... / ... / ... / Post Doc's / Dr. Kruizinga, P. (Pieter)

Dr. Kruizinga, P. (Pieter)

high-frame-rate imaging, beamforming, compressive imaging, computational ultrasound, functional ultrasound

Kruizinga, P. (Pieter)

Research area: high-frame-rate imaging, beamforming, compressive imaging, computational ultrasound, functional ultrasound

Office:    Ee2332a
Tel:        +31 (0)10 7044035
Fax:       +31 (0)10 7044720
Email:    p.kruizinga@erasmusmc.nl  


I am passionate about everything that has to do with imaging, and of course medical imaging in particular. I started my academic career exploring the use of photoacoustic imaging for visualizing tumours. For this particular technique both light and (ultra)sound are used to build an image. Since the absorption of light is different for various tissues, a photoacoustic image can used to uniquely discriminate between healthy and diseased tissue. Much of this technique I learned during a one year research visit at The University of Texas at Austin, USA in the lab of Prof. Stanislav Emelianov (who is now at Georgia Tech: http://ultrasound.gatech.edu/). Later, back at the Erasmus MC for my PhD research, I applied this imaging technique to visualize plaques inside the carotid artery. This resulted in a dissertation entitled 'Acoustic images of the carotid artery', where I outlined new imaging concepts using both photoacoustic imaging and high-frame-rate (HFR) ultrasound. Several of these new techniques were published in high ranked engineering journals. The thesis can be found here: https://repub.eur.nl/pub/77779/ . My google scholar account can be found here: https://scholar.google.nl/citations?user=TqG4j40AAAAJ&hl=nl&oi=ao 

Already during my PhD and later postdoctoral research I became more attracted to ultrasound imaging and in particular two areas: computational ultrasound and functional ultrasound imaging.

Computational ultrasound: Unlike photoacoustics, ultrasound imaging solely relies on the transmission and reception of ultrasound waves. Normally, ultrasound images are made using an array that consists of many (64 up to 10.000) small sensors that can transmit short ultrasound pulses in the medium and receive the subsequent echo's. All these sensors are needed make one focussed image. The main technique used to reconstruct an image from all the raw sensor signals is called beamforming, and this technique has in essence not been changed since the conception of ultrasound imaging in the 1970s. I, together with other researchers, now think that there are perhaps better, or more interesting ways, to make an image from the raw data by something that is called computational ultrasound. The idea of computational ultrasound is to use prior knowledge of the ultrasound field in a mathematical model and from that make the best image possible. This principle of using the computer to find the best image has enabled us to make a full 3D image using only one sensor! This work was published in the journal Science Advances. The paper can be found here:  http://advances.sciencemag.org/content/3/12/e1701423, a short movie about this work can be found here: www.youtube.com/watch?v=whbbaF1nT4A. Apart from showing that ultrasound imaging is possible with far less sensors, I also think that computational ultrasound holds great promise for making better ultrasound images even of objects that are normally very hard to image, like the brain behind the skull.   

functional ultrasound (fUS): Since a few years I am involved in applying the HFR ultrasound technique to image blood flow inside the brain of small animals. Through the process of neurovascular coupling we can now actually use HFR to visualize local brain activity. This particular combination of techniques is named functional ultrasound, or fUS in short.

The principles behind fUS are very similar to that of fMRI but with the difference that with fUS we have a higher spatial and much higher temporal resolution available. For fUS I developed new imaging algorithms that made it possible to use real-time fUS on a commercial ultrasound system. Together with the group of Prof. Georg Maret at the University of Konstanz, Germany, we successfully applied this fUS implementation in pigeons and now also on mice in the lab of Prof. Chris de Zeeuw at the Erasmus MC in Rotterdam. At the Erasmus MC we now aim to further advance this fUS technique and use it in the neurosciences but also in the clinic to help unravelling the mysteries of the brain.

My special interest and focus of my work lays in the combination of these two fields outlined above. Or to put it one sentence: "understanding brain functionality with computational ultrasound imaging".  


PUMA: 3D Plane-wave ultrasound matrix transducer for carotid artery diagnosis