Usefulness of combination of magnetization transfer ratios and proton MR spectroscopy in patients with chronic cerebro-vascular disease ; a comparative study with PET images

目的：1)从预后、治疗和管理的角度，评价磁化转移率(MTR)和磁共振波谱(MRS)技术在脑缺血组织中的应用价值。2)以PET参数值为金标准，明确MTR值与MRS值之间的关系。方法：对15例单侧颈内动脉和大脑中动脉闭塞患者的脑组织进行磁共振成像和正电子发射计算机断层扫描。在磁化传递图像(MTI)采集和MR机MRS测量后6h内，用PET机获得脑血流量(CBF)、脑氧代谢率(CMRO2)和氧摄取分数(OEF)图像。根据PET参数将脑组织缺血区分为轻、中、重度3组。分析各组MTR值与MRS数据的关系，以及正电子发射计算机断层扫描各参数与MRS指标…之间的关系结果：正常组NAA/Cr值、Cho/Cr值、MTR值均为正常值。轻、中度缺血组PET检查可逆性缺血时，NAA/Cr值正常，MTR值正常，Cho/Cr值正常。Cho/Cr值变化范围较大，但中度缺血区Cho/Cr值高于轻度缺血区。重度缺血组出现不可逆性缺血，NAA/Cr值降低，Cho/Cr值升高，MTR降低。MTR与CMRO2呈显著正相关，CMRO2与NAA/Cr值呈正相关。结论：MTR与MRS相结合可将脑缺血区分为3组，并可用于PET参数的分类。CMRO2与NAA/Cr、MTR呈显著正相关。MTR和MRS联合应用有助于评价血流动力学状态。较少

Purpose : 1)To assess the usefulness of combination of magnetization transfer ratio (MTR) and MR spectroscopy (MRS) technique in the ischemic brain tissue, from a point of view of prognosis, treatment and management. 2)To clarify the relationship between the values of MTR and MRS data, based on the values of PET parameters for gold standard.Methods : Using MR and PET machines, ischemic areas in brain tissue were investigated in 15 patients with unilateral ICA and MCA occlusion. Within 6 hours after magnetization transfer images (MTI) acquisition and MRS measurement by MR machine, cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction fraction (OEF) images were obtained by PET machine in the same patients. The ischemic areas of brain tissue were classified into 3 groups (mild, moderate and severe) based on PET parameters. In each group, the relationship between MTR and MRS data was analyzed, and the relationship between PET parameters and MRS indexes … More was also reviewed.Results : Individuals in the normal group revealed normal values of NAA/Cr, Cho/Cr and MTR. In the mild and moderate ischemic group, having reversible ischemia by PET study, the areas were characterized by normal NAA/Cr, normal MTR and normal Cho/Cr. Although the Cho/Cr values showed wide ranges, the Cho/Cr values in the areas of moderate ischemia revealed higher than those in the areas of mild ischemia. In severe ischemic group, having irreversible ischemia, decreased NAA/Cr, increased Cho/Cr, and reduced MTR were found. A significant correlation between the values of MTR and that of CMRO2 was found, a correlation between the values of CMRO2 and that of NAA/Cr was also discovered.Conclusion : The combination of MTR and MRS methods became feasible for classifying the ischemic areas into 3 groups, as well as in classifying the PET parameters. The values of CMRO2 correlated significantly with that of NAA/Cr and MTR. The combination of MTR and MRS was useful for assessment of hemodynamic status. Less