电针刺激穴位的脊髓fMRI初步研究

目的检测电针刺激合谷穴和曲池穴的脊髓fMRI的可行性。方法 8名健康志愿者,电针同时刺激右手合谷穴和右肘曲池穴,采用组块设计方法,使用SPM2软件得到功能激活的t检验图,在矢状位上分析脊柱不同区的激活总像素数和最大强度值,在横断位上观察激活区的位置,并对比不同刺激时间对激活分布和信号强度的影响。结果 8名志愿者脊髓中均存在激活,矢状面上激活点分布在脊柱C2～T1段,但主要集中在脊柱C2、C4、C5和C6段。横断面上主要激活区域位于同侧,尤其是在脊髓的后角及前角（功能区）,同时发现对侧后角有少量显著激活区。与刺激5次组相比,刺激3次组的最大激活信号强度较高,且伪激活数较少。结论使用电针刺激合谷穴和曲池穴,通过脊髓磁共振功能成像技术可观测到脊髓的功能激活区,而且激活分布具有一定特征性。     

MRI评价腰椎间盘突出症患者的椎旁肌改变

目的 探讨腰椎间盘突出症患者的椎旁肌面积及T₂WI信号强度变化,为腰椎间盘突出症的评估及康复治疗提供参考。方法 收集43例L_4-5椎间盘突出患者、45例腰椎间盘正常体检者,采用GE/HDXT/1.5T T₂WI序列分别测量L_4-5中心层面双侧椎旁肌(多裂肌、竖脊肌、腰大肌)横截面积、T₂WI信号强度,比较椎间盘突出组和正常组在椎旁肌横截面积、T₂WI信号强度的差异,组间采用两独立样本t检验、组内采用配对样本t检验。结果 腰突组和正常组比较,L_4-5右侧多裂肌T₂WI信号强度比值、右侧竖脊肌T₂WI信号强度比值差异有统计学意义(P<0.05);椎旁肌横截面积及T₂WI信号强度绝对值差异无统计学意义(P>0.05);43例腰突组组内比较,L_4-5两侧竖脊肌面积、两侧多裂肌T₂WI信号强度比值、两侧竖脊肌T_2<...     

1.5T磁共振不同序列对髌骨软化症诊断价值

目的:探讨1.5T磁共振不同序列在髌骨软化症诊断中的应用价值。材料与方法:采取回顾性方法对我院2013-06/2014-12间的186例髌骨软化症患者的磁共振资料进行分析。结果:MR诊断中I期8例,Ⅱ期19例,Ⅲ期98例,Ⅳ期61例,所占比例分别为4.4%、10.2%、52.6%、32.8%。矢状位梯度回波像与横断位T₂WI在早期髌骨软化症诊断效果高于矢状位的T₂WI效果,差异有统计学意义（P<0.05）;而晚期髌骨软化症诊断诊断中单独三种序列诊断比较无明显的差异（P>0.05）。结论:临床中采取1.5T磁共振不同序列对髌骨软化症诊断具有较好的效果,尤其矢状位与横断位梯度回波像联合检查可以提高临床诊断,在临床中具有较高应用价值。     

右美托咪定复合艾司氯胺酮对老年经皮椎体成形术患者应激反应的影响

目的 观察右美托咪定复合亚麻醉剂量艾司氯胺酮对老年经皮椎体成形术患者应激反应的影响。方法 选择择期行经皮椎体成形术的老年患者120例为研究对象,随机分为对照组、右美托咪定组、艾司氯胺酮组及复合组,每组30例。右美托咪定组、复合组在局部麻醉前10 min开始静脉泵注右美托咪定0.5μg/kg,随后按0.25μg/(kg·h)的速度持续泵注维持;艾司氯胺酮组、复合组给予艾司氯胺酮0.25 mg/kg;手术开始前,4组患者以1%盐酸利多卡因行局部浸润麻醉。记录入室5 min(T₀)、手术开始即刻(T₁)、穿刺针到达椎体时(T₂)、骨水泥注入时(T₃)、手术结束即刻(T₄)及返回病房前(T₅)的生命体征、疼痛视觉模拟评分法(VAS)评分及镇静Ramsay评分;检测T₀、T₁、T₃及T₄时血浆皮质醇(Cor)、血糖(Glu)、血浆肾上腺素(E)及去甲肾上腺素(NE)水平。结果 与...     

