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Harnessing physics to improve medical imaging | 4TU.techtalk #6

Tuesday, 8 March 2022

Medicine is becoming increasingly personalised. One-size-fits-all approaches make way for tailor-made treatments, for instance for cancer and cardiovascular disease. In the 4TU Precision Medicine programme, scientists are working towards this goal by improving medical imaging technologies in a fruitful interaction between science and clinical practice.

In the series 4TU.techtalk, a 4TU professional will discuss a topical subject with someone from another discipline or societal domain – on the lookout for each other’s viewpoints and the commonalities, the triumphs but also the dilemmas. Check them out

Text: Nienke Beintema | Photography: Dieuwertje Bravenboer

No two patients are the same, even if they have the same illness. Whether they have cancer, a cardiovascular or neurological disease, their diseases may be as different as day and night. Tumours in liver and breast tissue, for instance, may share more characteristics than two different breast tumours.

Clinical practice is increasingly tuned towards this reality. Scientists are looking for ways to characterise their patients and their diseases in more and more detail, in order to offer them tailor-made treatments. Not just to target their disease more effectively, but also to limit adverse side effects.

“Previously, if you had cancer, you’d be given a general cytotoxic drug, and hope that this quite drastic approach would mostly harm the cancer”, says cardiologist Thomas Treibel of University College London. “Now, we can use imaging, molecular and hormonal phenotyping to characterise the cancer and then use very specific drugs to target it, in very specific amounts. Our aim is to translate this approach also into cardiology.”

“Imaging is the backbone of this characterisation”, says Sebastian Weingärtner, assistant professor at TU Delft. “I’d argue that imaging puts the ‘precision’ into ‘precision medicine’.” Both scientist have known each other for many years. They’ve been working together in various projects, also during Sebastian’s previous positions.

Who?

Sebastian Weingärtner (1991) is an assistant professor at the Department of Imaging Physics at Delft University of Technology. Originally from Germany, he carried out his PhD research at Heidelberg University and Harvard Medical School. After further research positions in Minnesota and Stanford, he is now leading his own lab in Delft. His lab studies the physical phenomena behind magnetic resonance imaging (MRI), aiming to improve the technology to arrive at better quantitative analysis of health and disease.

Thomas Treibel (1979) is a British/German academic cardiologist and associate professor specialising in valvular heart disease, heart failure and multimodality imaging. Thomas combines research at University College London with clinical work at the Barts Heart Centre, London. He uses imaging techniques such as MRI to improve diagnostics and treatment plans for patients with cardiovascular diseases and is supported by the British Heart Foundation.

Imaging as a backbone – is that why 4TU Precision Medicine programme focuses specifically on imaging?

Sebastian: “Yes. If you want to treat a patient effectively, the very first step is an accurate diagnosis. Diagnostic parameters such as blood markers, body temperature and other biometrics are all systemic. They tell you about the state of the entire body. But imaging can tell you exactly what is going on, and where. Imaging is the only approach that can provide that level of detail.”

Thomas: “We cardiologists can make an electrocardiogram, or look for certain peptides that are markers for heart failure. But none of these data show any detail of the actual damage to the heart. Is it on the left or the right side, for instance? Hence, any medication would be quite generic. Imaging such as MRI can give you exact details on scarring in the muscle tissue, or on why a heart valve is malfunctioning.”

Sebastian, you are a physicist. How does physics help to improve MRI?

Sebastian: “The ingenuity of MRI lies in its physics. Much of the differences between the MRI machines that you find at different hospitals lies not in the engineering of the machines themselves, but in the programming of the underlying physics phenomena, and in the data analysis. By working on the underlying physics, we can unlock a wealth of new information. That is what sets MRI apart from other imaging modalities.”

Thomas: “Other techniques, such as ultrasound and X-ray, are about sending and receiving signals as well. But the difference is: with MRI, Sebastian can programme the signal that the magnet sends out, which affects the signal that comes back to the receiver [see text box, ed.]. This is what determines the image that we can then use for diagnostics.”

Sebastian: “An MRI machine can detect a huge amounts of contrasts. We are only starting to scratch the surface of all the information we can extract from these data.”

Magnetic Resonance Imaging (MRI)

MRI is a medical imaging technique used to look at tissues and physiological processes in great detail. It uses strong magnetic fields and radio waves to visualise contrasts between different tissues or structures. When subjected to a magnetic field, particles in our body will align with this magnetic field. Radio waves will then excite these particles out of their equilibrium. When the radio wave is turned off, the particles reassume their original state, sending off a signal in the process. Sensors can detect this signal. These signals are different for various types of tissues or structures, hence allowing for accurate diagnosis of conditions such as cancer, cardiovascular or neurological disease, stroke or inflammation.

How does your research reach the clinic?

Sebastian: “When there are new developments in the science behind MRI, hospitals don’t need to replace their machines. They just need to adjust what the machine does, which is relatively easy. What I develop today, could be used in practice next week. The turnaround times are extremely quick.”

