颈内动脉颅底段的CT测量及三维重建

Computed tomographic measurement and three-dimensional reconstruction for infracranial portion of the internal carotid artery

目的经鼻内镜鼻咽切除术是目前鼻咽颅底病变微创手术的首选,但颈内动脉损伤是该手术的潜在危险。通过术前对患者CT资料进行多层面观测和图像三维重建,评估颈内动脉的走行及其与相关结构的空间关系,以便指导鼻内镜鼻咽及咽旁隙颅底手术。方法选择40例(80侧)鼻咽及其周围颅底无病变表现的头部增强CT资料,在图像工作站上对不同层面中颈内动脉与周围骨性结构的关系进行测量,对图像进行三维重建观察颈内动脉与周围结构的空间关系。结果在骨性下鼻甲层面中,骨性下鼻甲后缘、翼内板后缘、翼外板后缘、中线与颈内动脉的距离分别为(38.8±4.0)、(25.9±2.8)、(19.7±3.8)、(23.8±2.7)mm;骨性下鼻甲后缘及翼内板后缘的延长线与颈内动脉的夹角为(15.0±4.0)、(17.0±6.0)°。在后鼻孔下缘层面中,翼内板后缘与颈内动脉的距离和角度分别为(27.2±3.5)mm和(12.0±4.0)°。三维重建获得清晰的立体图像。颈内动脉颈段的走行40%发生变异,其中大部分为弯曲型,位于口咽至咽隐窝水平,突向咽后壁。结论患者术前进行个体化CT三维重建能为经鼻内镜鼻咽颅底手术提供关键解剖信息,便于术中定位颈内动脉,提高手术安全性。人群中颈内动脉变异率较高,突向咽后壁,经鼻内镜鼻咽-咽旁颅底手术风险增高,术前应充分评估。

Objective Transnasal endoscopic nasopharyngectomy is currently the optimal choice of minimally invasive surgery for nasopharyngeal skull base lesions,but internal carotid artery(ICA)injury is a potential risk of this surgery.This study aims to evaluate the course of ICA and its spatial relationship with related structures through preoperative multiple dimensional observation and three-dimensional image reconstruction of computed tomography(CT)data of patients,so as to guide nasal endoscopic nasopharyngeal and parapharyngeal skull base surgery.Methods Head enhanced CT data of 40 cases(80 sides)without pathological manifestations of nasopharynx and its surrounding skull base were selected.The relationships between ICA and surrounding bone structures in different layers were measured on the image workstation,and the spatial relationships between ICA and surrounding structures were observed by three-dimensional reconstruction of the images.Results On the plane of the bony inferior turbinate,the distances from the posterior margins of the bony inferior turbinate(PMBIT),posterior margins medial pterygoid plate(PMMP),posterior margins lateral pterygoid plate(PMLP),midline to the ICA were(38.8±4.0)mm,(25.9±2.8)mm,(19.7±3.8)mm,(23.8±2.7)mm,respectively.The angles between the line PMBIT-ICA and the PMBIT elongation,the line PMMP-ICA and the PMMP elongation were(15.0±4.0)°and(17.0±6.0)°,respectively.On the plane of the inferior choanae,the distance from the PMMP to the ICA was(27.2±3.5)mm,the angle between the line PMMP-ICA and the PMMP elongation was(12.0±4.0)°.The three-dimensional reconstruction obtained clear stereoscopic images.Course variation occurred in 40%of the extracranial part of the ICA,most of which were tortuosity type,located at the level of oropharynx to pharyngeal recess and protruding to the posterior pharyngeal wall.Conclusions Individualized preoperative three-dimensional CT reconstruction can provide key anatomic information for transnasal endoscopic nasopharyngeal skull base surgery,facilitate intraoperative localization of ICA,and improve surgical safety.The extracranial part of ICA has a high variation rate,protrudates to the posterior pharyngeal wall with increased risk of endoscopic nasopharyngeal-parapharyngeal skull base surgery,which should be adequately evaluated before surgery.