MRI对诊断肺癌亚临床性颅内转移瘤的应用价值

目的：探讨MRI对诊断亚临床性肺癌颅内转移瘤的应用价值。资料与方法：对45例临床无颅脑病变相关症状的肺癌患者行头颅MRI检查，包括平扫和增强扫描；分析原发性肺癌亚临床性颅内转移瘤的发生率、MRI影像特点；并用Logistic逐步回归分析转移瘤的发生与患者的年龄、性别、原发肿瘤手术与否、肺癌－脑转移间期、原发性肺癌TNM分期、中央或周围性肺癌等因素的关系。结果：亚临床性脑转移的发生率为31％左右。MRI表现为脑实质内单发或多发结节，多分布在边缘带，增强扫描呈环状强化；常合并软脑膜－蛛网膜转移。颅内转移瘤的发生概率主要与原发肺癌淋巴结的分期及肺癌确诊后的时间长短有关，而与患者的年龄、性别、原发肿瘤手术与否、肺癌的大小、部位等因素无关。结论：对于原发性肺癌N2期以上、患病时间较长的患者，即使临床上无中枢神经系统症状或体征，也有必要作颅脑MRI增强扫描，以早期发现亚临床性脑转移。

Evaluation of MRI in Detecting Subclinical Intracranial Metastases from Pulmonary Cancer

Objective To assess the clinical application of MRI in diagnosing subclinical intracranial metastases from primary lung cancer.Materials and Methods Both plain and enhanced cranial MRI was performed in 45 patients with primary lung cancer who showed no craniocerebral symptoms clinically. The incidence of brain metastases was estimated, and the MRI features of the metastases were analyzed. Using Logistic stepwise regression analysis, the correlation of intracranial metastatic occurrence with the possible risk factors was statistically analyzed. The possible risk factors included age, sex, TNM stage, type (central or peripheral), surgically removed or not, the length of the interval period (from the establishment of the diagnosis to discovery of intracranial metastases).Results The incidence of subclinical intracranial metastases was about 31% (14/45). On MRI, the lesions usually displayed as solitary or multiple small nodules, distributed mainly in the peripheral zone with ring-like enhancement. Piamatral and arachnoid metastases were commonly accompanied. The occurrence of intracranial metastases was mainly related to the N stage and the length of the interval period.Conclusion In order to detect subclinical intracranial metastases as early as possible, cranial MRI is strongly recommended for asymptomatic patients who had lung cancer of N 2 or higher stage, or had a long course after the establishment of the diagnosis, even if no symptoms or signs of central nervous system are present clinically.