Investigations of brain injury by magnetic resonance imaging (MRI) and spectroscopy (MRS)
Prof Andrew M. Blamire
Magnetic resonance imaging (MRI) can detect structural abnormalities in the brain resulting from disease, injury or ageing. Changes observed on clinical MR scans often reflect the final stage of these processes, at a time when irreversible loss of brain tissue has occurred.
MRI shows the distribution of water within the tissue by detecting the magnetic resonance signal from the nucleus of the the hydrogen atoms in each water molecule (the H's in H2O). The technique of proton magnetic resonance spectroscopy (MRS) is similar to MRI but aims to detect signals from hydrogen atoms attached to other important metabolites within brain. Changes in the levels of these metabolites are expected to occur much earlier in the disease process and so may allow us to detect acute damage at a time when we can intervene and salvage brain tissue.
Unlike MRI, the technique of MRS does not generally produce images, instead creating spectra (see figure). Each peak in the spectrum arises from different brain metabolite (NAA, N-acetylaspartate; Cre, Creatine; Cho, Choline; myoI, myo-Inositol; Lac, lactate; Glx, Glutamate and Glutamine; GABA, gamma amino butyric acid). The height of each peak is an indication of metabolite concentrations. The NAA peak arises from the neurons in the brain. Loss of this metabolite indicates damage or loss of neurons.
Staff profile Prof Andrew M. Blamire
Brain Injury Publications from the MR Centre
- Blamire AM. Studying Stroke and Cerebral Ischemia by 1H MRS. eMagRes, 2015, Vol 4: 489–496. DOI 10.1002/9780470034590.emrstm1464.
- Moore SA, Hallsworth K, Jakovljevic DG, Blamire AM, He J, Ford GA, Rochester L, Trenell MI. Effects of Community Exercise Therapy on Metabolic, Brain, Physical, and Cognitive Function Following Stroke: A Randomized Controlled Pilot Trial. Neurorehabil Neural Repair. 2014 Dec 23. pii: 1545968314562116. [Epub ahead of print]. PMID: 25538152.
- Aribisala BS, Cowie CJ, He J, Wood J, Mendelow DA, Mitchell P, Blamire AM. A histogram-based similarity measure for quantitative magnetic resonance imaging: application in acute mild traumatic brain injury. J Comput Assist Tomogr. 2014 Nov-Dec;38(6):915-23. doi: 10.1097/RCT.0000000000000143. PMID: 25162292.
- Croall ID, Cowie C, He J, Peel A, Wood J, Aribisala BS, Mitchell P, Mendelow AD, Smith F, Millar D, Kelly T, Blamire AM. White Matter Correlates of Cognitive Dysfunction following Mild Traumatic Brain Injury. Neurology, in press (2014).
- Blamire AM. Seeing into the traumatically injured brain: Diffuse tissue damage and cognition. Neurology 2012 Mar 20;78(12):844-5. (*Invited review). Epub 2012 Feb 15. PMID:22345220
- Aribisala BA, Cowie CJA, He J, Wood J, Mendelow AD, Mitchell P, et al. Multi-parametric Classification of Traumatic Brain Injury Patients Using Automatic Analysis of Quantitative MRI Scans. Lecture Notes in Computer Science. 2010;6326:51-9.
- Blamire AM, Cader S, Lee M, Palace J, Matthews PM. Axonal damage in the spinal cord of multiple sclerosis patients detected by magnetic resonance spectroscopy. Magnetic Resonance in Medicine 2007; 58:880-5.