Construction of rabbit models of radiation-induced brain injury and selection of magnetic resonance parameters / 中国组织工程研究

ABSTRACT

BACKGROUND:Radiation-induced brain injury has recently become an increasing area of research, in particular in animal experimental studies. Domestic and international researches show that there have been no uniform scanning parameters used for examination of animal models of radiation-induced brain injury by magnetic resonance imaging. In this study, we performed magnetic resonance imaging in rabbits to determine related sequence parameters. OBJECTIVE:To establish the New Zealand rabbit models of radiation-induced brain injury, and obtain the brain magnetic resonance images of rabbits using LOOP7 coil, so as to provide experimental evidence for diagnosis of radiation-induced brain injury by magenetic resonance imaging. METHODS:Each of T2-weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy and magnetic susceptibility-weighted imaging were performed several times through the use of LOOP7 coil, to determine the optimal scanning parameters for each sequence. Rabbit models of radiation-induced brain injury were established and then their right hemispheres were irradiated using 6 MV X-rays at a single dose of 40, 80 and 120 Gy. The daily performance and dynamic magnetic resonance signs of rabbits were observed. The brain tissue was taken for pathological examination once abnormal magnetic resonance findings were observed or after 20 weeks of folow-up. RESULTS AND CONCLUSION:Only one rabbit model in the 40 Gy group had subdural hemorrhage. In the 80 Gy group, abnormal T2-weight imaging signals were observed in al rabbit models, which were pathologicaly confirmed as scattered degenerated neurons and infiltrated neutrophils. The abnormal signals that gradualy expanded over time were seen in rabbits from the 120 Gy group by magnetic resonance imaging and were pathologicaly confirmed as radiation-induced brain injury loci. The results confirm that establishing rat models of radiation-induced brain injury using radiation therapy system can better simulate the pathological process of radiation-induced brain injury; moreover, this model can be applied to receive routine magnetic resonance examination with LOOP7 coil.