扩散成像技术在臂丛神经病变的应用研究进展

扩散成像技术是利用组织的扩散特性成像的新型MRI检查技术,初期主要应用于中枢神经系统疾病的诊断,而后逐渐被应用于脊髓、坐骨神经、正中神经等。臂丛神经是人体最复杂的周围神经,支配上肢的感觉与运动功能。臂丛神经病变常见、多发。针对扩散成像技术原理、扩散成像在臂丛神经成像中的优势与限制及臂丛神经病变中的扩散成像技术应用研究作一综述,以提高扩散成像对臂丛神经病变诊断的应用价值。     

低场强磁共振弥散成像在急性脑梗死诊断中的应用价值

急性脑梗死是危害人类健康的重要疾病之一,急性脑缺血的快速评估对急性脑中风病人选择溶栓治疗或神经保护剂治疗至关重要.常规CT、MR检查不能在超早期发现缺血灶存在,磁共振弥散加权成像(diffusion weighted imaging,DWI)可以在超早期发现脑梗死并能对早期脑中风病人进行评估[1].本文旨在探讨弥散成像(DWI)在诊断急性脑梗死病变中的应用价值,现将59例急性脑梗死病例应用弥散成像(DWI)进行诊断的结果与体会报告如下:     

磁共振弥散成像在脑梗死诊断中的应用价值探讨

目的　探讨磁共振弥散成像对脑梗死的应用价值。方法　对 60例脑梗死患者行磁共振常规及弥散成像。结果　早期脑梗死DWI显示优于常规MRI,急性、亚急性和慢性脑梗死病灶在磁共振弥散加权图像的表现各有特点 ,ADC呈规律性变化。结论　合理的应用磁共振弥散成像可提高脑梗死的诊断准确性。     

功能性磁共振成像--神经影像学的研究热点

功能性磁共振成像(fMRI)所指为血氧水平依赖磁共振成像(BOLD MRI),灌注加权成像(PWI),弥散加权成像(DWI)和弥散张量成像(DTI),以及磁共振波谱分析(MRS)和化学位移成像(CSI).检索M edline网上近一年新收纳的fMRI文章,计4310篇,平均每天11.8篇.神经影像学众多研究课题中,fMRI平均每天有11篇以上论文发表,故fMRI是神经影像学的研究热点.fMRI的研究课题中,以BOLD MRI最热,且已热了10余年;近10年间Medline收纳这方面的论文达37050篇之多,而我国学者10年来在这方面所发表论文仅149篇,且其质量也多不甚高,可谓差距不小.对如何赶、超国际先进水平,作者们提出了自己的看法.     

子宫内膜异位症并发盆腔神经损伤的MR神经成像研究进展

疼痛是子宫内膜异位症患者最典型、最突出的临床表现之一,近年来研究表明疼痛的发生与病灶压迫和对邻近神经的侵犯有关。同时子宫内膜异位症患者行病灶切除术时,有可能造成盆腔神经的损伤,进而导致术后盆腔的持续性疼痛,是子宫内膜异位症最严重的术后并发症之一。随着医学影像学技术的不断发展,MR神经成像技术可对盆腔神经进行高对比度的清晰显示,为子宫内膜异位症患者盆腔神经的观察提供更多的参考信息,进而对盆腔神经损伤的明确诊断提供参考依据。本文主要通过综述子宫内膜异位症患者术前及术后疼痛与MR神经成像下盆腔神经异常影像学表现的相关性,从而探讨MR神经成像技术在子宫内膜异位症合并盆腔神经损伤中的诊断价值。     

颅神经三维磁共振成像技术的现状及展望

颅神经迂曲纤细,且毗邻复杂,很多疾病与其相关。三维磁共振成像技术具有较高的空间分辨力,且能够任意角度各向同性成像,已逐渐取代二维磁共振成像检查技术,成为颅神经成像的常用方法。对三维磁共振成像显示颅神经的现状及进展予以综述。     

颅神经三维磁共振成像技术的现状及展望

颅神经迂曲纤细,且毗邻复杂,很多疾病与其相关.三维磁共振成像技术具有较高的空间分辨力,且能够任意角度各向同性成像,已逐渐取代二维磁共振成像检查技术,成为颅神经成像的常用方法.对三维磁共振成像显示颅神经的现状及进展予以综述.     

扩散加权神经成像在腰骶丛神经影像诊断的临床应用

目的 探讨扩散加权磁共振神经成像(DW-MRN)和选择性水激励脂肪抑制技术(PROSET)腰骶丛神经成像特点及其临床应用价值.资料与方法 对25例腰骶部受检者行常规MRI、PROSET及DW-MRN.结果 PROSET对腰骶丛神经显示率达100%,对腰丛神经显示效果好于DW-MRN,差异有统计学意义(χ~2=6.300,P<0.05),对腰骶干和骶神经的显示效果亦好于DW-MRN,但差异无明显统计学意义(χ~2=5.922,P>0.05;χ~2=3.870,P>0.05).PROSET能清晰显示腰骶神经根和根鞘,对神经根病变显示良好.DW-MRN对腰骶从神经受累增粗和信号增高较敏感,最大密度投影(MIP)重组的3D图像可清晰显示腰骶丛节后神经.结论 DW-MRN可立体、直观地显示腰骶丛神经节及节后神经.PROSET与DW-MRN结合,能使腰骶丛神经病变在精确成像下直观诊断.     

