Measurements of the normal cervical spinal cord on MR imaging

The purpose of this study was to determine normal measurements of the C1-T3 spinal cord in anteroposterior and transverse planes from MR images and to compare these with previously published data. Seven hundred and fifty-six measurements were made from 66 randomly selected MR studies of the cervical spine. We measured the anteroposterior and transverse diameters of the cord at each vertebral level and computed the simple product of these diameters to provide a single useful numerical value, termed the approximate cord area (ACA). The cord varies in average anteroposterior and transverse diameters from 8.8 mm x 12.4 mm at C2 to 8.7 mm x 14 mm at C4 to 7.4 mm x 11.4 mm at C7. The cervical enlargement was found from C4 to C6 and was most evident by comparing the ACA values. At C2 the average ACA was 110 mm2, at C4 it was 121.9 mm2, and at C7 the average ACA was 84.6 mm2. Comparison of our data with the literature reveals disparate measurements that vary up to 6 mm from our mean values. However, our results correlated well with the postmortem studies of Nordquist (1964). A single number cannot be used as the basis for evaluating spinal cord size. Each level should be compared with the normal range specific for that level.     

Diffusion-weighted echo planar imaging of the normal human cervical spinal cord

We obtained diffusion-weighted echo planar images of the human cervical cord in vivo and correlated them with histopathologic findings. Images were obtained in 17 healthy volunteers using a 1.5 T clinical MR unit. When motion-probing gradients were added perpendicular to the long axis of the cord, the white matter was hyperintense because of anisotropic diffusion. However, the gracile fasciculus was hypointense probably due to the small diameter of neural fibers and the large extracellular space.     

磁共振扩散张量成像在正常颈髓中的应用研究

目的：比较不同b值及不同数量梯度场方向对正常人颈髓扩散张量成像（DTI）的影响,探讨正常人颈髓最佳DTI技术、扩散及各向异性特点。方法：分别施加6个和25个方向的扩散敏感梯度磁场,选择不同b值（0、100、200、400、600、800、1000s/mm2）,对25名健康志愿者行颈髓DTI成像,分析比较各自影像特点并分别在颈髓相对宽的C2～C3水平、颈髓相对窄的C4～C7水平选择感兴趣区（ROI）测量表观扩散系数（ADC）与部分各向异性（FA）值及第一、二、三本征值（1、2、3）。结果：①在其它参数不变的情况下,6个与25个方向相应部位的ADC值、FA值及本征值1、2、3无显著差异（P〉0.05）。②随着b值的增大,颈髓平均质量指数变小,b=100、200、400、600s/mm2间的质量指数差异无统计学意义（P〉0.05）,b=1000s/mm2时的质量指数与信噪比均较差,b=600s/mm2时与b=100、200、800、1000s/mm2之间差异有统计学意义（P〈0.01）,而b=600、400s/mm2间差异无统计学意义（P〉0.05）。③同一参数情况下,颈髓C4～C7水平所测的ADC值与FA值分别低于C2～C3水平所测值（P〈0.05）,本征值1〉2〉3（P〈0.05）。结论：运用GE1.5T超导磁共振系统,b值取0与600s/mm2,采集方向为6时可获得较好的颈髓DTI图像,颈髓具有明显的各向异性,平行于白质纤维方向的扩散梯度可得到较高的ADC值。     

Age-related changes of the diffusion tensor imaging parameters of the normal cervical spinal cord

BackgroundThe diffusion tensor imaging (DTI) parameters of the cervical spinal cord (CSC) changes with age. However, previous studies only examined specific CSC areas.ObjectivesTo analyze the DTI parameters in all intervertebral space levels of the whole normal CSC and to study the impact of age on these parameters in a Chinese population.MethodsThirty-six healthy subjects aged 20–77 years were recruited. DTI parameters were calculated for gray matter (GM) and white matter (WM) funiculi in all the CSC intervertebral spaces (C1/2-C6/7). Age-related changes of DTI parameters were analyzed for the GM and WM funiculi.ResultsFractional anisotropy (FA) and mean diffusivity (MD) were lower in GM than in WM. MD and FA values were lower in the WM in the lower CSC compared with the upper CSC (all P < 0.05), but no difference was observed in GM. In ventral funiculi, MD increased with age, while FA decreased (all P < 0.001). In lateral and dorsal funiculi, MD and FA decreased with age (all P < 0.001). In GM, MD and FA decreased with age (all P < 0.001). Significant age-related changes were observed in FA and MD from GM and WM funiculi. FA was correlated with age in all funiculi (ventral: r = −0.733; lateral: r = −0.468; dorsal: r = −0.607; GM: r = −0.724; all P < 0.01).ConclusionImportant changes in MD and FA were observed with advancing age at all levels of CSC in Chinese patients. DTI parameters may be useful to assess CSC pathology, but the influence of age and segments need to be taken into account in diagnosis.     

