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About the FMRIB Physics Group
Some of the research activity of the group
The FMRIB Physics Group works on the fundamentals of MR imaging.
| Quantitative Physiological Neuroimaging FMRI generally provides qualitative information about brain function, which puts constraints on its potential applications both in research and in the clinic. A major theme of the group’s work is the development of more quantitative imaging methods. Using graded functional stimuli and respiratory gas challenges, together with quantitative perfusion imaging, the group has developed improved methods for measuring oxygen metabolism. We are also investigating the interaction between various baseline physiological parameters such as resting blood flow and hematocrit on fMRI measurements. |
| Advanced Pulse Sequence Development We are developing novel methods for MR image acquisition, specifically to improve image quality in functional and diffusion MRI. Conventional methods for acquiring FMRI and diffusion images suffer from intense image distortion and regions with severe signal loss, and limit image resolution to 2-3 mm. We have developed a number of strategies for reducing these image artefacts and increasing spatial resolution, with particular focus in recent years on the use of steady-state free precession (SSFP) sequences. (more...) |
| High Resolution Imaging Traditional functional MRI studies have been of relatively low spatial resolution, typically ~3mm. However many structures, particularly in the deep grey matter and brain stem, are considerably smaller than this, and require higher spatial resolution to gain new insights. We are therefore attempting to develop high-resolution functional imaging techniques in the brain, so that small structures can be detected reliably. The group was also among the first to produce structural images of the myelination patterns of the visual cortex and verify their link to function. |
| Stroke Imaging Stroke Research is a growing interdisciplinary strength at Oxford and research in this area is set to expand when the Acute Vascular Imaging Centre (OxAVIC) is completed next year. The physics group is collaborating with clinical colleagues to initiate a stroke imaging research programme that will address the wide spectrum of cerebrovascular disease: transient ischaemic attack, chronic and acute stroke patients. We are focusing on the use of fast 3D imaging of the cerebral vessels and the measurement of regional perfusion. Initial results are promising and suggest that advanced MRI techniques can be used to improve clinical decision-making, bolstering our efforts in translational medicine. |
| Technology
A final thread of research in the group is in the area of technological development for high field MRI (3 Tesla and greater). Scanning at high field offers significant benefits to detect brain activations, but also comes with challenges such as increases in image distortion. Research in this area includes optimising the technology used to correct for inhomogeneities in the magnetic field in the scanner, using novel 'passive' shimming approaches and dynamic variation of the shim coil currents in real time, and developing pulse sequences that are less sensitive to these inhomogeneities. |