自然位与过屈位磁共振成像对平山病的诊断价值

目的:探讨颈椎自然位及过屈位磁共振成像对平山病的诊断价值.方法:对8例临床证实的平山病患者行颈椎自然位及过屈位磁共振平扫及增强扫描,所有患者均进行常规脑脊液检查、肌电图检查.结果:自然位MR扫描,8例均有C5～C7段脊髓轻度萎缩,前后径变短,过屈位扫描,7例患者可见颈髓前移,硬脊膜外腔增宽,1例患者可见硬膜外腔内流空血管影,7例在增强扫描中均可见不同程度的硬膜后间隙内异常强化影.结论:平山病患者在过屈位时颈髓及硬膜外腔的异常表现极具特征性,因此MRI过屈位平扫加增强扫描对平山病的诊断具有重要价值.     

平山病的MRI诊断价值

目的:探讨平山病的MR表现和价值,认识平山病的临床特征和可能的发病机制.方法:5例经临床确诊的平山病患者均隐匿起病,病变局限于上肢远端肌肉,4例单侧上肢前臂受累,1例双侧不对称性受累.5例患者均行颈椎X线平片检查,及颈髓常规自然体位MR平扫及屈颈位平扫 增强扫描.所有患者均进行常规生化检查,脑脊液检查,肌电图检查和肌肉活检.结果:5例患者普通X线检查4例可见颈椎生理曲度变直,自然体位MR平扫3例有低位脊髓萎缩变扁(萎缩水平在颈5-胸1,最明显在颈6水平),2例萎缩的脊髓内信号异常.曲颈MR检查时,除了可见自然体位MR的表现外,5例患者均可见特征性的颈髓前移、变平,硬脊膜向前移位,硬脊膜外腔增宽,4例患者在增宽的硬膜外腔均可见流空血管信号,增强扫描5例患者在增宽的硬脊膜外腔均可见强化的静脉丛.结论:平山病的MR表现存在一定的特征性,MR屈曲位平扫 增强扫描对平山病的诊断及其发病机制的理解有重要的价值.     

平山病的MRI诊断

目的 探讨平山病低位颈髓在自然位和过屈位特殊的动态变化对诊断的价值。方法 对18例临床确诊为平山病的患者和31例正常对照者进行MR自然位和过屈位的矢状面和轴面扫描，测量C6椎体上缘颈髓前后径（APD）和横径（TD），观察其动态改变。结果 （1）自然位，平山病组表现有低位颈髓萎缩（病例组11例，对照组2例，X^2=14．76，P=0．000）和变扁平（病例组7例，对照组1例，X^2=8．15，P=0．004），差异有统计学意义。（2）过屈位，平山病组颈髓均前移后显著变扁，脊膜后有“月牙”形异常信号影。（3）自然位平山病组和对照组APD分别为（5．6±0．7）、（6．7±0．5）mm，过屈位APD分别为（4．3±0．8）、（6．0±0．5）mm，差异均有统计学意义（t值分别为-5．802、-8．952，P值均为0．000）。结论 平山病低位颈髓在正常位和过屈位存在特殊的动态变化，过屈位MRI可协助诊断。     

平山病MRI诊断价值的初步研究

目的：探讨平山病的MRI表现及其诊断价值,加深对平山病的MRI表现及其可能的发病机制的认识。方法：回顾性分析5例经临床证实为平山病的MRI资料。所有患者均行颈椎常规仰卧位和屈颈位平扫及增强MRI检查。结果：常规仰卧位MPA显示5例患者中3例低位颈髓（C5-C7）萎缩,变扁平,髓内出现信号异常（主要位于灰质前角内）;屈颈位砌平扫5例均可见下段颈髓前移、变扁平加剧;4例硬脊膜外间隙增宽。增强MRI 3例患者可见增宽的硬膜外间隙内异常增粗并明显强化的静脉丛。结论：平山病的MRI表现有一定的特征性,屈颈位平扫及增强MRI对平山病的诊断有重要的价值。     

