Quantitative analysis and effectiveness of ¹⁸F-fluorodeoxyglucose brain PET on evaluation of unconscious patients.

Objectives: Making an accurate diagnosis and evaluating prognosis in patients with disorders of consciousness remains challenging. These days, The Coma Recovery Scale-Revised (CRS-R) is the gold standard behaviour scale to make the diagnosis of unconscious patients. And ¹⁸F-fluorodeoxyglucose (FDG) brain PET has been validated as an imaging diagnostic tool in these populations. But the correlation of these two diagnostic tools has not been clearly verified yet. So, the aim of this study is to verify correlation between CRS-R and FDG brain PET, and furthermore to verify effectiveness of ¹⁸F-FDG brain PET on evaluation of unconscious patients. Materials and Methods: We recruited 12 adult patients (one patient was excluded because of severe brain edema) from our hospital and 135 age-matched controls. Every patients were clinically divided into 2 groups (Minimally conscious state (MCS) vs Vegetative state (VS)). Every controls and patients had been examined ¹⁸F-FDG brain PET. Then, we performed statistical evaluation by using Statistical Parametric Mapping 12 (SPM12). The brain regions that had statistically hypo-metabolism were given by MNI coordinate, then we converted it as anatomical space (Brodmann areas).

Results: There were some significant difference in ¹⁸F-FDG brain PET results between MCS patients & VS patients with age-matched controls, respectively. The most notable difference is that MCS patients has some focal hypo-metabolic lesions while VS patients has diffuse hypo-metabolic lesions in fronto-parietal cortex compared to age-matched controls. And we performed direct comparison MCS with VS. The result of this comparison is that there is a statistically difference of metabolism in right superior frontal gyrus area and left cerebellum.

Conclusions: In this study, there were some correlation between CRS-R and ¹⁸F-FDG brain PET. So, we concluded that ¹⁸F-FDG brain PET can be used to evaluate unconsciousness patients supplement to CRS-R which is more subjective. Furthermore, follow up study could evaluate an effectiveness in prognosis prediction by using initial ¹⁸F-FDG brain PET studies.