Stable Xenon-CT Cerebral Blood Flow Imaging in Patients with Cerebral nfarction

ABSTRACT

BACKGROUND: Stable xenon-CT has been known to be a useful technique for measuring cerebral blood flow (CBF) and its direct correlation with CT anatomy. We evaluated the usefulness and limitations of stable xenon-CT cerebral hemodynamic status. METHODS: Xenon-CT was administered to 23 patients. Ten were normal controls and 13 were stroke patients (acute 4, subacute 5, chronic 2, hemorrhagic 2). Time dependent Xenon concentrations within various tissue segments of the brain was used to derive both the local partition-coefficient (lamda) and CBF in each tissue volume (voxel) of the CT image. RESULTS: In the controls, the regional CBF (rCBF) (ml/100 gm/min) was as follows frontal 22.9+/-7.3(Mean+/-SD), inferior temporal 23.9+/-3.2, superior temporal 27.4+/-7.3, parietal 30.0+/-10.1, occipital 24.3+/-8.4, cerebellar hemisphere 24.3+/-8.3, thalamus 31.1+/-7.1, and corona radiata 18.1+/-4.7. The cortical differences was within 10%. In the stroke patients, the rCBF in the infarcted area ranged from 0 to 26.5 ml/100 gm/min and interhemispheric cortical difference was above 50%. The routine CT revealed no abnormalitiy, particularly in acute stroke (within 6 hours after onset). However, a xenon-CBF showed perfusion defect which correlated with clinical signs. CONCLUSIONS: With xenon CT, CBF can be obtained within a few hours of stroke onset, result of which can be correlated with CT. In an acute stroke state, a Xenon-CBF map can be a more sensitive method than routine CT imaging. Low value of blood-flow and patient's in cooperation may limit use of Xe-CT.