Quick Project Snapshot
Mapping myeloarchitecture using diffusion MRI
The spatial organization of myelinated fibres in the cortex makes it possible to parcellate areas based on their myeloarchitecture, due to differences in the properties of the fibre layers and radial fibres. Non-invasive mapping of cortical myeloarchitecture has received increasing interest, with MRI methods based on T1-, T2- and T2*-weighting shown to produce detailed maps of human cortical areas based on surrogate measures of myelin content. In particular, many of these studies have shown well-defined areas of high myelination, among others, in the sensory-motor strip in the central sulcus, visual cortex, and auditory areas in the Sylvian fissure, and low myelination in, for example, frontal areas. Recent improvements in MRI hardware, acquisition methods, and higher-order models for the diffusion MRI signal have opened up the possibility of achieving a more robust characterisation of the microstructure properties of cortical grey matter using diffusion MRI, with very promising results. However, this requires further detailed investigation in whole-brain in vivo human data. We have recently demonstrated that high-quality diffusion MRI data and recent advances in diffusion fibre orientation modelling can be exploited to investigate cortical myeloarchitecture in the living human brain (see figure). This study demonstrated that in vivo human diffusion MRI data should provide a useful complementary non-invasive approach to study whole-brain cortical myeloarchitecture based on contrast related to tissue microstructure organisation. Our Lab will continue to develop, optimise, and validate diffusion MRI based methods to characterise myeloarchitecture.
Calamante F, Jeurissen B, Smith RE, Tournier J-D, Connelly A. Human In Vivo Myeloarchitecture Using Whole-Brain Diffusion MRI. In Proc. Annual Meeting of the Intl. Soc. Mag. Reson. Med. (ISMRM) 23 (2015), Toronto, Canada, p. 478.
Population average (n=8 subjects) using diffusion MRI, displayed on inflated surface (A: left, b: right hemispheres). High intensity areas how striking similarity to well-characterised areas of high myelin, including sensory-motor strip ('sm'), visual cortex ('vc'), and auditory areas ('aa'); similarly, low areas to areas of low myelin (e.g. frontal areas).
MRI Blood Flow and Brain Connectivity Laboratory
Recent advances in MRI have revolutionised the way we investigate brain structure, brain function, and brain network connectivity. Our lab's main research interests include the development and application of MRI methods to measure cerebral blood flow (Perfusion MRI), super-resolution MRI methods based on diffusion MRI fibre-tracking (Super-Resolution Track-Weighted Imaging), as well as the role of these methods to study brain structural and functional connectivity.
In particular, we specialise in the development of the two main Perfusion MRI techniques: Dynamic Susceptibility Contrast MRI (DSC-MRI) and Arterial Spin Labelling (ASL). The former is playing a key role in many clinical applications (e.g. stroke, tumours), while the latter provides a powerful quantitative tool to characterise functional connectivity.
Super-Resolution Track-Weighted Imaging provides a means to exploit the information from whole-brain diffusion MRI fibre-tracking to achieve image resolution not previously possible in the human brain in vivo. This method not only can generate images with exquisite image detail, but also provides a unique framework to combine structural and functional connectivity information, and therefore investigate the structural-function relationships in brain networks. Given that the pathophysiological basis of many brain disorders is related to abnormalities in the structural and/or functional connections, this method is expected to have a major role in clinical neuroscience.
All Projects by this LabPerfusion MRI: novel methods to image cerebral blood flow and brain functionSuper-resolution MRI methods for the Human Brain ConnectomeMapping myeloarchitecture using diffusion MRIMRI brain parcellation based on data-driven methodsMapping cerebral haematocrit using MRINovel MRI methods to study dynamic brain connectivity
The Florey is a world-leader in neuroimaging development and applied research. Both the Imaging and Epilepsy divisions specialise in advanced magnetic resonance imaging (MRI) methods development, especially related to diffusion MRI, perfusion MRI, and methods to study brain functional and structural connectivity. Functional MRI (fMRI) and simultaneous fMRI and electroencephalography (fMRI-EEG) methods development and application are also a major priority. Neuroimaging is also a crucial component of several studies undertaken in the Stroke division.