flow measurements techniques are available, such as Trans-Cranial Doppler ultrasonography (TCD) [14], Phase-Contrast MR imaging (PC-MR) and videodensitometry from X-ray images [15,16]. In TCD, the velocities in the arteries of interest cannot be measured simultaneously.…”

Model-based blood flow quantification from rotational angiography

“…Also a method to overcome artefacts due to the rotation is presented. A brief overview of the method was presented in Waechter et al (2007). Here a detailed description of the method and an extended validation will be presented.…”

Cerebral Blood Flow Assessment by Digital Subtraction Angiography

“…Accordingly, there is considerable research interest in quantifying blood flow with conventional DSA. Waechter 19,20 used model-based waveform analysis of the pixel intensity. Tenjin 21 correlated mean transit time and peak time to blood flow.…”