MR弥散加权成像在颈髓中的应用

目的　探讨颈髓磁共振弥散加权成像技术方法及其临床应用价值。方法　对 5名健康志愿者的正常颈髓、10例水肿型颈髓外伤者、18例颈椎椎间盘突出者进行SEEPI多次激发弥散加权成像扫描。扫描中使用外周搏动门控减少脑脊液搏动伪影 ,同时使用自动匀场、抑脂技术和自动导航技术以减少各种伪影和增加图像的清晰度。结果　 3 3例均获得弥散加权图像和弥散系数图。 10例水肿型脊髓外伤表现表面弥散系数 (ADC)减低 ,ADC图低信号 ;18例椎间盘突出ADC增高 ,ADC图高信号。结论　合理应用扫描技术 ,可实现颈髓弥散加权成像 ,对颈髓病变的早期诊断具有较高的临床应用价值。     

帕金森病神经黑色素磁共振成像技术的研究进展

帕金森病(PD)是常见的神经退行性疾病,神经黑色素与其病理生理过程密切相关.通过神经黑色素磁共振成像(NM-MRI)技术可在体观察脑干神经黑色素的生理性和病理性改变.本文重点综述PD患者的黑质和蓝斑NM-MRI特征及其与临床表征的相关性,并探讨NM-MRI在PD诊断及鉴别诊断中的应用价值和前景.     

腰骶部脊神经MRI成像技术的应用进展

MRI具有良好的组织对比分辨力,能清晰的显示腰骶部脊神经根及其周围的软组织,成为评估脊神经根病变的理想手段。随着MRI技术的发展,越来越多的新的成像技术应用于临床,包括磁共振神经成像术、选择性水激励脂肪抑制技术、平衡式稳态自由进动序列、扩散张量成像等对神经根病变的诊断、术前评估等方面起着越来越重要的作用。本文综述了MRI成像技术在腰骶部脊神经根中的应用进展。     

MR PROSET序列在正常腰骶部脊神经根成像中的应用

目的：观察磁共振PROSET序列对正常腰骶部脊神经根的显示,探讨磁共振PROSET序列在正常腰骶部脊神经根成像中的价值。方法：对30例正常健康志愿者采用PROSET序列做冠状面扫描,获得正常腰骶部脊神经根影像,所得原始图像经3D最大信号强度投影（MIP）处理。结果：30例PROSET成像及mMIP重建图像多方位旋转均清楚显示腰骶部硬脊膜囊、神经根鞘、脊神经根、神经节和部分节后段。结论：PROSET序列能清晰显示腰骶部神经根,结合常规磁共振图像,为临床诊治腰骶神经根病变提供影像学依据。     

Differentiation between Symptomatic and Asymptomatic Extraforaminal Stenosis in Lumbosacral Transitional Vertebra: Role of Three-Dimensional Magnetic Resonance Lumbosacral Radiculography

Objective

To investigate the role of lumbosacral radiculography using 3-dimentional (3D) magnetic resonance (MR) rendering for diagnostic information of symptomatic extraforaminal stenosis in lumbosacral transitional vertebra.

Materials and Methods

The study population consisted of 18 patients with symptomatic (n = 10) and asymptomatic extraforaminal stenosis (n = 8) in lumbosacral transitional vertebra. Each patient underwent 3D coronal fast-field echo sequences with selective water excitation using the principles of the selective excitation technique (Proset imaging). Morphologic changes of the L5 nerve roots at the symptomatic and asymptomatic extraforaminal stenosis were evaluated on 3D MR rendered images of the lumbosacral spine.

Results

Ten cases with symptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. On 3D MR lumbosacral radiculography, indentation of the L5 nerve roots was found in two cases, while swelling of the nerve roots was seen in eight cases at the exiting nerve root. Eight cases with asymptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. Based on 3D MR lumbosacral radiculography, indentation or swelling of the L5 nerve roots was not found in any cases with asymptomatic extraforaminal stenosis.

Conclusion

Results from 3D MR lumbosacral radiculography Indicate the indentation or swelling of the L5 nerve root in symptomatic extraforaminal stenosis. Based on these findings, 3D MR radiculography may be helpful in the diagnosis of the symptomatic extraforaminal stenosis with lumbosacral transitional vertebra.     

Diffusion tensor imaging in the diagnosis of primary lateral sclerosis

PURPOSE: To evaluate the utility of MR diffusion tensor imaging in diagnosing primary lateral sclerosis (PLS). MATERIALS AND METHODS: Five patients who met clinical criteria for a diagnosis of PLS, and two patients with possible PLS of less than three years duration and eight normal volunteers were studied using MR diffusion tensor imaging. RESULTS: All seven patients showed decreased diffusion anisotropy and increased diffusion constant in the PLIC, with complete separation from a normal control group, including patients early in the course of the illness. CONCLUSION: Quantitative diffusion tensor imaging appears to be a useful test to detect upper motor neuron damage and hence to help to establish the diagnosis of PLS.     

