A joint PhD position is available at Sorbonne Université in Paris, France and Memorial University of Newfoundland, Canada. The researcher will work three years at the Laboratoire d’Imagerie Biomédicale and spend at least one year within the research group of Alison Malcolm in the Department of Earth Sciences at Memorial University of Newfoundland. The goal of this project is to image and characterize blood flow within bones (intraosseous blood flow).
Although intraosseous blood circulation is thought to play a key role in bone growth and remodeling, in fracture healing and in the development of bone disorders, it is rarely considered because of the absence of a suitable technique for its in vivo evaluation in humans. We hypothesize that the development of intraosseous ultrasound imaging will enable the characterization of intraosseous blood circulation, i.e. the blood flow in the cortical bone tissue and in the bone marrow. The success of this work will help to build new in vivo knowledge on vascularization-related bone physio-pathological processes. Longer term, it may provide a clinical tool that does not exist today, and help in the early diagnosis of bone diseases or the monitoring of bone healing. In addition, it will broaden the range of clinical uses of ultrasound imaging, which cannot currently image bone.
A first requirement to achieve intraosseous ultrasound imaging is to reconstruct accurate anatomical images of the interior structure of a bone. To do so, we must relax the three major assumptions made in conventional medical ultrasound imaging: 1) the speed of sound in the human body is assumed to be uniform, 2) the multiple reflections experienced by ultrasound waves in the human body are neglected and 3) mode conversions experienced by ultrasound waves (compressional wave to shear wave, and vice versa) are neglected. The work of the PhD student will consist in selecting and adapting time-tested seismic imaging techniques.
Next, the PhD student will work on the development of transmission schemes for ultrafast ultrasound imaging and signal processing for measuring the magnitude and direction of intraosseous blood flows. This is challenging because intraosseous blood volume and flow velocity in bone are small! The selected techniques will be evaluated with numerical models, and then implemented on a fully programmable ultrasound scanner for in vitro validations. Finally, intraosseous ultrasound imaging will be tested in healthy volunteers at Hôpital Pitié-Salpêtrière in Paris.
Qualifications:
- Applicants with excellent academic records and a Master degree in physical acoustics, seismic imaging or medical ultrasound will be considered.
- Excellent level of English is required. French is not required.
Information and applications:
- Candidates are invited to contact Guillaume RENAUD for additional information and to submit their application (including cover letter, CV, names and contact details of 2-3 referees).
- Applications will be considered until May 15, 2018 but prospective candidates should contact Guillaume RENAUD as soon as possible.