TY - JOUR
T1 - Assessment of MRI parameters as imaging biomarkers for radiation necrosis in the rat brain
AU - Wang, Silun
AU - Tryggestad, Erik
AU - Zhou, Tingting
AU - Armour, Michael
AU - Wen, Zhibo
AU - Fu, De Xue
AU - Ford, Eric
AU - Van Zijl, Peter C.M.
AU - Zhou, Jinyuan
N1 - Funding Information:
This work was supported in part by grants from the National Institutes of Health (Grant Nos. EB009112, EB009731, EB015032, and RR015241 ) and the National Natural Science Foundation of China (Grant No. 81128006 ).
PY - 2012/7/1
Y1 - 2012/7/1
N2 - 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 × 10 mm 2) in the left brain hemisphere. MRI was acquired on a 4.7-T animal scanner at ∼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.
AB - 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 × 10 mm 2) in the left brain hemisphere. MRI was acquired on a 4.7-T animal scanner at ∼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.
KW - APT imaging
KW - Biomarker
KW - MRI
KW - Molecular imaging
KW - Radiation necrosis
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U2 - 10.1016/j.ijrobp.2011.12.087
DO - 10.1016/j.ijrobp.2011.12.087
M3 - Article
C2 - 22483739
AN - SCOPUS:84861618202
SN - 0360-3016
VL - 83
SP - e431-e436
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 3
ER -