鼻咽癌咀嚼肌间隙侵犯的MRI表现

MRI findings of nasopharyngeal carcinoma with masticator space infiltration

目的:探寻鼻咽癌咀嚼肌间隙侵犯的各种MRI表现。方法:100例病理确诊无远处转移NPC病例放疗前MRI检查。结果:100例中咀嚼肌间隙受侵犯58例。按咀嚼肌间隙侵犯途径及各部分受侵情况分为由内向外侵犯53例:翼内肌侵犯53例,翼内肌及间隙受侵33例,翼内外肌受侵21例,翼肌及颞肌受侵2例,翼肌、颞肌及咬肌受侵1例。经咽颅底筋膜与中颅窝底之间隙直接侵犯翼外肌3例;肿大淋巴结侵犯颞肌及咬肌各1例。按信号改变分为同时表现为T1WI信号降低,T2WI信号升高,增强后异常强化47例;MRI平扫未显示,仅增强后异常强化11例。结论:咀嚼肌间隙侵犯一般沿从内到外的途径。MRI咀嚼肌间隙侵犯的主要表现为T1WI信号降低,T2WI信号升高及增强后异常强化。

Objective：To investigate MRI findings of nasopharyngeal carcinoma （NPC） with masticator space infiltration.Methods：The study population included 100 patients with pathologically proved NPC and without metastasis.MRI examination was performed in all patients before radiotherapy.Results：Masticator space infiltration was found in 58 cases.The infiltration routes were of 3 types.Type 1 was from inside to outside in 53 cases：①medial pterygoid muscle infiltration in 53 cases,②pterygoideus space infiltration＋① in 33 cases,③lateral pterygoid muscle infiltration＋② in 21 cases, ④temporalis muscle infiltration＋③ in 2 cases,⑤masseter muscle infiltration＋④ in 1 case.Type 2 was the lateral pterygoid muscle infiltration via the gap between the pharyngeal fascia and the middle cranial fossa skull directly in 3 cases.Type 3 was temporalis or masseter muscle infiltration by lymph node directly in 1 case each.The lesions were hypointense on T1WI and hyperintense on T2WI,and abnormal enhancement were found in 47 cases.11 cases showed abnormal enhancement only.Conclusion：The usual route of masticator space infiltration by NPC is from inside to outside.The main MRI findings of masticator space infiltration by NPC include hopointensity on T1WI,hyperintensity on T2WI,and abnormal enhancement.