Silva Guilherme, Citterio Alberto
1 Neuroradiology Department of the São João Hospital Center, Porto, Portugal.
2 Neuroradiology Department of the Niguarda Hospital Center, Milan, Italy.
Neuroradiol J. 2017 Oct;30(5):470-476. doi: 10.1177/1971400917720829. Epub 2017 Jul 12.
Introduction Previous studies have shown that the arcuate fasciculus has a leftward asymmetry in right-handers that could be correlated with the language lateralisation defined by functional magnetic resonance imaging. Nonetheless, information about the asymmetry of the other fibres that constitute the dorsal language pathway is scarce. Objectives This study investigated the asymmetry of the white-matter tracts involved in the dorsal language pathway through the diffusion tensor imaging (DTI) technique, in relation to language hemispheric dominance determined by task-dependent functional magnetic resonance imaging (fMRI). Methods We selected 11 patients (10 right-handed) who had been studied with task-dependent fMRI for language areas and DTI and who had no language impairment or structural abnormalities that could compromise magnetic resonance tractography of the fibres involved in the dorsal language pathway. Laterality indices (LI) for fMRI and for the volumes of each tract were calculated. Results In fMRI, all the right-handers had left hemispheric lateralisation, and the ambidextrous subject presented right hemispheric dominance. The arcuate fasciculus LI was strongly correlated with fMRI LI ( r = 0.739, p = 0.009), presenting the same lateralisation of fMRI in seven subjects (including the right hemispheric dominant). It was not asymmetric in three cases and had opposite lateralisation in one case. The other tracts presented predominance for rightward lateralisation, especially superior longitudinal fasciculus (SLF) II/III (nine subjects), but their LI did not correlate (directly or inversely) with fMRI LI. Conclusion The fibres that constitute the dorsal language pathway have an asymmetric distribution in the cerebral hemispheres. Only the asymmetry of the arcuate fasciculus is correlated with fMRI language lateralisation.
引言 先前的研究表明，弓形束在右利手人群中存在向左的不对称性，这可能与功能磁共振成像所定义的语言侧化相关。然而，关于构成背侧语言通路的其他纤维的不对称性信息却很匮乏。目的 本研究通过扩散张量成像（DTI）技术，研究背侧语言通路中白质束的不对称性，以及与任务依赖性功能磁共振成像（fMRI）所确定的语言半球优势的关系。方法 我们选取了11名患者（10名右利手），这些患者已接受了针对语言区域的任务依赖性功能磁共振成像和DTI检查，且没有语言障碍或结构异常，这些异常可能会影响背侧语言通路中纤维的磁共振成像纤维束成像。计算了功能磁共振成像和每条束体积的偏侧性指数（LI）。结果 在功能磁共振成像中，所有右利手患者均表现为左半球侧化，而双手灵巧的受试者表现为右半球优势。弓形束LI与功能磁共振成像LI密切相关（r = 0.739，p = 0.009），在7名受试者（包括右半球优势者）中呈现出与功能磁共振成像相同的侧化。在3例中它没有不对称性，在1例中具有相反的侧化。其他束表现出向右偏侧化的优势，尤其是上纵束（SLF）II/III（9名受试者），但其LI与功能磁共振成像LI没有（直接或间接）相关性。结论 构成背侧语言通路的纤维在大脑半球中具有不对称分布。只有弓形束的不对称性与功能磁共振成像语言侧化相关。
