Rights: The University of Waikato Published 21 July 2007 Download

Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about the MRI scanner based at the Van der Veer Institute for Parkinson’s & Brain Research.

Not only does this MRI have twice the magnetic field strength of any MRI in New Zealand, but it will shortly have installed an EEG recording system, which will record electrical signals on the scalp.


This was installed here at the Van der Veer Institute in collaboration with the Christchurch Radiology group. We’ve been pushing the research applications of this new scanner, and we’re fortunate that we have the Canterbury Medical Research Foundation negotiated with Christchurch Radiology group to allow us access, for research, to this new technology. And it’s very expensive technology so we’re very happy that we have access to this.

So the equipment that we have here is a three tesla MRI scanner. Almost all the other scanners in New Zealand are 1.5 tesla MRI scanner, one and a half tesla. So we have twice the magnetic field of any of the other scanners in New Zealand. The stronger the magnetic field, the more you pull these hydrogen atoms into alignment with the field, so essentially the signal that we measure in the MRI varies more or less proportionally to the field strength. So if we’ve got double the field strength we’ve got double the signal. Which means that we’re gonna be much more sensitive to any changes.

We also have some quite unique facilities on this scanner. One of the facilities that we have is eye tracking. We can actually look at somebody’s eye ball within the scanner, and we can see where they’re looking. And some of the expertise here at the Van der Veer Institute has been in looking at Parkinson’s patients and how they can actually track just a simple spot on a screen, with their eyes. It’s a very simple test, but you can actually learn quite a lot from it.

Moving your eyes is another form of motor control, it’s like moving any other part of your body. And they’ve found that this is a very sensitive measure. So that’s one of the unique facilities that we have here in Christchurch. Another facility is a simultaneous EEG recording system. So EEG records electrical activity from the scalp. You have little electrodes that you stick on the head, and you can measure electrical signals which come from neurons firing. Now EEG and MRI both give images of the brain but they have different strengths. So in MRI we get very good structural images of the brain, we get generally very good spacial resolution, but in terms of time, we can’t image the brain very fast. When we’re doing our functional scans we’ll image the whole brain in maybe every two or three seconds. With EEG they have kind of the opposite issues. They don’t generate high resolution spacial images. Their spacial resolution is very very limited. But what they can do is they can measure changes over a very short periods of time, over milliseconds. So you’ve got this combination of the two techniques which we believe is gonna be a really nice combination which will help us to understand much more about the brain than either of the two techniques individually.