扩散张量成像及纤维束示踪成像观察正常脊髓

目的 探讨3.0T MR DTI及脊髓扩散张量纤维束示踪成像(DTT)技术的可行性及临床应用价值。 方法 应用3.0T MR成像系统对49名健康志愿者行脊髓DTI。分别测量颈髓、下段胸髓的ADC和FA值,同时进行各段脊髓DTT研究。采用单因素方差分析进行统计学分析。 结果 在颈髓与下段胸髓之间ADC和FA值差异均无统计学意义(P=0.745、0.196)。在DTT彩色编码图上,正常脊髓纤维束显示为头尾向的一束,存在头尾侧各向异性。 结论 脊髓DTI是描述扩散特征并直观显示脊髓纤维束的有效检查技术,可为脊髓病变提供扩散定量值参考。     

颈椎病脊髓损伤MRI弥散张量成像(DTI)的评价

目的探讨MRI弥散张量成像(DTI)对颈椎病脊髓损伤评价。方法对30例临床综合诊断为颈椎病患者,行颈椎常规序列MRI和颈髓弥散张量成像(DTI)检查,测量并比较所有椎间盘相应层面脊髓的表观扩散系数(ADC)、各项异性(FA)值,同时重建分析弥散张量纤维束(DTT)。结果所有研究对象的DTI均可得到颈髓的ADC图和FA图。突出椎间盘和未突出椎间盘相邻层面的颈髓FA值和ADC值差别有统计学意义(P0.05)。不同突出程度间颈椎间盘相应层面的颈髓ADC值和FA值差别有统计学意义(P0.05)。30例弥散张量纤维束中23例患者均观察到神经纤维束的受压、移位,更有11例显示部分腹侧神经纤维束中断。结论 DTI对评价颈椎病脊髓损伤具有重要价值。     

DTI在脊髓型颈椎病中的应用价值

目的探讨弥散张量成像(DTI)在脊髓型颈椎病(CSM)中的应用价值。方法40例临床及影像学证实为CSM且髓内无明显T2高信号患者,行颈髓MRI和扩散张量成像检查,并分析影像表现和测量其表观弥散系数(ADC)值及各向异性分数(FA)值。结果所有研究对象的DTI均可得到颈髓的ADC图及FA图。其中约90%(36/40)患者脊髓受压部位ADC值较正常部位升高(P=0.015),约70%(28/40)患者脊髓受压部位FA值较正常部位降低(P=0.037)。结论DTI对CSM患者早期脊髓损伤具有较高的敏感性。     

正常人颈髓扩散张量成像的定量分析

目的 定量分析健康人扩散张量成像(DTI)的部分参数值.方法 使用SE-EPI序列对22名健康志愿者行DTI扫描.在矢状位上分别测量不同节段颈髓各项参数值(ADC、FA、RA)以及本征值(λ1、λ2、λ3);在横轴位同一颈髓节段(C3水平)不同部位分别测量各项参数值.结果 矢状位测得颈髓C3水平FA值及RA值较其余部位高(P<0.05);横轴位测得颈髓前索FA及RA值较其余部位低而其ADC值较其余部位高(P<0.05).结论 使用SE-EPI序列行颈髓扩散张量成像的检查能够获得比较满意的图像;DTI可以定量测量颈髓的各项参数值.     

磁共振扩散张量成像对脊髓型颈椎病的初步研究

目的探讨扩散张量成像对检出脊髓型颈椎病颈髓早期损伤的敏感性。方法对13例健康志愿者和13例脊髓型颈椎病患者行常规MRI及扩散张量成像检查。测量C3～C7四组椎间盘层面的FA值、ADC值,并对所有受检者行颈髓纤维束重建。结果病例组ADC值大于对照组(t=8.495,P0.001);病例组FA值小于对照组(t=-14.328,P0.001),两者皆有统计学意义。病例组中约92.3%(12/13)患者脊髓受压部位伪彩图信号改变;约30.8%(4/13)患者T2WI脊髓内可见高信号,扩散张量成像比常规MRI对脊髓损伤更加敏感(P=0.002)。结论扩散张量成像可以提供脊髓的病理变化信息,在早期检出脊髓损伤方面比常规MRI敏感。     

