Frontline medical workers put themselves at risk during a pandemic to deliver critical health care and save lives. Personal protective equipment (PPE) such as gloves, gowns, and face shields can reduce the risk of infection. To prevent contamination through airborne droplets, healthcare workers can employ an air-purifying respirator to push filtered air into their face shield or hood.Read More
Only two in ten people diagnosed with brain cancer will survive for at least five years, a figure that has barely improved in the last 30 years. Due to the blood-brain barrier and the risk of damaging normal brain tissue, brain cancer treatments are complex and multidisciplinary. Despite advances in surgical techniques, radiotherapy and chemotherapeutics, brain tumours remain challenging to treat. Hence, image-guided microbeam radiation therapy (MRT) with nanoparticle enhancement is being investigated for the treatment of brain cancer in animal models.Read More
Until recently, reptilian evolutionary studies lacked an important resource – a lizard brain atlas. As the subject of numerous ecological and behavioural studies, the Australian tawny dragon (Agamidae: Ctenophorus decresii) was an ideal candidate for creating a high-resolution MRI atlas of a representative scaled reptile (squamata). Such data is not only a resource for studies of the genus but also informs environmental decision making through an improved understanding of animal adaptation and evolution.Read More
Proper vascular development of the human placenta is crucial for meeting the metabolic needs of the developing fetus during pregnancy. Maternal environmental stressors such as malnutrition disrupt the elaboration of the feto-placental vasculature that, in turn, impacts on placental function and results in reduced fetal growth. The ramifications of this are not only on short-term foetal health but also on long-term health outcomes. Indeed, distortion in placental shape and size strongly associate with later adult health outcomes such as cardiovascular disease, obesity and cancer.Read More
Re-regeneration to reduce adverse effects associated with tail loss
Caudal autotomy, the ability to drop and regenerate a portion of the tail, is a widely used anti-predation strategy in many lizard species. Intra-vertebral autotomy planes within a series of the lizard’s caudal vertebrae allow individuals to autotomise a portion of their tail to escape a threat, such as a predator’s grasp. Once autotomised, the tail regenerates with a rigid cartilage rod in place of the original bony vertebrae. Although an effective anti-predation strategy, it has both short and long-term costs to the individual associated with physical tail loss, as well as the energy required for regeneration. Additionally, a regenerated tail lacks autotomy planes, where subsequent autotomy events having to at a more proximal position at a caudal vertebra with an intact autotomy plane.Read More
Cardiovascular disease (CVD) is responsible for more than a quarter of all deaths in Australia and remains the global leading cause of death accounting for 17.9 million deaths per year. Of all CVDs, stroke and coronary artery disease account for the majority of deaths. A common underlying cause in these conditions in atherosclerosis, characterised by the build-up of abnormal deposits inside the arteries. Atherosclerotic plaques can rupture and cause thrombosis, or blood clots, resulting in stroke and myocardial infarction. Diagnostic strategies for the detection of thrombi are currently invasive and may not be sensitive to early biomarkers such as localised coagulation and inflammation.
A/Prof Ta, of Griffith University, has teamed up with researchers across Australia and internationally to develop a new form of MRI contrast agent. These ultra-small dual positive and negative contrast iron oxide nanoparticles (DCIONs) provide both T1-positive and T2-negative contrast effects, overcoming the limitations of single modality contrast agents. This duality is particularly important for imaging intravascular thromboses, as current single-contrast nanoparticles results in a black dye against a black artery. Further, the DCIONs are monodisperse, water-soluble, and biocompatible, of critical importance to biomedical applications.
Using non-invasive MRI at the NIF QLD Node, the application of a DCION conjugated to an enzyme found in activated platelets demonstrated accurate and sensitive detection of intravascular thrombosis. Work is continuing to further optimise the early detection of thrombi, expected to allow for earlier and more effective preventative treatments and improved clinical outcomes for patients at risk of stroke and myocardial infarction.
A/Prof Ta is enthusiastic about the future applications of DCIONs beyond thrombosis diagnoses, stating that “these nanoparticles have the potential to replace traditional gadolinium-based contrast agents due to their stronger T1 contrast effect. Existing alternatives cannot do what these nanoparticles can.”
If you have any concerns about heart disease or atherosclerosis, please talk to your GP and check this website.
Minimally invasive endovascular stent-electrode array for high-fidelity, chronic recordings of cortical neural activity
This news has been contributed by Assoc. Prof. Bradford Moffat of the Melbourne Brain Centre Imaging Unit, Department of Radiology and Medicine, The University of Melbourne, Parkville.
National Imaging Facility Fellow, Assoc. Prof. Bradford Moffat collaborated with Dr. Tom Oxley’s group at the University of Melbourne for this high profile publication that appeared in the journal “Nature Biotechnology”.