腰骶椎椎间盘突出的磁共振成像诊断

本组资料分析了腰低椎正常者45例,椎间盘突出者(LSDH)45例的MRI表现。45例正常腰骶椎的MRI表现为:矢状面观椎体呈方形,骨松质含脂肪信号强度高,周围骨皮质信号强度很低。椎间盘的髓核呈长方形或近似梭形,信号强度均匀。髓核周围有纤维环围成的低信号暗区,宽2～3mm。矢状面正常髓核的前后应有暗区存在,至少髓核不超出椎体前后缘。椎体后方有一条白色带状结构,从L_3向下逐渐增宽,前后宽度2～4mm。这是硬膜外脂肪形成的高信号区,身体肥胖者此     

三维磁共振影像评估脊柱病变的特征

目的:分析患者胸腰椎椎体的冠状位断层图像,探讨脊柱病变三维磁共振成像技术与临床应用。方法:选择2001-11/2002-03在广州市中山大学附属第二医院磁共振室行磁共振检查的患者87例。对其中资料齐全的27例正常成年人行椎体形态学研究分析。椎体肿瘤、脊柱结核、椎体骨折60例患者研究脊柱病变的三维磁共振应用价值。采用磁共振胸腰椎矢状位T2加权像测量T1～L12椎体的上、中、下矢状径,分析椎体形态学特点及其变化规律,进而确定磁共振I标准化椎体冠状位扫描的方法,层数等技术参数;对典型的脊柱病变与椎旁病变60例,研究脊柱肿瘤、结核、骨折等病变的三维磁共振特点与临床应用价值。结果:87例均进入结果分析。椎体形态学研究显示,从T1～L5椎体矢状径差别较大,说明从T1～L5椎体形态变化较大,加之脊柱生理弯曲的影响,只能采用标准化冠状位椎体成像技术,才能取得标准一致冠状位成像;对椎体病变的成像分析说明:标准化椎体冠状位扫描能够更好地显示椎体病变的位置、范围、有利于诊断,治疗的准确定位。结论:椎体特异性冠状位磁共振断层成像能补充矢状位、横轴位椎体断层成像的不足,可显示椎体病变的特点、程度、范围,具有临床应用价值;同时应用特异性椎体冠状位成像能够取得标准一致的椎体冠状位断层图像,可进行影像解剖学研究的测量分析。     

磁共振常规图像诊断腰椎间盘突出的不足:与手术结果对比研究

目的通过与手术结果比较,找出目前腰椎MR横轴位及矢状位图像诊断腰椎间盘突出的缺陷与不足,并提出解决方法。材料与方法回顾100例经手术证实存在腰椎间盘突出并术前有MR平扫资料的病例,观察MR常规序列(包括矢状位T1WI、T2WI及压脂序列,横轴位T2WI),分别以手术结果为标准,计算矢状位与横轴位图像诊断腰椎间盘突出的准确率及对腰椎间盘突出特殊征象的检出率,并分析横轴位及矢状位图像的漏诊原因。结果 MR横轴位图像对腰椎间盘突出总体诊断准确率为93.6%,矢状位为84.8%,前者高于后者(χ~2=5.02,P0.05);横轴位图像对腰椎间盘向上下方突出或脱出和髓核游离的检出率低(36.00%、45.45%),矢状位检出率高(96.00%、100.00%),前者检出率明显低于后者(χ~2=20.05、8.25,P0.05)。横轴位对椎间孔型及椎间孔外侧型椎间盘突出的检出率高(96.30%、88.89%),矢状位上分别为74.07%、38.89%,前者检出率明显高于后者(χ~2=5.28、9.75,P0.05)。横轴位局限于椎间隙层面的扫描范围和矢状位缺乏参照是MR常规图像漏诊椎间盘突出的主要原因。结论 MR常规图像对特殊类型椎间盘突出的漏诊,可以通过密切结合MR矢状位图像,根据需要局部增加横轴位扫描层面或结合三维电子计算机断层扫描(computed tomography,CT)检查来解决。     

