Comparison of different methods for attenuation correction in brain PET:: Influence on the calculation of the metabolic glucose rate

Aim: There are several approaches for correcting the effects of photon scatter or absorption by body tissues on positron emission tomography (PET). We examined the influence of told, hat and segmented transmission as well as of a mathematical procedure on attenuation correction using regional cerebral glucose metabolism (rMRGlu). Methods: 6 patients with different cerebral diseases were examined under resting conditions using on ECAT Exact 922/47. The attenuation-corrected data (corrected by means of cold, hot and segmented transmission as well as a mathematical procedure) were then quantified absolutely for assessment of regional glucose metabolism in 16 regions of interest (ROIs). Results: Using absolutely quantified glucose metabolism in 16 ROIs, no significant differences were found between cold transmission and the mathematical procedure except far three regions (left and right temporal occipital and right parietal occipital). Unlike the mathematical procedure, bath hot and segmented transmission showed a significantly tower value for regional glucose utilisation in all 16 ROIs than did cold transmission. The left and the right hemisphere both showed metabolic values (rMRGlu) in the same decreasing order: cold transmission, the mathematical procedure, hat or segmented transmission. There was no significant difference be tween global cerebral glucose metabolism values far cold transmission and the mathematical procedure (p = 0.25) while those far hot (p = 0.03) and segmented transmission (p = 0.03) did shaw a significant difference. Conclusions: Except far 3 regions (temporo-occipital left, temporo-occipital right and parieto-occipital right) attenuation correction procedures used far brain PET studies an patients show no significant quantitative differences between cold transmission and the mathematical procedure. rMRGlu of images corrected for attenuation using hot and segmented transmission is significantly lower than of attenuation corrected images where cold transmission was employed. For clinical routine examinations, the mathematical procedure seems the best alternative to cold transmission for a faster brain PET acquisition.