Adaptive bolus chasing computed tomography angiography by a local linear time and space parameter varying model: modeling, control, identification, and experimental results

Abstract

A high contrast to noise ratio (CNR) is always desirable for contrast-enhanced computed tomography angiography (CTA). To ensure a high CNR of the vascular images in CTA and potentially reduce the radiation exposure and contrast usage, an adaptive bolus chasing method is proposed and evaluated compared to the existing constant-speed method. The proposed method is based on a local time and space parameter varying model of the contrast bolus. Optimal scan time for the next segment of the vasculature is estimated and predicted in real time and guides the computed tomography (CT) scanner table movement that guarantees that each segment of the vasculature is scanned with the maximum possible enhancement. Simulations and experimental results show that the proposed bolus chasing method outperforms the conventional constant-speed method substantially.