Looking at the brain with MRI
Magnetic resonance imaging (MRI) is one of the best techniques for imaging the brain because it gives very high quality images, with excellent contrast between the different types of tissues.
Transverse view of the brain
Transverse view of the brain of a 75 year old male, taken with MRI. MRI scans give very high quality images, with excellent contrast between the different types of tissues, this makes it is one of the best techniques for imaging the brain.
Dr Richard Watts and his team at the University of Canterbury are studying what happens to the brain when it gets injured or diseased, and what happens in the brain when you carry out different tasks while in the MRI machine. This is called functional MRI.
Looking at brain injuries
Looking at head injuries in the MRI
Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about research they have done on a group of boxers, looking at the damage they receive through suffering repeat mild head injuries.
The information he is getting from these boxers can be used to understand what happens to other people who suffer brain injuries, such as after a fall or accident. At the time the damage may seem minor but, in many cases, patients develop symptoms in the long term that researchers are trying to better understand.
Richard’s team are studying the brains of a group of boxers using MRI. They are comparing a group of professional boxers with a similar group who have never boxed. Boxers make good case studies because they get frequent blows (chronic shocks) to the head. Richard wants to know if there are any cumulative effects from all those knocks. They are looking to see if, over time, many blows may have some lasting changes on the brain.
Looking at the brain in action
Richard is also looking at the functions of different parts of the brain. Functional MRI can reveal which parts of the brain are active when someone is doing different activities. It involves having someone in an MRI machine alternate between performing tasks and resting.
Functional MRI – looking at the brain over time
Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about functional MRI, which looks at how the brain responds over time as patients carry out tasks.
Richard explains that functional MRI is less concerned with high resolution images and more about looking at changes in the brain over time. It’s more like creating a movie than taking a picture. Richard is working at the Van der Veer Institute for Parkinson’s & Brain Research looking at patients with injury or disease to see how their brains are functioning.
An example of a task that is used in this work is the n-back test. The subject is shown a sequence of letters, and asked if the current letter matches the one presented ‘n’ letters ago. Matching the last-but-one letter (n=2) is quite difficult, and matching letters further back is even worse. This test shows which parts of the brain are involved in working memory and recall.
Images of the brain are taken throughout the time the person is in the machine. The differences in the images produced are identified as being due to performing the task. Richard and his team can then work out from these images which parts of the brain were involved in the task.
The future
MRI has an important advantage over other techniques like X-ray – it is so much safer since it does not involve ionising radiation. This means it is possible to do studies of child development as children grow, and to follow disease as it progresses in a patient, as well as the effects of any treatments. In Christchurch, the researchers are particularly interested in using this technique to learn more about Parkinson's disease, depression, bipolar disorder and responses to facial expressions.
Using MRI to understand Parkinson’s disease - Part A
Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about using MRI to look at the brains of patients with Parkinson's disease.
Richard and a team at the Van der Veer Institute for Parkinson’s & Brain Research are interested in a subset of patients who go on to develop dementia. He is working with a range of professionals, including neurologists, radiologists and psychologists, as well as using the MRI to better understand the disease.
Using MRI to understand Parkinson’s disease - Part B
Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about using MRI to look at the brains of patients with Parkinson's disease.
Richard and a team based at the Van der Veer Institute for Parkinson’s & Brain Research are using MRI to generate high resolution structural images to look at the size of different structures in the brain as well as using diffusion MRI that looks at water movement to see what cellular changes are taking place. They are also using a third technique of functional MRI to look at parts of the brain involved in memory to see how they are working and spectroscopy to look at chemical changes.
The results from these kinds of studies are providing new information on how a diseased brain and a healthy brain work and will lead to a much greater understanding of the human brain.
What is normal?
Dr Richard Watts from the Department of Physics and Astronomy at the University of Canterbury talks about variation in brains.
There is a lot of variation in brains from one individual to another, and it is not unusual to find little abnormalities. Researchers have to be very aware of this and handle the issues, when they arise, with sensitivity.
Citizen science opportunities
Research in Alzheimer’s disease has identified ‘stalls’ – small blockages in blood vessels in the brain that could be linked to the disease. Citizen science project Stall Catchers is a way you could help researchers by tagging the occurrence of stalls in videos of blood flow through mice brains.
Useful links
Brain scientist, Tracy Melzer from the New Zealand Brain Research Institute, hopes that magnetic resonance imaging (MRI) scans of blood flow in the brain will help pinpoint early changes of Parkinson's disease and dementia. Find out more in this Radio New Zealand interview Search for early signs of dementia with Parkinson's disease.
