The Canterbury Medical Research Foundation (CMRF) has worked with Christchurch Radiology Group (CRG) to enable researchers to have access to a state-of-the-art General Electric (GE) 3 Tesla HDx MRI scanner. The scanner is the first of its kind in New Zealand, and is sited in the same building as the Van der Veer Institute.

The Van der Veer Institute invites expressions of interest from researchers (both from Canterbury and beyond) who would like to use this unique facility. Our goal is to promote groundbreaking research to further establish the Van der Veer Institute as a centre of excellence in neurological imaging research.

Researchers from the Van der Veer Institute work closely with neurologists, radiologists and basic scientists in this extremely cross-disciplinary area. We also have a research agreement to work with General Electric (GE) Medical Systems to further develop MRI technology for clinical and research applications worldwide.

The increased magnetic field of this 3T scanner over the current generation of 1.5T scanners gives stronger signals, enabling scans to be performed faster, at higher resolution, and with better contrast.

One application that benefits especially from the use of higher magnetic field strengths is functional MRI. Functional MRI represents a significant change from conventional structural imaging in that it provides information about dynamic changes in the brain as a result of mental processes. This allows us to localise the parts of the brain involved in a particular task, and to better understand the workings of the brain and the effects of disease or injury. Functional MRI benefits twice from the use of higher magnetic fields; both the MRI signal itself and the amount of contrast are increased.

We also have particular interest and expertise in diffusion tensor MRI, a new application of MRI which is extremely sensitive to microstructural changes in the brain, and is also the only non-invasive technique that allows us to map out connections (white matter tracts) in the living brain.

The MRI facility is well equipped for imaging all parts of the body, but our specific research focus at the Van der Veer Institute is on brain imaging. We are fortunate to have access to research equipment that is unique in Australasia, and the combination of which may even be unique world-wide. This includes:

• Eye tracking. The Van der Veer has been at the forefront of developing the use of simple eye movement tests to better quantify the effects of brain injury or disease. This has particular applications to movement disorders such as Parkinson's disease, and may allow improved diagnosis, studies of disease progression and monitoring of the effects of treatment. We believe that the ability to perform eye-tracking in combination with functional MRI will provide new information of fundamental importance to the study of movement disorders. This research is being led by Michael MacAskill.
• EEG. The Van der Veer Institute has recently installed a MagLink MRI-compatible EEG system. This is a challenging but extremely powerful combination of imaging technology which overcomes many of the limitations of the two techniques individually. While functional MRI provides excellent spatial resolution, its contrast is based on blood flow responses that occur relative slowly (over several seconds). EEG provides extremely high temporal (time) resolution, but with poor spatial resolution. Richard Jones leads this research area.
• Binocular visual presentation. The ability to present different images to the two eyes within the MRI scanner enables many interesting research studies, including three-dimensional perception and virtual reality. We are actively researching binocular rivalry, in which contradictory images are presented to the eyes and our perception switches from one image to the other. There is some preliminary evidence that patients with bipolar disorder may show subtle differences in their responses.

• Child development - Lianne Woodward
• Parkinson's disease and movement disorders - Tim Anderson, John Dalrymple-Alford, Michael Macaskill
• Memory and dementia - John Dalrymple-Alford, Tim Anderson
• Sleep lapses - Richard Jones
• Head injuries - Marcus Heitger, Richard Jones, Tim Anderson
• Swallowing and stroke rehabilitation - Maggie-Lee Huckabee, John Fink

Scanner and Installation

Installation of the first 3T MRI scanner in New Zealand (August 2006)		3T MRI Facility

Structural MRI Examples

Note that the 3T MRI scanner is capable of imaging all parts of the body; only images relating to the brain are shown here.

3D T1-weighted images with an isotropic 1mm voxel size. This is often used as a background to lower resolution functional MRI data, and allows excellent reformatting along different planes to better show structures of interest. See Movie	Volume rendered example derived from the 3D T1-weighted images above. See Movie or QuickTime VR.
T2-weighted PROPELLER acquisition. This technique is substantially less sensitive to patient motion than conventional imaging, and so is particularly useful for imaging patients with movement disorders, anxiety or young children. See Movie.	Maximum intensity projection of a multislab 3D time-of-flight dataset, showing excellent delineation of the Circle of Willis and other cerebral arteries. Note that this data is acquired without the use of injected contrast agents, and uses blood flow as an intrinsic contrast mechanism. The use of 3T MRI further enhances the suppression of unwanted (stationary) background signal in this scan. See Movie or QuickTime VR.
Volume rendered views of the time-of-flight dataset. See Movie or QuickTime VR.	Volume rendering of high resolution 3D FIESTA imaging of the semicircular canals and the cochlea in the ear. See Movie or QuickTime VR.

Diffusion Tensor MRI

• Diagnosis and staging of stroke.
• Quantitative assessment of microstructural brain damage.
• Non-invasive determination of brain connectivity.

Functional MRI