Preservation of Vascular Tissues From Shrinkage During X-Ray 3D-CECT Imaging

Preventing shrinkage of biological tissues during X-ray microfocus computed tomography (3D-microCT) is essential to prevent motion artifacts and microstructural changes, which is particularly problematic in the context of 4D-microCT. While liquid immersion and parafilm wrapping are commonly used to limit dehydration, both methods present limitations for combining them with in situ mechanical testing. This work introduces an in-house environmental stage capable of controlling temperature and relative humidity (RH) around the sample during imaging with vapor phase method. Using 3D-microCT with stained porcine aortic tissues, we assessed the impact of temperature and RH on tissue volume change over time. Results demonstrated that both temperature and RH significantly influence shrinkage rate, with temperature playing a dominant role. Volume loss increased with decreasing RH and increasing temperature. Furthermore, shrinkage was heterogeneous and was particularly pronounced at cut tissue edges. Among all tested conditions, 10°C combined with 95% RH best preserved tissue hydration, showing minimal shrinkage and reduced motion artifacts. Validation at higher spatial resolution confirmed that this controlled environment enables prolonged acquisitions while maintaining image quality superior to imaging under ambient conditions. This study highlights the importance of environmental control during microCT imaging of soft tissues and provides a quantitative framework for selecting optimal atmospheric conditions.