NeuroImaging Laboratory
Welcome to the NeuroImaging Laboratory website. This laboratory was established in 1991 in response to a need for the assessment of brain images. This Laboratory brings together the knowledge/experience of a diverse group of researchers whose work is highly interdisciplinary and rests on both clinical/research psychiatry, neurosciences and the theoretical advances in mathematics/statistics, information theory and engineering.
We study neuroimaging to improve our understanding of the brain in health and disease. Great advances have been made in the acquisition of brain image data, e.g., the development of new and powerful scanners and imaging protocols for both structural and functional brain MRI. Investigations into brain structure and function require a diverse of tools to analyze and visualize the images thus acquired. Researchers at the Laboratory are developing new algorithms and methods as well as using existing software packages in their research. The Laboratory houses over 10 workstations (both Windows and Linux) and two data archival systems of about 8 terabytes. The MR images we study include 3D T1-weighted scans, T2-weighted (such as FLAIR sequence) scans, DTI (diffusion tensor imaging), 1H MRS (magnetic resonance spectroscopy), functional MRI (fMRI), Gd-perfusion MRI (pMRI), and will extend to ASL (arterial-spin labeling) etc. Our Laboratory used both PET and SPECT scans in the past and is able to carry out studies using these imaging modalities.
Our Laboratory collaborates with University of within Australia and three universities overseas, i.e. Johns Hopkins University, Baltimore, USA; Washington University in St. Louis, USA and Simon Fraser University, Vancouver, Canada in some of the algorithm development and data analysis.
Research opportunities
We welcome both postgraduate and undergraduate (honors program) to carry out research projects and work using our Neuroimaging Laboratory data (imaging and others) and facilities.
Interested potential postgraduate research students who are Australian residents can apply for the Australian Postgraduate Awards (APA). APA applications normally close on October 31 each year. Research students from countries outside Australia and New Zealand may be eligible to apply for an International Postgraduate Research Scholarship (IPRS). Applications normally close on September 30 each year.
We also provide competitive Ph.D. scholarships from our ARC and/or NHMRC projects to qualified candidates. While doing research project with our Laboratory, students have the opportunity of working on paid basis (casual or part-time) within the Lab.
Research projects available
Postgraduate projects: Two Ph.D. Scholarships Available - Click here for information.
Undergraduate projects: (Faculty of Medicine Honours Program)
Brain White Matter Fiber Track Investigation of Older Twins using DTI (Diffusion Tensor Imaging)
Twin neuroimaging studies present a remarkable opportunity to map the genetic influences on brain structure and function.
The Older Australian Twins Study (OATS) is a large multi-centre study aiming to discover how our environment and our genes influence our memory and thinking and in the influence on the brain structure as we grow older. We hope that the results from this study may help in identifying approaches that could slow the ageing process and prevent age-related diseases such as Alzheimer’s disease.
We are studying identical and non-identical twins and their siblings over the age of 65 years. We collect information about our participant’s lifetime physical and mental activity, diet, education, physical and psychological health as well as brain scans. Our aim is to have 1000 participants from New South Wales, Queensland and Victoria by May 2008, and to follow each participant for an initial period of 4 years. We have already collected over 80 brain scans in Sydney alone and we are starting to image the participants in Melbourne and Brisbane.
DTI is a quantitative MRI technique which measures the movement of water within the tissue microstructure. In an unconstrained environment, water molecules move about freely in random Brownian motion. This form of motion is termed isotropic. However, in the brain, the cell membrane, myelin sheath, microtubules and neurofilaments act as a barrier to free diffusion. This results in a restricted form of diffusion along the longitudinal axis of the axon fibres. This directionally dependent movement is termed anisotropic. Measurement of anisotropic water diffusion would allow us to map white matter fibre systems and provide a measurement of its microstructural integrity.
Research students taking up this project will be processing DTI data using some public domain DTI processing/analysis packages to generate ADC, FA maps etc and then analyzing these maps using either a region-of-interest (ROI) method or automated or semi-automated method. Statistical data analysis after having obtained the tissue diffusion measures is naturally part of the project.
Figure 1. White matter fibre tracts are indicated using colour-coded Fractional Anisotropy (FA) map of a brain of a twin subject on a Philips 1.5T MR system at St George Hospital, Sydney. The colour map is based on the principal diffusion directions: green represents anterior-posterior, blue for feet-head and red for left-right orientation.
