PURPOSE To investigate the impact of blood-brain barrier (BBB) alterations induced by an experimental tumor and radiotherapy on MRI signal intensity (SI) in deep cerebellar nuclei (DCN) and the presence of gadolinium after repeated administration of a linear gadolinium-based contrast agent in rats. METHODS Eighteen Fischer rats were divided into a tumor (gliosarcoma, GS9L model), a radiotherapy, and a control group. All animals received 5 daily injections (1.8 mmol/kg) of gadopentetate dimeglumine. For tumor-bearing animals, the BBB disruption was confirmed by contrast-enhanced MRI. Animals from the tumor and radiation group underwent radiotherapy in 6 fractions of 5 Gray. The SI ratio between DCN and brain stem was evaluated on T1-weigthed MRI at baseline and 1 week after the last administration. Subsequently, the brain was dissected for gadolinium quantification by inductively coupled plasma-mass spectrometry. Statistical analysis was done with the Kruskal-Wallis test. RESULTS An increased but similar DCN/brain stem SI ratio was found for all three groups (p = 0.14). The gadolinium tissue concentrations (median, nmol/g) were 6.7 (tumor), 6.3 (radiotherapy), and 6.8 (control) in the cerebellum (p = 0.64) and 17.8/14.6 (tumor), 20.0/18.9 (radiotherapy), and 17.8/15.9 (control) for the primary tumor (p = 0.98) and the contralateral hemisphere (p = 0.41) of the cerebrum, respectively. CONCLUSION An experimental brain tumor treated by radiotherapy or radiotherapy alone did not alter DCN signal hyperintensity and gadolinium concentration in the rat brain 1 week after repeated administration of gadopentetate. This suggests that a local BBB disruption does not affect the amount of retained gadolinium in the brain.

中文翻译：

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重复施用钆造影剂后脑肿瘤和放射治疗对大脑中钆存在的影响：一项在大鼠中进行的实验研究。

目的 研究实验性肿瘤和放疗引起的血脑屏障 (BBB) 改变对小脑深部核团 (DCN) MRI 信号强度 (SI) 的影响以及重复施用线性钆对比剂后钆存在的影响大鼠体内的代理。方法18只Fischer大鼠分为肿瘤组（胶质肉瘤，GS9L模型）、放疗组和对照组。所有动物每天接受 5 次钆喷酸二葡胺注射（1.8 mmol/kg）。对于荷瘤动物，BBB 破坏通过对比增强 MRI 得到证实。肿瘤组和放射组的动物以 5 格雷为 6 次进行放射治疗。在基线时和最后一次给药后 1 周，通过 T1 加权 MRI 评估 DCN 和脑干之间的 SI 比率。随后，解剖大脑，通过电感耦合等离子体质谱法进行钆定量。通过 Kruskal-Wallis 检验进行统计分析。结果 所有三组的 DCN/脑干 SI 比率均有所增加，但相似 (p = 0.14)。小脑中的钆组织浓度（中位值，nmol/g）分别为 6.7（肿瘤）、6.3（放射治疗）和 6.8（对照）（p = 0.64）以及 17.8/14.6（肿瘤）、20.0/18.9（放射治疗）、原发肿瘤 (p = 0.98) 和大脑对侧半球 (p = 0.41) 分别为 17.8/15.9（对照）。结论 重复给予钆喷替酯 1 周后，通过放疗或单独放疗治疗的实验性脑肿瘤不会改变大鼠脑中的 DCN 信号高信号和钆浓度。这表明局部血脑屏障破坏不会影响大脑中保留的钆量。