Prognostication of Recovery of Consciousness in Patients in a Vegetative State Using Proton Magnetic Resonance Spectroscopy

Objectives. To study the predictive significance of proton magnetic resonance spectroscopy (MRS) in patients in a vegetative state. Materials and methods. Multivoxel MRS was carried out in 34 patients in a vegetative state with voxels in the thalamus, globus pallidus, putamen, internal capsule, fornix, brainstem, and the temporal and frontal areas of the cortex. Patients were divided into groups depending on the etiology of vegetative state: 22 patients had the sequelae of traumatic brain injury (TBI) and 12 patients had the sequelae of hypoxic brain damage. The groups were comparable in terms of age and the duration of the vegetative state (mean 2.3 months). Neurological status was assessed both during the hospitalization period and at 6–12 months using the Coma Recovery Scale (CRS-R). MRS results obtained at 6–12 months were compared with baseline data. The outcome of patients with the sequelae of TBI were as follows: persistent vegetative state in six patients, minimally conscious state plus in nine patients, recovery from the state of minimal consciousness in seven. Outcomes of patients with the sequelae of hypoxia were: persistent vegetative state in 10 patients and minimally conscious state plus in two. Results. Decreases in the N-acetylaspartate/creatinine ratio in the thalamus, internal capsule, and temporal cortex correlated with poor outcomes in both groups, while higher values correlated with further recovery of consciousness. Decreases in the N-acetylaspartate/creatinine ratio and the N-acetylaspartate/N-acetylaspartate + choline + creatine ratio in the midbrain correlated with poor outcomes only in patients with the sequelae of hypoxia. Conclusions. The results obtained here suggest that MRS provides a more accurate determination of the outcome in patients with hypoxic brain damage and patients with TBI, who showed recovery of consciousness to the level of coming out of the vegetative state.