Nico de Jong

‘Watching the heart in action in real time: it can be done with a matrix transducer with integrated electronics.’



Nico de Jong studied Physics at TU Delft between 1972 and 1978. He obtained his doctorate in 1993 from the Erasmus University in the field of medical ultrasonics and became closely involved with the introduction of ultrasonic contrast agents and new innovative transducers. He has been a part-time professor in Twente since 2003, in the field of medical bubbles. De Jong has had a double post at TU Delft from 2011, at the Faculty of Applied Science, in the field of medical transducers and imaging.


Erasmus MC - Thorax Centre BME
TU Delft - Imaging Science & Technology

The heart in 4 dimensions

Real time 3D image of the heart: 4D

‘What we are working on here is the development of transducers that produce a three-dimensional image of the heart in real time, which results in the heart in 4 dimensions: the heart ‘in action’ as it is. Transducers produce ultrasonic sound, and record the echo of that sound signal as it returns from the body. This allows us to ‘look’ into the tissue. Until about five or six years ago, we could only make two-dimen- sional images: cross sections. Now we can also do it in three di- mensions. Thirty years ago they were already able to produce 3D images: they just irradiated the body part with a single, strongly diverging bundle of ultrasonic sound, then they collected and saved all the echo information and used it to construct the image. But the technical capacity at the time meant that you had to allow for an entire day of com- putations in order to produce a single 3D image. Now we can do it in real time. Thanks to ultra-fast processing technology. And thanks to the collaboration with TU Delft.’

Determine the stiffness of the heart tissue using a 3D probe

‘Heart failure is often preceded by the stiffening of the tissue of the left ventricle. This is then unable to dilate as it should. Cardiologists would like to be able to measure the stiffness, for example in order to check whether a particular form of therapy is effective, but there is not a good method for doing so. You can do it invasively, howev- er: by inserting a catheter into the ventricle that can measure the state of affairs in situ. But we don’t like invasive methods. There is a project running here to try to determine the stiffness of the heart tissue using a 3D probe. We think that we’ll be able to measure it by using the ‘shockwave’ that travels through the heart whenever a particular valve shuts itself abruptly. As you know, vibrations travel faster in stiffer material. The speed of this wave is 10 m/s, so if you want to see the wave passing through the heart in true 3D you need a high frame rate, roughly 2000-5000 frames per second. To achieve this you need to call upon the exper- tise at Delft once again.’

Development of a 3D transducer

‘In another project we are working on the development of a 3D transducer that we introduce through the oesophagus in order to study the ‘back’ of the heart. This is already being done, but only to make two-dimensional images for operative treatment of heart rhythm disorders. Heart rhythm disorders develop when a form of ‘short-circuit’ occurs in the heart whereby a contraction immediately triggers a following contraction. To prevent this, the interventional cardiologist can burn off the piece of tissue that causes the short-circuit. This is a risky operation. But if the inter- ventional cardiologist could be provided with 3D images, taken from the oesophagus, which showed him exactly what he was doing, then in the future the operation could be performed much faster and with greater chance of success. As it is now, 60 to 70 per cent of the patients experience a return of the heart rhythm disorders.’

Placement of TAVIs with the help of 3D images

‘Another promising piece of re- search that we are coordinating here concerns the assistance in the placement of so-called Tran- scatheter Aortic Valve Implanta- tions (TAVIs) with the help of 3D images. TAVIs are aortic valves that are inserted using a catheter. The valves are then inflated in the heart, thus securing themselves. Correct placement is obviously very important, and the valves should not leak. You can see all this very clearly with 3D images. Placing one of these TAVIs with a catheter is clearly much cheaper and much less taxing for the patient than an operation.’

Cardiologists and engineers need to be on the same wavelength

‘Look, I’m a physicist myself, and we like to think here that we can do pretty much everything ourselves. But when it comes to mathematics, demanding computational problems and good simulations, Delft comes to our assistance. We also rely on Delft to design and manu- facture specialised chips that are able to digitise directly the torrent of information that a 3D transducer produces. In such a case we have to ensure that the cardiologists here and the engi- neers there are all on the same wavelength.’

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