Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):2047-54. doi: 10.1016/j.ijrobp.2011.03.057. Epub 2011 Jun 12.
To characterize therapy-induced changes in normal-appearing brainstems of childhood brain tumor patients by serial diffusion tensor imaging (DTI).
We analyzed 109 DTI studies from 20 brain tumor patients, aged 4 to 23 years, with normal-appearing brainstems included in the treatment fields. Those with medulloblastomas, supratentorial primitive neuroectodermal tumors, and atypical teratoid rhabdoid tumors (n = 10) received postoperative craniospinal irradiation (23.4-39.6 Gy) and a cumulative dose of 55.8 Gy to the primary site, followed by four cycles of high-dose chemotherapy. Patients with high-grade gliomas (n = 10) received erlotinib during and after irradiation (54-59.4 Gy). Parametric maps of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed and spatially registered to three-dimensional radiation dose data. Volumes of interest included corticospinal tracts, medial lemnisci, and the pons. Serving as an age-related benchmark for comparison, 37 DTI studies from 20 healthy volunteers, aged 6 to 25 years, were included in the analysis.
The median DTI follow-up time was 3.5 years (range, 1.6-5.0 years). The median mean dose to the pons was 56 Gy (range, 7-59 Gy). Three patterns were seen in longitudinal FA and apparent diffusion coefficient changes: (1) a stable or normal developing time trend, (2) initial deviation from normal with subsequent recovery, and (3) progressive deviation without evidence of complete recovery. The maximal decline in FA often occurred 1.5 to 3.5 years after the start of radiation therapy. A full recovery time trend could be observed within 4 years. Patients with incomplete recovery often had a larger decline in FA within the first year. Radiation dose alone did not predict long-term recovery patterns.
Variations existed among individual patients after therapy in longitudinal evolution of brainstem white matter injury and recovery. Early response in brainstem anisotropy may serve as an indicator of the recovery time trend over 5 years after radiation therapy.
通过连续扩散张量成像（DTI）对儿童脑瘤患者正常脑干的治疗诱导变化进行特征描述。
我们分析了 20 例脑瘤患者的 109 项 DTI 研究，这些患者年龄在 4 至 23 岁之间，治疗区域包括正常脑干。10 例患者患有髓母细胞瘤、幕上原始神经外胚层肿瘤和非典型畸胎样横纹肌样瘤（n=10），他们接受了术后颅脊髓照射（23.4-39.6Gy）和 55.8Gy 的原发性部位累积剂量，然后进行四个周期的高剂量化疗。10 例高级别神经胶质瘤患者（n=10）在照射期间和之后接受了厄洛替尼治疗。计算了各向异性分数（FA）和表观扩散系数（ADC）的参数图，并将其空间配准到三维辐射剂量数据。感兴趣的体积包括皮质脊髓束、内侧丘系和脑桥。为了进行比较，我们还纳入了 37 项来自 20 名 6 至 25 岁健康志愿者的 DTI 研究。
中位 DTI 随访时间为 3.5 年（范围 1.6-5.0 年）。中位脑干平均剂量为 56Gy（范围 7-59Gy）。在 FA 和表观扩散系数的纵向变化中观察到了 3 种模式：（1）稳定或正常的发育趋势，（2）初始偏离正常，随后恢复，（3）无完全恢复迹象的进行性偏离。FA 的最大下降通常发生在放射治疗开始后 1.5 至 3.5 年。在 4 年内可以观察到完全恢复的时间趋势。不完全恢复的患者在第一年 FA 的下降往往更大。单独的辐射剂量并不能预测长期恢复模式。
治疗后，个别患者的脑干白质损伤和恢复的纵向演变存在差异。脑干各向异性的早期反应可能是放射治疗后 5 年恢复时间趋势的一个指标。
