PET Imaging Aids Diagnosis of Vegetative State
(HealthDay News) — Positron emission tomography (PET) imaging may be used in conjunction with examinations to assess long-term outcomes in patients in a vegetative state, according to a study published online April 16 in The Lancet.
Johan Stender, MD, from the University of Liège in Belgium, and colleagues conducted a validation study of two neuroimaging-based diagnostic methods. 18F-fluorodeoxyglucose (FDG) PET imaging and functional magnetic resonance imaging (fMRI) were compared to determine their diagnostic accuracy in 41 patients with unresponsive wakefulness syndrome, four patients with locked-in syndrome, and 81 patients in a minimally conscious state (traumatic, 48; non-traumatic, 78). The Coma Recovery Scale-Revised (CRS-R) served as the diagnostic reference.
The researchers found that 18F-FDG PET had high sensitivity for identification of patients in a minimally conscious state (93%) and high congruence (85 percent) with behavioral CRS-R scores. The sensitivity was lower for diagnosis of a minimally conscious state with the active fMRI method (45%) and congruence with behavioral scores (63%) was lower overall, compared to PET imaging. Outcomes were correctly predicted in 75 of 102 patients using 18F-FDG PET and in 36 of 65 patients using fMRI. Nearly one-third (32%) of the behaviorally unresponsive patients (diagnosed as unresponsive with CRS-R) showed brain activity compatible with (minimal) consciousness on at least one neuroimaging test.
"Cerebral 18F-FDG PET could be used to complement bedside examinations and predict long-term recovery of patients with unresponsive wakefulness syndrome," the authors write.