平山病的MRI诊断

目的:总结分析平山病的MRI表现,探讨MRI对平山病的诊断价值。方法:回顾性分析经临床及肌电图证实为平山病的11例患者的影像资料。结果:9例颈椎生理曲度变直或反弓;11例均有MRI上低位颈髓不同程度变扁、变细、萎缩,屈曲位均可见背侧硬脊膜向前移位、后硬脊膜外间隙增宽及弧形或梭形T2WI异常高信号。结论:平山病的MRI表现有一定的特征性,低位颈髓的局限性萎缩、细扁改变、屈曲位后硬脊膜外间隙T2WI高信号及流空信号对本病的诊断具有重要价值。     

平山病2例报告并文献复习

目的 探讨平山病的颈髓磁共振(MRI)表现及其诊断价值.方法 对2例平山病患者的临床、神经电生理、MRI影像学资料进行分析,并复习相关文献,总结平山病的颈髓MRI特点.结果 2例均为青年男性,主要表现为局限于手和前臂肌萎缩.肌电图均示神经源性损害.自然位MRI扫描,2例均有C4～C7段脊髓轻度萎缩,前后径变短.屈颈位MRI平扫2例均可见下段颈髓前移、变扁平加剧,硬脊膜外间隙增宽,其内可见蚓状异常血管流空信号.增强MRI2例均可见增宽的硬膜外间隙内异常增粗并明显强化的静脉丛.结论 平山病的MRI表现有一定的特征性,屈颈位平扫及增强MRI对平山病的诊断有重要的价值.     

颈椎过屈位磁共振成像在平山病诊断中的应用

目的:研究颈椎过屈位MRI对平山病诊断的价值。材料和方法:对13例临床确诊为平山病的患者和10例正常对照者进行颈椎过屈位MRI矢状面和轴面扫描,观察低位脊髓萎缩、变扁、C6椎体上缘水平颈髓前后径及硬膜外异常信号。结果:①低位颈髓的萎缩:病例组9例(69%),对照组1例(10%)。②低位脊髓变扁:仅见于病例组11例(84%),其中有10例(77%)为不对称变扁,脊髓呈"梨形",1例(7%)呈三角形变扁。对照组未出现脊髓变扁的表现。③C6水平颈髓前后径与对照组相比明显变窄,差别有统计学意义(t=-4.54,P<0.05)。④低位颈椎椎管内硬膜后方T_2WI异常信号:仅见于患者组的10例(77%)。结论:颈椎过屈位MRI对诊断平山病有重要的价值。     

MRI诊断平山病的应用价值

目的回顾性分析平山病患者的颈椎中立位和过曲位MRI表现,探讨MRI对平山病的诊断价值。方法 14例经临床确诊为平山病患者,均行颈椎过屈位MRI检查,其中11例患者行中立位MRI检查,分别对患者不同体位的MRI图像进行分析。结果 11例行颈椎中立位MRI检查的患者中,存在颈椎曲度异常者7例,脊髓出现萎缩、变细者6例,失连接现象仅4例;14例行颈椎过屈位检查的患者均存在硬膜囊后壁前移、脊髓受压变细、硬膜囊外后间隙扩张、失连接现象等征象,其中5例脊髓内出现长T2信号,且出现部位略高于脊髓受压最显著处。结论颈椎过屈位MRI对诊断平山病具有重要价值。     

不同体位颈椎MRI对平山病的影像诊断

目的 探讨平山病患者自然位和前屈位颈椎MRI表现及其诊断价值.资料与方法 对6例经临床确诊的平山病患者及6名正常自愿者均行颈椎自然位+前屈位+增强MRI,对比分析平山病患者低位颈髓的MRI表现.结果 自然位:6例患者颈椎生理曲度变直,低位颈髓变细;6名正常自愿者可见颈膨大(约脊髓C6～T2段).前屈位:6例患者低位颈髓变扁、萎缩,两种体位低位颈髓前后径差值与正常自愿者相比差异有统计学意义(P<0.05),另可见背侧硬膜囊后壁前移、硬膜外间隙增宽,内见迂曲、条形流空信号,增强后明显强化;正常自愿者低位颈髓较自然位略变细,背侧硬膜囊无前移、扩张,其内未见流空信号.结论 不同体位MRI均能显示平山病患者颈椎的异常表现,尤其是前屈位对平山病的诊断具有重要价值.     

