脑肿瘤MR弹性成像的初步临床研究

目的 探讨MR弹性成像(MRE)在脑肿瘤手术前评价其硬度的价值.方法 14例常规影像检查确定为实性脑肿瘤患者(男5例、女9例,年龄16～63岁),术前接受脑MRE检查,以脑白质为参照对肿瘤硬度进行评价.采用自行研制的用于脑MRE成像的激发装置,固定于头线圈上,并与患者头部固定,产生低频率振荡经颅骨传至颅内,引起剪切波在脑组织内传播;脉冲序列采用相位对比梯度回波序列,获得相位图像,从而显示脑组织内剪切波的传播.相位图像经局部频率估算法(LFE)处理后获得弹性图像;肿瘤的硬度在术中与正常脑白质对比,由术者判断分为偏软、中等和偏硬.将MRE的评价结果与手术结果作对照.结果 MRE检查结果显示,1例肿瘤的弹性模量低于正常脑白质、11例高于正常脑白质、2例与正常脑白质相似;术中检查1例肿瘤硬度偏软、11例偏硬,2例中等.14例由MRE评估的肿瘤弹性均与手术结果相符.结论 MRE可以无创地显示脑肿瘤的弹性,在术前对脑肿瘤的硬度进行评价.

Preliminary study of MR elastography in brain tumors

Objective To investigate the potential values of magnetic resonance elastography (MRE)for evaluating the brain tumor consistency in vivo.Methods Fourteen patients with known solid brain tumor(5 male,9 female;age range:16-63 years)underwent brain MRE studies.Informed consent was obtained from all patients.A dedicated external force actuator for brain MRE study Was developed.The actuator was fixed to the head coil.During scan.one side of the actuator was attached to the patients'head.Low frequency oscillation Was produced by the actuator and caused shear waves propagating into brain tissue.The pulse sequence used in the study Writs phase-contrast gradient-echo sequence.Phase images of the brain were obtained and the shear waves within the brain were directly imaged.Phase images were processed with local frequency estimation (LFE) technique to obtain the elasticity image.Consistency of brain tumors Was evaluated at surgery and Was classified as soft,intermediate,or hard with comparison to the white matter of the brain.Correspondence of MRE evaluation with operative results was studied.Results The elastic modulus of the tumor Was lower than that of white matter in 1 patient,higher inll patients,and similar in 2 patients.At surgery,the tumor manifested a soft consistency in I patient,hard consistency in 11 patients,intermediate consistency in 2 patients.The elasticity of tumors in 14 patients evaluated by MRE was correlated with the tumor consistency on the operation.Conclusion MRE Can noninvasively display the elasticity of brain tumors in vivo,and evaluate the brain tumor consistency before operation.