Research Sketch -- PD iron

In a paper published on-line yesterday (https://doi.org/10.1007/s10072-021-05223-0), Minkyeong Kim and Seulki Yoo (two lead authors) presented results of an iron-sensitive MRI biomarker study in early Parkinson's diseases patients. This work started in 2017 as part of a broader 3T neuro MRI collaboration between SKKU and SMC, with the SMC team led by Drs. Jin Whan Cho and Jinyoung Youn. 

At least 19 PD patients and 16 normal volunteers were brought from SMC to SKKU for a 3T MRI scan, from which 14 patients and 12 healthy subjects' data were selected for analysis of iron-sensitive MR imaging. Part of the funding came from IBS, and part from SKKU intramural research grant of 2019. 

For a clinical study the work used relatively small number of samples. The novelty claim has been laid on the use of relatively homogeneous, early-stage PD patients and investigation of non-motor symptoms. The main finding of the paper is the existence of non-negligible correlation between certain non-motor symptoms (such as sleep disorder) and R2* values in deep brain regions (such as red nucleus, amygdala, and hippocampus). Since R2* is sensitive to tissue iron level, this observation suggested that iron in specific brain regions of PD patients may be indicative of non-motor clinical symptoms. 

Despite much effort and time spent in data collection and analysis, the study exposed limitations of using iron-sensitive MRI for clinical research. Most significantly from the Lab's point of view, the QSM results were highly variable among subjects, to a degree much greater than inter-group differences expected from early PD cohorts. Motion, head orientation, and other physiological factors appear to affect QSM much more than R2* and other established, magnitude-based contrasts. 

This observation, made early on in the project, strongly suggested the need of longitudinal studies to follow variation of QSM on individual subjects. Such studies can greatly benefit from the ability to post-process routine clinical MR scans collected in SMC. To this end, the team has looked into the possibility of including multi-echo GRE scans, including phase images, in the routine scan protocol at SMC. Hopefully this line of research will continue in the near future for more fruitful clinical collaboration.

2021 Spring semester started

In fact this year's spring semester started from late February. The campus atmosphere is still somewhat heavy and subdued because of the pandemic, but the number of students and other pedestrians on and around the campus has clearly increased from a month ago, and also when compared to about this time last year. More classes are being offered in-person, and the degree of fear for the unknown appears to be less intense. The Lab now has officially 5 graduate students, after welcoming Jun-Ho Kim in to the incoming class. To celebrate this and other events (see News for publication updates), back-to-back small-group lunch meetings were held (as mandated by the local health authority) in the past week. May this semester be another successful one with continued progress in work and personal developments for all.

2020 fall undergraduate research presentation

This is the third time this year when undergraduate lab interns held a research presentation session. On the 21th of December, three students, Sung-Joon Yoon, Ji-Sung Barg, and Joon-Ho Kim each spoke about what they did and learned in the Fall semester. The session was held in one of the main lecture rooms of the N center, with 7 people in the audience seated far apart from each other, all wearing a mask. The presentations showcased the substantial involvement of the students in different lab projects, from RF coil design and electrical property measurements, to gradient coil theory. Holding this event in a physical place, rather than on-line, was a good idea in terms of enabling more lively discussions among the students.

7T MRI at KBSI

On Monday November 16th, Dr. Lee (SK) and two graduate students (HS Kim, BP Song) visited the Korea Basic Science Institute (KBSI) at Ochang. Dr. Sukhoon Oh kindly hosted the delegates to provide a tour of the MRI research building, in particular the human 7T scanner. Currently, Korea has three human 7T scanners (one in SKKU, from Siemens; another in Gachon Univ. also from Siemens, and the one in KBSI from Philips). Of these the ones in SKKU and KBSI are currently fully operational for human scanning. The KBSI scanner is being used for fMRI, extremities imaging, and RF hardware development. Compared to the SKKU scanner, it has more coil options including a diverse set of non-proton coils. A downside of the scanner is that Philips is not actively pursuing 7T imaging products, so the upgrade options are limited; however the scanner can be a good platform for basic science and engineering research at ultra-high magnetic field with human-sized bore space.

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