Cerebral glucose metabolism in acute and persistent vegetative state

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Vegetative state (VS) results from severe brain injury, often due to anoxia.
• Distinguishing between acute (AVS) and persistent (PVS) vegetative states is crucial for prognosis.
• Regional cerebral glucose metabolism (rCMRglc) can reflect brain function.

Purpose of the Study:

• To investigate regional cerebral glucose metabolism (rCMRglc) in patients with AVS and PVS.
• To compare metabolic rates between AVS and PVS patients and relate them to outcomes.
• To explore the relationship between brain metabolism and neuropathological changes in VS.

Main Methods:

• Used 18F-2-fluoro-2-deoxy-D-glucose (FDG) and positron emission tomography (PET) to measure rCMRglc.
• Studied 24 patients with VS (11 AVS, 13 PVS) following cardiorespiratory arrest.
• Compared metabolic rates to age-matched controls and analyzed outcomes after 12 months.

Main Results:

• Overall glucose utilization was significantly reduced in VS patients compared to controls.
• Cortical metabolic rates were significantly lower in PVS patients than in AVS patients (p<0.05).
• Infratentorial hypometabolism was less pronounced than in cortical regions.

Conclusions:

• Persistent vegetative state is associated with progressive loss of cortical function.
• Reduced cortical metabolism in PVS reflects neuropathological degeneration following anoxic brain injury.
• Metabolic differences between patients who died or remained in PVS were not statistically significant, possibly due to age differences.