MRM Q&A posts
BY MATHIEU BOUDREAU
The February 2017 Editor’s Pick is from Kimberly Chan and Richard Edden, researchers at John Hopkins University and the F.M. Kirby Center for Functional Brain Imaging in Baltimore. Their paper presents a study aimed at optimizing the echo time for measuring glutathione using J-difference editing. Glutathione is the brain’s main antioxidant, and may play an important role in several psychiatric and neurological illnesses, such as schizophrenia, bipolar disorder, and Parkinson’s disease. We recently spoke with Kim and Richard about their project.
BY RYAN TOPFER
Among the Editor’s picks for February comes a work from the Center for Magnetic Resonance Research at the University of Minnesota, where they’ve paired loops with dipoles for a novel hybrid transceiver. Last year, we featured the work of Alexander Raaijmakers (second author of the current work) on the fractionated dipole antenna design and we published the feature under the headline “We need antennas – not coils!” To understand this seeming about-face, we confronted Arcan and Greg over Skype about their decision to defy their collaborator’s unconventional wisdom.
BY BENJAMIN DE LEENER, NIKOLA STIKOV
In early 2017, the Highlights team had our first ever in-person interview with authors of this January’s Editor’s pick. For this historic event, we met with Gabriel A. Devenyi and Jamie Near, researchers at the Douglas Mental Health University Institute in Montreal, and authors of the recent MRM article “Advanced Processing and Simulation of MRS Data Using the FID Appliance (FID-A)—An Open Source, MATLAB-Based Toolkit”. It was noon on Friday, and we decided to get an early start on the weekend by heading to a most Canadian interview location – a skating rink at Beaver Lake in Montreal. Over beer and bison hamburgers, we discussed spectroscopy, open science, and the musical inspiration behind the acronym FID-A.
BY BLAKE DEWEY
In the early days of 2017, we sat down (virtually, of course) to have a conversation with Moritz Zaiss, Johannes Windschuh and Alexander Radbruch. Our topic was their recent MRM paper, “Downfield-NOE-Suppressed Amide-CEST-MRI at 7 Tesla Provides a Unique Contrast in Human Glioblastoma”. Chemical Exchange Saturation Transfer (CEST) imaging is an indirect imaging technique for the protons of certain metabolites, where saturation is applied off-resonance (with respect to water). Saturated protons are then allowed to exchange with water protons and then imaged using conventional imaging methods. However, frequency selection is not always enough to specifically target a functional group, such as amide groups, which are common in CEST imaging methods, producing a “mixed” contrast. Moritz, Johannes and Alexander, together with others in their group, have been slowly removing confounding effects in an attempt to isolate the measurement of amide proton transfer. In this paper, they continue their efforts by removing the downfield Nuclear Overhauser Effect (NOE), resulting in clinically relevant findings and correlation with gadolinium uptake in patients with glioblastoma.
BY MARK CHIEW
Two days after American Thanksgiving, we had the opportunity to speak with Lia Hocke, Yunjie Tong and Blaise Frederick about their recent MRM paper “Comparison of peripheral near-infrared spectroscopy low-frequency oscillations to other denoising methods in resting state functional MRI with ultrahigh temporal resolution”. Working out of the McLean Hospital, part of Harvard Medical School, they shared their perspective on the mutual information contained in peripheral NIRS (near infrared spectroscopy) and fMRI signals. They also used the word “photoplethysmograph” correctly in a sentence, and left us with a delightful shout-out to statistical rigor.
BY XIN MIAO
Dongwook Lee is currently a PhD student at the Korea Advanced Institute of Science and Technology (KAIST). He works on advanced image reconstruction techniques for dynamic MRI. His paper, selected as the Editor’s Pick for December, is entitled “Acceleration of MR parameter mapping using annihilating filter-based low rank Hankel matrix (ALOHA)”. ALOHA is a novel image reconstruction algorithm with the goal of clear, artifact free images acquired from very fast imaging schemes. For this paper, ALOHA was applied to accelerated MR parameter mapping, but could also be used for dynamic and parallel MRI, and even non-MR applications. We recently invited Dongwook and his supervisor, Dr. Jong Chul Ye, to talk about this paper.
α-trideuteromethyl[15N]glutamine: A long-lived hyperpolarized perfusion marker, by Markus Durst, Enrico Chiavazza, Axel Haase, Silvio Aime, Markus Schwaiger and Rolf F. Schultz.
December Editor’s Picks
Comparison of peripheral near-infrared spectroscopy low-frequency oscillations to other denoising methods in resting state functional MRI with ultrahigh temporal resolution, by Lia M. Hocke, Yunjie Tong, Kimberly P. Lindsey and Blaise de B. Frederick. Link to audio slides.
Acceleration of MR parameter mapping using annihilating filter-based low rank hankel matrix (ALOHA), by Dongwook Lee, Kyong Hwan Jin, Eung Yeop Kim, Sung-Hong Park and Jong Chul Ye. Link to audio slides.
BY THIJS DHOLLANDER
Recently, we had a chat with Elias Kellner, Valerij Kiselev and Marco Reisert from the University Medical Center Freiburg about their MRM paper entitled “Gibbs-Ringing Artifact Removal Based on Local Subvoxel-Shifts”. A challenge in time zone management, the interview was an early morning event for the MRM highlights editor (Nikola, in Montreal) and a late evening for the interviewer (Thijs, in Melbourne); however, that didn’t stop us discussing not only the paper, but also the art of paper writing and valuable lessons for the developers of novel acquisition strategies.
BY JESSICA MCKAY
This month’s Editor’s Pick features a project that makes kurtosis imaging more accessible to clinicians and researchers, alike, from a group in Denmark that includes our interviewees: Brian Hansen and Sune Jespersen. Diffusion kurtosis imaging (DKI) increases sensitivity to microstructural changes by extending the diffusion signal expression to account for non-Gaussian effects, but it typically requires time-consuming acquisitions with high diffusion weighting. Brian and Sune’s group had previously described a fast protocol, referred to as the 1-3-9 scheme, that includes three diffusion directions at a low b-value to determine the mean diffusivity and 9 specific diffusion directions at a higher b-value to calculate mean kurtosis [Hansen et al. MRM 69, 2013]. In this work, they extend the protocol to make it more robust to experimental imperfections by acquiring all 9 directions at the lower b-value, which they call 1-9-9. They further characterize the optimum b-values and propose a method to correct for imperfect diffusion directions. Keep reading to find out how their acquisition scheme expands the clinical value and feasibility of kurtosis imaging and you may even be inspired to add this ~1-minute scan onto your own protocol.
BY YOGESH MARIAPPAN
As the field of MRI is slowly but surely moving from qualitative to quantitative, and from imaging structures to imaging other properties, the choice of this month’s Highlights article is apt: the research group led by Ingolf Sack has been at the forefront of both of these aspects with their work on MR Elastography (MRE). This is a quantitative imaging technique capable of measuring the mechanical properties of tissues of interest and is available from all the major vendors. The current clinical application is focused on liver where the stiffness (measured in kilopascals) is used for fibrosis assessment. In this article they have provided recent results from their “In vivo wideband multi-frequency work” on liver and brain.