Thomas: “When Sebastian writes a new algorithm, we just need to get a software upgrade, and then we’d immediately get an improved picture or more stable image, for instance.”

How does this benefit the patient?

Thomas: “Well, obviously the patient benefits from a faster and better diagnosis, and hence more targeted treatment. But improved MRI also increases patient-friendliness. At University College London, we are looking at using MRI to reduce the need for invasive biopsies in cases of suspected prostate cancer. There is a cost aspect, but definitely also improved patient comfort and safety. There are huge patient benefits.

Another example: in case of MRI of the heart, the patient has to lie flat and hold his breath during scanning. With increased picture stability, scanning is considerably faster. Sebastian wrote a sequence, for instance, that allows us to quantify tissue changes in the heart in a single breath hold.”


“The 4TU programme fits into this larger international network and benefits from it. But it works both ways: the programme also helps to advance the national research agenda. It groups together scientists from disciplines that wouldn’t usually cooperate”
Sebastian Weingärtner
Assistant professor; Department of Imaging Physics (TU Delft)


How important is cooperation between science and clinic, like in the 4TU programme?

Sebastian: “Realistically, advancing MRI technology is not on the mind of your average cardiologist. Our tasks as scientists is to make a contribution and then go out and distribute it among hospitals, if the technique proves to be beneficial.”

Thomas: “But to prove that it is beneficial, you need to gather evidence. Not just of economic benefits, but also of benefit to patients, both in the short and the long term. To gather this evidence, you need an effective interface between academic institutions and the clinic. Not just to have an optimal exchange of knowledge, but also just to have sufficient patient numbers. For this, you need an international network. I’ve been working with Sebastian for many years now, and also with other scientists in Europe and elsewhere in the world.”


“If we can make our scans faster and better, and generate more data, we can improve patient health and comfort and generate a better diagnostic yield in the same amount of time”
Thomas Treibel
Senior Lecturer at University College London/ Honorary Consultant Cardiologist at Barts Health


Sebastian: “At 4TU, we cooperate closely with clinical centers, such as Holland Proton Therapy Centre, where I perform most of my MRI research, as well as with academic hospitals in the Netherlands, and many clinical partners abroad. The 4TU programme fits into this larger international network and benefits from it. But it works both ways: the programme also helps to advance the national research agenda. It groups together scientists from disciplines that wouldn’t usually cooperate.”

And what about the interface with industry?

Sebastian: “We also work closely together with large industry players, like Philips. Here, too, the benefits work both ways.”

Thomas: “And hospitals benefit too. If we can make our scans faster and better, and generate more data, we can improve patient health and comfort and generate a better diagnostic yield in the same amount of time. This will become increasingly important, as we expect the disease burden to keep rising due to the ageing population and post-covid disease, for instance. We’ll need to keep speeding up and improving our diagnostics. A faster, physics-driven approach can do that.”

Which are the main challenges on the road to clinical application?

Sebastian: “As physicists, after having shown on a small scale that our innovations can make a difference, we need to show that our results have a broader applicability, and are reproducible across many different centres. That kind of research is a lot harder to finance. That is where programmes like 4TU Precision Medicine can make a difference.

And there are also considerable regulatory burdens. So there are always translational gaps that we still need to bridge. It’s a long and strenuous road.”

Are you optimistic in this regard?

Thomas: “It is not a question of optimism or pessimism. It is a question of time. The technique needs to be so solid that we can make life-and-death decisions based on it. So we need to be patient. Getting a new technique implemented in all the hospitals in the Netherlands, for instance, is a daunting task. But eventually it can make a difference for hundreds of thousands of people, so it is definitely worthwhile. And in the meantime, we are already using increasingly advanced imaging techniques in our patients, delivering more and better quality information and choosing more personalised treatments.”

Sebastian: “Oh, definitely. Every small innovation is already making a difference for patients. Advanced MRI is a clinical workhorse. It is not something that we tinker up in our lab and maybe three people are using it. Its application is speeding up in clinical settings around the world. Where we stand at the moment is quite staggering.”

4TU Precision Medicine

Precision Medicine is a programme within the 4TU Federation and part of the 4TU capacity building programme ‘High-Tech for Sustainable Future’. The programme aims to take diagnostics to a higher level through a combination of artificial intelligence and medical imaging techniques: from a one-size-fits-all approach to a tailor-made, personalised approach. According to the Precision Medicine team, this is the best way to keep healthcare accessible and affordable in the long term.

The team includes seven Tenure Trackers: excellent scientists who are given the opportunity to progress to the position of professor. Sebastian Weingärtner, featured in this interview, is one of them. Some of the scientists have a dual position at medical centres. In addition, there is collaboration with clinical partners within the Centers for Medical Imaging of the Innovative Medical Devices Initiative (IMDI): Quantivison (Amsterdam UMC, NKI/AVL), IDII (TU/e, Maastricht UMC+ , UMC Utrecht), CMINEN (UT, Radboudumc, UMC Groningen) and Medical Delta (TU Delft, Leiden UMC, Erasmus MC).