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

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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