FDG Uptake of Normal Canine Brain Assessed by High-Resolution Research Tomography-Positron Emission Tomography and 7 T-Magnetic Resonance Imaging

Abstract

ABSTRACT. The purpose of this study was to assess the normal distribution of 18 F-fluoro-2-deoxy-D-glucose (FDG) uptake of canine brain structures using a high-resolution research tomography-positron emission tomography (HRRT-PET) and 7 T-magnetic resonance imaging (MRI) fusion system. FDG-PET and T2-weighted MRI of the brain were performed on 4 healthy laboratory beagle dogs. On MRI, regions of interests (ROIs) were manually drawn over 51 intracranial structures, including nine gross structures and 42 detailed structures. Relative standard uptake value ratio (rSUV=SUV of ROI/SUV of whole brain) was calculated for each ROI. The HRRT-PET and 7 T-MRI fusion imaging system demonstrated significant differences in glucose metabolism among various intracranial structures. Among gross structures, the midbrain and the pons and medulla oblongata had the highest uptake (rSUV: 1.12 ± 0.03) and lowest uptake (rSUV: 0.90 ± 0.06) of FDG, respectively. When rSUVs were calculated on detailed regions, the caudal colliculus and the longitudinal fibers of pons had the highest (rSUV: 1.62 ± 0.05) and the lowest (rSUV: 0.63 ± 0.03) glucose metabolism, respectively. Because the high resolution of PET-MRI fusion images provided clearly identifiable metabolic activities of canine brain, the HRRT-PET and 7 T-MRI fusion imaging might be a good tool for evaluation of intracranial diseases in canines. KEY WORDS: 7 T-MRI, canine brain, FDG, HRRT-PET.

Fdg‐pet in Healthy and Epileptic Lagotto Romagnolo Dogs and Changes in Brain Glucose Uptake With Age

“…Additionally, the aforementioned study used a different anesthetic protocol, and anesthetic protocols have been shown to affect SUV values . A recent study specified SUV values for numerous detailed brain structures . The distribution of SUV values (i.e., the highest and the lowest glucose uptake pattern) was similar to that in our study.…”

“…The distribution of SUV values (i.e., the highest and the lowest glucose uptake pattern) was similar to that in our study. In the previous study, they detected the highest glucose uptake in the caudal colliculi, followed in order by the cerebellar vermis and the caudate nuclei . In our study, the highest glucose uptake was also detected in the caudal colliculi, followed by the caudate nuclei and the cerebellar vermis (the latter only in adult dogs).…”

“…In our study, the highest glucose uptake was also detected in the caudal colliculi, followed by the caudate nuclei and the cerebellar vermis (the latter only in adult dogs). In several studies, the highest glucose uptake among the cerebrocortical substractures occurred in the frontal and occipital cortices . In our study, the temporal and parietal cortices had a higher glucose uptake than did the frontal and occipital cortices (Table ), but the differences are small, as a recent study pointed out (in that study mean SUVs for temporal lobe 3.73, parietal lobe 3.86, frontal lobe 3.91, occipital lobe 3.90) …”

“…Due to their lower anatomic resolution, SPECT and PET are dependent on co‐registration with MRI for precise anatomic correlations . Only a few studies have utilized PET imaging in dogs, including PET after brain microembolization, PET imaging in canine necrotizing meningoencephalitis, oncological studies, behavioral medicine, and PET imaging of normal dogs . To the best of our knowledge, functional neuroimaging in idiopathic epilepsy of dogs has been utilized in only one study investigating regional brain perfusion with SPECT, but no studies have explored FDG‐PET in idiopathic epilepsy in dogs.…”

Primary brain involvement of disseminated histiocytic sarcoma in a Rottweiler dog - histopathology, ¹⁸F-fluorodeoxyglucose positron emission tomography and 7 T-magnetic resonance imaging findings: a case report

“…However, CT has a number of shortcomings in soft tissue imaging; therefore, MRI can be utilised for precise anatomical localisation of malignant lesions as an alternative to CT (Cho et al 2008). Clinical application of PET/CT has been reported in a number of dogs with spontaneously occurring tumours , whereas use of PET/MRI in canines is limited to the healthy or epileptic brain, intracranial HS and pituitary microtumours (Kang et al 2009;Kang et al 2012;Jokinen et al 2014;Son et al 2015). In the present case, 7 T-MRI clearly visualised the cerebellar and thyroid lesions, thus helping in the identification of the anatomical location of the hypermetabolic lesions on PET.…”