MRI区分肺癌肿块与阻塞性肺炎或肺不张:与CT对照

Differential Diagnosis of Bronchogenic Carcinoma with Postobstructive Pneumonitis and Atelectasis by MRI: a Comparison with CT

通过与CT对照，探讨MRI信号强度区分肺癌及其继发改变的价值。材料和方法：114例肺癌均经病理证实，包括男性82例，女性32例；年龄26－80岁，平均56．49±8．09岁。应用Disonics0．35T超导成像系统，以10mm层厚行横断T1、T2及冠状面T1加权成像。结果：MRI显示阻塞性炎症40例（35．1％），T1WI27例肿块与阻塞性肺炎可区分，占67．5％；T2WI第一回波上25例可分开，占625％；第二、三回波上28例可区分开，占70％；第四回波上29例可分开，占72．5％。虽然在第四回波上区分率最高，但各序列之区分率之间无明显差别。阻塞性肺炎信号强度大于或小于肿块之间亦无显著差别。33例发生肺不张，占28．9％。T1WI36％（12例）的病人肺不张与肿块可分，64％的病人不可分；T2WI第一回上17例可分，占52％；第二及第三回波上均有18例可分，各占56％；第四回波上对例可分，占64％。也就是说在T1WI上大多数肺不张难与肿瘤区分开，而T2WI上尤其是长回波图像上大部份可与肿瘤区分。统计学结果表明，T2WI区分率明显高于T1WI。CT增强与MRIT1WI相仿，CT平扫最差。后三者的区分率都在50％以下，即多数都难以区分。MRI上肺不张的信号多低于肿块，尤其在T1WI上；CT平扫以低密度居多，增强后肺不张的密度多大于肿块。

To evaluate the role of MRI in the differentiation of lung cancer from pneumonitis and atelectasis. Material and mathods: 114 cases of pathologically confirmed lung cancer scanned by a DIASONICS 0.35T super-conducted imaging system with transaxial T1、T2WI and coronal T1WI were analysed. Results: 40(35.1%) patients with postobstructed pneumonitis were found on MRI images; 76. 5%(27)can be differentiated from tumors on T1 WI, while 62. 5%, 70%, 70%, and 72% can be differentiated on the four echos of T2 WI. Statistic results showed that there is no significant difference between the various sequences Atelectasis were found in 33 patients, 12(36%) of them were distinguishable on T1 WI; while 52%, 56%, 56% and 64% on be differentiated from tumor on the four echos of T2WI; the findings on enhanced CT were equivalent to those of MRI T1 WI(37% ); non-enhanced CT was the worst(15%). The signal intensities of most atelectasis were lower than those of the tumors, especialy on T1 WI; but on enhanced CT, the densities of most atelectasis were higher than the tumors. Conclusion: MRI is able to differentiate most of the obstructive pneumonitis and atelectasis from tumors, it is superior to CT.