MRI在鼻咽癌临床分期中的价值

Application of Magnetic Resonance Imaging to Clinical Classification of Nasopharyngeal Carcinoma

背景与目的:鼻咽癌的临床分期主要依据影像学资料。本研究探讨磁共振成像(magnetic resonance imaging,MRI)技术在鼻咽癌P92临床分期中的价值。方法:2002年5月至2005年6月,共有100例经病理组织学诊断并在治疗前能同时或短时间内(不超过15天)作计算机断层扫描(computed tomography,CT)增强扫描和MRI增强扫描的鼻咽癌初治患者。其中男性74例,女性26例,年龄21～60岁,中位年龄46岁。分别计算两种检查方法所显示的各解剖部位受侵犯的阳性率,用卡方检验比较这两种检查方法对各解剖部位的检出率。按鼻咽癌P92分期标准,分别以CT加临床体检和MRI加临床体检对100例患者进行临床分期,用卡方检验比较两种方法所划分的各期病例数的构成比。结果:CT和MRI对颅底骨质破坏的检出率分别为31.0%(31/100)和56.0%(56/100),两种检查方法比较差异有显著性(χ2=12.715,P=0.000)。CT和MRI对咽后淋巴结的检出率分别为40.0%和55.0%,差异有显著性(χ2=4.511,P=0.034)。对于T分期,用CT和MRI划分的各期病例数构成比差异有显著性(χ2=8.339,P=0.039),而CT和MRI对于N分期(χ2=0.275,P=0.965)和临床分期(χ2=5.525,P=0.137)划分的各期病例数构成比比较则无显著性差异。结论:MRI对鼻咽癌颅底骨质破坏和咽后淋巴结的检出率高于CT。MRI使鼻咽癌的T分期升级,对临床分期有升级的趋势,而对N分期则无影响。

BACKGROUND ＆ OBJECTIVE： The clinical classification of nasopharyngeal carcinoma （NPC） depends mainly on the materials of medical imaging. This study was to investigate the application of magnetic resonance imaging （MRI） to the clinical classification of NPC. METHODS. One hundred patients with NPC confirmed by pathohistology received MRI and computed tomography （CT） within 15 days before treatment from May 2002 to Jun. 2005. The patients included 74 men and 26 women with a median age of 46 （21-60）. The detection rates of involved sites by MRI and CT were calculated and compared using X2 test. The clinical classification was performed according to 92＇ staging system of China. The constituent ratios of cases at different T, N, and clinical stages classified by MRI and CT were analyzed by x^2 test. RESULTS： The detection rates of skull base bone destruction and retropharyngeal lymph node involvement were significantly lower by CT than by MRI （31.0% vs. 56.0%, x^2=12.715, P=0.000; 40.0% vs. 55.0%, x^2=4.511, P=0.034）. The constituent ratio of cases at T1-T4 stages classified by MRI was different from that classified by CT（x^2=8.339, P=0.039）, but there was no difference in N staging （x^2=0.275, P =0.965） and clinical classification （x^2=5.525, P=0.137）. CONCLUSIONS： MRI is more sensitive than CT in detecting skull base bone destruction and retropharyngeal lymph node involvement of NPC. MRI may upstage T classification, tends to upstage clinical classification, and has no influence on N classification of NPC.