Mismatch cases between clinical finding and image finding on ¹⁵O gas PET/CT study caused by misregistration of PET data relative to CT-based attenuation maps

Abstract

CT attenuation correction (AC) is a major clinical advantage of PET/CT. However, motion can induce artifacts because of misregistration of the CT attenuation map and emission data. The aim of this study was to investigate the effect of misregistration in cerebrovascular disease patients. We collected six patients who showed mismatch between clinical finding and ¹⁵O gas PET/CT imaging, and confirmed dislocation less than 2 cm from initial position. Three patients showed decreased cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO₂) on the opposite side or ipsilateral side. The other patients showed an unexpected artifact on oxygen extraction fraction (OEF) map. These data suggest that misregistration can affect patient diagnosis with dependent on the degree of misregistration.