Q&A with Sebastian Papazoglou and Siawoosh Mohammadi

In today’s interview, we highlight the recent work by first author Sebastian Papazoglou and last author Siawoosh Mohammadi from University Medical Center Hamburg-Eppendorf. They propose a new biophysically motivated method for removing the orientation-dependent part of R2* using a single GRE measurement.  The authors show us some exciting results using 7T ex-vivo optic chiasm data and share their personal experiences about the project.  

For those who would like to get a quick overview of our discussion, below is an annotation of the interview. Clicking on the timestamp will take you to the exact video location where the topic is discussed.

0:33 Audioslides: There is an orientation dependence of R2* in white matter, such that its value depends on the sample positioning inside the MR scanner. The authors developed a method that separates the orientation dependant part from the orientation independent part, using only a single GRE measurement at an arbitrary unknown angle of the sample.

5:54 The authors give us an overview on how they got involved in MRI research. Sebastian and Siawoosh both wrote their master thesis on condensed matter theory in the same office in Hamburg. Siawoosh got into the field of MRI through a civil service position in diffusion tensor imaging and encouraged Sebastian to join him.

9:10 Sebastian and Siawoosh explain how they got involved with this particular project. Sebastian joined the project in 2017 when he saw the opportunity to work again with Siawoosh as a postdoc. Siawoosh started the project soon after the paper by Wharton et al. was published in 2012 and he got interested in pursuing the inverse problem.

11:43 The authors explain how dependent their results are on the accuracy of the hollow-cylinder-fiber model and what are the key things to watch out for, such as differences in T2 relaxation times and most importantly the violation of the static dephasing regime.

15:23 The authors discuss the possible information that is captured in the orientation dependent and independent parameters that arise from their model, and if they find one more interesting than the other.

19:17 Siawoosh discusses how they have been working on trying this same technique at the whole brain in-vivo level and shares with us some of the problems they are currently facing.

22:15 The authors open up about the biggest challenges they encountered during the project. It was especially challenging to keep track of the different orientations and drawing the ROIs in the optic chiasm.

25:52 We close with the biggest takeaways from their work and what the main contributions are to the MRI community.