Assessment of MRI Parameters as Imaging Biomarkers for Radiation Necrosis in the Rat Brain

作者：Wang, Silun; Tryggestad, Erik; Zhou, Tingting; Armour, Michael; Wen, Zhibo; Fu, De Xue; Ford, Eric; van Zijl, Peter C M; Zhou, Jinyuan^*

来源：International Journal of Radiation Oncology, Biology, Physics, 2012, 83(3): E431-E436.

DOI：10.1016/j.ijrobp.2011.12.087

• Radiation necrosis
• Biomarker
• APT imaging
• Molecular imaging
• MRI

Purpose: Radiation necrosis is a major complication of radiation therapy. We explore the features of radiation-induced brain necrosis in the rat, using multiple MRI approaches, including T-1, T-2, apparent diffusion constant (ADC), cerebral blood flow (CBF), magnetization transfer ratio (MTR), and amide proton transfer (APT) of endogenous mobile proteins and peptides.
Methods and Materials: Adult rats (Fischer 344; n = 15) were irradiated with a single, well-collimated X-ray beam (40 Gy; 10 x 10 mm(2)) in the left brain hemisphere. MRI was acquired on a 4.7-T animal scanner at similar to 25 weeks' postradiation. The MRI signals of necrotic cores and perinecrotic regions were assessed with a one-way analysis of variance. Histological evaluation was accomplished with hematoxylin and eosin staining.
Results: ADC and CBF MRI could separate perinecrotic and contralateral normal brain tissue (p < 0.01 and < 0.05, respectively), whereas T-1, T-2, MTR, and APT could not. MRI signal intensities were significantly lower in the necrotic core than in normal brain for CBF (p < 0.001) and APT (p < 0.01) and insignificantly higher or lower for T-1, T-2, MTR, and ADC. Histological results demonstrated coagulative necrosis within the necrotic core and reactive astrogliosis and vascular damage within the perinecrotic region.
Conclusion: ADC and CBF are promising imaging biomarkers for identifying perinecrotic regions, whereas CBF and APT are promising for identifying necrotic cores.

• 出版日期2012-7-1
• 单位南方医科大学