Simplified nonlinearity correction of oxygen-15-water regional cerebral blood flow images without blood sampling

A noninvasive method, the double-integration method, was developed to estimate regional cerebral blood flow (rCBF) by using ¹⁵O-water and PET. It relies on the acquisition of images with a correction of nonlinearity of brain tissue counts and can produce rCBF images on a pixel-by-pixel basis. Methods: Oxygen-15-water PET studies were performed on five normal human volunteers, and continuous sampling from the radial artery was conducted to generate functional CBF images according to the invasive catheterization method. The method centers on a computer-based program elaborated to calculate an arterial input function with an assumption of the whole brain blood rate of 50 ml/dl/min and consequently does not require arterial catheterization or arterial input function sampled from other studies. Results: The results indicate a good correlation between this method and the invasive method (r > 0.966, p < 0.001). Conclusion: This noninvasive method was demonstrated to provide an accurate estimation of rCBF and may simplify the activation studies.