体外菲立磁标记恒河猴骨髓基质细胞自体移植入纹状体后磁共振对标记细胞形态学的示踪观察

目的:体外菲立磁标记的骨髓基质细胞经单细胞悬液微移植后,观察将其在恒河猴纹状体的存活、迁移、分化和整合状况,为细胞移植治疗疾病奠定基础。方法:实验于2004-04/2005-05在南方医科大学珠江医院全军神经医学研究所和解放军第四军医大学神经科学研究所完成。纳入健康恒河猴3只,离恒河猴骨髓基质细胞,利用神经干细胞培养基、白血病抑止分因子和碱性成纤维母细胞生长因子进行细胞扩增并诱导成骨髓基质源神经干细胞,再经体外菲立磁和活细胞荧光染料PK67标记后,采用微移植的方法,通过脑立体定位仪上用微玻璃针将干细胞分别植入脑纹状体内。细胞移植后1,4,8周应用核磁共振成像对脑内移植的细胞进行活体示踪,最后利用光镜和电镜观察标记细胞在脑内的形态学情况。结果:①体外菲立磁标记结果:骨髓基质细胞经微移植后可在脑内纹状体区域存活,移植的干细胞可向周围的脑实质内迁移和整合,迁移细胞沿特定的纹状体结构分布,少量细胞可分化成神经元。②核磁共振成像检查结果:发现脑内移植的标记细胞在磁共振上呈明显的低信号改变,未标记细胞侧脑组织无明显的低信号改变,与组织学切片结果基本相一致。结论:髓基质源神经干细胞移植后,可在脑内存活、迁移、分化和整合,骨利用核磁共振成像技术可以对脑内移植后的标记细胞进行初步的活体追踪。

Syringomyelia after operation:diagnosis and its formational mechanism

Objective： To describe the MRI findings and discuss the pathogenesis formation mechanism of syringomyelia in the patients after spine surgical operation. Methods： Totally 13 patients were been enrolled in the study. Before operation, none of our patients presented with spinal cord syringomyelia. The mean follow-up duration was 6 years （range 2-10 months） by MRI. Four of the 13 patients after spinal cord tumor removed operation, 3 patients after spinal trauma operation, 2 cases had scoliosis before, 2 cases were cervical spondylotic myelopathy and 2 cases had tethered cord syndrome before operation. MR features of pre- and post-operation on all patients were been studied in contrast with surgical results and clinical symptoms. The radiology diagnostic was made by 3 different radiologists respectively. The characteristics of length, width, signals, shape of cavity and spinal cord position as well as subarachnoid shape were focused on. Results： All the patients had no syringomyelia on MRI before operation. The spinal cord of 7 patients showed persist compression and 2 patients had tethered cord before operation. MRI features of syringomyelia after operation in our cases showed longitudinal cavity with syrinx fluid had T1 and T2 relation characteristics of cerebrospinal fluid （CSF）. The mean length was 5.5 spinal segment, 4 cord of 13 patients presented cord compressed from anterior materials, 4 occurred postoperative adhesion to the back of lumbar spinal canal and spinal cord of 1 cases clung to the front wall of cervical spinal canal. Conclusion： The mechanism of syringomyelia in the patients after spinal surgical intervention may be the persisting compression or intention of the spinal cord in the period of pre- or post-operation. The edema, cyst, malacia of spinal cord are the most important lesions and risk factors resulted in the syringomyelia.

Magnetic Resonance Imaging of Retropharyngeal Lymphadenopathy in Nasopharyngeal Carcinoma

OBJECTIVE The aim of our study was to document the patterns of RLN spread by using MRI. METHODS The MR images of 294 patients with newly diagnosed NPC were reviewed retrospectively. Criteria for metastatic lymph nodes included： shortest axial diameter, nodal necrosis, extracapsular spread, and a contrast enhancing rim. RESULTS RLN involvement was detected in 190 （64.6%） patients. A significantly higher incidence of metastatic RLNs was observed in patients with involvement of the oropharynx, nasal cavity, pre-styloid parapharyngeal space, post-styloid parapharyngeal space, levator muscle of the velum palatini, and tensor muscle of the velum palatine. Patients with level Ⅱ,Ⅲ, and Ⅴ node involvement also had a higher incidence of metastatic RLNs. Of the 231 patients who had metastatic RLNs or cervical lymph nodes, 43 （18.6%） had only metastatic RLNs, 41 （17.7%） had only metastatic cervical lymph nodes, and 147 （63.6%） exhibited an involvement of both the RLNs and cervical lymph nodes. The difference between the incidence of RLN involvements （82.3%） and the incidence of cervical lymph node involvement （81.4%） was very small. CONCLUSION Metastatic RLNs are significantly associated with early stage primary tumor involvement and supper cervical lymph node metastasis in NPC.

Cervical spine clearance in obtunded patients after severe polytrauma

Objective： To provide clinicians with data supporting three different clearance techniques in the obtunded patients after severe polytrauma. Methods： This study gave an overview of the available and pertinent literature regarding cervical spine clearance in obtunded patients after severe polytrauma. Results： Currently, there were three accepted techniques for clearance of the cervical spine in obtunded patients after severe polytrauma. Each of these methods has advantages and disadvantages to both of the patients and the clinicians, Conclusions： There are continuous improvements in both computed tomography （CT） and magnetic resonance imaging （MRI） techniques that increase their sensitivities. The continued use of plain radiographs is called into question with respect to cost and time requirements. An algorithmic approach to the evaluation of the cervical spine in the obtunded patients will lead to fewer missed injuries.

Correlation of MR imaging and histopathology after partial resection of normal rabbit brain

Abstract Objectives To investigate the findings of magnetic resonance (MR) imaging and histopathology in early postoperative normal brain, and to define the correlation between MR images and histopathology. Methods Thirty-six New Zealand rabbits weighing 2.0 to 3.0*!kg were divided into 10 groups according to different postoperative days: 1 to 10 days. A partial resection of the parietooccipital region was performed under usual aseptic conditions after the animals were anesthetized intravenously with 3% pentobarbital (30*!mg/kg). MR imaging procedures consisted of pre- and postcontrast scanning and were carried out on postoperative days 1 to 10. Brain tissue samples were prepared for examination immediately after MR scanning. Histopathological examination was done under light both and electron microscopes. The findings of MR imaging were compared with histopathologic findings.Results Surgical margin contrast enhancement on MR images could be seen 24 hours after surgery. The degree of contrast enhancement increased gradually up to 5 days postoperation, and no remarkable changes were present from days 5 to 10. Disruption of the blood brain barrier (BBB) was the main cause of contrast enhancement during the first 3 postoperative days. After that period, the mechanism responsible for contrast enhancement was the formation of neovascularity and a broken BBB. An increase in the amount of neovascularity played a predominant role in contrast enhancement in normal postoperative brain tissue. Conclusions The features of enhanced MR images present at the surgical margin followed a typical time course during the early postoperative period. The role of neovascularity and BBB disruption in the formation of contrast enhancement at the surgical margin varies with time. Knowledge of the features of contrast enhancement in postoperative MR images of normal brain can help in differentiating benign changes from residual malignant glioma.