1984 年 6 巻 1 号 p. 42-43
The application of positron emission tomography (PET) to the study of cerebral ischemic disorders allows for the first time to measure at the local level the cerebral metabolic rate of oxygen (CMRO2) and/or the cerebral glucose utilization (CMR Glc), together with cerebral blood flow (CBF). The high incidence and morbidity of stroke and the limitations of animal stroke models appear to amply justify the financial and human investment necessary for this endeavour.
PET can theoretically provide clues to a number of yet unanswered questions, such as 1) are there any quantitative patterns of changes in CBF and CMRO2 that can predict final tissue outcome, i.e. structural integrity or necrosis, in acute ischemic stroke? Do these patterns suggest any adapted therapeutic approach to improve the outcome of the tissue otherwise condemned to necrosis? What are the effects of therapy on local CBF and CMRO2 is acute ischemic stroke? Does the circumscribed structural damage induce functional alterations at remote sites, yet structurally intact? What would be the role of such remote functional changes in the clinical symptomatology and the final degree of clinical recovery? Is PET able to demonstrate chronic hemodynamic ischemia and, so, to help in the selection of patients for surgical revascularization procedures, the circulatory and metabolic effects of which could then be locally measured? Could the combined measurement of CMRO2 and CMR Glc determine the conditions of occurrence and prognostic significance of uncoupling of glucose oxidation? Can local tissue pH be measured in cerebral ischemia? We have addressed a number of the above questions in our PET center, using either the oxygen-15 contiunous inhalation technique to measure CBF and CMRO2, or the 18F-Fluoro-2-Deoxy-D-Glucose (FDG) technique (usign the “kinetic” approach) to measure CMR Glc, or both combined techniques; preliminary studies of the cerebral acid-base balance have have used 11C labeled DMO as a pH sentitive tracer. Our main findings can be summariesd as follows :