Aetiological differences in neuroanatomy of the vegetative state: insights from diffusion tensor imaging and functional implications

Virginia Fj Newcombe (1) , Guy B Williams (2) , Daniel Scoffings (3) , Justin Cross (3) , T.Adrian Carpenter (3) , John D Pickard (4) , David K Menon (5)

1 University Division of Anaesthesia, University of Cambridge
2 Wolfson Brain Imaging Centre, University of Cambridge
3 Department of Radiology, Addenbrooke's Hospital
4 Academic Department of Neurosurgery, University of Cambridge
5 Division of Anaesthesia, University of Cambridge

Background: An improved in vivo understanding of variations in neuropathology in the vegetative state (VS) may aid diagnosis, improve prognostication and help refine the selection of patients for particular treatment regimes. We have used diffusion tensor imaging (DTI) to characterise the extent and location of white matter loss in VS secondary to traumatic brain injury (TBI) and ischaemic-hypoxic injury (IHI). Methods: Twelve patients with VS (7 TBI, 5 IHI) underwent DTI at a minimum of three months post injury. Mean ADC, FA and eigenvalues were obtained for whole brain grey and white matter, the pons, thalamus, ventral midbrain, dorsal midbrain and the corpus callosum. DTI measures of supratentorial damage were compared to a summed measure from the JFK modified Coma Recovery Scale (CRS-R) and to a three point scale of fMRI response to an auditory paradigm to assess whether residual integrity of supratentorial white matter connectivity correlated with cortical processing. Results: Conventional radiological approaches did not detect lesions in regions where quantitative DTI demonstrated abnormalities. There was evidence of marked, broadly similar, abnormalities in the supratentorial grey and white matter compartments from both aetiologies. In contrast, discordant findings were found in the infratentorial compartment, with DTI abnormalities in the brainstem confined to the TBI group. Supratentorial DTI abnormalities correlated with the CRS-R as well as responses to an fMRI paradigm that detected convert cognitive processing. Conclusion: DTI may help to characterise differences in patients in VS. These findings may have implications for response to therapies, and should be taken into account in trials of interventions aimed at arousal in VS.

Mots clés: MRI; NEURORADIOLOGY; PERSISTENT VEGETATIVE STATE

Virginia Fj Newcombe, Guy B Williams, Daniel Scoffings, Justin Cross, T.Adrian Carpenter, et al.. Aetiological differences in neuroanatomy of the vegetative state: insights from diffusion tensor imaging and functional implications. Journal of Neurology, Neurosurgery and Psychiatry, 2010, 81 (5), pp.552. ⟨10.1136/jnnp.2009.196246⟩. ⟨hal-00557428⟩