Session MOD. There are 5 abstracts in this session.

Session: ADVANCES IN MRI, time: 4:00 - 4:25 pm

Tissue Microstructure Assessed by Quantitative Temporal Diffusion Spectroscopy  

John Gore; Sean Devan; Xiaoyu Jiang; Junzhong Xu
Vanderbilt University Medical Center, Nashville, TN

Diffusion MRI techniques provide information on the compartmental microstructure within cellular and porous media. A variety of methods have been developed which may be used to quantify microstructural properties based on models of diffusion within cells and spaces of varying complexity. Temporal Diffusion Spectroscopy is one promising approach which makes use of diffusion encoding gradients with different temporal waveforms that probe diffusion rates over different time scales. This allows the derivation of cell sizes and intrinsic diffusion rates within tissue compartments based on a relatively simple set of acquisitions and data analyses. This method is of particular interest as it can be translated to clinical applications using current MRI scanners.


Session: ADVANCES IN MRI, time: 4:25 - 4:50 pm

How to Overcome Speed Limits in MRI

J├╝rgen Hennig1; Antonia Barghoorn-Reinke1; Burak Akin1; Bruno Riemenschneider1; Fei Wang1; Pierre Levan2
1University Hospital Freiburg, Freiburg, Germany; 2University Calgary, Calgary, Canada

Acquisition speed in MRI has gone considerably beyond the limits set by the Nyquist theorem. Compressed sensing, which makes use of the insight that images are structured and thus are or can be sparsified in some domain, allowed to exceed acceleration factors used in parallel imaging. AI allows further acceleration by lowering the amount of data required for image reconstruction based on ‘learning’ from previous images. Acquisition speed thus becomes ultimately dependent on how much prior knowledge is used for image reconstruction, how much new information needs to be acquired, and the most efficient sampling strategy to acquire these data. ‘Use cases’ from different scenarios – from ultrafast fMRI to high resolution structural imaging – illustrate the possibilities and challenges.

Session: ADVANCES IN MRI, time: 4:50 - 5:15 pm

Exploiting rotating fields in MRI and neuromodulation

Silvia Mangia
CMRR - Univ. of Minnesota, Minneapolis, MN

Methods of MRI relaxation in the rotating frame allow flexible non-invasive MRI contrasts which can probe microstructural environments due to their sensitivity to slow molecular dynamics. In particular, the methods based on frequency swept pulses developed by our group are exceptionally sensitive to subtle alterations of the brain white and grey matter, thus offering new markers of neurodegeneration and, possibly, neuroplasticity. Our group has exploited the concept of rotating fields also in the context of neuromodulation, and introduced the principle of orientation selective stimulation (OSS) with phase steering of the electrical field for both Deep Brain and Spinal Cord stimulation. Combined together, rotating fields in MRI and neuromdulation establish a rich foundation and framework for studying the central nervous system.

Session: ADVANCES IN MRI, time: 5:15 - 5:30 pm

Augmented Reality Visualization and Reslicing of MRI Data

Bragi Sveinsson; Neha Koonjoo; Matthew Rosen
MGH - Martinos Center, Charlestown, MA

Great advances have recently been made in developing low-cost, portable hardware for MRI data acquisitions, expanding the user base of MRI to poorer regions and more mobile situations. Less emphasis has been put on increased affordability and portability of equipment to view images post-acquisition. MRI data is typically visualized on a computer workstation with specialized medical image viewing software. In addition to suboptimal cost and portability, operating such software often requires considerable expertise, particularly for advanced operations such as freely choosing a slice orientation not orthogonal to the original scan plane. Here, we introduce a smartphone app designed to enable MRI visualization on a standard iPhone.

Session: ADVANCES IN MRI, time: 5:30 - 5:45 pm

A longitudinal MR study of the therapeutic effects of yoga in post-stroke recovery 

Rama Jayasundar1; Rajesh Mishra1; Dushyant Kumar1; Govind Maurya1; Senthil Kumaran1; Chahat Kumar2; Priyanka Bhagat2; Padma Srivastava2
1Department of NMR, AIIMS, New Delhi, India; 2Department of Neurology, AIIMS, New Delhi, India

This MR study has evaluated for the first time, the effects of yoga in post-stroke (ischemic) recovery. Patients (n=8) with motor deficits practiced yoga for one hour daily for six months under the supervision of certified yoga trainers. Pre- and post- (3, 6 months) yoga intervention assessment involved NIHSS (National Institutes of Health Stroke Scale) score and MRI (3T MR scanner). The latter included 3D-T1, 3D-FLAIR and fMRI (motor task). Preliminary MR findings from pre- and 3 months post-yoga intervention showed individual patients’ positive response to yoga reflected in the significantly reduced NIHSS scores, in the recovery of fMRI activation in the affected motor cortex and changes in cortical thickness of gray matter.