Barcelo Céline, Faruch Marie, Lapègue Franck, Bayol Marie-Aurélie, Sans Nicolas
Central Department of Radiology, Purpan University Hospital, Toulouse, France.
Eur Radiol. 2013 Nov;23(11):3124-30. doi: 10.1007/s00330-013-2955-2. Epub 2013 Jul 7.
To apply diffusion tensor imaging (DTI) and tractography to the median nerve by use of a 3-T MRI device in order to demonstrate potential differences in diffusion parameters between healthy subjects and patients with carpal tunnel syndrome (CTS).
The median nerve of 15 patients and 20 healthy volunteers was examined in two sequences: DTI and a high-resolution T1-weighted sequence. Mean fractional anisotropy (FA) and mean apparent diffusion coefficient (ADC) were measured based on tractography findings. Mean FA was significantly lower in CTS patients (P = 0.01) whereas no significant difference was found in mean ADC. Focal measurements of FA and ADC were also obtained at three locations along the course of the median nerve.
We observed a highly significant difference (P < 0.0001) between FA measured at the proximal carpus and FA measured at the distal carpus in healthy subjects and CTS patients. Focal FA values along the median nerve showed an opposite trend in the two groups: in healthy subjects FA tended to increase (P < 0.05) whereas in subjects with CTS it tended to decrease (P = 0.0001). We defined a threshold value of -0.058 (FA3-FA1) that was sensitive and specific for nerve compression.
DTI and tractography can detect chronic nerve compression.
• Diffusion tensor magnetic resonance imaging offers new information about carpal tunnel syndrome. • Diffusion tensor MRI of the median nerve provides some functional data. • Mean fractional anisotropy (FA) was lower in patients with CTS than volunteers. • There was no significant difference in ADC values between patients and volunteers. • Fractional anisotropy seems a sensitive and specific predictor of chronic nerve compression.
利用3-T磁共振成像（MRI）设备对正中神经进行扩散张量成像（DTI）和纤维束成像，以显示健康受试者与腕管综合征（CTS）患者之间扩散参数的潜在差异。
对15例患者和20名健康志愿者的正中神经进行两个序列的检查：DTI和高分辨率T1加权序列。根据纤维束成像结果测量平均分数各向异性（FA）和平均表观扩散系数（ADC）。CTS患者的平均FA显著较低（P = 0.01），而平均ADC未发现显著差异。还在正中神经走行的三个位置进行了FA和ADC的局部测量。
我们观察到，在健康受试者和CTS患者中，近端腕部测量的FA与远端腕部测量的FA之间存在高度显著差异（P < 0.0001）。两组中沿正中神经的局部FA值呈相反趋势：在健康受试者中FA趋于增加（P < 0.05），而在CTS受试者中则趋于降低（P = 0.0001）。我们定义了-0.058（FA3-FA1）的阈值，该阈值对神经受压敏感且具有特异性。
DTI和纤维束成像可检测慢性神经受压。
• 扩散张量磁共振成像提供了有关腕管综合征的新信息。• 正中神经的扩散张量MRI提供了一些功能数据。• CTS患者的平均分数各向异性（FA）低于志愿者。• 患者与志愿者之间的ADC值无显著差异。• 分数各向异性似乎是慢性神经受压的敏感且特异的预测指标。
