正中神经3.0TMRIDTI及纤维束示踪成像

正目的采用3.0 T MR DTI与纤维束示踪技术行正中神经成像,目的是观察健康人与腕管综合征(CTS)病人尺神经扩散差异。方法纳入15例CTS病人与20名健康志愿     

正中神经扩散张量成像在复发性腕管综合征中的应用初探

正目的采用扩散张量成像(DTI)研究复发性腕管综合征(CTS)正中神经结构,并将DTI所见与MRI解剖成像相联系以评估正中神经功能。方法定量观察复发性CTS与健     

颈髓白质纤维束磁共振扩散张量成像的初步研究

目的:利用磁共振弥散张量成像(DTI)研究正常成人颈髓的各向异性程度,探讨颈髓白质纤维束成像的可能性和应用价值。方法:使用单次激发自旋回波平面回波(SE-EPI)序列对14例MR检查正常的健康志愿者行颈髓弥散张量成像检查。重建FA图,在颈髓各节段分别测量FA值。利用日本东京大学Masutani开发的DTVⅡ和VolumeOne纤维束示踪成像软件进行白质纤维束成像。结果:颈髓平均FA值0.6583±0.0737,所有FA图上颈髓显示清晰,没有明显图像失真。白质纤维束成像三维显示颈髓大部分主要的纤维束。结论:DTI有效地显示颈髓白质纤维的各向异性特征及白质纤维束的分布和走向,对颈髓疾病的研究提供了新的方法。     

腕管综合征的3.0T扩散张量成像与电生理的对照研究

目的 评估常规MRI和DTI对腕管综合征(CTS)的诊断价值,评价其在CTS分级中的作用.方法 对16名志愿者32个腕关节及21例患者31个腕关节进行常规MRI、DTI扫描及神经电生理检查.测量不同层面正中神经的MRI数据,计算膨胀率(MNSR)、扁平率(MNFR)、弯曲率(BR);测量平均FA值及ADC值.分别对患者和志愿者的MRI数据以及其与电生理结果进行统计学分析.结果 CTS患者的MNSR、MNFR及BR值较志愿者明显增大;正中神经T2WI信号均有不同程度的增高.患者平均FA值显著低于志愿者(t=15.05,P＜0.01).患者平均FA值与神经电生理的严重程度呈负相关(r=-0.69,P＜0.001).轻度组的平均FA值明显高于中-重度组(t=4.14,P＜0.01).结论 常规MRI和DTI不仅能从形态上反映已经发生病变的神经,且对CTS的分级诊断具有一定的价值.     

正常女性盆底纤维束扩散张量成像的可行性

目的前瞻性研究纤维束扩散张量成像(DTI)三维(3D)观察正常女性盆底解剖结构的可行性。方法5名未生育过的年轻女性[平均年龄(28±3)岁]作为本次研究对象,于3.0TMR设备上行DTI检查。采用二维扩散加权横断位自旋平面     

扩散张量的三维纤维束成像在多发性硬化中的应用

目的 应用三维纤维束成像技术,研究多发性硬化(multiple sclerosis,MS)脱髓鞘斑块引起的白质纤维束的改变. 资料与方法 应用3 T 磁共振对34例MS患者和25名非MS健康志愿者行常规头颅MRI和扩散张量成像(DTI),观察MS病灶处和正常表现脑白质的纤维束变化. 结果 三维纤维束成像可以清楚显示脑内白质纤维束的方向、形态和结构.在MS斑块处可见纤维束中断、病灶远端纤维束缺失或稀少.病灶周围的纤维束表现为受压、推移改变.与相同年龄段的正常人对照,MS患者的正常表现胼胝体内纤维束稀少. 结论 基于DTI技术的纤维束成像能够直观地显示脑内白质纤维束,反映病变对纤维造成的影响.     