电针刺激脊髓损伤患者穴位的脊髓磁共振功能成像激活区特征

背景:研究发现脊髓功能激活区域和电生理等理论对应区域相一致,多数学者认为使用功能磁共振技术检测脊髓神经功能是可行的.目的:检测电针刺激脊髓损伤患者的脊髓磁共振功能成像激活区特征,验证使用脊髓磁共振功能成像技术来客观评价针灸治疗脊髓损伤疗效的可行性.方法;使用电针同时刺激3例脊髓损伤患者和5名健康志愿者的右手合谷穴和曲池穴,采用组块设计方法,使用SPM2软件得到患者和健康志愿者脊髓内真实的激活区,分析激活区在矢状位和横断位上的分布特征,并与健康志愿者的激活分布对比,找出患者的激活分布差异.结果与结论:5名健康志愿者在脊柱C2、C5段均重复出现激活信号,在C6段4名出现激活;3例脊髓损伤患者在脊柱C2,C6段均出现均重复出现激活,其中1例患者与健康志愿者激活分布特征基本一致.可以观察到针灸刺激脊髓损伤患者的脊髓功能激活,因此可以根据功能激活区的分布及强度,在一定程度上客观评价针灸治疗脊髓损伤的疗效.     

国人腰椎椎体性别差异的分析

背景:近年来的研究表明人体的许多器官、组织等都存在着明显的性别差异,骨及骨内的神经生长等也存在性别差异,且骨科及其他学科的一些精细手术如膝关节的假体置换,肘关节的骨折治疗等都要考虑到性别差异的影响.目的:比较国人腰椎椎体的性别差异.方法:收集中山大学第二附属医院磁共振室行腰椎磁共振检查资料齐全的正常成年人67名,其中男35名,年龄20-51(39.4±4.3)岁;女32名,年龄19～52(41.2±5.6)岁.T2加权像横轴位测量比较成年男,女腰椎椎体的面积S;正中矢状位测量椎体的上矢状径Dn,中矢状径Dm,下矢状径Dd,前高Ha,中高Hm,后高Hp;然后根据测量结果推算椎体的高度比:前高比Ha,Dm,中高比Hm,Dm,后高比Hp/Hm.结果与结论:国人男女椎体的性别差异显著,从L1～L5,椎体面积逐渐升高,男性椎体面积始终大于女性;男性椎体的矢状径Dn,Dm,Dd总大于女性,男性椎体的高度Ha,Hm,Hd大于女性;但是女性椎体的前高比Ha/Dm,中高比Hm/Dm,后高比Hp/Hm总大于男性.     

MRI在椎间盘平面和椎体平面测量颈脊髓值差异的比较

背景:颈脊髓的矢状径测量简单易行,能直接反映脊髓在椎管中状态,但目前对颈脊髓矢状径的测量多局限于椎体平面,椎间盘平面的测量较少见.目的:通过MRI分别对颈椎椎间盘平面和椎体平面的脊髓矢状径进行测量,比较椎间盘平面和椎体平面各测量值异同.设计、时间及地点:对比分析,于2006-03/2007-04在解放军第二军医大学长征医院完成.参试者:选取门诊招募的无颈脊髓的神经症状和体征志愿者120例,男48例,女72例;年龄17～71岁,平均41.4岁.方法:所有受试者行颈椎MRI检查,在MRI片上,对各节段(椎体平面和椎间盘平面)颈脊髓矢状径、颈椎管有效矢状径进行测量,并计算颈脊髓矢状径与颈椎管有效矢状径的比值.主要观察指标:椎体平面脊髓矢状径,椎间盘平面脊髓矢状径,椎体平面椎管有效矢状径,椎间盘节段椎管有效矢状径,同节段脊髓矢状径和有效椎管矢状径的比值.结果:椎体平面平均脊髓矢状径大于椎间盘平面平均脊髓矢状径(t=2.42,P＜0.01);椎体平面平均椎管有效矢状径大于椎间盘平面平均椎管有效矢状径(t=2.67,P＜0.01):椎体平面平均脊髓和椎管有效矢状径比值、椎间盘平面平均脊髓和椎管有效矢状径比值及全部节段的平均脊髓和有效椎管有效矢状径比值比较差异无显著性(F=0.703,P=0.495).结论:椎间盘平面的脊髓矢状径和颈椎管有效矢状径与椎体节段是明显不同的,在测量中不能忽视椎间盘平面的测量;颈脊髓矢状径和椎管有效矢状径比值可作为评价颈脊髓病变的客观标准.     

