Post-doctoral position : Electrical property imaging by MRI
Contexte et mission :
The objective of the project is to develop novel acquisition and reconstruction methods for imaging electrical properties (i.e. conductivity and permittivity) in-vivo in humans. MR-EPT (MR electrical property tomography) relies on the fact that electrical property changes throughout the patient result in a small – yet measurable – spatial modulation of the transmit and receive radiofrequency fields (B1+ and B1-). Various methods have been proposed based on B1+ mapping, phase images (spin-echo or bSSFP sequences), or ultra-short echo time sequences (UTE/ZTE). In previous work we have developed a new method based on a UTE sequence and a generalized reconstruction framework [1]. This involved solving a modified Helmoltz equation of the form ∆B/B κ^(-1)+∇B/B∙∇(κ^(-1) )≈iμ ω, with B^2 the complex UTE image and κ=σ+iωε_0 ε_R the complex admittivity (σ the conductivity, ε_R the relative permittivity). The aim of the project is to improve and further validate the technique for in-vivo application. In particular the following aspects can be investigated: robust denoising of the input data prior to Laplacian calculation, region-wise reconstruction using a prior segmentation from another imaging contrast (e.g. T1-weighted or T2-weighted), source separation methods to eliminate spin-density contrast in the raw UTE images.
[1] P Soullié et al., Magn Reson Med. 2021;85(2):762–76.
Diplômes requis :
PhD degree.
Compétences requises :
The position is open for candidates with strong background in MRI physics, applied mathematics or image processing.
Rémunération :
12-month (possible extension to 24 months) post-doctoral position position, starting from January 2022. Salary depending on candidate previous experience.
Structure :
A 12-month (possible extension to 24 months) post-doctoral position is available in IADI (Inserm U1254, Université de Lorraine), Nancy, France. This project is part of the ANR-funded project ELECTRA (Electrical property imaging by MRI: application to the MR-safety of medical devices). IADI has expertise in MR image reconstruction, and has access to a Siemens 3T Prisma scanner. A vector network analyser and relevant instrumentation are available for ground truth electrical property measurements in phantoms. Ethics protocols are available to test the methods in healthy subjects and patients.