脑梗死患者磁共振扩散张量纤维束成像的随访研究

目的应用磁共振扩散张量纤维束成像(DTT)研究梗死灶与皮质脊髓束的空间关系,并随访观察受损纤维束的功能重组与代偿情况,探讨DTT技术对预测患者运动功能转归的价值。方法选择左侧内囊周围区脑梗死患者19例,分别于发病7、30、90天进行磁共振扩散张量成像(DTI)检查,应用DTT技术进行皮质脊髓束三维重建,采用FuglMeyer量表评价患者的运动功能,分析脑梗死灶及皮质脊髓束受累程度与患者运动功能恢复的关系。结果 DTT显示19例左侧内囊周围区梗死患者,根据患侧皮质脊髓束受累情况分为3型,I型5例,皮质脊髓束位于梗死灶外,FM评分96.46±7.68;II型6例,皮质脊髓束部分位于梗死灶内,但受侵范围1/3;或受压、迂曲、推移改变,FM评分94.20±6.84;III型8例,皮质脊髓束1/3位于梗死灶内,FM评分82.37±22.14。19例患者发病7天,皮质脊髓束损伤分型与FM评分呈显著负相关(r=-0.490,P=0.033)。DTT对患者皮质脊髓束的动态观察显示,8例III型患者中4例90天皮质脊髓束显示良好,患者运动功能完全恢复;2例患者皮质脊髓束自身发生再生修复,90天后仅遗留部分运动功能障碍;2例未发现纤维再生修复,90天仍遗留严重运动功能障碍。结论 DTT能够直观显示脑梗死患者的皮质脊髓束受累程度及其动态变化,对评价其运动功能恢复提供重要的客观影像学依据。     

人脑投射纤维弥散张量纤维束成像的初步研究

目的 利用弥散张量纤维束成像显示人脑内部分投射纤维的三维结构，探讨其与解剖学描述的一致性。资料与方法 对1名正常志愿者进行单次激发回波平面弥散张量成像，利用纤维束成像软件包显示人脑部分投射纤维的三维结构，观察重建的投射纤维与解剖学描述的一致性。结果 通过选择恰当的感兴趣区，设置不同的部分各向异性阈值、角度阈值、步长和体素长度内采样数目等参数，弥散张量纤维束成像可以清楚地显示皮质脊髓束、视放射、内侧丘系、小脑上脚、中脚和下脚等投射纤维的三维结构，显示结果与解剖学描述具有较好的一致性。结论 投射纤维纤维束成像的结果与解剖学描述具有较好的一致性，该方法是一种较可靠的研究人脑纤维连接的方法。     

腕管综合征病人术前与术后正中神经的扩散张量成像

正摘要目的利用术前与术后扩散张量成像(DTI)监测腕管综合征(CTS)病人正中神经的完整性。方法对照12例病人、12例年龄匹配者和12例年轻对照者沿正中神经的扩散及各向异性影像,并分析与电生理神经影像的相关性。计算层向DTI参数值,重点观察局部改变。结果术前病人与年龄匹配对     

Diffusion tensor imaging and tractography of the median nerve in carpal tunnel syndrome: preliminary results

The purpose was to demonstrate the feasibility of in vivo diffusion tensor imaging (DTI) and tractography of the human median nerve with a 1.5-T MR scanner and to assess potential differences in diffusion between healthy volunteers and patients suffering from carpal tunnel syndrome. The median nerve was examined in 13 patients and 13 healthy volunteers with MR DTI and tractography using a 1.5-T MRI scanner with a dedicated wrist coil. T1-weighted images were performed for anatomical correlation. Mean fractional anisotropy (FA) and mean apparent diffusion coefficient (ADC) values were quantified in the median nerve on tractography images. In all subjects, the nerve orientation and course could be detected with tractography. Mean FA values were significantly lower in patients (p=0.03). However, no statistically significant differences were found for mean ADC values. In vivo assessment of the median nerve in the carpal tunnel using DTI with tractography on a 1.5-T MRI scanner is possible. Microstructural parameters can be easily obtained from tractography images. A significant decrease of mean FA values was found in patients suffering from chronic compression of the median nerve. Further investigations are necessary to determine if mean FA values may be correlated with the severity of nerve entrapment.     

Diffusion tensor imaging of the median nerve in healthy and carpal tunnel syndrome subjects

Purpose

To determine if diffusion tensor imaging (DTI) of the median nerve could allow identification of patients with carpal tunnel syndrome (CTS).

