Advancing Preclinical Micro-Photon Counting CT Perfusion Imaging: From Phantom Experiments to In Vivo Applications
In preclinical studies, micro-CT is frequently employed to yield valuable anatomical insights. However, there has been an increasing need for micro-CT in extracting functional measurements such as with perfusion imaging. Perfusion imaging plays a crucial role in understanding and quantifying tissue vascular properties. This paper focuses on our development of preclinical micro-photon counting (PC)CT perfusion imaging and demonstrates quantification of perfusion metrics in a controlled fluid flow phantom experiment. For this study, we utilized a novel bioprinted perfusion phantom and a dedicated preclinical photon-counting CT (PCCT) system to estimate perfusion maps at different flow rates. A continuous water flow through the phantom was maintained by a peristaltic pump. PCCT imaging was performed during a delayed contrast injection of clinical iodinated contrast agent. Imaging was repeated under 3 different flow rates: 4, 6, and 8 mL/min. Our results demonstrate successful visualization and quantification of flow parameters by employing gamma variate curves fit to voxel measurements of temporal PCCT reconstructions as well as decomposed iodine material maps, enabling the calculation of volumetric maps for mean transit time, blood volume index, and blood flow index. Furthermore, we showcase the application of this technique in quantifying in vivo perfusion characteristics in a head and neck cancer model in a mouse. Through our research, we aim to highlight the potential of preclinical micro-PCCT perfusion imaging in advancing our understanding of tissue perfusion dynamics and its potential applications in studying various pathologies and cardiovascular conditions.
