Stroke - MRI

The primary focus of research at NRC-IBD (West) is the development and application of state-of-the-art magnetic resonance and infrared imaging technologies for the study of neurological disorders such as stroke.

MR Imaging Of Stroke In Neonates - Sensitivity of White Matter

Oxygen deprivation (for example, during birth) can result in strokes in neonates. In a number of studies, NRC-IBD researchers have demonstrated that there are differences between MR images of the brains of oxygen-deprived immature and those of older juvenile rats.

These results demonstrate that the nature and extent of brain injury caused by oxygen deprivation in diseases, such as stroke, differ depending on the maturity of the brain[1].

*Stroke

Rather unique to the oxygen-deprived neonatal brain is the sensitivity of white matter to damage[2] that can cause cerebral palsy.

One goal is to Improve diagnosis using rather novel magnetic resonance imaging techniques and determine how they correlate with tissue death or injury[3].

Selective White Matter Injury (MR Changes-Arrows)

 

Blood Brain Barrier Function (Histology)

Magnetization Transfer Imaging

Functional MR Imaging Following Stroke and other Neurological Disorders

Another research area of interest focuses on understanding functional brain activation in response to forepaw stimulation or direct brain stimulation ([4],[5]). MRI and infrared spectroscopy have been used to show important effects of hypertension or hypotension on blood oxygenation or blood flow in response to electrical stimulation of the forepaw.

These studies are important for understanding the effect that blood pressure changes related to anxiety or pain or effects of epilepsy might have on fMRI studies in human subjects.

Molecular Imaging of Inflammation in Cerebral Ischemia

Researchers from NRC-IBD (West), in collaboration with the University of Calgary, are using novel contrast agents (e.g. GdsLex) targeted to specific receptors involved in the neuroinflammatory process to image this process following stroke in mice. This holds promise for the development of MR contrast agents for molecular imaging of injurious processes and their treatment in patients[6].

Molecular Imaging of Inflammation in Cerebral Ischemia

Treatment of Recurrent Stroke

Recent experiments have developed a novel model of recurrent stroke as is observed frequently in patients. This model mimics a transient ischemic attack or mild stroke followed by a larger stroke (below). We will use this model to test mechanisms of combined injury and beneficial interventions such as administration of resveratrol, the active ingredient in red grapes.

Model of Recurrent Stroke in the Rat: Effect of Resveratrol Treatment

MRI

References:

1. Qiao M, P Latta, T Foniok, R Buist, S Meng, B Tomanek and U I. Tuor. Cerebral Blood Flow Response During Hypoxia-Ischemia and Reperfusion Differs in Neonatal and Juvenile Rats. MAGMA 17:117-124, 2004.
2. Meng S, Qiao M, Scobie K, Tomanek B, Tuor UI. Evolution of magnetic resonance imaging changes associated with cerebral hypoxia-ischemia and a relatively selective white matter injury in neonatal rats. Ped Res. 2006 59:554-9.
3. Tuor, UI. Meng, S. Qiao, M. Webster, N. Crowley, S. Dyck, RH, Tomanek, B. Differential Progression of Magnetization Transfer Imaging Changes Depending on Severity of Cerebral Hypoxic-Ischemic Injury. J. Cereb. Blood Flow Metab. 2008 28:1613-23.
4. Tuor, UI, R Wang, Z Zhao, T Foniok, D Rushforth, JI Wansteeker, M Qiao. Transient Hypertension Concurrent with Forepaw Stimulation Enhances Functional MRI Responsiveness in Infarct and Peri-Infarct Regions. J. Cereb. Blood Flow Metab. 2007 27:1819-29.
5. Dunn, Jeff F., U.I. Tuor, John Kmech, Nicole A. Young, Amy K. Henderson, Jesse C. Jackson, Pamela A. Valentine and G. Campbell Teskey. Functional Brain Mapping at 9.4T Using a New MRI Compatible Electrode Chronically Implanted in Rats. Magn Reson Med. 2009 61:222-8.
6. Barber, P.A., T. Foniok, D. Kirk, A.M. Buchan, S. Laurent, S.Boutry, R.N. Muller, L. Hoyte, B. Tomanek, U.I. Tuor. MR Molecular Imaging of Early Endothelial Activation in Focal Ischemia. Ann Neurol. 56:116-120, 2004.

Related Information

Read more about Stroke - MRI:

• Cardiac MRI
• Functional Magnetic Resonance Imaging (fMRI)
• Grain/teeth MRI
• Magnetic Resonance Technology Development
• Molecular Imaging - MR

Related Programs:

• Medical Photonics
• MR Research and Technology Development
• Neuroscience

Institutes:

• NRC Institute for Biodiagnostics