Methods for Motion Correction

Thursday 15 May 2014

M. Dylan Tisdall^1,2, Himanshu Bhat³, Keith Heberlein³, and André J. W. van der Kouwe^1,2
1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States, ²Radiology, Harvard Medical School, Boston, Massachusetts, United States, ³Siemens Medical Solutions USA Inc., Charlestown, Massachusetts, United States

We demonstrate the use of EPI-based volumetric navigators (vNavs) in 3D FLASH for prospective correction of head motion. Unlike in previous works with vNavs, where the navigator was inserted into dead time (e.g., TR or TI fill), in vNav FLASH we use the same pulse and TR for both vNavs and the FLASH TRs, allowing us to alternate between them without disturbing the magnetization steady state. We demonstrate the use of this sequence to perform prospective motion correction in a volunteer.

Maximilian Haeberlin¹, Alexander Aranovitch^1,2, Lars Kasper¹, Christoph Barmet¹, and Klaas Paul Pruessmann^1
1Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland, ²Department of Physics, Technische Universität München, Bavaria, Germany

Neuro applications such as fMRI, DWI or PWE imaging that use EPI readouts for image encoding often suffer from rigid body motion of the head. We present a method that uses the high frequency content of the EPI trajectory to track the positions of a field probe array attached to the head that is robust against field fluctuations and is combined with concurrent field monitoring in the head frame of reference. We report a localization precision of 12 micrometers and show successful continuous slice tracking during a 3-minute EPI acquisiton well suited for fMRI.

Michael Schär^1,2, Holger Eggers³, Nicholas R Zwart², Yuchou Chang², Akshay Bakhru⁴, and James G Pipe^2
1Philips Healthcare, Cleveland, OH, United States, ²Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, ³Philips Research, Hamburg, HH, Germany, ⁴Philips Healthcare, Bangalore, Karnataka, India

The readout direction in PROPELLER MRI is rotated over 180°. The water-fat shift may blur fat, or the motion correction may try to remove the fat blurring at the expense of water sharpness. Here we propose to use Dixon water-fat separation per blade to reconstruct either water only images, or to combine water with fat shifted back to its original position for each blade before running the PROPELLER motion correction algorithm. This work shows that the proposed method improves shift estimation, reduces blurring in images acquired with and without bulk motion, and allows water and fat separated PROPELLER MRI.

Aleksandra Sulikowska¹, Samuel Wharton¹, Paul M Glover¹, and Penny A Gowland^1
1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

We have characterised the size and locations of the maximum B0 field shifts within the brain at 7T for head pitch and roll angles in order to determine how these may be accounted for in motion correction. B0 difference maps of the brain were acquired from 5 healthy volunteers, each being imaged at 4 different head orientations. Eight small VOIs located at the positions of the largest observed field changes were analysed for each subject. The B0 field difference maps are spatially similar across all subjects and the magnitude of shift shows a linear dependence on the angle of both pitch and roll. The maximum frequency shift occurs in the frontal lobe during pitch where the sensitivity is -1.32±0.02 Hz/degree.

Gastao Cruz¹, David Atkinson², Christoph Kolbitsch¹, Tobias Schaeffter¹, and Claudia Prieto^1
1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom, ²Centre for Medical Imaging, University College London, London, United Kingdom

We propose a motion compensation framework for 3D free-breathing abdominal MRI. This approach uses a general matrix description that incorporates motion compensation directly into the reconstruction process. The proposed method is compared with a recently introduced motion compensation technique based on image warping and the conventional gated approach. Results show the proposed approach produces images sharper than the image warping approach and gated reconstruction.

Anne Menini^1,2, Pauline Ferry³, Marine Beaumont^4,5, Jeffrey A. Stainsby⁶, Glenn S. Slavin⁷, Laurent Bonnemains⁵, Jacques Felblinger^1,4, and Freddy Odille^3
1IADI, Université de Lorraine, Nancy, France, ²Global Research, GE, Garching b. München, Germany, ³U947, INSERM, Nancy, France, ⁴CIC, INSERM, Nancy, France, ⁵CHU Nancy, Nancy, France, ⁶Healthcare, GE, Toronto, ON, Canada, ⁷Healthcare, GE, Bethesda, MD, United States

Dynamic quantification of myocardial T₁ pre- and post-injection is a useful tool to evaluate fibrosis. These quantifications require numerous acquisitions and are therefore very sensible to inter- and intra-acquisition motion, especially in patients who can barely hold their breath. Here, we propose a motion compensation method that can be applied on multi-contrast acquisitions by taking advantage of redundant information. This motion correction was applied on data sets acquired in free-breathing in two patients with Duchenne Muscular Dystrophy. The proposed method was shown to improve the differentiation between regions of the myocardium with different stages of fibrosis.

Francisco Contijoch¹, Yuchi Han¹, Michael Schacht Hansen², James J Pilla¹, Joseph H Gorman¹, Robert C Gorman¹, and Walter RT Witschey^1
1University of Pennsylvania, Philadelphia, PA, United States, ²NHLBI, NIH, Bethesda, MD, United States

Although cardiovascular magnetic resonance imaging (MRI) is the gold standard for assessment of cardiac function, image quality is compromised in patients with ectopy. We sought to understand how ECG-gated retrospective reconstruction fails despite arrhythmia rejection before developing a retrospective reconstruction method using cardiac self-gating on low spatial resolution images are obtained from golden angle radial MRI data. Myocardial systolic and diastolic motion was inferred from segmented ventricular volumes and golden angle projections were retrospectively reconstructed to obtain high quality images. The effectiveness of the method was evaluated in 2 patients with severe ventricular arrhythmia.

Jonathan Powell¹, Markus Henningsson¹, Claudia Prieto^1,2, Peter Koken³, and Rene Botnar^1
1Division of Biomedical Engineering and Imaging Sciences, King's College London, London, London, United Kingdom, ²Escuela de Ingeniería, Pontificia Universidad Catolica de Chile, Santiago, Chile, ³Philips Research, Hamburg, Germany

We use a novel 3D beat-to-beat cardiac navigator to retrospectively correct 3D CMRA datasets. As a result we achieve an effective 100% navigator efficiency with equivalent image quality compared to 8mm gated CMRA scans.

Julian Maclaren¹, Murat Aksoy¹, Jakob Ehrl¹, Manojkumar Saranathan¹, and Roland Bammer^1
1Dept. of Radiology, Stanford University, Stanford, CA, United States

Due to the advent of optical prospective motion correction techniques, it is becoming increasingly common to place MR-compatible video cameras inside the scanner bore during imaging. In this work, we show that video data of the skin can be used to obtain both cardiac and respiratory signals from the subject without requiring a marker or any other form of physical contact.

Aditya Singh¹, Benjamin Zahneisen¹, Brian Keating¹, Michael Herbst², Maxim Zaitsev², and Thomas Ernst^1
1JABSOM, University of Hawaii, Honolulu, Hawaii, United States, ²University Medical Center Freiburg, Freiburg, Germany

Prospective motion correction (PMC) using camera-based tracking of a skin-attached marker may suffer from problems such as loss of marker visibility and false tracking signals due to squinting or twitching. We introduce a PMC system that is capable of mitigating these problems by simultaneously tracking two markers placed on the object to be imaged. Experiments demonstrate improved image quality during obstruction of the line-of-sight and when a subject squints. The techniques developed can be applied to any optical tracking system and can be adapted to the use of more than two markers.