CT所见咽周间隙的改变在判断鼻咽癌侵犯定位中的意义

Peripharyngeal Space on CT Scans: Its Value in Judging the Infiltration Extent of Nasopharyngeal Carcinoma

目的 为在CT上更准确判断鼻咽癌(NPC)的侵犯部位。资料与方法 搜集初诊NPC 30例,同时进行鼻咽部CT和MRI扫描,将其咽周间隙的影像学表现对照观察。结果 鼻咽缝间隙对称存在14例,1例椎前肌受累,占7.14％;不对称性变窄或消失者16例,椎前肌受累14例,占87.5％。CT上咽旁间隙变窄伴线样低密度影或密度增高20例,MRI上其间隙内的高信号脂肪影受压或间隙极度变窄,但仍连续无中断;CT上咽旁间隙消失5例,MRI上翼内肌均受累。结论 鼻咽缝间隙不对称性变窄或消失高度提示椎前肌受累;咽旁间隙变窄伴线样低密度影或密度增高时,肿瘤未跨越咽旁间隙;当咽旁间隙消失时,肿瘤多已突破咽旁间隙累及颞下窝。

Objective To precisely determine the infiltration extent of nasopharyngeal carcinoma (NPC) on CT scans. Materials and Methods CT and MRI scanning of nasopharynx were performed in 30 patients with pathologically proved NPC . CT and MRI manifestations of peripharyngeal space (PPS) were compared with each other. Results Imaging findings were as follows, (1) Symmetrical nasopharyngeal raphe space (NRS) was demonstrated in 14 cases, of which involvement of prevertebral muscle was seen in one (7.14%) . (2) Asymmetrical narrowing or disappearing of NRS was presented in 16 cases, of which involvement of prevertebral muscle was seen in 14 (87.5%) . (3) On CT scans, narrowed PPS with linear hypodense or hyperdense shadow was seen in 20 cases. The high signal of the fat within PPS on MRI, although it was continuous, showed oppressed or extremely narrowed. (4) On CT scans, disappearing of PPS was seen in 5 cases, and all of them showed involvement of medial pterygoid muscle on MRI. Conclusion The sign of asymmetrical narrowing or disappearing of NRS highly suggests the involvement of prevertebral muscle. Narrowed PPS with linear hypodense or hyperdense shadow indicates that the tumor has not crossed PPS. Disappearing of PPS indicates that the tumor has broken through PPS and infiltrated into the infratemporal fossa.