Introduction: The morphological and functional information provided by micro-CT and micro-PET allows monitoring of acute and chronic disease states in small laboratory animals. We examined in-vivo micro-CT and micro-PET as non-invasive tools to assess pulmonary fibrosis in mice. Material/Methods: Pulmonary fibrosis was induced in mice by intratracheal delivery of an adenoviral gene vector encoding biologically active TGF-β1. Respiratory gated and ungated micro-CT was performed in 18 mice at 1 to 4 weeks after pulmonary adenoviral gene vector delivery. In 5 additional mice 18 F-FDG micro-PET and micro-CT was performed. Imaging was correlated to histopathology and findings in animals exposed to a control vector. Radiation doses were measured using thermoluminescence dosimeters. Results: Significant correlation between Ashcroft histology scoring and micro-CT was found for visual assessment scoring (p<0.001) and automated quantification by a region growing segmentation algorithm (p=0.004 for gated and p=0.006 for ungated exams). 18 F-FDG micro-PET showed slight increase of glucose metabolism in the consolidated lung areas determined by micro-CT, which was coregistered to the micro-PET data using anatomical landmarks. Radiation doses for micro-CT ranged from 174 to 277 mSv. For micro-PET an expected dose of 140 mSv was calculated from the measurements. Conclusion: Micro-CT and micro-PET allow valid visualisation of morphology and metabolism for the assessment of fibrosis in mice. The measured radiation doses allow serial examinations without deterministic radiation effects.
Rodt et al. (Thu,) studied this question.