High-fidelity intracranial electrode arrays for recording and stimulating brain activity have facilitated major advances in the treatment of neurological conditions over the past decade. Traditional arrays require direct implantation into the brain via open craniotomy, which can lead to inflammatory tissue responses, necessitating the development of minimally invasive approaches that avoid brain trauma. Here we demonstrate the feasibility of chronically recording brain activity from within a vein using a passive stent-electrode recording array (stentrode). We achieved implantation into a superficial cortical vein overlying the motor cortex via catheter angiography and demonstrate neural recordings in freely moving sheep for up to 190 d. Spectral content and bandwidth of vascular electrocorticography were comparable to those of recordings from epidural surface arrays. Venous internal lumen patency was maintained for the duration of implantation. Stentrodes may have wide-ranging applications as a neural interface for treatment of a range of neurological conditions. The following figures are representative images that appear in the article and were generated from data acquired on the 7T MRI scanner at the University of Melbourne node of NIF.
This technology has been licensed by Synchron and is in currently undergoing a first in man clinical trial (https://www.synchronmed.com/stentrode/). For further information, the interested reader is pointed to our full publication which can be accessed at (http://dx.doi.org/10.1038/nbt.3428).
- Oxley, T.J., N.L. Opie, S.E. John, G.S. Rind, S.M. Ronayne, T.L. Wheeler, J.W. Judy, A.J. McDonald, A. Dornom, T.J.H. Lovell, C. Steward, D.J. Garrett, B.A. Moffat, E.H. Lui, N. Yassi, B.C.V. Campbell, Y.T. Wong, K.E. Fox, E.S. Nurse, I.E. Bennett, S.H. Bauquier, K.A. Liyanage, N.R. van der Nagel, P. Perucca, A. Ahnood, K.P. Gill, B. Yan, L. Churilov, C.R. French, P.M. Desmond, M.K. Horne, L. Kiers, S. Prawer, S.M. Davis, A.N. Burkitt, P.J. Mitchell, D.B. Grayden, C.N. May, and T.J. O’Brien. ‘Minimally invasive endovascular stent-electrode array for high-fidelity, chronic recordings of cortical neural activity’, Nat Biotech, 2016.
MRtrix3: Advanced tools for the analysis of diffusion MRI data
Diffusion-weighted MRI (dMRI) is a commonly-used medical imaging modality for the investigation of tissue microstructure, exploiting the local hindrance and restriction of water diffusion as indirect probes. The neuroimaging research community utilises this technology extensively for the study of brain white matter in particular, reconstructing structural connectivity pathways and analysing estimated tissue properties. To do so requires extensive complex computations, including image pre-processing, biophysical modelling, digital reconstruction of neuronal fibre trajectories, and tailored statistical analysis and visualisation tools. The quality and capabilities of neuroscience research utilising this technology – as well as other applications such as neurosurgical planning – rely on all utilised aspects of this pipeline being robust yet powerful.
The recently released MRtrix 3.0.0 is a free, open-source software package that incorporates various state-of-the-art technologies in the field of dMRI, combining high computational performance with a consistent, user-friendly interface. It is built principally around the “spherical deconvolution” model, which is regularly utilised in the field as the reference model for optimal resolution of the various complex fibre configurations found throughout the brain white matter. Additional tools are provided for both quantitative estimations of structural connectivity between brain grey matter regions, and data-driven hypothesis testing of quantitative white matter imaging metrics, in the presence of such tissue complexity.
An international collaboration of researchers has recently published the implementation of MRtrix3 in the peer-reviewed journal, NeuroImage. Lead author Dr J-Donald Tournier and colleagues provide “a high-level overview of the features of the MRtrix3 framework and general-purpose image processing applications provided with the software”, highlighting the guiding principles of development including reproducible neuroscience and consistent documentation. This manuscript also details the underlying software framework and Application Programming Interface (API) of the MRtrix3 software to encourage utilisation of its library features by other neuroscience methods developers.
NIF Facility Fellow Dr Robert Smith, of the Florey Node, is one of two principal developers of this software package, with over 3,200 code commits and 220,000 lines of code contributed. His involvement with the software project began not long after the commencement of his PhD candidature in 2009, for which Dr Tournier was a supervisor. The two key technical developments resulting from his PhD – the “Anatomically-Constrained Tractography (ACT)” and “Spherical-deconvolution Informed Filtering of Tractograms (SIFT)” methods (each of which has over 250 citations on Google Scholar) were developed & distributed with the MRtrix3 package, improving the biological accuracy and quantitative properties of white matter connectivity experiments throughout the worldwide neuroscience community.
The MRtrix3 community forum, where users of the software interact directly with developers and one another, currently has over 900 active users and over 1.5 million page views. The manuscript describing the previous version of this software (“MRtrix 0.2”), published in 2012, now has over 500 citations; while the MRtrix3 manuscript was published too recently to accumulate a large citation count, its long-term influence would be reasonably expected to exceed this. Google Scholar searches yield over 1500 hits for “mrtrix diffusion mri”, and over 450 hits for “mrtrix surgery”. Some of the capabilities included in MRtrix3 are incorporated in Siemens’ Track Density Imaging and tractography prototype, currently available for early testing at participating Siemens MRI research sites. The software is also utilised by many companies that specialise in providing third-party services for image processing and analysis. The development team additionally runs software workshops to teach usage of the software to the research community.
The tools provided within this software package can improve the accuracy and utility of diffusion MRI analysis in many contexts, both neuroscientific and clinical. This will, over time, include characterisation of various brain disorders, tracking the efficacy of potential treatments of such, neurosurgical planning, and diagnosis.
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