Grane P, Lindqvist M
Department of Neuroradiology, Karolinska Hospital, Stockholm, Sweden.
Acta Radiol. 1997 Nov;38(6):1035-42. doi: 10.1080/02841859709172126.
Two new signs of lumbar nerve-root affection have been reported in recent years on the basis of MR examinations, namely: thickening in nerve roots; and contrast enhancement in nerve roots. The aim of this study was to assess contrast enhancement in nerve roots in a standardised way, and to evaluate the clinical significance of contrast enhancement and of nerve-root thickening in the symptomatic post-operative lumbar spine.
A total of 121 patients (who had previously been operated on for lumbar disc herniation) underwent 152 MR examinations, mainly on a 1.5 T system. Focal nerve-root enhancement was identified by visual assessment. Intradural enhancement was also quantified by pixel measurements that compared the affected nerve roots before and after contrast administration. Non-affected nerve roots were used as reference.
Enhanced nerve roots in the dural sac increased at least 40-50% in signal intensity after contrast administration compared to pre-contrast images and also compared to non-affected nerve roots. Intradural nerve-root enhancement was seen in 10% of the patients and focal enhancement in the root sleeve was seen in a further 26%. Nerve-root thickening was seen in 30%. Good correlation with clinical symptoms was found in 59% of the patients with intradural enhancement, in 84% with focal enhancement, and in 86% with nerve-root thickening. The combination of thickening and enhancement in the nerve root correlated with symptoms in 86% of the patients.
Nerve-root enhancement (whether focal or intradural) and thickening in the nerve root are significant MR findings in the post-operative lumbar spine. In combination with disc herniation or nerve-root displacement, these two signs may strengthen the indication for repeat surgery. However, root enhancement within 6 months of previous surgery may be a normal post-operative finding.
近年来基于磁共振成像（MR）检查报告了两种新的腰椎神经根受累征象，即神经根增粗和神经根强化。本研究的目的是以标准化方式评估神经根强化情况，并评估症状性腰椎术后神经根强化及神经根增粗的临床意义。
共有121例（既往接受过腰椎间盘突出症手术）患者接受了152次MR检查，主要使用1.5T系统。通过视觉评估确定局灶性神经根强化。还通过像素测量对硬膜内强化进行量化，比较对比剂注射前后受累神经根情况。以未受累神经根作为对照。
与注射对比剂前图像以及未受累神经根相比，硬膜囊内强化的神经根在注射对比剂后信号强度至少增加40% - 50%。10%的患者可见硬膜内神经根强化，另外26%的患者可见神经根袖套处局灶性强化。30%的患者可见神经根增粗。硬膜内强化患者中59%、局灶性强化患者中84%以及神经根增粗患者中86%与临床症状有良好相关性。神经根增粗与强化同时出现的患者中86%与症状相关。
神经根强化（无论是局灶性还是硬膜内强化）以及神经根增粗是腰椎术后重要的MR表现。与椎间盘突出或神经根移位相结合，这两种征象可能会加强再次手术的指征。然而，上次手术后6个月内出现的神经根强化可能是正常的术后表现。