磁共振扩散张量成像在急性隐匿性颈髓损伤中的诊断价值

目的探讨磁共振扩散张量成像(DTI)在急性隐匿性颈髓损伤(CSCI)中的诊断价值。 方法选取2016年6月至2017年7月在九江市中医医院骨伤科及神经外科就诊,72 h内有明确外伤史,临床诊断为CSCI而常规磁共振(MR)序列显示脊髓无异常信号(隐匿性脊髓损伤)患者30例(损伤组)及30例健康志愿者(对照组)分别接受常规MR序列、DTI序列检查。对两组的DTI进行数据处理与分析,获得扩散张量纤维束成像(DTT)。分别测量损伤组和对照组的各向异性分数(FA)值和表观扩散系数(ADC)值,采用两独立样本t检验比较两组间差异。 结果损伤组的FA值(0.53±0.22)明显低于对照组FA值(0.65±0.12),差异具有统计学意义(t＝5.00,P<0.01)。损伤组的ADC值[(1.15±0.28)×10^－3mm²/s]明显高于对照组ADC值[(1.04±0.57)×10^－3mm²/s],差异具有统计学意义(t＝11.20,P<0.01)。损伤组颈髓DTT图示受损区域的白质纤维束稀疏、扭曲及断裂。 结论DTI的FA值和ADC值可定量分析CSCI患者脊髓白质损伤的严重程度,DTT图可准确描绘脊髓白质损伤的位置及范围,是目前无创性诊断隐匿性颈髓损伤和评估预后的一个重要手段。     

健康脊髓及脊髓疾病DTI量化研究进展

目前,脊髓磁共振成像存在诸多局限性,近年来随着扩散张量成像(diffusion tensor imaging,DTI)应用,改善了脊髓成像质量,使定量测量成为可能,并逐渐应用于各种脊髓疾病诊断.作者对脊髓DTI成像技术及在健康脊髓、肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)、...     

扩散张量成像在急性脊髓损伤中的研究进展

脊髓是中枢神经系统的重要组成部分,不同时期、不同程度的脊髓损伤造成的后果及预后也不同,急性脊髓损伤病情发展迅速且较为严重。常规磁共振成像(magnetic resonance imaging,MRI)上的信号变化对于临床评估具有一定的局限性,磁共振扩散加权成像(diffusion weighted imaging,DWI)和磁共振扩散张量成像(diffusion tensor imaging,DTI)通过测量水分子的扩散运动,从微观上反映脊髓的损伤情况,不仅能早期及时地判断出急性脊髓损伤,而且能定量分析白质纤维束损伤的严重程度,为临床对这类患者的干预提供一定的价值信息。本文简要介绍了磁共振扩散加权成像和磁共振扩散张量成像技术在急性脊髓损伤中的应用情况及研究进展。     

扩散张量成像数据分析方法概述

扩散张量成像(DTI)是唯一可在体显示脑白质纤维束的无创成像方法,其利用组织内水分子扩散的各向异性特征进行成像。本文以DTI基本原理为出发点,对DTI的主要研究方向和数据分析方法进行分析。     

