TRADITIONAL POSTER - ismrm

Poster Sessions
3043. T2-Prepared Segmented 3D-Gradient-Echo as Alternative to T2-Weighted TSE for Fast High-
Resolution Three-Dimensional Imaging
Jian Zhu 1,2 , Axel Bornstedt 1 , Vinzenz Hombach 1 , Alexander Oberhuber 3 , Genshan Ma 2 , Naifeng Liu 2 ,
Volker Rasche 1
1 Department of Internal Medicine II, University Hospital of Ulm, Ulm, Germany; 2 Department of Cardiology, Zhongda Hospital,
Southeast University, Nanjing, China; 3 Department of Thorax and Vascular Surgery, University Hospital Ulm, Ulm
Spin-echo and multi-spin echo sequences are still the gold standard for generation of a T2 – weighted image contrast. A major drawback of this technique
rises from the long repetition times required for achieving sufficient recovery of the longitudinal magnetization, which cause long acquisition times
especially in high-resolution volumetric imaging. In this study, the use of a fast gradient echo sequence with T2 preparation is investigated for generating a
T2 weighted image contrast similar to a multi-spin echo approach, but with an up to 8-fold reduction of the acquisition time.
3044. Differential Subsampling with Cartesian Ordering (DISCO): A Novel K-Space Ordering Scheme for
Dynamic MRI
Dan Rettmann 1 , Manojkumar Saranathan 1 , James Glockner 2
1 Applied Science Lab, GE Healthcare, Rochester, MN, United States; 2 Radiology, Mayo Clinic, Rochester, MN, United States
Dynamic contrast enhanced MRI (DCEMRI) and MR angiography (MRA) are both beset by the conflicting requirements of spatial and temporal resolution.
Various schemes have been proposed and evaluated for high spatio-temporal resolution MR imaging which incorporate combinations of partial Fourier
imaging, sub-sampling, view sharing and parallel imaging to effect acceleration. We propose DISCO (DIfferential Subsampling with Cartesian Ordering), a
flexible k-space segmentation scheme that minimizes sensitivity to eddy currents and motion for dynamic imaging while dispersing artifacts and residual
ghosting and demonstrate its use in first pass contrast enhanced liver imaging.
Motion Correction
Hall B Tuesday 13:30-15:30
3045. Advancements in Contact-Free Respiration Monitoring Using RF Pick-Up Coils
Ingmar Graesslin 1 , Giel Mens 2 , Alexander Guillaume 1 , Henry Stahl 3 , Peter Koken 1 , Peter Vernickel 1 , Paul
Harvey 2 , Jouke Smink 2 , Kay Nehrke 1 , Peter Boernert 1
1 Philips Research Europe, Hamburg, Germany; 2 Philips Healthcare, Best, Netherlands; 3 FH Westküste, Heide, Germany
Advanced methods of motion detection and motion artifact reduction help to improve diagnostic image quality. The use of conventional navigators requires
additional planning and adversely influences the steady state, which can result in image artifacts. A new approach was presented that uses the detection of
changes of RF coil loading induced by the respiratory motion of the patient. This paper describes the application of a real-time self-navigated respiration
monitoring approach using dedicated RF monitoring pulses instead the RF excitations of the imaging sequence. RF amplifier drift is analyzed, and a
compensation scheme is proposed to overcome this problem.
3046. 3D TOF Angiography Using Real Time Optical Motion Correction with a Geometric Encoded Marker
Daniel Kopeinigg 1,2 , Murat Aksoy 1 , Christoph Forman 3 , Roland Bammer 1
1 Department of Radiology, Stanford University, Palo Alto, CA, United States; 2 Institute of Medical Engineering, University of
Technology Graz, Graz, Austria; 3 Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
Correction of motion artifacts is an ongoing and very important task in MRI. This motion, most often introduced by patients that suffer from a medical
condition, which makes it difficult to remain motionless during MRI acquisitions, can significantly corrupt the resulting images and their diagnostic value. In
this study we show first in-vivo results of our prospective optical motion correction system applied to three-dimensional time of flight (3D TOF)
angiography. Results show that compared to the non-motion corrected case the real-time motion correction is able to dramatically improve image quality of
3D TOF angiograms.
3047. Motion Characterisation Using FID Navigators and Spatial Pattern of MRI Coil Arrays
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, Lausanne, Switzerland; 4 Departments of Radiology, Universities of Lausanne and Geneva, Switzerland
In this work we investigate the potential to characterise rigid-body head motion by monitoring free induction decay (FID) changes over time in coil arrays.
The technique makes use of the fact that FID signals detected by local coil elements change as a function of object distance. Assuming a sufficient coverage
of the scanned object with local coil elements, the inverse problem of back-calculation of the rigid motion parameters may be solvable. In this investigation,
a framework to derive these motion parameters is developed and first results are shown from phantom and human scans using a 32-channel head coil array.
3048. Iterative Motion Compensated Reconstruction
Tim Nielsen 1 , Peter Boernert 1
1 Philips Research Europe, Hamburg, Germany
Motion during data acquisition can seriously degrade image quality. Motion compensated reconstruction can restore image quality if the motion is measured
with suitable navigator signals. We present a new scheme for motion compensated reconstruction which can be applied to segmented Cartesian acquisitions
(e.g. TSE, TFE). It can be combined with parallel imaging and is fast because it works mainly in the spatial domain avoiding many Fourier-transforms
between k-space and image space. The motion is detected and quantified by adding an orbital navigator echo in front of the imaging echoes.