Quantitative MRI in murine radiation‐induced rectocolitis: comparison with histopathological inflammation score |
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| Authors: | Magaly Zappa Sabrina Doblas Dominique Cazals‐Hatem Fabien Milliat Jérémy Lavigne Fanny Daniel Abelhak Jallane Philippe Garteiser Valérie Vilgrain Eric Ogier‐Denis Bernard E Van Beers |
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| Institution: | 1. H?pitaux Universitaires Beaujon, Radiology, Université Paris VII, Clichy, France;2. Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149, INSERM, University Paris‐Diderot, Paris, France;3. Hopital Beaujon, Pathology, Université Paris VII, Clichy, France;4. Laboratory of Intestinal Inflammation, Center of Research on Inflammation, UMR 1149, INSERM, University Paris Diderot, Paris, France;5. Institute for Radiological Protection and Nuclear Safety (IRSN), Research Laboratory in Radiobiology and Radiopathology, Fontenay‐aux‐Roses, France |
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| Abstract: | Murine radiation‐induced rectocolitis is considered to be a relevant animal model of gastrointestinal inflammation. The purpose of our study was to compare quantitative MRI and histopathological features in this gastrointestinal inflammation model. Radiation rectocolitis was induced by localized single‐dose radiation (27 Gy) in Sprague‐Dawley rats. T2‐weighted, T1‐weighted and diffusion‐weighted MRI was performed at 7 T in 16 rats between 2 and 4 weeks after irradiation and in 10 control rats. Rats were sacrificed and the histopathological inflammation score of the colorectal samples was assessed. The irradiated rats showed significant increase in colorectal wall thickness (2.1 ± 0.3 mm versus 0.8 ± 0.3 mm in control rats, P < 0.0001), normalized T2 signal intensity (4 ± 0.8 versus 2 ± 0.4 AU, P < 0.0001), normalized T1 signal intensity (1.4 ± 0.1 versus 1.1 ± 0.2 AU, P = 0.0009) and apparent and pure diffusion coefficients (ADC and D) (2.06 × 10?3 ± 0.34 versus 1.51 × 10?3 ± 0.23 mm2/s, P = 0.0004, and 1.97 × 10?3 ± 0.43 mm2/s versus 1.48 × 10?3 ± 0.29 mm2/s, P = 0.008, respectively). Colorectal wall thickness (r = 0.84, P < 0.0001), normalized T2 signal intensity (r = 0.85, P < 0.0001) and ADC (r = 0.80, P < 0.0001) were strongly correlated with the histopathological inflammation score, whereas normalized T1 signal intensity and D were moderately correlated (r = 0.64, P = 0.0006, and r = 0.65, P = 0.0003, respectively). High‐field MRI features of single‐dose radiation‐induced rectocolitis in rats differ significantly from those of control rats. Quantitative MRI characteristics, especially wall thickness, normalized T2 signal intensity, ADC and D, are potential markers of the histopathological inflammation score. |
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| Keywords: | colitis inflammation MRI pathology radiation‐induced rats |
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