This blog describes the technique of FDG-PET in measuring brain metabolism in patients in the inter-ictal continuum..
- PET is co-registered to T1 MRI images.
- 10% color gradation (blue [hypo], green, yellow, red [hyper])
- cerebellum set to yellow
- measure maximum standardized uptake value (SUVmax)
- mesial temporal
- basal ganglia
- neo-cortex (frontal, temporal, parietal, occipital)
- SUVmax = voxel of highest SUV for a specified region
- SUV = ratio of radioactivity per voxel expressed as concentration (megaBeckquerel/Kg) divided by injected dose of radiation/Kg body mass
- Options for reference? (reference SUVmax or rSUVmax)
- internal control: 20% relative difference in SUVmax
- if focal: use contralateral homologous region
- cerebellum: compare to total cerebellar SUVmax
- if bilateral: 50% increase of SUVmax relative to cerebellum
- classify hyper- / hypometabolism as
- focal (single region)
- regional (extends to subcortical / adjacent)
- or diffuse (bilateral)
Renard, D. et al. “Teaching Neuroimages: FDG-PET In Progressive Supranuclear Palsy”. Neurology74.14 (2010): e60-e60.
Struck, Aaron F. et al. “Metabolic Correlates Of The Ictal-Interictal Continuum: FDG-PET During Continuous EEG”. Neurocritical Care 24.3 (2016): 324-331.