Solving MRI inversion problems for quantitative multi-parameter estimation

Topic: Inversion problems, regularization, bSSFP, MRI simulations, data processing and analysis, complex systems.
Who: Students with a background in mathematics, computer science, physics, electrical or bio(medical) engineering. Everyone who is interested in new and creative mathematical models and solutions, regularization, computer simulations and parameter estimation on real experimental data.

Background: In quantitative MRI the dynamics of a complex physical system is described by the combination of a set of physical equations leading to a certain kind of quantitative model or quantitative map. Those respective models/maps are used for the quantification of e.g. water-fat fractions or T1- and T2-time. By trying to map acquired/simulated data to the quantitative parameter of interest, inversion problems are frequently encountered. Depending on the problem, inversions can be challenging to solve. The challenge can either originate on the sparsity of acquired data or also on the mathematical model itself. The quantification of multi-Compartment systems in MRI exhibits a lot of inversion operations, where some problems arise as ambiguities or so called “ill-posed problems”. Sometimes it is possible to find solutions of the inversion by constraining the system to boundary conditions, by reducing the complexity or dimensionality of the model or bring it in another mathematical formulation. Some of those problems are not well understood yet and their solution is key for a robust quantification of multi-compartment systems in MRI.

Project: In this project, we aim to first identify a system with known dynamics, and then develop a solution for the identified system. The prospective student will investigate inversion problems arising in parameter quantification in multi-compartment systems, like water and fat, with special focus on the bSSFP-sequence. We will investigate whether a problem can be solved analytically/numerically by an unambiguous mathematical representation or develop a regularized inverse problem-solving technique. Elaborated solutions will be tested in simulations (Bloch-Simulation) and on real experimental data.

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Latest posts

  • Welcome Yves

    Yves is a student in the MSc program in Biomedical Engineering at the University of Bern. He will work with us on quantitative susceptibility mapping at 7T, together with Berk. We are excited to have you on the team!

  • Welcome Guillaume, Janick, and Matteo

    Three new Biomedical Engineering Master students have joined the QIS lab. They will be working on biomarker mapping in the human brain, fat-free relaxometry of the human liver, and free-breathing cardiac image reconstructions. Welcome to the team!

  • Welcome to Kelly Bonzon and Melina Gilsing

    Two new Biomedical Engineering Master students have joined the QIS lab. They will be working on the implementation of open source pulse sequences and AI tools for advanced processing and reconstruction of MRI data. Welcome to the team!

  • Jessica Bastiaansen teaches in the ESMRMB School of MRI about Advanced and Applied MRI Principles

    Jessica gives a lecture on the topic “Fat suppression and Introduction to Quantitative Imaging”, which is part of the Practical MR Physics course organized by the ESMRMB School of MRI. The lecture series is composed of different topics geared around the field of magnetic resonance imaging. More information can be found on the following link.

  • Jessica Bastiaansen joins the Annual Meeting Program Committee (AMPC) of the ISMRM

    Jessica was invited to serve on the Annual Meeting Programming Committee (AMPC) of the International Society for Magnetic Resonance in Medicine (ISMRM). “It is a true honour to be asked to be part of the AMPC, and I look forward to contribute to the organization of the next three ISMRM meetings!”. The annual meeting attracts […]

  • Dr. Rahel Heule presented about asymmetries in the brain at 9.4T

    Dr Rahel Heule from the Max Planck Institute in Tuebingen and the children’s hospital in Zuerich visited our imaging center in Bern. She gave a seminar entitled “Asymmetries in the Brain: A Methodological Exploration of bSSFP MRI in Neuroimaging at 3T and 9.4T“. Our belief in bSSFP methods to uncover novel biomarkers have only been […]

  • Prof. Jürgen Hennig visits and talks about the evolution of field strength

    Professor Jürgen Hennig visited the Translational Imaging Center in Bern as well as several MRI research groups. Besides his seminar on “The Evolution of Field Strength in MR: Back to the Future?“, he shared his insights on open source MRI sequence programming as well as his academic career. We had a blast, and we were […]

  • Prof. Bastiaansen joins the editorial board of Circulation: Cardiovascular Imaging

    Prof. Dr. Jessica Bastiaansen, head of the QIS LAB, joins the editorial board of the journal Circulation: Cardiovascular Imaging.

  • Nils Plähn wins the Röntgen-Prize

    Every year, the Physics Institute of the Faculty of Physics and Astronomy at the University of Würzburg awards the Wilhelm Conrad Röntgen Prizes to the best students (top 10%). This year, Nils Plähn, PhD candidate at the QIS lab, was among its recipients. Congratulations!! Wilhelm Conrad Röntgen (1845 -1923), 1st Nobel Prize winner for physics […]

  • QIS Lab joins the Cardiovascular Research Cluster Bern

    We are extremely excited to join this effort! The Cardiovascular Research Cluster Bern (CVRC) was established for all UniBE and Inselspital members with an interest in cardiovascular research. The goal is to promote the cardiovascular research teams in Bern as leaders in the understanding of cardiovascular (patho)physiology and in the development of approaches to reduce disease […]