白血病脑实质浸润的弥散张量成像应用研究

目的探讨1．5T磁共振弥散张量成像（diffusiontensorimaging，DTI），部分各向异性（fractionalanisotropy，FA）和表观扩散系数（apparentdiffusioncoefficient，ADC）及弥散张量纤维束成像（diffusiontensortractography，DTT）在成人白血病脑实质浸润的应用价值。方法回顾性分析经临床证实的8例白血病脑实质浸润病例DTI之ADC、FA参数图，分别测量病变、水肿及健侧相应部位FA值和ADC值；观察各例在DTT图的变化。结果白血病脑实质浸润的肿瘤实质部分FA值8例全部较健侧降低，ADC值5例减低，3例增高；周围水肿区FA值全部降低，ADC值全部增高；脑白质纤维束DTT显示有中断、移位、浸润。结论DTI对脑侵犯神经纤维束损伤具有独特诊断价值；DTI的参数变化能够量化神经纤维受压后微细结构的变化，DTT图像重建能直观显示脑白质纤维束的完整性及损伤程度，DTI联合DTT可更加准确地评估白血病脑侵犯的损害程度。

Application of diffusion tensor imaging in brain parenchymal infiltration of leukemia

Objective To discuss the application value of diffusion tensor imaging （DTI） at 1.5 T magnetic resonance in brain parenchymal infiltration of adult leukemia by measuring the fractional anisotropy （FA） value and apparent diffusion coefficient （ADC） value and diffusion tensor tractography （DTT）. Methods 8 cases of patients diagnoseas leukemia with brain parenchymal infiltration by clinical method were selected. Their DTI parameters in ADC and FA maps were analyzed respectively. Changes were observed by measuring FA and ADC values in each lesion, edema and the contra-lateral corre-sponding part. Changes in DTT were analyzed too. Results Compared with the contralateral side, the FA values of tumors reduced in all 8 cases, the ADC values of tumors reduced in 5 cases and increased in 3 patients. As for the periph eral edema areas, all the FA values reduced and all the ADC values increased. DTT demonstrated interruption, replace-ment or infiltration for cerebral white matter fiber bundles. Conclusion DTI has unique diagnostic value in brain invasion and fiber tracts injury. Changes of DT1 parameters and DTT can directly show the cerebral white matter fiber tract integri- ty and damage degree. Combined with DTT, the extent of the damage in brain invasion of leukemia can be assessed accu- rately.