磁共振成像弛豫时间测定在颅内肿瘤组织定性诊断中的价值

目的：探讨磁共振成像序列中测出的弛豫时间在确定颅内肿瘤组织类型方面的价值。材料和方法：选用最佳参数成像后对有病理证实的３４例（１１种）颅内肿瘤的弛豫时间进行测定和分析。结果：星形细胞瘤、室管膜瘤、髓母细胞瘤及神经纤维瘤病的Ｔ１延长最为明显，Ｔ２也较长。转移瘤、垂体瘤及软骨瘤的Ｔ１、Ｔ２呈中度延长。囊性颅咽管瘤可呈短Ｔ１长Ｔ２表现。听神经鞘瘤的Ｔ１最短，与其它肿瘤无重叠，Ｔ２则较长。结论：部份肿瘤的弛豫时间较有特征性，可用作鉴别诊断的参考，大部份肿瘤的弛豫时间在分布上弥散和重叠明显，不能明确分界，因而不能单凭弛豫时间作出组织类型诊断。

The Evaluation of Tissue Characterization of Intracranial Tumor Using T_1 and T_2 Relaxation Times

To evaluate the usefulness of MR relaxation time in the tissue characterization of intracranial tumor.Materials and Methods:34 histologically confimed intracranial tumors (11 types)were examined with optimal imaging parameters.T1,T2, relaxation rates (1/T1, 1/T2),and T1/T2 of the tumor were calculated and analysed.Results: Astrocytoma,ependymoma, medulobla stoma and neurofibromatosis pocessed the longest T1 in all groups and their T2 were also rather long. The T1 and T2 of metastasis, pituitary adenoma and chondroma were prolonged moderately. Meningioma and malignant lymphoma had T1 and T2 value were comparable to those of normal cortex.cystic craniopharygioma showed very short T1 and long T2. The T1 of acoustic neurinoma was significantly shorter than that in all other tumors studied, while T2 prolonged considerably. Conclusion: Some tumors had characteristic relaxation times which can be used to differentiate tumor tissue types. But most of them with T1 and T2 values scattered and overlapped.Therefore, the tissue characterization can not be made solely on relaxation times.