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Catherine Morgan: Looking inside our bodies with physics

27 September 2021
Catherine Morgan is one of only a handful of MRI physicists across New Zealand.

Picture a physicist. Do you imagine someone madly scribbling equations about nuclear energy or black holes? What about someone doing research on dementia? Or figuring out better ways to do high-tech medical imaging? These are the sorts of things a Magnetic Resonance Imaging (MRI) physicist does. 

 is one of only a handful of MRI physicists across New Zealand.

She has a split job: half her time, she鈥檚 a research fellow at Waipapa Taumata Rau, University of Auckland鈥檚 , while the other half of the time, she鈥檚 the senior MRI physicist at the , a UniServices business unit based at the Faculty of Medical and Health Sciences that offers cutting-edge imaging for both clinical and research purposes. 

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Catherine Morgan

In some respects, the two aspects of Morgan鈥檚 job are quite different 鈥 but both her research and clinical work are solidly focused on helping people.

Morgan鈥檚 path to what she鈥檚 doing now was a bit circuitous. As a young girl growing up in England, she enjoyed physics, so when she went to university, that鈥檚 what she majored in. When she graduated, she got a job as a 鈥渜uant鈥 鈥 a quantitative analyst who does financial modelling 鈥 at a property company in London.

鈥淚 did that for about a year, then I found myself in a meeting at two o鈥檆lock in the morning about tax and accounting codes for a bid we were putting in the next day and I just thought, 鈥楾his is not for me or what I want to do with my life,鈥欌 says Morgan. 

It was Morgan鈥檚 mother, a nurse, who suggested medical physics. Taking advantage of a National Health Service (NHS) training scheme, Morgan enrolled in a master鈥檚 programme that combined working in hospitals with part-time study. She loved it and went on to do a PhD in the field. 

鈥淚 really enjoy my job. It doesn鈥檛 feel like work,鈥 says Morgan. 鈥淚鈥檇 be richer if I鈥檇 stuck with tax and accounting, but this is a real opportunity for me to do something meaningful as a physicist.鈥

The physics of MRI聽

MRI has a lot of complex physics behind it. Invented in the 1970s, it relies on powerful magnets that produce such a strong, uniform magnetic field that it forces most of the water molecules in your body 鈥 or more specifically, the hydrogen protons in them 鈥 to line up.

An MRI scan directs radio frequency pulses at specific parts of the body, forcing the water molecules at a lower energy state to spin around. When the pulse stops, they return to their original state and release the energy they temporarily absorbed. Because different types of tissue release energy differently, MRI can use this to create detailed images of what鈥檚 inside our bodies. 

鈥淚 really enjoy my job. It doesn鈥檛 feel like work. I鈥檇 be richer if I鈥檇 stuck with tax and accounting, but this is a real opportunity for me to do something meaningful as a physicist.鈥

Catherine Morgan

By changing settings such as the timing and type of radio frequency or by making small adjustments to the magnetic field, researchers and clinicians can focus on different elements even within the same part of the body. For example, one brain scan might focus on white matter while another might measure blood flow.

鈥淵ou can either use settings that come from the manufacturer of the scanner or, if you have a knowledge of how it works, you can change those settings,鈥 says Morgan. 鈥淭hat鈥檚 where I often come in. New ways of doing things can lead to better-informed, clearer diagnoses for clinical work or new discoveries on the research side. For example, there鈥檚 lots of work being done in areas such as how our brain ages or how visual processing works. It鈥檚 helping us understand normal brain functioning, which is still a bit mysterious.鈥

As CAMRI鈥檚 MRI physicist, Morgan works with medical imaging technologists to help researchers and clinicians with new and better ways of doing imaging. One week she might be checking the quality of new advanced methods for imaging prostate cancer, while the next week, she might be matching CAMRI scanner settings to another centre in Canada for a joint project on whether preterm babies have different outcomes based on their nutrition. She regularly talks to MRI physicists around the world about new types of scans for hearts, brains and more.

鈥淚 really enjoy how varied the work is,鈥 says Morgan.

Finding early predictors of dementia

Morgan鈥檚 own research focuses on brain imaging to understand how dementia develops. She鈥檚 part of a large national study, the , studying people with mild cognitive impairment (MCI) in Aotearoa. People with MCI have marked deficits in cognition but can cope with everyday tasks and live independently. Some people deteriorate into dementia while others do not.

The DPRC team is following more than 250 participants nationally over years, regularly taking MRI scans, blood samples, medical assessments and tests examining multiple domains of cognition. The project aims to find early signs that differentiate people who progress to Alzheimer鈥檚 disease and those who don鈥檛. 

From the MRI scans, researchers will examine factors such as brain volume, since brains shrink in dementia, as well as blood flow in the brain and white matter tracts, which connect different regions of the brain. 

Brain scan imagery

The scan results, when combined with other data from the study, have the potential to be groundbreaking, but the MRI techniques themselves are well established.

Morgan is leading a smaller side study using brand new MRI methods. One scanning method focuses on iron deposition, since some evidence suggests elevated brain iron levels can be damaging. Another examines blood flow in the brain using a new type of scan originally developed for the heart, known as 4D flow, which allows for precise measurements of blood flow through a vessel.

A third new technique examines the blood-brain barrier, a protective layer around the blood vessels in the brain. New evidence suggests the blood-brain barrier may be dysfunctional in MCI.

Normally a contrast agent 鈥 a chemical injected into a patient to improve clarity of images 鈥 would be used. However, there is some concern that some patients who have many MRIs using certain forms of the contrast agent could end up with small amounts of gadolinium, a metal used in the contrast agent, building up in the brain and other tissues. That鈥檚 why Morgan and her team are trying a new technique focusing on water molecules already in our bodies.

鈥淲e may not need to use contrast agents at all. Or we may uncover a new aspect of brain health related to water transport. It鈥檚 an exciting study and we鈥檙e close to putting it all together,鈥 says Morgan. 鈥淚f we can uncover something people haven鈥檛 thought of before in terms of the way Alzheimer鈥檚 develops, there could be new options for treatments.鈥

Want to learn how advanced MRI techniques could apply to your research or enhance your imaging outcomes?