Brain Metabolism: a Single Voxel MRS (Magnetic Resonance Spectroscopy) Study of Older Twins
Twin neuroimaging studies present a remarkable opportunity to map the genetic influences on brain structure and function.
The Older Australian Twins Study (OATS) is a large multi-centre study aiming to discover how our environment and our genes influence our memory and thinking and in the influence on the brain structure as we grow older. We hope that the results from this study may help in identifying approaches that could slow the ageing process and prevent age-related diseases such as Alzheimer’s disease.
We are studying identical and non-identical twins and their siblings over the age of 65 years. We collect information about our participant’s lifetime physical and mental activity, diet, education, physical and psychological health as well as brain scans. Our aim is to have 1000 participants from New South Wales, Queensland and Victoria by May 2008, and to follow each participant for an initial period of 4 years. We have already collected over 80 brain scans in Sydney alone and we are starting to image the participants in Melbourne and Brisbane.
MRS provides a useful method for studying metabolites in human brain. Efforts are also being made to link MRS measures of cerebral metabolism with neurophysiologic and neurocognitive process.
Research students taking part in with this project will be using a popular MRS package
MRUI to process raw spectroscopic data from the Sydney scanner. Statistical data analyses will be focusing on the MRS correlates of the OATS participants with consideration of brain structural correlates as well.
Figure 2. in vivo proton MRS brain (posterior cingulate) examination of one of our participants from Sydney: the location of the voxel (volume) is shown as the red box in the structural scan above the spectra. A typical in vivo proton MRS shows localization of 4 major peaks for NAA (2.02 ppm), Cr (3 ppm), Cho (3.2 ppm) and mI (4.05 ppm).
Cerebral Microbleeds (CMB): a Prevalence and Topographic Investigation in Cognitively Normal and MCI (Mild Cognitive Impairment) Subjects
The brain scans are drawn from
Memory and Ageing Study. The Memory and Ageing Study is a large, population-based study looking at people aged 70 – 90 in the Eastern Suburbs of Sydney (chosen because of proximity to the University). We collect information on people both with and without memory problems, and then follow them over time. We are hoping we may be able to identify some risk, or even protective factors against developing dementia. We are collecting information on our participants’ lifestyle, diet, education, physical and psychological health, as well as doing blood tests and brain scans. We have now finished recruitment of just over 1000 participants, and have commenced the 2 year follow up of people we first saw in 2005.
To assess the potential role of cerebral microbleeds as one of the indicators of cerebral small-vessel disease, we are acquiring so-called susceptibility weighted imaging (SWI) brain scans of the participants of this study. CMB identification criteria from our literature review comprise a rounded area of marked and homogenous signal loss (see Figure 3), not located in sulcal areas to avoid confusion with cerebral vessels.
Research students taking part in this project will be visually inspecting and rating the CMBs from participants’ 3D SWI scans. The volumes of CMBs will be calculated and the anatomical locations of them will be marked. We will also create a 3D probability map of the CMB occurrences in various locations of the brain. The relationship between CMB measures and risk factors, e.g. intracerebral hemorrhage etc and neuroncognitive scores will also be explored.
Figure 3. Susceptibility weighted imaging (SWI) showing a possible cerebral microbleeds (CMB) spot. This is a slice from the 3D SWI scan of one of our Memory & Ageing Study subject.
Are there Differences in Shape and Size of the Brain Subcortical Structures (e.g. Hippocampus, Amygdala, Basal Ganglia etc.) between Cognitively Normal and MCI (Mild Cognitive Impairment) Subjects? An Anatomical Investigation of the Subcortical Structures
The brain scans are drawn from
Memory and Ageing Study. The Memory and Ageing Study is a large, population-based study looking at people aged 70 – 90 in the Eastern Suburbs of Sydney (chosen because of proximity to the University). We collect information on people both with and without memory problems, and then follow them over time. We are hoping we may be able to identify some risk, or even protective factors against developing dementia. We are collecting information on our participants’ lifestyle, diet, education, physical and psychological health, as well as doing blood tests and brain scans. We have now finished recruitment of just over 1000 participants, and have commenced the 2 year follow up of people we first saw in 2005.