BOLD and blood volume-weighted fMRI of rat lumbar spinal cord during non-noxious and noxious electrical hindpaw stimulation

Spinal cord fMRI is a useful tool for studying spinal mechanisms of pain, hence for analgesic drug development. Its technical feasibility in both humans and rats has been demonstrated. This study investigates the reproducibility, robustness, and spatial accuracy of fMRI of lumbar spinal cord activation due to transcutaneous noxious and non-noxious electrical stimulation of the hindpaw in alpha-chloralose-anesthetized rats. Blood oxygenation level-dependent (BOLD) and blood volume-weighted fMRI data were acquired without and with intravenous injection of ultra small superparamagnetic iron oxide particles (USPIO), respectively, using a gradient echo (GE) echo planar imaging (EPI) technique at 4.7 T. Neuronal activation in the spinal cord induced by noxious stimulation to the hindpaw (2 ms wide, 5 mA amplitude, known to activate C-fibers) can be robustly detected by both fMRI techniques with excellent reproducibility and peaked at the stimulus frequency of 40 Hz. However, both fMRI techniques were not sensitive to neuronal activation in spinal cord induced by non-noxious stimulation (0.3 ms, 1.5 mA, known only to activate A-fibers). Spatially, the fMRI signal extended approximately 5 mm in the longitudinal direction, covering L(3)-L(5) segments. In the cross-sectional direction, the highest signal change of blood volume-weighted fMRI was in the middle of the ipsilateral dorsal horn, which roughly corresponds to laminae V and VI, while the highest signal change of BOLD fMRI was in the ipsilateral dorsal surface. This study demonstrates that spinal cord fMRI can be performed in anesthetized rats reliably and reproducibly offering it as a potential tool for analgesic drug discovery.     

Predictive model of intersegmental mobility of lumbar spine in the sagittal plane from skin markers

This article describes a sagittal motion model that transforms skin marker coordinates into corresponding vertebral body coordinates. Coordinate data were obtained from 45 subjects with radiopaque skin markers over the vertebral spinous processes. Data of 30 subjects were used for model development while data of the other Fifteen subjects were used for model validation. The subjects were subjected to lateral spinal radiographs in positions of neutral, flexion, and extension. The model was developed by taking the non-linear difference between lumbar spinal profile and skin profile, the L₄ skin-fold, and the difference of L₁-S₁ skin distraction into consideration. Regression analysis shows high coefficients of determination (range, 62.43–99.86%; mean, 86.41%) in comparing the estimated position data with the actual data in all vertebral body positions. Based on the estimated coordinates, both the intersegmental joint angles and intersegmental joint mobilities were calculated. The result of this study using the non-invasive protocol and the transformation matrices demonstrated that the intersegmental sagittal motion of lumbar spine can be obtained with error ranged from 0.05 to 0.56 degrees.     

Mapping of neuronal function in the healthy and injured human spinal cord with spinal fMRI

Functional magnetic resonance imaging of the human spinal cord is carried out with a graded thermal stimulus in order to establish the relationship between signal changes and neural activity. Studies of the lumbar spinal cord in 15 healthy subjects with 10 degrees C stimulation of the skin overlying the calf demonstrate a pattern of activity that matches the neuronal anatomy of the spinal cord. This pattern shows primarily dorsal horn activity, with expected components of motor reflex activity as well. Moreover, a later response shifting to noxious cold over time is also demonstrated with a shift to more dorsal horn activity. Signal intensity changes detected at different degrees of thermal stimulation have a biphasic nature, with much larger signal changes below 15 degrees C as the stimulus becomes noxious, and agree well with electrophysiological results reported in the literature. These findings demonstrate a strong correspondence between Spinal fMRI results and neural activity in the human spinal cord. Spinal fMRI is also applied to studies of the injured spinal cord, below the site of injury. Results consistently demonstrate activity in the spinal cord even when the subjects cannot feel the stimulus being applied. Signal intensity changes demonstrate the same stimulus-response pattern as that in noninjured subjects, but the areas of activity in the spinal gray matter are notably altered. In subjects with complete injuries, activity is absent ipsilateral to the thermal stimulation, but appears to be enhanced on the contralateral side. These findings demonstrate the reliability of Spinal fMRI and its clinical potential.     

