Parametric imaging in cerebral radionuclide angiography (RNA) by planar imaging improving presentation and objectivation of cerebral blood flow

Methods of parametric imaging of radionuclide angiography using parameters like appearance time, peak time, transit time, height of peak, arterial slope and area of inflow were developed and evaluated regarding their diagnostic meaning in 111 patients suffering from TIA or PRIND and in 30 normal persons. The meaning of these single parameters depended on the specificity of the diagnostic question. Local cerebral blood flow can be estimated most favourably by parametric images of area of inflow whereas transit time is most promising as a diagnostic tool for evaluation of total cerebral flood flow classified with reference to severity of the perfusion disturbance. Appearance time is suited very well to estimation of collateral perfusion. Blood flow in great cerebral arteries could be seen well by non parametric imaging of radioactivity inflow in the brain supplying arterial vessels in the cranial floor. Applying a combination of the parametric images, the sensitivity for detection of disturbances of cerebral blood flow amounts to 0.91. A specificity of 0.88 and accuracy of 0.90 were found. The described combination of evaluation of RNA using various parameters is considered a well suited method for detection of disturbances in local and total cerebral blood flow by means of planar imaging. (orig.)