Miot E, Hoffschir D, Alapetite C, Gaboriaud G, Pontvert D, Fetissof F, Le Pape A, Akoka S
Laboratoire de Biophysique Cellulaire et RMN, Institut National de la Santé et de la Recherche Medicale, Tours, France.
AJNR Am J Neuroradiol. 1995 Jan;16(1):79-85.
To use the pig brain as a large-animal model to examine the effects of high-dose single-fraction irradiation on MR images, T2 relaxation time, and histologic integrity.
A total of 24 Meishan pigs were studied: 20 irradiated animals and 4 unirradiated controls. A high dose was delivered to the right hemisphere of the animals, using a 12-MeV electron beam. Ten animals received 40 Gy at the 90% isodose, and 10 animals received 60 Gy. Quantitative measurement of T2 relaxation time was compared with qualitative analysis of T2-weighted images and histologic studies.
Quantitative analysis revealed a reproducible increase of the T2 parameter within the irradiated areas. The T2 kinetic could be analyzed in two phases, which appeared before the visualization of ventricle compression, necrosis, and edema. The first is characterized by vascular inflammation and the latter by radiation necrosis and edema. Both are dose dependent.
These results underline the ability of quantitative MR for early diagnosis of brain radiation lesions in vivo.
使用猪脑作为大动物模型，研究大剂量单次分割照射对磁共振成像（MR）图像、T2弛豫时间和组织学完整性的影响。
共研究了24只梅山猪，其中20只接受照射，4只为未照射的对照。使用12兆电子伏的电子束对动物的右半球进行高剂量照射。10只动物在90%等剂量线处接受40戈瑞照射，10只动物接受60戈瑞照射。将T2弛豫时间的定量测量结果与T2加权图像的定性分析及组织学研究结果进行比较。
定量分析显示，照射区域内T2参数出现可重复的增加。T2动力学可分为两个阶段，这两个阶段出现在脑室受压、坏死和水肿显现之前。第一个阶段的特征是血管炎症，第二个阶段的特征是放射性坏死和水肿。两者均与剂量相关。
这些结果强调了定量磁共振成像在体内早期诊断脑辐射损伤的能力。
