Meoded A, Faria A V, Hartman A L, Jallo G I, Mori S, Johnston M V, Huisman T A G M, Poretti A
From the Section of Pediatric Neuroradiology (A.M., T.A.G.M.H., A.P.).
Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Sciences (A.V.F., S.M.).
AJNR Am J Neuroradiol. 2016 May;37(5):924-31. doi: 10.3174/ajnr.A4647. Epub 2016 Jan 14.
Hemispherectomy is a neurosurgical procedure to treat children with intractable seizures. Postsurgical improvement of cognitive and behavioral functions is observed in children after hemispherectomy suggesting plastic reorganization of the brain. Our aim was to characterize changes in DTI scalars in WM tracts of the remaining hemisphere in children after hemispherectomy, assess the associations between WM DTI scalars and age at the operation and time since the operation, and evaluate the changes in GM fractional anisotropy values in patients compared with controls.
Patients with congenital or acquired neurologic diseases who required hemispherectomy and had high-quality postsurgical DTI data available were included in this study. Atlas- and voxel-based analyses of DTI raw data of the remaining hemisphere were performed. Fractional anisotropy and mean, axial, and radial diffusivity values were calculated for WM and GM regions. A linear regression model was used for correlation between DTI scalars and age at and time since the operation.
Nineteen patients after hemispherectomy and 21 controls were included. In patients, a decrease in fractional anisotropy and axial diffusivity values and an increase in mean diffusivity and radial diffusivity values of WM regions were observed compared with controls (P < .05, corrected for multiple comparisons). In patients with acquired pathologies, time since the operation had a significant positive correlation with white matter fractional anisotropy values. In all patients, an increase in cortical GM fractional anisotropy values was found compared with controls (P < .05).
Changes in DTI metrics likely reflect Wallerian and/or transneuronal degeneration of the WM tracts within the remaining hemisphere. In patients with acquired pathologies, postsurgical fractional anisotropy values correlated positively with elapsed time since the operation, suggesting a higher ability to recover compared with patients with congenital pathologies leading to hemispherectomy.
大脑半球切除术是一种治疗儿童难治性癫痫的神经外科手术。大脑半球切除术后儿童的认知和行为功能有所改善，提示大脑发生了可塑性重组。我们的目的是描述大脑半球切除术后儿童剩余半球白质束中扩散张量成像（DTI）标量的变化，评估白质DTI标量与手术年龄及术后时间之间的关联，并与对照组相比评估患者灰质各向异性分数值的变化。
本研究纳入了患有先天性或后天性神经疾病且需要进行大脑半球切除术并具备高质量术后DTI数据的患者。对剩余半球的DTI原始数据进行了基于图谱和体素的分析。计算了白质和灰质区域的各向异性分数以及平均、轴向和径向扩散率值。使用线性回归模型分析DTI标量与手术年龄及术后时间之间的相关性。
纳入了19例大脑半球切除术后患者和21例对照组。与对照组相比，患者白质区域的各向异性分数和轴向扩散率值降低，平均扩散率和径向扩散率值升高（P <.05，经多重比较校正）。在患有后天性病变的患者中，术后时间与白质各向异性分数值呈显著正相关。与对照组相比，所有患者的皮质灰质各向异性分数值均升高（P <.05）。
DTI指标的变化可能反映了剩余半球内白质束的华勒氏变性和/或跨神经元变性。在患有后天性病变的患者中,术后各向异性分数值与术后经过时间呈正相关，这表明与导致大脑半球切除的先天性病变患者相比，其恢复能力更强。