Investigation of human cervical and upper thoracic spinal cord motion: implications for imaging spinal cord structure and function.

Spinal cord (SC) motion is thought to be the dominant source of error in current diffusion and spinal functional MRI (fMRI) methods. However, until now, such motion has not been well characterized in three dimensions. While previous studies have predominantly examined motion in the superior/inferior (S/I) direction, the foci of the present study were the anterior/posterior (A/P) and right/left (R/L) components of human cervical and upper thoracic SC motion. Cardiac-gated, turbofast low-angle shot (turbo-FLASH) cinematic MRI was employed at 3T to acquire images of the cord at 24 phases throughout the cardiac cycle. Time-dependent signal fluctuations within voxels adjacent to the cord/cerebrospinal fluid (CSF) interface were then used to measure SC motion, which was found to occur predictably as a function of cardiac activity. Cord movement was largest in the A/P direction, for which principal components of motion were calculated, thereby indicating consistent patterns of SC oscillation that can potentially be used to improve SC imaging.     

Transient oedema of the cervical spinal cord

Transient but very intense oedema of the cervical spinal cord was observed in two patients with obstruction of the cerebrospinal fluid (CSF) pathways. Both presented with hydrocephalus, one due to an infratentorial obstructing mass and the other due to postmeningitic adhesive obstruction of the outlet foramina of the fourth ventricle. In animal experiments with obstruction of CSF pathways (due to outlet foramina obstruction or to downward tentorial herniation) flattening and stretching of the ependymal cells along the central canal is observed, followed by disruption and splitting of the ependymal lining and then by extracellular oedema of the subependymal tissue. Without treatment, frank cavity formation develops in a fourth stage. In our two patients, however, most probably because of appropriate decompressive therapy, the oedema disappeared completely without a residual spinal cord lesion. Received: 17 September 1998 Accepted: 29 July 1999     

正常人颈髓MR扩散张量成像的初步研究

目的探讨颈髓扩散张量成像(DTI)的方法,获取正常人颈髓DTI的参数值,为颈髓病变的DTI研究提供依据。方法使用单次激发自旋回波平面回波(SE-EPI)序列对36例健康志愿者行颈髓扩散张量成像检查。在颈髓各节段分别测量其表观扩散系数(ADC)值、各向异性分数(FA)值、第1本征值(λ1)、第2本征值(λ2)以及第3本征值(λ3)。结果所有志愿者均完成该项检查,后处理图像上颈髓显示清晰,没有明显图像失真。颈髓ADC值为(914.44±82.61)×10-6mm2/s,FA值为(593.84±52.22)×10-3,λ1、λ2、λ3分别为(1585.10±130.07)×10-6mm2/s、(559.84±66.49)×10-6mm2/s、(613.28±128.71)×10-6mm2/s。λ1与λ2、λ3值比较,λ1值明显大于λ2及λ3,差异有统计学意义(P<0.05),λ2与λ3之间差异无统计学意义(P>0.05)。2λ1/(λ2+λ3)的比值为2.74±0.32。结论使用SE-EPI序列行颈髓DTI的检查能够获得比较满意的图像,测得的各项张量参数值稳定。平行于脊髓长轴方向的水分子扩散活动明显强于垂直于脊髓长轴方向的扩散,从而提示脊髓具有圆柱状的扩散特点。     

Sildenafil-induced cervical spinal cord infarction

We present a patient with an acute cervical spinal cord infarction resulting from the use of sildenafil (Viagra) in combination with his hypertension medication. Symptoms were acute and rapidly progressive, and MR imaging with DWI was crucial in confirming the diagnosis.     

Functional imaging of the rat cervical spinal cord

PURPOSE: To examine functional magnetic resonance imaging (fMRI) of the rat cervical spinal cord using painful stimulation. MATERIALS AND METHODS: fMRI of the rat cervical spinal cord was performed at 9.4 T. Stimuli included injection of 25 microL of capsaicin (128 microg/mL in 7.5% dimethylsulfoxide (DMSO)) into the right dorsal forepaw and electrical stimulation (15 V, 0.3 msec, 3 Hz) of the left dorsal forepaw. RESULTS: Activation in the dorsal horn of the spinal cord, which is known to be associated with the transmission of pain, was found in all rats (N = 4) following injection of capsaicin into the dorsal forepaw. It was possible to reproduce the pain response in a given animal several times throughout the course of an experiment, provided that sufficient time was allowed between capsaicin injections. Regions of the spinal cord associated with motor and pain response were observed in functional imaging experiments involving subcutaneous electrical stimulation of the dorsal forepaw. CONCLUSION: Spinal fMRI using electrical stimulation and capsaicin-induced painful stimulation can be a useful tool in an animal model of pain and injury.     