Neuroanatomical structures may be profoundly or subtly affected by the interplay of genetic and environmental factors, age, and disease. The ability to use imaging to identify structural brain changes associated with different neurodegenerative disease states will be useful for diagnosis and treatment. Our group and collaborators have developed some computerised methods that can capture morphological variability of the human brain. These methods use mathematical models sensitive to the changes in the size and shape of brain structures affected by neurodegenerative diseases. Neuroanatomical features can be compared within and between groups of individuals, taking into account age, sex, genetic background, and disease state, to assess the structural basis of normality and disease. In this project, we will collaborate with our overseas partners to investigate the possible differences in the size and shapes of subcortical structures including hippocampus, amygdale and basal ganglia.
Volume loss has been detected in the head of the hippocampus and along the lateral edge of the hippocampal body in patients with very mild Alzheimer’s disease, but in non-demented elderly controls a general flattening of the structure without volume loss was detected. Therefore, the known biological and pathological differences between ageing and Alzheimer’s disease can be appreciated at the macroscopic structural level. The basal ganglia and thalamus may play a critical role for behavioral inhibition mediated by prefrontal, parietal, temporal, and cingulate cortices. The cortico-basal ganglia-thalamo-cortical loop with projections from frontal cortex to striatum, then to globus pallidus or to substantia nigra pars reticulata, to thalamus and back to cortex, provides the anatomical substrate for this function.
Research students taking part in this project will be using some neuroimaging software package to landmark subcortical structures (typically around 20 points for each structure). Data analyses will then follow.
Figure 4. Landmarked hippocampus (both left- and right-hand sides) were landmarked and their surfaces were then extracted. This image is from a study of younger population. Notice the red and blue contours in the coronal cut of the MRI scan: they are the surfaces generated from the landmarks.
Losing Grey Matter? An Anatomical Investigation of Cortical Thinning in MCI Subjects in Comparison with Age-Matched Normals
The brain scans are drawn from
Memory and Ageing Study. The Memory and Ageing Study is a large, population-based study looking at people aged 70 – 90 in the Eastern Suburbs of Sydney (chosen because of proximity to the University). We collect information on people both with and without memory problems, and then follow them over time. We are hoping we may be able to identify some risk, or even protective factors against developing dementia. We are collecting information on our participants’ lifestyle, diet, education, physical and psychological health, as well as doing blood tests and brain scans. We have now finished recruitment of just over 1000 participants, and have commenced the 2 year follow up of people we first saw in 2005.
Neuroanatomical structures may be profoundly or subtly affected by the interplay of genetic and environmental factors, age, and disease. The ability to use imaging to identify structural brain changes associated with different neurodegenerative disease states will be useful for diagnosis and treatment. Our group and collaborators have developed some computerised methods that can capture morphological variability of the human brain. These methods use mathematical models sensitive to the changes in the size and shape of brain structures affected by neurodegenerative diseases. Neuroanatomical features can be compared within and between groups of individuals, taking into account age, sex, genetic background, and disease state, to assess the structural basis of normality and disease. In this project, we will collaborate with our overseas partners to investigate the cortical thickness of the brain.
Our hypothesis includes: for each structure, the change in cortical mantle thickness in MCI and dementia over time is distinct from that in normal aging and can discriminate between these groups. For instance, in dementia, these time-dependent atrophy measures in the sub-regions of the thalamus and hippocampus known to connect to prefrontal and temporal cortices are more likely to show inward deformation than sub-regions connected to other cortices.
Research students taking part in this project will be using some neuroimaging software packages to extract some region-of-interest (ROI), and then segment these ROIs into gray matter, white matter and CSF (cerebrospinal fluid) and then estimate the cortical thickness of the structures as outlined in these ROIs. Statistical data analyses will be carried afterwards. We may also look into other using different computerized methods to examine cortical thickness.
Figure 5. Gray matter volume reduction can be detected using various computerized methods. This figure shows the gray matter volume reduction in relation (controlled for both total gray matter volume and age) to the whole brain white matter hyperintensity (WMH) volume using a method called VBM. The colors show the T values.
Staff:
Dr. Chen, Xiaohua
Dr. Elias, Alby
Mr. Liu, Tao
Dr. Wen, Wei (Laboratory Director)
Dr. Zhu, Wanlin
Mr. Zhuang, Lin (Johnny)
Ms. Zhang, Haobo
Visiting Fellows and Research Collaborators:
Dr Beg, Mirza Faisal (Simon Fraser University, Vancouver, Canada)
A/Prof. Pham, (ADFA @ UNSW) Tuan
Dr Ratnanather, John Tilak (Johns Hopkins University, Baltimore, USA)
Dr Wang, Lei (Washington University in St. Louis, USA)
A/Prof Xia, Aihua (Melbourne University, Australia)