Bartos Robert, Jech Robert, Vymazal Josef, Petrovický Pavel, Vachata Petr, Hejcl Ales, Zolal Amir, Sames Martin
Department of Neurosurgery, J.E. Purkinje University and Masaryk Hospital, Ustí nad Labem, Czech Republic.
Acta Neurochir (Wien). 2009 Sep;151(9):1071-80. doi: 10.1007/s00701-009-0368-4. Epub 2009 May 5.
Functional magnetic resonance imaging (fMRI) is a widely used method for research and visualization of the brain function. However, its clinical use is still limited. Our objective was to study fMRI reliability in localizing the primary hand motor cortex (M1) under pathological conditions caused by the proximity of a brain tumour. The results were then compared with standard technique of cortical function mapping-electric cortical stimulation (ECS).
We compared M1 areas localized with the fMRI and ECS in 18 patients with brain tumours in fronto-parietal regions. The 1.5 T blood oxygenation-level dependent (BOLD) fMRI was performed preoperatively using a motor task involving rhythmic touching of the thumb consecutively with other fingers on the same hand contralateral to the affected hemisphere. Each individual fMRI result was displayed at the P < 0.05 significance level corrected for family wise error (more conservative approach) or at the P < 0.001 level uncorrected (less conservative approach) and projected on the T1-weighted image used for neuronavigation.
In 12 patients (66.6%) we found full agreement between the fMRI and ECS. In 3 patients (16.6%) the overlap was only partial, with one ECS testing position on motor response found outside the BOLD signal cluster. In another 3 cases (16.6%) there was a discrepancy between the two methods. The fMRI sensitivity for localizing the ECS reactive M1 cortex was 71%. The fMRI/ECS consistency was within a 5-mm range in 77% of the testing positions used for ECS which complies with the inherent accuracy of the navigation system.
Because the overlap between the two methods never exceeded 10-mm, we found that the fMRI method correctly guided the ECS to the M1 cortex in 83% of patients. Infiltrative growth of the tumour and collateral oedema were the reasons for the BOLD signal suppression in three patients. Our results support using ECS as a more reliable tool for M1 cortical mapping than fMRI.
功能磁共振成像（fMRI）是一种广泛用于脑功能研究和可视化的方法。然而，其临床应用仍然有限。我们的目的是研究在脑肿瘤临近导致的病理条件下，fMRI在定位主要手部运动皮层（M1）方面的可靠性。然后将结果与皮层功能映射的标准技术——皮层电刺激（ECS）进行比较。
我们比较了18例额顶叶脑肿瘤患者通过fMRI和ECS定位的M1区域。术前使用涉及患侧半球对侧手上拇指与其他手指有节奏地连续触碰的运动任务进行1.5T血氧水平依赖（BOLD）fMRI检查。每个个体的fMRI结果在针对族系误差校正的P<0.05显著性水平（更保守的方法）或未校正的P<0.001水平（不太保守的方法）下显示，并投影到用于神经导航的T1加权图像上。
在12例患者（66.6%）中，我们发现fMRI和ECS完全一致。在3例患者（16.6%）中，重叠仅为部分，在BOLD信号簇外发现一个运动反应的ECS测试位置。在另外3例（16.6%）中，两种方法存在差异。fMRI定位ECS反应性M1皮层的敏感性为71%。在用于ECS的77%的测试位置，fMRI/ECS一致性在5毫米范围内，这符合导航系统的固有精度。
由于两种方法之间的重叠从未超过10毫米，我们发现fMRI方法在83%的患者中正确地将ECS引导至M1皮层。肿瘤的浸润性生长和侧支水肿是3例患者BOLD信号抑制的原因。我们的结果支持将ECS作为比fMRI更可靠的M1皮层映射工具。