兔坐骨神经扩散张量纤维束示踪

目的:探讨DTI成像能否用于显示兔的坐骨神经.方法:三只成年家兔,运用3T磁共振扫描仪、8通道相控阵膝关节线圈和DTI成像方法扫描兔股部,后处理3D显示坐骨神经的走行.结果:运用DTI 3D纤维束成像显示了兔的坐骨神经,其路径与兔坐骨神经大体解剖部位一致.结论:DTI成像在动物周围神经的研究中有一定的应用前景.     

正常视神经MR扩散张量成像扫描参数初步研究

目的：探讨视神经MR扩散张量成像最佳的扫描参数,获得最佳的图像质量。方法：采用GE Signa Twin1．5T超导磁共振扫描仪,头颅8通道相控阵线圈,单次激发ZOOM自旋回波平面成像序列,选择30例正常成人志愿者,随机分为三组,使用不同的扩散敏感梯度方向数、b值和层厚／层间距,对视神经进行MR扩散张量成像研究。将扩散张量成像原始数据输入个人计算机,应用Volume-one 1．72软件进行后处理。结果：扩散敏感梯度方向数为13个方向、b值1000s／mm^2、层厚／层间距为3／0mm的扫描参数,可以获得高质量的视神经扩散张量图像,图像清晰,信躁比高,无明显伪影及扭曲、变形。结论：本研究初步建立了视神经最佳的磁共振扩散张量成像扫描参数,获得的图像清晰,能够满足临床研究和应用的需要。     

正常腰骶部脊神经根的解剖及MR PROSET成像表现

目的观察和探讨正常腰骶部脊神经根的解剖和磁共振PROSET序列显示腰骶部神经根的价值。方法采用PROSET技术做冠状面正常腰骶部神经根成像20例,所有原始图像均经3D最大信号强度投影(MIP)后处理。结果20例PROSET成像均清楚显示硬膜囊、硬脊膜鞘外形及脊神经根、神经节和部分节后段的走形,MIP重建图像能多方位观察神经根走形。结论PRO-SET序列对显示腰骶神经根解剖具有独特优势,结合常规磁共振图像,为临床诊治腰骶神经根病变提供满意的影像学依据。     

肌肉失神经改变的MRI表现及研究进展

肌肉失神经支配可导致形态学、电生理学及组织代谢等多方面的改变。MRI不仅能有效评价失神经支配肌肉的形态学及病生理学改变,也可以利用扩散加权成像(DWI)及扩散张量成像(DTI)等技术探测肌细胞内外水分子运动状况。受损的神经在一定时间内再生可以恢复对靶肌的支配,近年来部分研究者提出可通过观察不同程度神经损伤后靶肌肉信号的演变从而预测神经损伤的类型及预后。就肌肉失神经改变的MRI表现及研究进展进行综述。     

MR imaging of the cauda equina in hereditary motor sensory neuropathies: correlations with sural nerve biopsy

BACKGROUND AND PURPOSE: Although spinal root abnormalities are known to occur, spinal MR examination is seldom performed in hereditary motor and sensory neuropathies (HMSN). The following work was undertaken to assess the MR imaging spectrum of lumbosacral spinal nerve root abnormalities and determine whether intradural nerve root involvement could be related to any biopsy feature. METHODS: Ten consecutive patients (eight male, two female; age range, 28-65 yrs) with Charcot-Marie-Tooth (CMT) (type I = 5, type II = 2) and Déjèrine-Sottas disease (DSD) (n = 3) underwent a contrast-enhanced lumbosacral MR examination. Sural nerve biopsy was performed in all patients. Atypical clinical features were present in two patients. The MR scans of each patient were reviewed for possible causes of myeloradiculopathy, spinal nerve root and ganglia dimensions, signal change, and abnormal enhancement. RESULTS: In the seven patients with CMT, abnormal MR findings were intradural nerve root hypertrophy (n = 2), signal abnormalities (n = 2), and enhancement (n = 3). Two of three patients with DSD had the abnormal MR finding of intradural nerve root enhancement. In both patients with atypical clinical features, MR imaging showed nerve root hypertrophy and enhancement. Both findings were related to an increased number of onion bulbs at sural nerve biopsy. Inflammatory infiltrates were not observed in any patients. CONCLUSION: In patients with HMSN enhancement of intradural spinal nerve roots, whether or not associated with marked thickening, may be found on lumbosacral MR examinations. Spinal nerve root thickening may be responsible for atypical symptoms, and its visibility on MR images represents a useful adjunct to diagnosis. Lumbosacral spinal nerve root abnormalities were related to an extremely high number of onion bulbs (indicating active demyelination) at sural nerve biopsy. Nerve root enhancement does not seem to be related to inflammatory infiltrates.