Materials and Methods

A total of 13 healthy subjects and 9 CTS patients were scanned on a 3T magnetic resonance imaging (MRI) scanner. The MRI protocol included a DTI sequence from which the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and the parallel and radial diffusivities could be extracted. Those parameters were quantified at different locations along the median nerve (proximal to the carpal tunnel, within the carpal tunnel, and distal to the carpal tunnel).

Results

At the carpal tunnel, the FA, radial diffusivity, and ADC differed significantly between healthy subjects and CTS patients (P < 0.0002). This highly significant difference between the two groups was due to an opposite trend of changes in the DTI indices between the proximal to the carpal tunnel and within the carpal tunnel locations. In healthy subjects the FA increased (+20%, P < 0.001) and the radial diffusivity and ADC decreased (by ?15% and ?8%, respectively, P < 0.05) between the proximal to the carpal tunnel and within the carpal tunnel locations. In CTS subjects the FA decreased (by ?21%, P < 0.05) and the radial diffusivity increased (by +23%, P < 0.01) between the proximal to the carpal tunnel and within the carpal tunnel locations.

Conclusion

DTI enables visualization and characterization of the median nerve in healthy subjects and CTS patients. DTI indices show clear‐cut discrimination between the two groups and in fact enables the of use DTI in the diagnosis of CTS. J. Magn. Reson. Imaging 2009;29:657–662. © 2009 Wiley‐Liss, Inc.

     

Diffusion tensor imaging of the median nerve in recurrent carpal tunnel syndrome - initial experience

Objectives

To investigate median nerve structure in patients with recurrent carpal tunnel syndrome (CTS) using diffusion tensor imaging (DTI) and to relate DTI changes to anatomical MRI and to measures of median nerve function.

Methods

Median nerve structure was quantified according to DTI in patients with recurrent CTS and in healthy controls of similar age. Anatomical MRI was used to identify the presence of nerve compression and fibrosis. Median nerve function was measured using electromyography, a force-tracking task (accuracy of precision grip control) and clinical measures.

Results

Patients showed reduced apparent diffusion coefficient (ADC), reduced axial diffusivity (AD) and radial diffusivity (RD) along the median nerve compared with controls (P?<?0.001). Patients with endoneural fibrosis had the greatest reductions in ADC and in RD. ADC and AD correlated positively with nerve conduction velocity (R?=?0.54 and R?=?0.68, respectively) and fractional anisotropy correlated negatively with error during force-tracking (R?=?-0.58).

Conclusions

A specific pattern of DTI changes in the median nerve was identified in patients with recurrent CTS. Fibrosis may be underlying these structural changes. The correlations with nerve conduction velocity and accuracy of force control suggest that DTI is a promising technique in the study of median nerve structure in recurrent CTS.

Key Points

? Diffusion tensor imaging (DTI) offers further possibilities in musculoskeletal magnetic resonance imaging. ? DTI reveals median nerve changes in recurrent carpal tunnel syndrome. ? DTI changes were greater with signs of median nerve fibrosis. ? DTI parameters correlated with nerve conduction and force control measures. ? DTI is a promising technique in recurrent carpal tunnel syndrome.     

Diffusion tensor imaging of the median nerve before and after carpal tunnel release in patients with carpal tunnel syndrome: feasibility study

Objectives

To evaluate diffusion tensor imaging (DTI) indices of the median nerve pre and postoperatively in patients with carpal tunnel syndrome (CTS) to determine whether indices acquired prior to surgery differ from those acquired postoperatively.

Methods

Following IRB approval, ten patients with a diagnosis of CTS were prospectively recruited. Eight patients completed the study (seven women, one man). All had bilateral asymmetric symptoms, with subsequent carpal tunnel release on the more symptomatic side. DTI of both wrists were performed using single-shot spin-echo echo-planar imaging (TR/TE, 7,000/103 ms; b value 1,025 s/mm²) preoperatively, 6 weeks and 6 months after carpal tunnel release. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the median nerve at the level of the distal radioulnar joint and pisiform were determined by one investigator blinded to clinical data, side, and time relative to surgery.

