岛叶与锥体束空间关系的影像学和解剖学研究

Neuroanatomy and neuroimaging study of the relationship between the insular and the pyramidal tract

目的研究岛叶与锥体束的空间位置关系,为岛叶病变手术中保护锥体束和减少术后运动功能障碍提供指导。方法2013年3—10月,选取10例健康志愿者采用MR弥散张量纤维束成像（ DTT）重建锥体束影像,选取6例成人颅脑标本运用Klingler白质纤维解剖技术解剖岛叶区域显露内囊和放射冠,在标本上进行断层解剖观察并测量岛叶标志点与内囊和放射冠的间距,结合MRI与解剖观察结果,对岛叶与锥体束的空间位置关系进行前瞻性研究。结果岛叶标志点在颅脑标本和MRI中均容易辨认。 DTT重建影像显示锥体束经过了岛叶后上部的深部。在解剖标本利用上中央岛点（ UCIP）和后下岛点（ PIIP）间连线将岛叶划分成前下部和后上部两个区域。岛叶后上部皮层与锥体束之间为最外囊、屏状核和外囊,而无壳核和苍白球。 UCIP和后上岛点（ PSIP）距其深部的放射冠分别为（5.0依0.3）mm和（4.7依0.3）mm,PIIP距其深部的内囊后肢（5.7依0.5）mm。结论利用UCIP和PIIP连线所划分出的岛叶后上部因毗邻锥体束是手术危险区域。岛叶危险区域的划分有助于术前评估手术风险和预后,术中保护锥体束,降低术后运动功能障碍的发生率。

Objective To investigate the spatial interrelationship between the insular and the pyramidal tract （ PT） and provide the guidance for the protection of PT and reduction of postoperative motor dysfunction during insula lesions surgery. Methods From March 2013 to October 2013, magnetic resonance images of the PT of 10 healthy volunteers were acquired by using diffusion tensor tractography （ DTT ） . The corona radiata and internal capsule were exposured by Klingler’s white matter anatomy technique in 6 cadaveric brains. The distances from the insular landmarks to the corona radiata and internal capsule were measured on the sections of the cerebral specimens. The spatial interrelationship between the insular landmarks and the PT were analyzed by combining magnetic resonance images and anatomical results. Results Insula landmarks in brain specimens and magnetic resonance images were easily identifiable. The DTT image displayed that the PT went through the deep area of the posterosuperior part of the insular. The connecting line between the upper central insular point（UCIP） and the posterior inferior insular point （ PIIP ） divided the insular into the anteroinferior region and the posterosuperior region. Anatomical specimens showed there were extreme capsule, claustrum and external capsule between the posterosuperior part of the insular cortex and the PT, while the putamen and globus pallidus were absent in that area. The mean distance from the UCIP and the posterior superior insular point（PSIP）to the corona radiata was （5. 0 ± 0. 3）mm and （4. 7 ± 0. 3）mm. The mean distance from the PIIP to the posterior limbs of the internal capsule was （5. 7 ± 0. 5） mm. Conclusions The posterosuperior region of the insular, divided by connecting the line between UCIP and PIIP, is near to the PT and is a dangerous area in the operation. The division of the dangerous area can help to estimate the risk of operation and prognosis, protect the PT, and reduce the occurrence of postoperative motor dysfunction.