Intra-arterial Perfusion in Interventional Radiology

Overview

Patients are being asked to participate in a study to better determine blood flow going to tumors in the liver. They will undergo an embolization procedure in interventional radiology where the goal is to provide treatment directly into the liver tumor. These treatments are delivered into the blood vessels feeding the tumors. Improving these treatments relies on better understanding the blood flow into the tumor. By understanding how much blood flows into the tumors, the goal is to make sure there is the best chance of killing the tumor. The investigators are attempting to use a special type of CT scan during the procedure to determine the blood flow to the tumors.

Accurate liver imaging is critically important for the appropriate management of hepatocellular carcinoma (HCC) patients. The unique capability of the 4 dimensional (4D) CT system that combines CT and vascular imaging in real time has the great potential to provide physiologic and functional information to the operators to help guide therapy decisions during interventional procedures. However, the workflow, protocols and parameters have not been studied and optimized to support the use of perfusion techniques during interventional procedures. Efforts to reduce contrast and radiation doses associated with perfusion imaging to as low as reasonably achievable (ALARA) are also important steps to ensure patient safety while generating clinically meaningful images. Reducing radiation doses may be achieved by adjusting scan parameters, then applying reconstruction techniques to improve the image quality. The new generation of reconstruction algorithms, such as Model-Based iterative reconstruction, or deep-learning reconstruction algorithms (e.g. AiCE), simultaneously improve noise (lower dose) and enhances low contrast characteristics (less contrast). This pilot study aims to demonstrate the use of 4D CT system to acquire liver perfusion information to support the interventional procedure, and to derive as low as reasonably achievable (ALARA) dose levels and examine the robustness of reconstruction algorithms that generate clinically meaningful perfusion maps. The study will investigate the impact of different dose levels, and the robustness of reconstruction algorithms on CT perfusion maps. A successful study could allow for dissemination of these methods for use to the wider physician audience with an optimum ALARA dose levels. Furthermore, the potential knowledge gained from this study will further educate the medical community about the potential benefits of 4D CT intra-arterial CT perfusion as an adjunct imaging technique and may steer the direction for future larger scale trials and studies.