ELECTRONIC POSTER - ismrm

14:00 5036. Real-Time Motion Correction for High-Resolution Imaging of the Larynx:
Implementation and Initial Results
Joëlle Karine Barral 1 , Juan M. Santos 1 , Dwight G. Nishimura 1
1 Electrical Engineering, Stanford University, Stanford, CA, United States
Respiratory motion is currently the main limitation to high-resolution MR imaging of the larynx. A novel algorithm integrating
Compressed Sensing and the Diminishing Variance Algorithm is proposed and implemented within the framework of the real-time
system RTHawk. The effectiveness of the approach is demonstrated on phantoms and in vivo.
14:30 5037. Real-Time Motion Detection for Structural Brain Imaging Using Multi-Coil FID
Navigators
Tobias Kober 1,2 , José P. Marques 1,3 , Rolf Gruetter 1,4 , Gunnar Krueger 2
1 Laboratory for functional and metabolic imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne,
Switzerland; 2 Advanced Clinical Imaging Technology, Siemens Suisse SA - CIBM, Lausanne, Switzerland;
3 Department of Radiology, University of Lausanne, Switzerland; 4 Departments of Radiology, Universities of
Lausanne and Geneva, Switzerland
Subject motion is often affecting the quality of MRI data. In this work, we investigate the feasibility to detect motion by monitoring
repetitive FID navigator signals from arrays of receive coils. Object motion is shown to induce changes in the FID signal intensity. For
proof of concept, the technique was applied to structural MP-RAGE scans of the brain. Subject motion was reliably detected. The
technique has the potential to provide a scan quality measure and motion parameters for real-time or retrospective correction. It could
be used in other MR sequences without time or signal penalty.
15:00 5038. Real-Time Intra-Volume Motion Correction in EPI Using Active Markers
Melvyn Boon King Ooi 1,2 , Sascha Krueger 3 , William J. Thomas 2 , Truman R. Brown 1,2
1 Biomedical Engineering, Columbia University, New York, NY, United States; 2 Radiology, Columbia
University, New York, NY, United States; 3 Philips Research Europe, Hamburg, Germany
Head motion is a fundamental problem in fMRI. A prospective, slice-by-slice compensation strategy for rigid-body motion is
presented for EPI sequences. Before the acquisition of each EPI-slice, a short tracking pulse-sequence is used to measure the positions
of three micro RF-coil "active markers" integrated into a headband worn by the subject. During head motion, the rigid-body
transformation that realigns these markers to their initial positions is fed back to update the image-plane – maintaining it at a fixed
orientation relative to the head – before the next EPI-slice is acquired. EPI time-series are obtained that demonstrate real-time imageplane
realignment during volunteer motion.
Image Correction - Non-Motion
Hall B Monday 14:00-16:00 Computer 122
14:00 5039. Application of K-Space Energy Spectrum Analysis for Inherent and Dynamic B 0
Mapping and Distortion Correction in DTI
Trong-Kha Truong 1 , Nan-kuei Chen 1 , Allen W. Song 1
1 Brain Imaging and Analysis Center, Duke University, Durham, NC, United States
Diffusion tensor imaging (DTI) is vulnerable to spatial and temporal B 0 variations due to susceptibility effects, eddy currents, subject
motion, physiological noise, and system instabilities, resulting in geometric distortions and subsequent errors in the derivation of the
diffusion tensor. Here, we propose a novel method based on k-space energy spectrum analysis, which can inherently and dynamically
generate a B 0 map from the k-space data for each baseline (b = 0) and diffusion-weighted image, without requiring any additional data
acquisition, to effectively and efficiently correct for such artifacts and achieve a high spatial fidelity and accuracy.
14:30 5040. A Blood Flow Navigator for Assessing Physiologic Noise in EPI Data
Andre van der Kouwe 1 , Matthew Dylan Tisdall 1 , Oliver Hinds 1 , Aaron Hess 2 , David
Salat 1 , Douglas Greve 1
1 Radiology, Massachusetts General Hospital, Charlestown, MA, United States; 2 Biomedical Engineering,
University of Cape Town, Cape Town, South Africa
A rapid single slice EPI acquisition (neck blood flow navigator) is interleaved between slices of a conventional multislice 2D BOLD
EPI acquisition in a single sequence that provides information with high temporal resolution describing blood flow in the major
arteries of the neck. This signal is tightly coupled to blood flow in the brain and may be used to assess and correct for physiologic
noise in the BOLD signal. Navigator images are reconstructed in real-time during acquisition and it is shown that the timing of the
cardiac signal derived from the navigators closely matches the timing of the photoplethysmograph.
15:00 5041. CINE Images of a Beating Rodent Cardiac Phantom
Steven Fortune 1 , Ian Marshall 1 , Maurits A. Jansen 1 , Peter R. Hoskins 1 , Tom Anderson 1
1 Medical Physics, University of Edinburgh, Edinburgh, United Kingdom
Small animal cardiac MRI is challenging due to small dimensions and fast heart rates. In order to assist in the development and testing
of MRI sequences a rodent cardiac phantom has been designed and tested. It consists of a single chamber of PVAC housed in a water
bath, expanded by an external pump. Initial CINE images of the phantom show this phantom functions with similar parameters to a rat