平山病屈颈位磁共振扫描技术研究

目的:探讨平山病屈颈位磁共振扫描技术成功的关键。方法:对6例临床确诊平山病患者行屈颈位磁共振扫描,采用GE 1.5T HD扫描系统,CTL线圈。均行两次屈颈位MR扫描(传统过屈位:患者单纯颈部垫楔形物;优化的过屈位:颈部垫楔形物同时要求患者收下颌),比较两次硬膜外腔宽度,对比分析流空血管的显示情况。结果:优化的屈颈扫描硬膜外宽度明显大于传统的屈颈扫描(P<0.05),两者存在显著性差异;流空血管的显示,传统的屈颈扫描3例,优化的屈颈扫描5例。结论:在平山病屈颈位磁共振扫描技术中,收下颌是扫描成功的关键,能清楚显示扩张的硬膜外腔和流空的异常血管。     

Forward shifting of posterior dural sac during flexion cervical magnetic resonance imaging in Hirayama disease: An initial study on normal subjects compared to patients with Hirayama disease

Objective

Forward shifting of the posterior cervical dural sac is the most important sign in diagnosing Hirayama disease but can also be seen in normal subjects, causing potential diagnostic dilemma. We aim to explore the degree of forward displacement of posterior dural sac in normal subjects compared to that with Hirayama disease.

Materials and methods

50 healthy male teenagers and 3 patients with Hirayama disease were recruited into the control group and patient group, respectively. MR imaging of the cervical spine was performed in both neutral and flexion positions for all subjects, with the following parameters measured: maximal distance of forward shifting of posterior dural sac, dimension of dural sac and spinal cord.

Results

Forward shifting of the posterior cervical dural sac was depicted in 46% of normal subjects upon flexion position but without associated cord compression due to intrinsic expansion of the spinal canal volume. This intrinsic compensatory mechanism was inadequate in diseased patients leading to cord compression with significant increment in ratio of anteroposterior diameter of forward displacement of posterior dural wall/anteroposterior diameter of spinal canal (“x/y”), and decrement in ratio of anteroposterior diameter of spinal cord/perpendicular transverse diameter of spinal cord (“a/b”).

Conclusion

Depicting of forward shifting of posterior dural sac alone on flexion position cannot reliably diagnose Hirayama disease, which should be established only if there is forward shifting of posterior dural sac, plus increased ratio of x/y and decreased ratio of a/b on flexion position from associated mass effect on the spinal cord.     

Classification system based on kinematic MR imaging in cervical spondylitic myelopathy.

BACKGROUND AND PURPOSEFunctional myelographic studies are often used to evaluate the dynamic changes of the cervical spinal canal during flexion and extension. The purposes of this study were to use kinematic MR imaging to assess the dynamic changes of the cervical spine in patients at different stages of degenerative disease and to describe a classification system based on static and dynamic factors in the pathogenesis of cervical spondylitic myelopathy.METHODSEighty-one patients with different stages (I-IV) of degenerative disease of the cervical spine were examined with MR imaging. In the neutral position (0 degrees) and at maximum flexion and extension, spinal stenosis was classified for each segment according to the following grading system: 0 = normal, 1 = partial obliteration of the anterior or posterior subarachnoid space, 2 = complete obliteration of the anterior or posterior subarachnoid space, and 3 = cervical cord compression or displacement.RESULTSAt flexion and extension, the prevalence of spinal stenosis and cervical cord impingement increased as the stage of degenerative disease progressed. With regard to a pincer effect (anterior and posterior cord impingement) and cord encroachment at multiple segments, statistically significant differences were observed at stages III and IV as compared with stages I and II. Significant increase in cord impingement was seen in 22 (27%) of 81 patients at extension, as compared with four (5%) of 81 patients at flexion.CONCLUSIONRegardless of the stage of degenerative disease and grade of spinal stenosis at the neutral position (0 degrees), cervical spinal motion may contribute to the development of cervical spondylitic myelopathy.     

Hirayama flexion myelopathy: neutral-position MR imaging findings--importance of loss of attachment

PURPOSE: To investigate the sensitivity and specificity of various neutral-position magnetic resonance (MR) imaging findings in the diagnosis of Hirayama flexion myelopathy. MATERIALS AND METHODS: The neutral-position cervical MR images of 46 patients and 51 control subjects were evaluated for the following findings: localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature, loss of attachment (LOA) between the posterior dural sac and subjacent lamina, and noncompressed intramedullary high signal intensity on T2-weighted MR images. The difference in frequency of these findings between the control and patient groups was examined by means of the chi(2) test. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of these MR imaging findings in the diagnosis Hirayama disease were calculated. Multivariate analysis of these findings was also performed. RESULTS: There was a significant difference in the frequency of these MR imaging findings between the control and patient groups (all comparisons, P 相似文献   

Are magnetic resonance flexion views useful in evaluating the cervical spine of patients with rheumatoid arthritis?

