Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
Neuroradiology. 2011 Sep;53(9):633-41. doi: 10.1007/s00234-010-0801-7. Epub 2010 Nov 16.
Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.
Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20-72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.
In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.
DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.
弥散加权成像（DWI）可以提供有价值的结构信息，可能有助于评估腰椎神经根的病理变化。弥散加权磁共振（MR）神经成像最近已被引入作为一种可视化神经的替代方法，但迄今为止，定量 DWI 和 MR 神经成像尚未应用于评估腰椎神经根的病理。
我们的目的是通过 MR 神经成像可视化腰椎神经根并分析其形态，并使用 1.5-T MR 成像测量由椎间盘突出症压迫的腰椎神经根的表观扩散系数（ADC）。连续 10 例（中位年龄 48.0 岁，范围 20-72 岁）因腰椎间盘突出症引起单根症状的患者和 14 名健康志愿者进行了研究。在 DWI 上，在背根神经节（DRG）和远端脊髓神经上放置感兴趣区，以量化平均 ADC 值。MR 神经成像还显示了神经根受压部位的神经根肿胀等异常。
在患者中，受压的 DRG 和远端脊髓神经的平均 ADC 值明显大于完整神经。MR 神经成像还显示了在有症状的神经根受压部位和下方的神经肿胀等异常。ADC 值的增加被认为是由于受压神经根的水肿和沃勒变性。
DWI 是分析椎间盘突出症压迫的腰椎神经根病理生理学的一种有潜力的工具。
