Tackling the diffusion problem of contrast-enhanced microCT imaging of whole tissues with engineering solutions

Details

Supervisors

Kerckhofs, Greet

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

enThe growing demand for high-resolution 3D imaging in histopathology has driven significant progress in microscopic imaging technologies. Among these, X-ray microfocus computed tomography (microCT) has emerged as a cost-effective technique offering high spatial image resolution. While it performs well for dense tissues, its effectiveness for soft tissues is hindered by their low X-ray attenuation. To overcome this limitation, contrast-enhanced X-ray microfocus computed tomography (CECT) utilizes contrast-enhancing staining agents (CESAs) that penetrate into the tissue and bind to specific tissue components, thereby increasing X-ray attenuation and enabling the visualization of soft-tissue structures. However, many CESAs penetrate tissues slowly, which presents a bottleneck in time-critical contexts such as clinical diagnostics. This highlights the importance of developing engineering strategies to enhance the staining process. In this master’s thesis, porcine abdominal aortic tissue was used to investigate the potential of enhancement techniques to improve the penetration of the CESA, Hafnium-substituted Wells-Dawson 1:2 polyoxometalate (Hf-WD POM). Four experimental conditions were compared to assess their impact on the staining process: static control, ultrasound, increased temperature, and shaker plate. Penetration of Hf-WD 1:2 POM was assessed using front tracking and grey value (GV) analysis on CECT datasets. The results demonstrated that temperature and ultrasound conditions led to an increased penetration rate compared to the static control. The shaker plate showed slightly faster penetration than the static control. These findings indicate that Hf-WD 1:2 POM penetration is enhanced by temperature, likely due to increased diffusion, and by ultrasound and shaker plate movement, which promote advection. Additionally, advection-enhancing conditions (ultrasound and shaker plate) had a more pronounced effect on the adventitial side of the aortic tissue, suggesting that advective transport is more effective in this region. Importantly, contrast-enhancing properties were not affected by the conditions, meaning that the effectiveness of the CESA remains consistent regardless of the condition. These findings highlight the potential of engineering-based approaches to accelerate CESA penetration in soft tissues, paving the way for more time-efficient CECT imaging protocols.