Variability of Image Features Computed from Conventional and Respiratory-Gated PET/CT Images of XXXX .

@entity1 @entity2 @entity5 @entity5516
Radiomics is being explored for potential applications in radiation therapy. How various imaging protocols affect quantitative image features is currently a highly active area of research. To assess the variability of image features derived from conventional [three-dimensional (3D)] and respiratory-gated (RG) positron emission tomography (PET)/computed tomography (CT) images of @entity2 @entity1 , image features were computed from 23 @entity2 @entity1 . Both protocols for each @entity1 were acquired during the same imaging session. PET @entity5 volumes were segmented using an adaptive technique which accounted for background. CT @entity5 volumes were delineated with a commercial segmentation tool. Using RG PET images, the @entity5 center of mass motion, length, and rotation were calculated. Fifty-six image features were extracted from all images consisting of shape descriptors, first-order features, and second-order texture features. Overall, 26.6% and 26.2% of total features demonstrated less than 5% difference between 3D and RG protocols for CT and PET, respectively. Between 10 RG phases in PET, 53.4% of features demonstrated percent differences less than 5%. The features with least variability for PET were sphericity, spherical disproportion, entropy (first and second order), sum entropy, information measure of correlation 2, Short Run Emphasis (SRE), Long Run Emphasis (LRE), and @entity5516 ( @entity5516 ); and those for CT were minimum intensity, mean intensity, Root Mean Square (RMS), Short Run Emphasis (SRE), and @entity5516 . Quantitative analysis using a 3D acquisition versus RG acquisition (to reduce the effects of motion) provided notably different image feature values. This study suggests that the variability between 3D and RG features is mainly due to the impact of respiratory motion.
