Steal physiology is spatially associated with cortical thinning
- Jorn Fierstra1,2,
- Julien Poublanc1,
- Jay Shou Han1,
- Frank Silver3,
- Michael Tymianski2,
- Adrian Phillip Crawley1,
- Joseph Arnold Fisher4,
- David John Mikulis1
- 1Department of Medical Imaging, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada
- 2Department of Neurosurgery, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada
- 3Department of Neurology, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada
- 4Department of Anesthesia and Pain Management, University Health Network, Toronto General Hospital, Toronto, Ontario, Canada
- Correspondence to Dr D J Mikulis, Medical Imaging, University Health Network, Toronto Western Hospital, Department of Medical Imaging, McLaughlin Pavilion, 3rd Floor Room 431, 399 Bathurst St, Toronto, M5T 2S8 ON, Canada;
- Received 6 July 2009
- Revised 23 November 2009
- Accepted 24 November 2009
Background The physiological impact of severely impaired cerebral autoregulatory vascular reactivity on cortical integrity is unknown. The purpose of this study is to determine the relationship between severe impairment of autoregulatory flow control associated with steal phenomenon and its impact on cortical thickness.
Methods 250 blood oxygen level dependent (BOLD) MRI cerebrovascular reactivity (CVR) studies were reviewed in order to identify subjects with severe unilateral exhausted cerebrovascular reserve demonstrating steal physiology but with normal appearing cortex on fluid attenuated inversion recovery imaging. 17 patients meeting the inclusion criteria were identified. A reconstructed inflated cortical surface map was created for every subject using Freesurfer software (http://surfer.nmr.mgh.harvard.edu/). The region of interest (ROI) reflecting the steal physiology was determined by overlaying the subject's CVR map on to the cortical surface map. This ROI was compared with the corresponding area in the healthy hemisphere which provided control cortical thickness measurement in each subject.
Results The hemisphere with steal physiology showed an 8% thinner cortex (2.23±0.28 mm) than the corresponding healthy hemisphere (2.42±0.23 mm) (p=0.0005).
Conclusions Our findings indicate that a spatial correspondence exists between impairment of autoregulatory capacity with steal physiology and cortical thinning.
Linked articles 201459.
Funding JP and DJM are supported by the Ontario Research Fund Brain Consortium Grant (RE02-002).
Competing interests JAF and DJM contributed to the development of the Respiract. These authors stand to gain financially if the device is successfully commercialised by Thornhill Research Inc, a University of Toronto/University Health Network related company.
Ethics approval This study was conducted with the approval of the UHN Research Ethics Board Office, Toronto, Ontario.
Provenance and peer review Not commissioned; externally peer reviewed.