磁共振扩散张量成像对脊髓型颈椎病脊髓慢性损伤的评价

目的 评价磁共振扩散张量成像（DTI）对脊髓型颈椎病脊髓慢性损伤早期诊断的可行性。方法 采用单次激发平面回波成像（SE-EPI）序列对31例临床确诊的脊髓型颈椎病患者行颈髓常规MRI和DTI检查。测量病变处ADC值和FA值并按病变常规T2WI高信号阳性与阴性分组进行数据分析,计算常规MRI和DTI对颈髓病变检出的敏感度、特异度、阳性预测值（PPV）、阴性预测值（NPV）。结果所有脊髓型颈椎病患者均能完成DTI检查,后处理图像颈髓显示清晰,无明显图像变形及伪影。9例（29%）表现为颈髓病变T2WI高信号的患者均出现颈髓受压平面ADC值升高,FA值下降,平均ADC值为（1183.44±121.96）×10-6mm2/s,相应FA值为（432.56±59.97）×10-3,与正常值相比有统计学意义;22例（71%）颈髓病变T2WI高信号阴性患者中,7例（32%）病变处平均ADC值及FA较正常值无明显变化;15例（68%）颈髓受压平面ADC值升高,FA值下降,平均ADC值（1055.07±80.61）×10-6mm2/s,FA值为（501.87±41.09）×10-3,有统计学意义。检查方法的敏感度常规T2WI为29.0%,DTI为67.7%;特异度常规T2WI为71.0%,DTI为22.6%;PPV常规T2WI为27.3%,DTI为72.7%;NPV常规T2WI为75.9%,DTI为24.1%。结论 DTI较常规MRI更早期而准确地诊断脊髓型颈椎病颈髓慢性损伤,是一种显示脊髓型颈椎病颈髓病变和观察病变修复过程的有效手段。     

Advanced diffusion-weighted magnetic resonance imaging techniques of the human spinal cord

ABSTRACT: Unlike those of the brain, advances in diffusion-weighted imaging (DWI) of the human spinal cord have been challenged by the more complicated and inhomogeneous anatomy of the spine, the differences in magnetic susceptibility between adjacent air and fluid-filled structures and the surrounding soft tissues, and the inherent limitations of the initially used echo-planar imaging techniques used to image the spine. Interval advances in DWI techniques for imaging the human spinal cord, with the specific aims of improving the diagnostic quality of the images, and the simultaneous reduction in unwanted artifacts have resulted in higher-quality images that are now able to more accurately portray the complicated underlying anatomy and depict pathologic abnormality with improved sensitivity and specificity. Diffusion tensor imaging (DTI) has benefited from the advances in DWI techniques, as DWI images form the foundation for all tractography and DTI. This review provides a synopsis of the many recent advances in DWI of the human spinal cord, as well as some of the more common clinical uses for these techniques, including DTI and tractography.     

脊髓损伤的弥散张量成像研究进展

MR DTI作为目前唯一能显示水分子运动方向和强度的成像技术,可以动态反应中枢神经系统白质的超微结构及相应病理生理改变,为研究脊髓损伤提供了新的方法。近年来脊髓DTI已应用于临床。本文对脊髓DTI技术的应用、发展趋势进行综述。     

Detection of multiple pathways in the spinal cord using q-ball imaging

Magnetic resonance diffusion tensor imaging (DTI) has been extensively applied to the spinal cord for depicting its architecture and for assessing its integrity following spinal lesions. However, DTI is limited in representing complex white matter architecture, notably in the presence of crossing fibres. Recently, q-ball imaging (QBI) has been proposed as a new method for recovering complex white matter architecture. We applied this technique to both ex vivo and in vivo spinal cords of cats using a 3T scanner. For the purpose of comparison, gradients have been applied in 55 and 100 encoding directions and b-values varied from 800 to 3000 s/mm(2). As a result, QBI was able to retrieve crossing fibre information, where the DTI approach was constrained in a unique diffusion direction. To our knowledge, this is the first study demonstrating the benefits of QBI for detecting the presence of longitudinal, commissural and dorso-ventral fibres in the spinal cord. It is a first step towards in vivo characterization of the healthy and injured human spinal cord using high angular resolution diffusion imaging and QBI.     

