MRI在鼻咽癌分期中的作用

背景与目的:随着磁共振成像(magnetic resonance imaging,MRI)的广泛应用,MRI对于鼻咽癌的诊断价值已被证实明显优于CT.本研究旨在分析MRI与CT检查对鼻咽癌'92分期及6th UICC/AJCC分期的影响.方法:收集2003年1月至2004年6月收治的、经病理证实的初诊鼻咽癌250例,所有病例同时具有治疗前鼻咽和颈部的增强CT及MRI资料.结合临床资料如颅神经受损及颈淋巴结大小,分别采用CT和MRI检查进行'92分期及6th UICC/AJCC分期,评价两者之间的差异.结果:MRI在诊断鼻咽癌软组织超腔侵犯(口咽、鼻腔、咽旁间隙)、咽后淋巴结转移以及颅底骨质、副鼻窦、海绵窦/颅内、颞下窝及颈椎侵犯等方面均明显优于CT,而对于颈部巴结转移的检出两者无显著性差异.对于'92分期,MRI使32.0%的T分期发生改变(26.0%升级,6.0%降级);11.6%的N分期发生改变(6.4%升级,5.2%降级);30.4%的临床分期发生改变(24.0%升级,6.4%降级).对于6th UICC/AJCC分期,MRI使39.6%的T分期发生改变(36.0%升级,3.6%降级);9.2%的N分期发生改变(5.6%升级,3.6%降级);37.6%的临床分期发生改变(33.6%升级,4.0%降级).结论:MRI检测鼻咽癌局部病灶的侵犯范围要明显优于CT,而在颈部淋巴结转移的检出方面与CT结果相似.建立新的、以MRI为主要手段的鼻咽癌临床分期系统的研究具有临床必要性及可行性.

Influences of magnetic resonance imaging on the staging system of nasopharyngeal carcinoma

BACKGROUND & OBJECTIVE: The value of magnetic resonance imaging (MRI) in assessing the extension of nasopharyngeal carcinoma (NPC) is better than that of computed tomography (CT). This study was to analyze the influences of MRI on the Chinese '92 staging system and the 6th edition International Union Against Cancer/American Joint Committee on Cancer (UICC/AJCC) staging system of NPC. METHODS: From Jan. 2003 to Jun. 2004, 250 naive patients with histologically diagnosed NPC, with no metastasis, received both enhanced spiral CT and MRI scans of the nasopharynx and cervix. Clinical stage was classified according to the Chinese '92 staging system and the 6th edition UICC/AJCC staging system, respectively, based on both CT/MRI imaging data and clinical information. RESULTS: MRI was better than CT in detecting the invasion of NPC in the extra-nasopharyngeal cavity (the oropharyrnx, nasal cavity, and parapharyngeal spatium), retropharyngeal lymph node, base of skull, paranasal sinuses, intracranial cavernous sinus, infratemporal fossa, and cervical vertebra. There was no statistical difference between CT and MRI in detecting cervical lymph node metastasis. Compared with CT, MRI made changes in 32.0% of T stage (including 26.0% up-staging and 6.0% down-staging), 11.6% of N stage (6.4% up-staging and 5.2% down-staging), and 30.4% of clinical stage (24.0% up-staging and 6.4% down-staging) for the Chinese '92 staging system, while made changes in 39.6% of T stage (36.0% up-staging and 3.6% down-staging), 9.2% of N stage (5.6% up-staging and 3.6% down-staging), and 37.6% of clinical stage (33.6% up-staging and 4.0% down-staging) for the 6th edition UICC/AJCC staging system. CONCLUSIONS: Compared with CT, MRI has a remarkable advantage in detecting the primary tumor extension of NPC, but has no advantage in detecting cervical lymph node metastasis. It is necessary and feasible to establish a new clinical staging system of NPC based on MRI.