Performance evaluation of a C-Arm CT perfusion phantom.

PURPOSE: Brain perfusion measurement in stroke patients provides important information on the infarct area and state of involved tissue. Interventional C-Arm angiography systems can provide perfusion measurements. A CT perfusion phantom was developed for C-Arm perfusion imaging to test and evaluate this method and to aid in the design and validation of scan protocols.
METHODS: A phantom test device was designed based on the anatomy of the human head. Four feeding arteries divided into sixteen sub-branches that lead into a sintered board simulating brain parenchyma. Perfusion measurements were performed using two conventional clinical CT scanners as the gold standard and with a C-Arm CT system to test and compare the implementations. The phantom's input parameters, contrast medium and flow properties were varied. A cerebral perfusion deficit was simulated by occlusion of a feeding artery tube.
RESULTS: CT perfusion maps of the sintered board brain tissue surrogate were computed and qualitatively compared for both conventional CT and C-Arm CT systems. A characteristic flow pattern of the tissue board was identifiable in both modalities. The characteristic flow pattern of the resulting perfusion maps is reproducible. The calculated flow and volume were directly related.
CONCLUSIONS: A new CT perfusion phantom was developed and tested. This phantom is an appropriate model for CT-based tissue perfusion measurements in both conventional CT scanners and C-Arm CT scanners. The influence of input parameter changes can be visualized. Perfusion deficits after occlusion of a feeding artery are readily simulated and identified with CT.