Unusual Brainstem Twisting Revealed by MRI Tractography in a Patient Who Survived a Severe Traumatic Upper Spinal Dislocation

June 2013

Calixto Machado
Jesús Pérez Néllar
Rafael Rodriguez-Rojas
Mauricio Chinchilla
Philip A. DeFina
…and others.

ABSTRACT: We report unusual twisting of the brainstem in MRI tractography in a patient who survived a traumatic brain injury with upper spinal dislocation. A 39-year-old male patient involved in a high-speed car accident was admitted in coma on February 2003. He had a Glasgow Coma Scale of 4, respiratory arrhythmia and tetraplegia. Four weeks later he was diagnosed as being in a persistent vegetative state (PVS). Our group evaluated him for first time in 2010. The patient was then in a minimally conscious state (MCS), with a limited but clear evidence of awareness of the environment, based on a reproducible gestural response following simple commands and visual pursuit of relatives and other persons in his room. He maintained a severe tetraplegia, hyperreflexia, and bilateral Babinski sign. Neuroimaging studies (Figure 1) performed according to our protocol for the assessment of PVS/MCS,1,2 demonstrated a severe atrophic and twisted brainstem. There was an MRI-T2 hyperintensity in the lower part of the medulla oblongata that suggested the presence of an old infarct, probably due to an ischemic and/or hemorrhagic insult because of the compression of the brainstem. MRI-Tractography revealed brainstem long tracts twisting. In order to have a better visualization of bone abnormalities, CT with 3D reconstruction was performed demonstrating a rotatory deformity of the upper spine. In our patient hypoxic encephalopathy secondary to acute respiratory insufficiency was surely the cause of his chronic consciousness disorder.1,2 Probably his critical condition, and the needs of life support protocols upon arrival to the intensive care, hampered the with upper spinal dislocation diagnosis,3-5 leading to a lack of radiological evidence, or due to the presence of additional injuries where a clinical examination is impossible. The demonstration of brainstem twisting instead of section in MRI-Tractography has is an unusual neuroimaging finding, and scientifically highlights the neuroimaging findings in this patient who survived severe upper spinal dislocation.

Click here for a link to the PDF. 

###

Zolpidem induces paradoxical metabolic and vascular changes in a patient with PVS

August 2013

Rafael Rodriguez-Rojas
Calixto Machado
Lazaro M Alvarez
Philip A Defina
…and others.

ABSTRACT: Introduction: Zolpidem is a non-benzodiazepine drug used for the therapy of insomnia, which has selectivity for stimulating the effect of GABA-A receptors. Recently, a paradoxical arousing effect of zolpidem in patients with severe brain damage has been repeatedly reported. Methods: A placebo-controlled magnetic resonance study was conducted to evaluate its effect on BOLD and metabolites spectral signals in a patient with severe brain injuries and an age-matched healthy volunteer. A multi-modal analysis was used to assess aspects in the pharmacologically-induced changes in the resting-state brain metabolism. Results: A significantly increased BOLD signal was transiently localized in the left frontal cortices, bilateral anterior cingulated areas, left thalamus and right head of the caudate nucleus. The healthy subject showed a deactivation of the frontal, parietal and temporal cortices. BOLD signal changes were found to significantly correlate with concentrations of extravascular metabolites in the left frontal cortex. It is discussed that, when zolpidem attaches to modified GABA receptors of neurodormant brain cells, brain activation is induced. This might explain the significant correlations of BOLD signal changes and proton-MRS metabolites in this patient after zolpidem. Conclusion: It was concluded that proton-MRS and BOLD signal assessment could be used to study zolpidem-induced metabolic modulation in a resting state.

Click here for a link to the PDF. 

###