含短T_1信号的颅内先天性肿瘤的MRI表现及信号的病理基础

目的　探讨颅脑先天性肿瘤 MRI短 T1 高信号与肿瘤成分之间的关系 ,加深对该病的认识 ,提高影像诊断正确率。材料与方法　经手术病理证实的并在 MR T1 WI上表现为短 T1 高信号或混杂信号的 9例颅脑先天性肿瘤 ,全部行常规 MR检查及脂肪抑制序列扫描 ,将 MRI信号特征与病理结果进行对照分析。结果　颅咽管瘤 3例 ,在 T1 WI上均为混杂信号 ,其中 2例短 T1 高信号经 CT及病理证实为钙化 ,1例短 T1 高信号为脂肪成分。表皮样囊肿 4例 ,2例为均匀的短 T1 高信号 ,2例为混杂信号 ,肿瘤成分为液态的高浓度蛋白。皮样囊肿及畸胎瘤各 1例 ,均为混杂信号 ,其中的短 T1 高信号经脂肪抑制序列及术中所见证实为脂肪成分。结论　先天性肿瘤中的短 T1 高信号是由高浓度蛋白、脂肪及钙化成分组成。 MRI对先天性肿瘤有定性诊断价值

MR Imaging Manifestations of Congenital Intracranial Tumors Containing High Signal Intensity on T_1 WI and Their Pathological Bases

Objective To explore the relationship between high signal intensity on T 1WI and composition of the congenital intracranial tumors, to make a further understanding of the tumor and to improve the diagnostic accuracy.Materials and Methods Conventional MR sequence and fat suppressed sequence scanning were performed in 9cases with surgically proved intracranial tumors which demonstrated high or mixed signal intensity on T 1WI.Results Of 3 cases with craniopharyngioma which showed mixed signal intensity on T 1WI, with CT and pathologic examination high signal intensity was proved to be the calcifications in 2 cases, and the fat in one case. Of 4 cases with epidermoid cyst, 2 demonstrated homogeneous high signal intensity and 2 showed mixed signal intensity, the component of the cyst was liquid, highly concentrated protein. Dermoid cyst (n=1) and teratoma (n=1) displayed mixed signal intensity. The high signal intensity in the lesion on T 1WI was due to the presence of fat composition, which was verified with fat suppressed sequence scan and surgical results.Conclusion Highly concentrated protein, fat and calcification in congenital intracranial tumors are the components producing high signal intensity on T 1WI. MRI is very useful in diagnosing congenital intracranial tumors.