脊髓慢性压迫损伤的磁共振扩散张量成像研究

目的研究脊髓慢性压迫损伤的扩散张量成像(DTI)表现及临床应用价值。方法对32例脊髓慢性压迫损伤患者和25例健康志愿者行常规MRI和横轴面DTI,测量其表观扩散系数(ADC)值、部分各向异性(FA)值。结果32例脊髓压迫损伤患者中13例可见T2WI高信号。压迫部位ADC值增高28例,不变4例,平均ADC值明显高于正常脊髓组织。ADC值和压迫程度、临床症状严重程度呈正相关。压迫部位FA值下降15例,不变11例,增高5例,平均FA值低于正常脊髓组织。FA值和压迫程度、临床症状严重程度呈负相关。结论DTI对判断脊髓慢性压迫损伤有一定价值,ADC值敏感度最高。     

用磁共振扩散张量成像研究犬急性脊髓损伤后可降解支架及神经干细胞移植的作用

目的用磁共振扩散张量成像(DTI)观察犬急性脊髓损伤后可降解支架及神经干细胞移植的作用.方法制作犬T13脊髓左半横断损伤模型.将18只犬分为假手术组(1)、对照组(5)、支架组(5)和干细胞组(7).假手术组不损伤脊髓.对照组仅损伤脊髓,不做移植.损伤后1周时,干细胞组将填充Hoechst标记的神经干细胞的可降解支架植入损伤区;支架组仅植入可降解支架.分别于损伤前、损伤后1周、移植后1周(即损伤后2周)、移植后4周及移植后8周时行MRI检查,用DTI测量损伤侧和未损伤侧的表观扩散系数(ADC)值及部分各向异性(FA)值,并对结果进行统计学分析.DTI用SSFSE序列,b=500 s/mm2,扩散敏感梯度方向为13.结果损伤前,脊髓左右两侧对比,ADC和FA值的差异无统计学意义.损伤后ADC值升高,FA值降低,随时间延长而逐渐恢复,干细胞组恢复更明显.移植后4周时,对照组脊髓左右两侧的ADC值和FA值的差异有统计学意义,支架组和干细胞组脊髓左右两侧的ADC值和FA值的差异无统计学意义.结论DTI对实验性脊髓损伤后脊髓损伤和修复过程的观察能提供有价值的信息.     

扩散磁共振成像和纤维束示踪成像在脊髓成像中的临床应用

磁共振弥散张量成像和纤维束示踪成像能够显示白质纤维的结构,在脊髓的应用也越来越广泛,对检出病变和判断病变性质的敏感性较常规MRI高,能够提供更多诊断及鉴别诊断依据,同时能更好地进行术前疗效评估及判断预后.     

Investigating cervical spinal cord structure using axial diffusion tensor imaging

This study describes a new technique for Diffusion Tensor Imaging (DTI) that acquires axial (transverse) images of the cervical spinal cord. The DTI images depict axonal fiber orientation, enable quantification of diffusion characteristics along the spinal cord, and have the potential to demonstrate the connectivity of cord white matter tracts. Because of the high sensitivity to motion of diffusion-weighted magnetic resonance imaging and the small size of the spinal cord, a fast imaging method with high in-plane resolution was developed. Images were acquired with a single-shot EPI technique, named ZOOM-EPI (zonally magnified oblique multislice echo planar imaging), which selects localized areas and reduces artefacts caused by susceptibility changes between soft tissue and the adjacent vertebrae. Cardiac gating was used to reduce pulsatile flow artefacts from the surrounding cerebrospinal fluid. Voxel resolution was 1.25 x 1.25 mm(2) in-plane with 5-mm slice thickness. Both the mean diffusivity (MD) and the fractional anisotropy (FA) indices of the cervical spinal cord were measured. The FA index demonstrated high anisotropy of the spinal cord with an average value of 0.61 +/- 0.05 (highest value of 0.66 +/- 0.03 at C3), comparable to white matter tracts in the brain. The diffusivity components parallel and orthogonal to the longitudinal axes of the cord were lambda( parallel) = (1648 +/- 123) x 10(-6) mm(2)s(-1) and lambda( perpendicular) = (570 +/- 47) x 10(-6) mm(2) s(-1), respectively. The high axial resolution allowed preliminary evaluation of fiber connectivity using the fast-marching tractography algorithm, which generated traces of fiber paths consistent with the well-known cord anatomy.