Department of Oncology, Division of Cancer Survivorship, St Jude Children's Research Hospital, 332 North Lauderdale St, Memphis, TN 38105, USA.
Brain. 2009 Nov;132(Pt 11):3087-95. doi: 10.1093/brain/awp241. Epub 2009 Oct 5.
Posterior fossa syndrome is characterized by cerebellar dysfunction, oromotor/oculomotor apraxia, emotional lability and mutism in patients after infratentorial injury. The underlying neuroanatomical substrates of posterior fossa syndrome are unknown, but dentatothalamocortical tracts have been implicated. We used pre- and postoperative neuroimaging to investigate proximal dentatothalamocortical tract involvement in childhood embryonal brain tumour patients who developed posterior fossa syndrome following tumour resection. Diagnostic imaging from a cohort of 26 paediatric patients previously operated on for an embryonal brain tumour (13 patients prospectively diagnosed with posterior fossa syndrome, and 13 non-affected patients) were evaluated. Preoperative magnetic resonance imaging was used to define relevant tumour features, including two potentially predictive measures. Postoperative magnetic resonance and diffusion tensor imaging were used to characterize operative injury and tract-based differences in anisotropy of water diffusion. In patients who developed posterior fossa syndrome, initial tumour resided higher in the 4th ventricle (P = 0.035). Postoperative magnetic resonance signal abnormalities within the superior cerebellar peduncles and midbrain were observed more often in patients with posterior fossa syndrome (P = 0.030 and 0.003, respectively). The fractional anisotropy of water was lower in the bilateral superior cerebellar peduncles, in the bilateral fornices, white matter region proximate to the right angular gyrus (Tailerach coordinates 35, -71, 19) and white matter region proximate to the left superior frontal gyrus (Tailerach coordinates -24, 57, 20). Our findings suggest that multiple bilateral injuries to the proximal dentatothalamocortical pathways may predispose the development of posterior fossa syndrome, that functional disruption of the white matter bundles containing efferent axons within the superior cerebellar peduncles is a critical underlying pathophysiological component of posterior fossa syndrome, and that decreased fractional anisotropy in the fornices and cerebral cortex may be related to the abnormal neurobehavioural symptoms of posterior fossa syndrome.
后颅窝综合征的特征是小脑功能障碍、口运动/眼运动失用、情绪不稳定和颅后窝损伤后的缄默症。后颅窝综合征的潜在神经解剖学基础尚不清楚，但齿状核丘脑皮质束已被牵连。我们使用术前和术后神经影像学来研究儿童胚胎性脑肿瘤患者在肿瘤切除后发生后颅窝综合征时近端齿状核丘脑皮质束的受累情况。评估了以前因胚胎性脑肿瘤接受手术的 26 名儿科患者的队列的诊断影像学（13 名患者前瞻性诊断为后颅窝综合征，13 名未受影响的患者）。使用术前磁共振成像定义相关肿瘤特征，包括两种潜在的预测措施。术后磁共振和弥散张量成像用于描述手术损伤和基于束的水扩散各向异性的差异。在后颅窝综合征患者中，初始肿瘤位于第四脑室较高处（P=0.035）。在后颅窝综合征患者中，更常观察到术后磁共振信号异常位于小脑上脚和中脑（分别为 P=0.030 和 0.003）。双侧小脑上脚、双侧穹窿、右侧角回附近的白质区域（Tailerach 坐标 35、-71、19）和左侧额上回附近的白质区域（Tailerach 坐标-24、57、20）的水各向异性分数较低。我们的发现表明，近端齿状核丘脑皮质通路的多处双侧损伤可能使后颅窝综合征易于发生，小脑上脚内包含传出轴突的白质束的功能障碍是后颅窝综合征的关键潜在病理生理学组成部分，穹窿和大脑皮层中的各向异性分数降低可能与后颅窝综合征的异常神经行为症状有关。