Spinal cord functional MRI at 3 T: gradient echo echo-planar imaging versus turbo spin echo

The purpose of this study was to evaluate and compare turbo spin echo (TSE) with gradient echo echo-planar imaging (GE-EPI) pulse sequences for functional magnetic resonance imaging (fMRI) of spinal cord activation at 3 T field strength. Healthy volunteers underwent TSE and GE-EPI spinal fMRI. The activation paradigm comprised the temporal alternation of finger motion and rest. Pulse sequences were optimized to obtain sufficient image quality and optimal sensitivity to small T(2) or T(2)* relaxation time changes. Spinal cord activation measured by the two pulse sequences was evaluated with respect to spatial distribution of activation, signal sensitivity, and reproducibility. For the GE-EPI sequence, fMRI activation was maximal in the spinal cord segments at the levels of the fifth cervical down to the first thoracic vertebra. For the TSE sequence, fMRI measurements showed no distinct location with maximal activation. Percentage signal change and number of activated voxels were approximately twice as high for GE-EPI compared to TSE fMRI. Reproducibility of the signal changes was much better for GE-EPI than for TSE imaging. To conclude, multi-subjects averaged GE-EPI is more location specific for blood-oxygen-level-dependent (BOLD) activation, more sensitive, and is suggested to be more reproducible than TSE fMRI.     

Proton-density-weighted spinal fMRI with sensorimotor stimulation at 0.2 T

Proton-density-weighted fMRI at low field (0.2 T) was carried out in the cervical spinal cord of healthy volunteers in this study to examine the feasibility of detecting proton density alteration accompanying activation in the spinal cord. Subjects were asked to grip both hands simultaneously, providing sensorimotor simulation for spinal fMRI. Over 70% subjects recruited had activation localized at C6-C7 spinal levels with discrete activation detected in both the anterior and posterior horns of the cervical spinal cord, and the average fractional signal change was 4.06%. The 0.2 T low magnetic field and the 24 ms short TE used in this study diminished the BOLD effect to a negligible level, thus the observed signal change was believed to be mainly attributable to proton density increase during neuronal stimulation. Our results suggested the existence of task-driven proton density change in the cervical spinal cord.     

Single, slice-specific z-shim gradient pulses improve T2*-weighted imaging of the spinal cord

T2*-weighted imaging of the spinal cord suffers from signal dropouts that hamper blood-oxygenation-level-dependent functional magnetic resonance imaging (fMRI). They are due to field inhomogeneities caused by the different magnetic susceptibilities of the vertebrae and the intervertebral disks that vary periodically along the cord and, thus, cannot be compensated appropriately with conventional (constant) shimming. In this study, a single, slice-specific gradient pulse (“z-shim”) is applied in echo-planar imaging of axial sections in order to compensate for the corresponding through-slice signal dephasing without affecting the acquisition time, i.e. the temporal resolution. Based on a reference acquisition sampling a range of compensation moments, the value yielding the maximum signal amplitude within the spinal cord is determined for each slice. Severe N/2 ghosting for larger compensation moments is avoided by applying the gradient pulse after the corresponding reference echoes. Furthermore, first-order flow compensation in the slice direction of both the slice-selection and the z-shim gradient pulse considerably reduces signal fluctuations in the cerebro-spinal fluid surrounding the spinal cord, i.e. would minimize ringing artifacts in fMRI. Phantom and in vivo experiments show the necessity to use slice-specific compensation moments in the presence of local susceptibility differences. Measurements performed in a group of 24 healthy volunteers at 3T demonstrate that this approach improves T2*-weighted imaging of axial sections of the cervical spinal cord by (i) increasing the signal intensity (overall by about 20%) and (ii) reducing signal intensity variations along the cord (by about 80%). Thus, it may help to improve the feasibility and reliability of fMRI of the spinal cord.     

