icMRI 2020

The annual scientific meeting of KSMRM, icMRI, was held (finally) on Tues-Wednesday of this week (11/3-4). The meeting was postponed twice, originally scheduled for March but delayed due to uncertainties related to the pandemic. From now on the meeting is likely to be held every November. Given the circumstances, the meeting was run smoothly, with over 1000 registrants reported, on par with  the previous years. The meeting provided a much awaited platform for technical exchange and information flow in the new socially distanced era, but the limitation of on-line meeting sessions was also clear, in terms to lack of speaker-audience interaction, or even speaker-speaker conversations off-stage. For one thing, everybody was stiffer and looking/sounding more serious in front of the cameras.  

MRI education day by KSMRM

 

This year's annual MRI education day for radiologists was held in Sungkyunkwan University on Saturday October 24th. Due to the Covid pandemic, many meetings and conferences are being held on-line without live audience, and this event was no exception. The event itself had been scaled back from 6 hours to 4 hours, and much effort was spent to ensure stable on-line streaming to sufficient participants to maintain the reach and quality of the education. All the eight speakers participated in person in a lecture room at the N center (picture), and at least 270 people had pre-registered for the event, which exceeded expectation. The lectures were delivered on time, without incident. They were recorded for future reference, and hopefully will provide a guide to organizing similar events in the future.

Introducing our paper: Author interview with Seulki Yoo

Title of release: Peer-reviewed journal publication by a GBME graduate student and alumnus.
Lead authors: Seulki Yoo (GBME, 4^th year graduate student in Master-PhD program),  Hayoung Song (GBME, Master 2019, now at Univ. of Chicago)
Title of paper: Feasibility of head-tilted brain scan to reduce susceptibility-induced signal loss in the prefrontal cortex in gradient echo-based imaging
Author interviewed: Seulki Yoo

Congratulations on your publication!

1. Please describe what you did.

We proposed a novel solution to a well-known problem in high-field brain MRI. The problem is that the static magnetic field (B0) is very inhomogeneous just above the nose/sinus cavity. That is where the bottom of the frontal brain lobe is. Traditionally, the B0 field is so non-uniform in this region that typical functional MRI has very poor quality, often with a “black hole” in part of the region. We found that if we image subjects with their head tilted backward (in a “star-gazer” or “hair-salon” position), the B0 field becomes much more uniform and much of the lost signal is recovered.

2. Please explain to the GBME students why this work is important.

The benefit of ultra-high-field brain MRI is partly negated by the presence of strong B0 non-uniformity. Prefrontal region is particularly notorious. Many researchers (tens, if not hundreds) have published methods to tackle this, by shim coils, sequence modification, and post-processing. Our method does not require any of these, but shows that simple backward head tilting can greatly improve the B0 uniformity in the prefrontal brain. We found many volunteers could easily be scanned with the new head positioning. In the future this work may enable more robust imaging in fMRI, diffusion MRI, and R2* and QSM studies in the pre-frontal region.

3. Please describe any “aha” moment, “wow” moment, and “oh, crap” moment.

- Aha! (inspiration): When we first imaged a volunteer (my advisor) in head-tilted position and saw a day-and-night difference in the EPI signal in the prefrontal region.
- Wow! (excitement): When we saw that fMRI activation was enhanced even in areas outside the prefrontal cortex, although we still don’t know exactly why. Also, when we saw that the B0 map is more homogeneous than with (simulated) 3^rd-order shimming.
- Crap! (frustration): For some volunteers the head tilting angle was limited by their chin running into the coil housing.

4. What kind of future papers should cite this?

- Any paper that discusses MRI image quality in the prefrontal cortex.
- Papers that mention various ways to improve B0 uniformity.
- Papers on multi-orientation imaging, of humans or animals.

5. To the extent you can disclose, how can this work be followed up in the future?

This work was done at 3T. I want to see if 7T MRI can also benefit from this method, even if the head coil there (Nova coil) has more limited internal space for head rotation. Also, this work may be combined with other methods to improve pre-frontal imaging, such as the one with a new spatio-temporal encoding (ERASE) from Prof. Jang-Yeon Park’s lab.

For more information, see the link to the publication:

https://doi.org/10.1016/j.neuroimage.2020.117265

Summer undergraduate research presentation

 The two-month summer vacation is almost over, and on Friday 8/21 Seok-Jin Yeo, an undergraduate junior who worked in the Lab, presented his summer research to the GBME colleagues and senior students. Mr. Yeo had successfully calculated the convolution kernels for computing the static magnetic field vectors induced by an object magnetized in an arbitrary direction, and extended gSVC -- generalized susceptibility voxel convolution -- to arbitrary orientations. The results were presented with appropriate levels of details. The students had a pizza lunch after the presentation. Good job Seok-Jin!

RF vector field mapping

 

The multi-orientation B1 mapping method successfully created a first-ever radio-frequency 3D vector magnetic field map in a liquid phantom using MRI. Hard work by Hyeong-Seop Kim to interface a custom-made surface coil with a commercial 3T scanner, unaffected by large orientation changes of the RF coil, paid off to conduct experiments reproducibly. The results are nicely visualized above in a spinning 3D GIF animation created from within Matlab.

Undergraduate research

Jisung Barg, a junior (3rd year undergrad), presented his work in the Lab in the spring semester to his colleagues on Monday 7/6. As a significant achievement, we have recently obtained a 3D vector plot of the RF field in a liquid phantom, produced by a surface coil at 123 MHz using 3T (2.895T) MRI. Mr. Barg's work was on studying the principles and visualizing the results in 3D vector arrow plots in Matlab, and process them to improve the quality of visualization. This summer there will be no intern students from outside the department, but the Lab's undergraduate research will continue with the BME students. Some new & existing ideas will be able to find their way to materialization in this way.

End of the semester, spring 2020

A highly unusual 15-week semester finally came to an end today, Friday 6/19/2020. The lab members went out for a celebratory lunch in Homaesil, and took a picture in the N center outdoor court area with masks off (!) for two minutes. Such gathering is generally discouraged, and can be frowned upon, but it was determined that any risk is sufficiently low that this modest, once-in-6-months lab activity should go head. During the semester, the BME Electromagnetics course was successfully delivered on-line, and the students' feedback has been positive. The graduate students had two papers accepted in international journals and one brand-new paper is now under consideration. The multi-orientation B1 mapping data were collected with very promising vector B1 field results, and the human 7T head coil engineering is making slow progress. Some of the research highlights will be posted soon on this site. In the summer, neither the department nor the lab has any active plans for summer internship. Exchanges and visits of intern students will generally be suppressed across the country for the year. In many labs more time will be spent for internal research and self development.