A preliminary study on adaptive field-of-view tracking in peripheral digital subtraction angiography

About two million peripheral angiographies are performed annually in the United States, hence a reduction in exposure would yield significant healthcare benefits. The synchronization of bolus traveling, the table motion, and the fluoroscopic imaging chain can be highly effective for dose reduction in Digital Subtraction Angiography (DSA) by minimizing the field-of-view according to the vascular anatomy of the region traveled by the bolus. The goal of this paper is to demonstrate the feasibility of adjusting the field-of-view while tracking the contrast bolus, thus reducing the dosage of both the bolus and the radiation. The speed of the bolus is respectively estimated in the systole and diastole stages. An EKG-gated Hammerstein model is used to predict the bolus chasing speed. A real-time algorithm is designed to extract the bolus dynamics, and define the field of view transversely and longitudinally. A limb stabilization technique is also presented to suppress any significant image misalignment. Our simulation results show that the proposed techniques are promising for clinical applications.