Results

All patients had resolution of symptoms on the surgical side at 6 months. A significant increase in FA (p?=?0.018) and decrease in ADC (p?=?0.017) were found proximally at 6 months compared to baseline on the operative side. A significant increase in FA was observed on the operative side distally at 6 weeks (p?=?0.012) and 6 months (p?=?0.017). There was a significant difference in the percentage change in FA values from baseline to 6 months on the operative side in comparison with the non-operative side (p?=?0.017).

Conclusions

A significant increase in FA and decrease in ADC of the median nerve are seen following decompression surgery in patients with CTS.     

Pre- and post-operative diffusion tensor imaging of the median nerve in carpal tunnel syndrome

Objectives

To use pre- and post-operative diffusion tensor imaging (DTI) to monitor median nerve integrity in patients suffering from carpal tunnel syndrome (CTS).

Methods

Diffusivity and anisotropy images along the median nerve were compared among 12 patients, 12 age-matched and 12 young control subjects and correlated with electrophysiological neurography results. Slice-wise DTI parameter values were calculated to focus on local changes.

Results

Results of pre-operative patients and age-matched control subjects differed only in the distal nerve. Moreover, pre-operative patients differed significantly from young controls and post-operative patients. The main abnormalities were increased diffusivity and decreased anisotropy in the carpal tunnel and distal median nerve. Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. Slice-wise analysis showed high pre-operative diffusivity at the distal nerve. All groups had relatively large inter-subject variation in both diffusivity and anisotropy.

Conclusions

DTI can provide information complementary to clinical examination, electrophysiological recordings and anatomical MRI of diseases and injuries of peripheral nerves. However, similar age-related changes in diffusivity and anisotropy may weaken DTI specificity. Slice-wise analysis is necessary for detection of local changes in nerve integrity.

Key Points

? Diffusion tensor magnetic resonance imaging provides information complementary to conventional diagnostic methods. ? Age caused similar changes to diffusivity and anisotropy as carpal tunnel syndrome. ? Post-operative clinical improvement was reflected in diffusivity, but not in anisotropy. ? Inter-subject variation in diffusivity and anisotropy was considerable.     

Diffusion tensor imaging and fiber tractography in cervical compressive myelopathy: preliminary results

Objective  

To assess diffusion tensor imaging (DTI) parameters in cervical compressive myelopathy (CCM) patients compared to normal volunteers, to relate them with myelopathy severity, and to relate tractography patterns with postoperative neurologic improvement.     

Bifid median nerve in the carpal tunnel: integrated imaging

PURPOSE: Carpal Tunnel Syndrome (CTS) is a neuropathy caused by compression of the median nerve at the level of the wrist, which is caused by different pathologic conditions. In some cases it has been associated with anatomic variations of the median nerve, mainly with the early duplication of the nerve inside the carpal tunnel (III Group of Lanz). The treatment of CTS is mainly surgical consisting in decompression by transection of the transverse carpal ligament, which is better performed by endoscopic release. The aim of our study was to evaluate the possibility to detect this anatomic variant by integrated imaging and assess the value of this information for planning treatment. MATERIAL AND METHODS: We report 6 cases of bifid median nerve examined by Ultrasonography (US) using mechanic sectorial and linear array transducers operating at 10 to 13 MHz, and by MR imaging using 0.2 T equipment. RESULTS: In all cases US transverse scans showed two adjacent oval formations with a structure similar to that of the median nerve. CONCLUSIONS. MR imaging confirmed the sonographic findings in all cases. All patients underwent open surgical treatment by decompression of the median nerve; in all cases an early duplicated median nerve was confirmed.     

Diffusion tensor imaging and fiber tractography in Parry-Romberg syndrome

We report a case of Parry-Romberg syndrome in a 32-year-old woman presenting with intermittent headache and mild sensory disturbance. MR imaging revealed minimal asymmetric atrophy of the right hemisphere with a few nonspecific white matter hyperintensities. Diffusion tensor imaging and fiber tractography, however, demonstrated clear fiber derangement, especially in the sensory tract of the right cerebral white matter.