Objective. To determine whether MR imaging in flexion adds value relative to imaging in the neutral position with respect to displaying involvement of the subarachnoid space, brainstem and spinal cord. Design and patients. T1-weighted MR images of the cervical spine in 42 rheumatoid arthritis patients with cervical spine involvement were obtained and analyzed prospectively. We assessed changes between images obtained in the neutral position and following active flexion, especially horizontal atlantoaxial and subaxial motion, presence or absence of brainstem compression, subarachnoid space involvement at the atlantoaxial and subaxial level and the cervicomedullary angle. Vertical atlantoaxial subluxation and the amount of pannus were correlated with motion and change in subarachnoid space. Results. The flexion images showed horizontal atlantoaxial motion in 21 patients and subaxial motion in one patient. The flexion view displayed brainstem compression in only one patient. Involvement of the subarachnoid space increased at the atlantoaxial level in eight (19%) patients (P=0.004) and at the level below C2 in five (12%) patients (P=0.03). There were no patients with a normal subarachnoid space in neutral position and compression in the flexed position. The cervicomedullary angle changed significantly with flexion. Vertical atlantoaxial subluxation and the amount of pannus did not show a significant correlation with motion or subarachnoid space involvement. Conclusion. MR imaging in the flexed position shows a statistically significant narrowing of the subarachnoid space at the atlantoaxial level and below C2. Cord compression is only observed on flexion views if the subarachnoid space in neutral position is already decreased. MR imaging in the flexed position might be useful, since subarachnoid space involvement may be an indicator for the development of neurologic dysfunction. Received: 15 June 1999 Revision requested: 29 July 1999, 20 September 1999 Revision received: 2 October 1999 Accepted: 26 October 1999     

Hirayama disease: MR diagnosis.

We report the MR findings in two cases of Hirayama disease, a kind of cervical myelopathy related to flexion movements of the neck. In flexion MR studies, we can see the striking and pathognomonic picture of anterior shifting of posterior dura at the lower cervical spinal canal. In nonflexion studies, we find that asymmetric cord atrophy, especially at the lower cervical cord, though subtle, is highly suggestive of Hirayama disease. When it is seen, a flexion MR study is warranted to prove this diagnosis.     

Cervical degenerative disease at flexion-extension MR imaging: prediction criteria

PURPOSE: To determine if there are any neutral-position imaging criteria that can help predict functional cord impingement at flexion-extension cervical magnetic resonance (MR) imaging. MATERIALS AND METHODS: Sixty-two patients with cervical degenerative disease were evaluated with regard to the dynamic changes of canal stenosis at flexion-extension MR imaging. Functional cord impingement was considered if the cord was impinged or more impinged after neck flexion or extension. Selection criteria for neutral-position MR imaging, such as cervical curvature, canal space, degenerative stage, intramedullary high signal intensity on T2-weighted images, and resting instability, were evaluated for their ability to predict functional cord impingement at flexion-extension MR imaging (Fisher exact test, logistic regression analysis). RESULTS: MR images in 19 (31%) of 62 patients showed functional cord impingement at extension MR imaging compared with images in two (3%) patients at flexion MR imaging. Statistically significant differences were found for the criteria cervical degeneration stage (P <.001) and spinal canal space (P =.037) for predicting functional cord impingement at extension MR imaging. In contrast, no significant differences were found among selection criteria for flexion MR imaging. Probabilities of functional cord impingement at extension MR imaging were calculated with different combinations of degenerative stages and canal spaces. Probability could increase to 79% if the patient had both stabilization degeneration (disk protrusion or osteophytic formation with hypertrophy of the ligamentum flavum) and C7 canal space of 10 mm or less. CONCLUSION: None of the selection criteria evaluated in this study has the ability to predict functional cord impingement at flexion MR imaging; however, prediction of impingement at extension MR imaging can increase from 31% to 79% if proper criteria are selected.