颈椎病磁共振扩散张量成像的研究

目的探讨颈椎病磁共振扩散张量成像（MRDTI）的特点。方法应用3．0TMRI仪对颈椎病患者进行M_RDTI检查,根据MRI显示的脊髓受压严重程度将颈椎病患者分为轻度组、中度组、重度组及严重度组。分析各组纤维示踪（FT）图的特征及各定量参数的变化。结果60例颈椎病患者FT显示纤维束狭窄、离断、稀疏,随着脊髓受压程度的加重而加重。FA值、Ez值、E3值、E⊥值、MD值在各组之间均存在差异（P〈0．05）。随着MRI评估的脊髓受压程度加重,E2值、E3值、E⊥值、MD值逐渐升高,FA值逐渐降低。结论MRDTI可以定量、直观显示颈椎病的脊髓受压程度。     

Diffusion Tensor Imaging Following Shunt in a Patient with Hydrocephalus

We report on a patient with hydrocephalus who was evaluated by diffusion tensor imaging (DTI) follow‐up study before and after a shunt operation. A 48‐year‐old male patient and 6 age‐matched control subjects were evaluated. The patient presented with hydrocephalus due to hemorrhage caused by the rupture of a right middle cerebral artery bifurcation aneurysm. Three longitudinal DTIs were acquired from the patient (pre‐shunt, post‐shunt 2 weeks, and post‐shunt 8 weeks). The fractional anisotrophy values in the adjacent structures of the lateral ventricle, which were increased before the shunt operation, were decreased after the shunt operation. We think that DTI could be a useful tool for the evaluation of hydrocephalus.     

Diffusion Tensor Imaging in Radiation‐Induced Myelopathy

Radiation myelopathy (RM) is a rare complication of spinal cord irradiation. Diagnosis is based on the history of radiotherapy, laboratory tests, and magnetic resonance imaging of the spinal cord. The MRI findings may nevertheless be quite unspecific. In this paper, we describe the findings of diffusion tensor imaging in a case of the delayed form of RM. We observed areas of restricted diffusion within the spinal cord which probably corresponded to the ischemic changes. This would concur with the currently accepted pathogenetic theory concerning RM.     

Spinal Cord Injury Induced by a Cervical Spinal Cord Stimulator

Objective: The use of cervical spinal cord stimulators for the treatment of refractory neck and upper extremity pain is widely accepted and growing in use as a treatment modality. This case highlights a previously unreported potential complication of spinal cord stimulators. Methods: Analysis of a patient with a cervical spinal cord stimulator presenting with a spinal cord injury. Patient was followed from presentation in the emergency room until 1‐year follow‐up in the office. Results: The patient in this case presented after a fall and sustained a cervical spinal cord injury induced by the electrodes of her spinal cord stimulator working as a space occupying mass. Conclusion: As more patients are undergoing implantation of spinal cord stimulators we must be aware of the long‐term risks that can be encountered.     

Spatial Profiling of the Corticospinal Tract in Amyotrophic Lateral Sclerosis Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) was used as a noninvasive method to evaluate the anatomy of the corticospinal tract (CST) and the pattern of its degeneration in amyotrophic lateral sclerosis (ALS). METHODS: Fourteen patients with ALS and 15 healthy controls underwent DTI. Parameters reflecting coherence of diffusion (fractional anisotropy, FA), bulk diffusion (apparent diffusion coefficient, ADC), and directionality of diffusion (eigenvalues) parallel to (lambda( parallel)) or perpendicular to (lambda( perpendicular)) fiber tracts were measured along the intracranial course of the CST. RESULTS: FA and lambda( parallel) increased, and ADC and lambda( perpendicular) decreased progressively from the corona radiata to the cerebral peduncle in all subjects. The most abnormal finding in patients with ALS was reduced FA in the cerebral peduncle contralateral to the side of the body with the most severe upper motor neuron signs. lambda( parallel) was increased in the corona radiata. Internal capsule FA correlated positively with symptom duration, and cerebral peduncle ADC positively with the Ashworth spasticity score. CONCLUSION: There is a spatial dependency of diffusion parameters along the CST in healthy individuals. Evidence of intracranial CST degeneration in ALS was found with distinct diffusion changes in the rostral and caudal regions.     

Imaging Spinal Cord Damage in Multiple Sclerosis

During the past 2 decades, the considerable improvement of magnetic resonance (MR) technology and the development of new MR strategies capable of providing an in vivo overall assessment of multiple sclerosis (MS) pathology have allowed us to obtain important novel pieces of information on disease evolution in the brain. However, despite this, the correlation between brain MR imaging metrics and clinical disability are still suboptimal. A reason for this discrepancy might be the involvement of clinically eloquent structures, such as the spinal cord, which owing to technical challenges have not been extensively studied using MR imaging until very recently. An objective and accurate estimate of the presence and extent of spinal cord damage might indeed contribute to increasing the strength of the correlations between clinical and MRI metrics. This review summarizes the main results obtained from the application of conventional and modern MR-based techniques for the evaluation of spinal cord damage in MS.     

白质纤维束的弥散张量成像在脑胶质瘤外科的应用

目的:探讨MRI弥散张量成像(DTI)显示脑白质纤维束在脑胶质瘤外科的意义。方法:2003年9月至2004年12月,30例脑内肿瘤患者接受术前常规头颅MRI序列检查的同时,进行DTI序列扫描,经后处理得到各向异性分数(FA)图显示脑白质纤维束结构,并进行FA值、图像信号强度及对比度的分析研究。结果:所有病例均成功实现包括DTI序列扫描以及FA图像生成。脑白质纤维束显示为显著的高信号结构;灰质显示为等信号;脑脊液显示为低信号;脑内肿瘤呈类圆形等、低信号灶;肿瘤周围间质水肿区白质纤维束仍能在DTI的FA图上显像。DTI的FA图像对于脑白质纤维束显影的信号对比度明显优于常规的T1W图像。结论:DTI影像可以清晰显示脑白质纤维束的形态结构。结合其他序列的MRI应用于脑胶质瘤的术前诊断,可以准确判别肿瘤和周围脑白质纤维束的毗邻关系,对脑胶质瘤手术方案设计以及术后神经功能障碍的预测与预防具有重要意义。