Morphological analysis of the cervical spinal canal,dural tube and spinal cord in normal individuals using CT myelography

To verify the conventional concept of developmental stenosis of the cervical spinal canal, we performed a morphological analysis of the relations of the cervical spinal canal, dural tube and spinal cord in normal individuals. The sagittal diameter, area and circularity of the three structures, and the dispersion of each parameter, were examined on axial sections of CT myelograms of 36 normal subjects. The spinal canal was narrowest at C4, followed by C5, while the spinal cord was largest at C4/5. The area and circularity of the cervical spinal cord were not significantly correlated with any parameter of the spinal canal nor with the sagittal diameter and area of the dural tube at any level examined, and the spinal cord showed less individual variation than the bony canal. Compression of the spinal cord might be expected whenever the sagittal diameter of the spinal canal is below the lower limit of normal, that is about 12 mm on plain radiographs. Thus, we concluded that the concept of developmental stenosis of the cervical spinal canal was reasonable and acceptable.     

MRI of the chronically injured cervical spinal cord

Thirteen patients with prior cervical spinal cord injury resulting in quadriplegia were evaluated with magnetic resonance imaging (MRI) long after their initial injury, either because of the relatively recent onset of new and worsening neurologic symptoms or to rule our residual compression on the spinal cord or nerve roots. The results of MRI were compared with delayed metrizamide computed tomography (CT) in 10 cases, and in five of those the results were also compared with intraoperative spinal sonography. It was found that MRI more accurately demonstrated the intramedullary abnormalities in the injured spinal cord than did delayed metrizamide CT because the former could separate myelomalacia from a posttraumatic spinal cord cyst, a differentiation that was frequently difficult with delayed metrizamide CT. T2-weighted spin-echo pulsing sequences with long echo times were particularly useful in evaluating these patients.     

Effects of cord motion on diffusion imaging of the spinal cord.

Measurement of diffusion and its dependence on direction has become an important tool for clinical and research studies of the brain. Diffusion imaging of the spinal cord may likewise prove useful as an indicator of tissue damage and axonal integrity; however, it is more challenging to perform diffusion imaging in the cord than in the brain. Here we report a study of the effects of motion on single-shot fast spin echo (FSE) diffusion tensor imaging (DTI) of the spinal cord. Diffusion imaging was performed at four different times in the cardiac cycle both without and with velocity compensation of the diffusion gradients. Uncompensated diffusion images demonstrated substantial signal loss artifacts in the cord that were strongly dependent on the delay after the pulse-oximeter trigger. Quantitative diffusion analysis was also strongly affected by this motion artifact. The use of flow-compensated gradients helped to restore normal signal in the cord, especially at particular trigger delays. Theoretical arguments suggest that improved spatial resolution may help eliminate this signal loss. Even with higher spatial resolution, motion-related signal attenuation may still occur in diffusion imaging of pathologies that alter the motion of the cord. However, this same cord motion may contain diagnostically valuable information when probed using appropriate diffusion imaging approaches.     

颈髓损伤后的低钠血症

低钠血症是颈髓损伤的严重并发症之一，最早由Hald报告，已有40年历史，如治疗不当，低钠血症则难以纠正，且可加重脊髓损伤或使已经恢复的神经功能再次丧失。以前，并未引起广泛的注意。近年来，颈髓损伤后水电解质紊乱尤其是低钠血症(其他如：低氯血症、代谢性酸中毒、高钙血症等)愈来愈受到重视。     

急性中央颈脊髓损伤

急性中央颈脊髓损伤是最常见的颈脊髓急性不完全性损伤。这一综合征主要临床特点为上肢运动功能受累明显、而下肢受累较轻或不受累、直肠膀胱功能障碍以及损伤平面以上感觉不同程度损害。急性中央颈脊髓损伤预后一般较好     

Morphology of the cervical spinal cord on computed myelography

Summary To ensure adequate use of the technique of computed myelography (CM) it is necessary to have an exact picture of the morphology of the normal spinal cord as demonstrated by this technique. This has been obtained by studying the morphology and measuring the frontal and sagittal diameter of the cervical cord in 20 patients. The normal values are presented. The changes of this morphology in one patient with a tumour, one patient with atrophy of the spinal cord and in some patients with congential malformations are also reported.     

MR imaging in neuroborreliosis of the cervical spinal cord

The central nervous system is involved in 10–20% of cases in Lyme disease. The neurological symptoms, time course of the disease and imaging findings are multifaceted. We report two patients with cervical radiculitis. Magnetic resonance imaging revealed strong enhancement of the cervical nerve roots on contrast-enhanced T1-weighted images. These imaging patterns of borrelia-associated radiculitis have not been reported before. Knowledge of these imaging features may help to diagnose neuroborreliosis, which presents with non-specific symptoms.