脊髓损伤恒河猴下肢残留跨步能力的评估

目的 观察评估脊髓损伤后恒河猴的下肢残留跨步能力。方法 成年雌性恒河猴4只,胸椎T_7-9右半侧切除脊髓组织1 cm。分别在脊髓损伤前、脊髓损伤后6周和12周,采用VICON系统进行双下肢步态测试,获取动物在跑步机上连续跨步中的双下肢步态周期时长,步长、步高、膝/踝关节角度幅值以及联动参数比值,并量化分析。结果 脊髓损伤后,恒河猴双下肢的协调性破坏,右下肢明显拖拽;左下肢步态周期时长显著增加(P < 0.001),膝/踝关节角度屈曲/伸展的幅值均显著增大( P < 0.001)。联动参数比值在脊髓损伤前后均无显著性差异( P > 0.05)。左下肢步态周期时长与步长( r= 0.838, P = 0.001)、步高(r= 0.726, P = 0.007)和踝关节角度变化幅值(r= 0.766, P = 0.004)均相关,踝关节角度变化幅值与步长呈正相关(r= 0.627, P = 0.029)。结论 脊髓损伤后恒河猴健侧肢体步态模式发生改变。健侧下肢代偿性调整运动策略,以适应患侧下肢功能的缺失。     

Cervical spinal cord BOLD fMRI study: modulation of functional activation by dexterity of dominant and non-dominant hands

The objective of this study was to investigate the effect of dexterity on the magnitude of signal changes in functional magnetic resonance imaging (fMRI) in the cervical spinal cord with unilateral finger-tapping. Right-handed healthy volunteers were investigated with blood oxygenation level-dependent (BOLD) fMRI. Spinal cord BOLD functional MR images were acquired from 10 healthy right-handed volunteers who performed four sessions of unilateral finger-tapping tasks: left sequential (LS), right sequential (RS), left interleaved (LI), and right interleaved (RI) tasks. Our results from the difficulty measurement test showed that finger-tapping in interleaved order was more difficult than in sequential order. For the functional activation, seven out of 10 subjects had activation in all four fMRI sessions (two of the subjects who showed no detectable activation had problems in volume registration). The mean contrast value of the activation area inside the entire cervical spinal cord was significantly higher in performing LS than RS tasks. The increase in the mean contrast value was because the less skilled and competent right hemisphere required additional processing power for doing the left hand task than the left hemisphere required in doing the right hand task. The analysis of the interleaved finger-tapping tasks did not show any significant difference in the results. This was probably because the interleaved task was similarly challenging for both hands, and required high dexterity. Therefore, differences in activity between the left and right hands were less apparent. Our results showed the modulation of activation intensity in the spinal cord by the dexterity.     

Functional magnetic resonance imaging within the rat spinal cord following peripheral nerve injury

Functional magnetic resonance imaging (fMRI) was used to detect the effects of graded peripheral nerve injury at the spinal level. Graded peripheral nerve injury in rats was accomplished by transection of nerves entering the spinal cord at the L3 and L4 levels of the spinal cord segments. Electrical stimulation of the hindpaw was used to elicit activity within the spinal cord. The stimulation experimental paradigm consisted of 62 functional images, 5 slices each, with a total of 3 rest and 2 stimulation periods. A 9.4 T MRI system and a quadrature volume rf coil covering the lumbar spinal cord were used for the fMRI study. Sets of fast spin echo images were acquired repeatedly following sham preparatory surgery under control conditions and in rats following sham surgery (pre nerve cut), followed by L3 nerve and then L4 nerve section. In rats with sham surgery, there was a significant activation within the dorsal horn of slices corresponding to L3 and L4 spinal cord segments. Following section of the L3 nerve, there was a reduction in the number of active voxels in the L3 and L4 spinal cord segments. The activation was reduced further by sectioning of the L4 nerve. Thus, following an increasing loss of axonal connections to the spinal cord, there was a decreasing number of active voxels within the spinal cord. The results demonstrate that spinal fMRI in the rat has sufficient sensitivity to detect within the spinal cord the effects of a graded reduction in peripheral connectivity.