Positron emission tomography for quantitative determination of glucose metabolism in normal and ischemic brains in rats: An insoluble problem by the Harderian glands

Abstract

To examine the reliability of quantitative positron emission tomography studies in the rat (Rat-PET), we assessed the influence of radioactivity accumulated in the Harderian glands on PET CMR(glc), determination. We measured CMR(glc) by PET and ex vivo dissection methods by using 2- [18F]fluoro-2-deoxy-D-glucose in rats with and without focal brain ischemia. The CMR(glc) values obtained by PET, after correcting with recovery coefficients, were higher than those measured by the ex vivo method at rostral slices, and reduction of the CMR(glc) in the ischemic brain was not demonstrated by PET in the frontal cortex. The radioactivity accumulated in the Harderian glands prevents the quantitative determination of CMR(glc) using Rat-PET.