Characteristics of Physiological 18F-Fluoro-2-Deoxy-D-Glucose Uptake and Comparison Between Cats and Dogs With Positron Emission Tomography

Abstract

This study aimed to identify the physiological 18F-fluoro-2-deoxy-D-glucose (FDG) uptake in cats using positron emission tomography/computed tomography (PET/CT) and determine its characteristics by comparing physiological differences with dogs. Seven healthy cats and six healthy beagle dogs were examined using FDG-PET/CT. Regions of interest (ROIs) were manually drawn over 41 detailed structures of 5 gross structures (brain, head and neck, musculoskeleton, thorax, and abdomen). The mean and maximum standard uptake values (SUVmean and SUVmax) were calculated for each ROI. Physiological variation was classified as having increased radiopharmaceutical activity with no evidence of abnormal clinical or radiological findings. The brain had the highest SUV, which was observed in the cerebellum of both cats (SUVmean: 4.90 ± 1.04, SUVmax: 6.04 ± 1.24) and dogs (SUVmean: 3.15 ± 0.57, SUVmax: 3.90 ± 0.74). Cats had a significantly higher intracranial uptake than dogs did (P < 0.01). In the digestive system, the SUVs of the duodenum and jejunum were significantly higher in dogs than in cats (P < 0.05). FDG uptake of the submandibular tip, tonsils, neck of the gallbladder, and caudal colliculus were physiologically increased in cats. This study demonstrates physiological FDG uptake in normal tissues, and the differences between cats and dogs were interpreted based on species-specificity. This information contributes to improving the accurate diagnosis of cancer in cats and will aid in understanding glucose metabolism in both cats and dogs.

18F-Fluorodeoxyglucose positron emission tomography characteristics of a gastric tumour pre- and post-surgery in a dog: A case report of near-infrared fluorescence-guided imaging surgery using indocyanine green

“…Although 18F-FDG ndings of gastric tumours have been reported in human medicine, to the best of our knowledge, 18F-FDG PET characteristics in canine gastric tumours have not been reported in veterinary medicine. In a study on the physiological uptake of 18F-FDG in normal dogs, the maximum and mean SUVs were 1.70 ± 0.36 and 0.89 ± 0.25, respectively (12). In this case, the mean and maximum SUVs were 4.596 and 6.234, respectively, which are substantially higher than those of normal dogs.…”

Case report: Evaluation of hindlimb ischemia using 18F-fluorodeoxyglucose positron emission tomography in a cat with cardiogenic arterial thromboembolism

“…Additionally, the mean SUV of the caudal part of the bilateral thighs was lower than that of the cranial part of the thighs, indicating that the thrombus partially obstructed the aorta below the branch of the deep circumflex iliac artery that supplied blood to the cranial thigh muscles. The mean SUV of cranial parts of thighs was higher than that of normal feline thigh muscle mean SUV (0.62 ± 0.13) ( 13 ). In addition, there was extensive infiltration of macrophages and other leukocytes in histopathological examination.…”

“…The left tibial region showed a mean SUV of 0.29 and a maximal SUV of 1.75, and the right tibial region showed a mean SUV of 0.08 and a maximal SUV of 0.48. There was also low 18F-FDG uptake of mean SUV of 0.06 and maximal SUV of 0.24 in both caudal muscles around the femurs (RI = 0.62 ± 0.13 for mean SUV and 1.10 ± 0.32 for maximal SUV) ( 13 ). However, the cranial part of the left thigh muscles showed a mean SUV of 3.78 and a maximal SUV of 8.26 ( Figures 2B,C ).…”

“…However, the cranial part of the left thigh muscles showed a mean SUV of 3.78 and a maximal SUV of 8.26 ( Figures 2B,C ). The mean and maximal SUV for the forelimbs of the cat were 0.92 and 1.47, respectively (RI = 1.09 ± 0.37 for mean SUV and 2.48 ± 1.21 for maximal SUV) ( 13 ).…”

“…The absence of 18F-FDG uptake in tissues normally exhibiting physiological 18F-FDG uptake suggests a non-viable status or necrosis ( 12 ). In veterinary medicine, the distribution of 18F-FDG has been described in healthy cats, and there is limited information on its use in cats with neoplasia ( 13 , 14 ). However, no studies have described the use of 18F-FDG PET/CT to evaluate skeletal muscular ischemia in cats with arterial disease, such as ATE.…”