Time

Prog #

Michael Markl¹, Stephan Scherer¹, Alex Frydrychowicz¹, Dieter Burger¹, Annette Geibel², Jürgen Hennig¹

¹Dept. of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; ²Dept. of Cardiology, University Hospital, Freiburg, Germany

The purpose of this study was to evaluate the performance of SSFP-Tagging at 1.5T and 3T and to define the ideal settings with respect to optimized tag contrast throughout the cardiac cycle for both field strengths. For SSFP-Tagging at 3T, the combination of T1 lengthening and superior myocardial SNR is highly promising and has the potential to improve the depiction of tagged myocardial function throughout the entire cardiac cycle.

Andrea K. Rutz¹, Sebastian Kozerke¹, Robert Manka¹, ², Peter Boesiger¹, Juerg Schwitter³

¹University and ETH, Zurich, Switzerland; ²German Heart Institute, Berlin, Germany; ³University Hospital, Zurich, Switzerland

An accelerated 3D tagging acquisition was used to quantify left ventricular dyssynchrony in patients after acute myocardial infarction relative to a control population. Volumetric tagging data of the entire heart were acquired in only three breath-holds and an enhanced variant of the harmonic phase (HARP) analysis was applied for post-processing. Temporal and spatial dyssynchrony was significantly increased in patients compared to healthy volunteers (p<0.0001). Combined with CMR viability imaging, the approach shows potential to improve individual responsiveness to cardiac resynchronization therapy and to predict left ventricular remodeling.

Iris K. Rüssel¹, Gerjan J. de Roest¹, J T. Marcus¹, Cornelis P. Allaart¹, Carel C. de Cock¹, Marco J. Götte¹, Albert C. van Rossum¹

¹VU University Medical Center, Amsterdam, Netherlands

Since left ventricular torsion is directly related to myocardial fiber structure, patients eligible for cardiac resynchronization therapy probably show a disorder in torsion. From tagged MRI, basal and apical rotation were determined in patients and controls. In patients, the maximum relative increase in dP/dt during biventricular pacing in different locations was measured as acute response to pacing. With respect to controls, several patients have inverted apical rotation and respond well to biventricular pacing.

Khaled Zakarya Abd-Elmoniem¹, Jerry L. Prince¹, Matthias Stuber¹

¹The Johns Hopkins University, Baltimore, Maryland, USA

A fast imaging strategy is proposed to accelerate zHARP 3-D myocardial regional function imaging using a dumbbells-shaped k-space trajectory. The strategy reduce the acquisition time for zHARP imaging from two breath-holds to four heart beats without sacreficing image or calculated strain quality The scheme has the potential to significantly abbreviate a 3D cardiac strain imaging as compared to more conventional approaches.

Pelin Aksit¹, Ajit Shankaranarayanan², Sandeep N. Gupta¹, Philip J. Beatty², Anthony H. Aletras³, Maggie M. Fung¹, Ehud J. Schmidt¹, Maureen N. Hood⁴, Vincent B. Ho⁴

¹GE Healthcare, Bethesda, Maryland, USA; ²GE Healthcare, Menlo Park, California , USA; ³NIH, Bethesda, Maryland, USA; ⁴Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA

Un-accelerated DENSE reveals high-spatial-density myocardial strain, however requiring long breath-holds.  DENSE imaging benefits from flexible parallel imaging acceleration factors to tailor acquisition time to patients’ heart rates and breath-hold capacity.  A DENSE sequence was modified to allow integer and non-integer acceleration factors, with or without a variable sampling density, using the ARC parallel imaging reconstruction method. DENSE with ARC is shown, in 9 normal subjects, to provide consistent strain maps with acceptable noise levels, at acceleration factors of 1.0-2.0 (14-29 cardiac cycles scan time), suggesting its appropriateness for a range of patient populations, without compromising the ability to quantify strain.

Maggie M. Fung¹, Pelin Aksit¹, Sandeep N. Gupta¹, Ajit Shankaranarayanan², Philip J. Beatty², Anthony H. Aletras³, Ehud J. Schmidt⁴, Maureen N. Hood⁵, Vincent B. Ho⁵

¹GE Healthcare, Bethesda, Maryland, USA; ²GE Healthcare, Menlo Park, California , USA; ³National Institute of Health, Bethesda, Maryland, USA; ⁴GE Healthcare, Boston, Massachusetts, USA; ⁵National Naval Medical Center, Bethesda, Maryland, USA

DENSE is a high-resolution method for evaluating cardiac contractility. Breath-held DENSE requires prolonged breath-holding (>20 sec) and is relatively low in SNR due to STEAM acquisition and limited time for T1-weighted magnetization recovery. A respiratory-triggered DENSE acquisition using dual navigator echoes was developed, increasing the magnetization recovery time from 1 heart cycle (<1s) to 1 respiratory cycle (4-5s), and thus providing a significant SNR improvement. The SNR improvement is shown to improve the reliability of the resulting strain maps, or, alternatively, it allows the use of greater acceleration factors to reduce the scan time.

Tamer A. Basha¹, ElSayed H. Ibrahim¹, Monda L. Shehata¹, Robert G. Weiss¹, Nael F. Osman¹

¹Johns Hopkins University, Baltimore, Maryland, USA

Strain Encoding (SENC) is a new MRI technique for quantifying regional myocardial strain. However, it suffers from its intrinsically low SNR. The purpose of this work is to improve the SENC images SNR by combining it with the SSFP pulse sequence which is known for its intrinsically high SNR and excellent blood-tissue contrast. This combination could offer substantial improvement in the image SNR, and thereby enhances the qualitative and quantitative analysis of heart wall motion.  The SENC-SSFP sequence was tested in phantom and human experiments, and showed significant improvement (about 100%) in SNR compared to conventional SENC.

Daniela Foell¹, Elfriede Schilli¹, Felix Staehle¹, Bernd Jung¹, Christoph Bode¹, Juergen Hennig¹, Michael Markl¹

¹University Hospital Freiburg, Freiburg, Germany

Using CINE phase contrast MRI (Tissue Phase Mapping, TPM) we analyzed myocardial velocities in all spatial directions of the left ventricle. A segmental assessment covering the entire left ventricle of 60 healthy volunteers in 3 age-groups was performed. Our data clearly demonstrate age- and gender specific alterations of regional myocardial motion. Most noticeably, we found an increased reduction in regional diastolic velocities in women during the process of aging, whereas myocardial velocities of young women exceeded those of age-matched men. These differences may have been missed, if analysis of cardiac function was restricted to an evaluation of global velocities.

Felix Staehle¹, Bernd André Jung¹, Daniela Föll¹, Elfriede Schilli¹, Jürgen Hennig¹, Michael Markl¹

¹University Hospital Freiburg, Freiburg, Germany

This abstract is a feasibility study of the calculation of acceleration data from highly time resolved tissue phase mapping (TPM) of the myocardium. Velocity data of a group of 10 healthy volunteers and two patients were measured and evaluated by voxel tracking between successive time frames and a non-linear curve fit to determine the acceleration value. The mean time courses of acceleration data show a different sensitivity to pathology than the velocity data. The evaluation of peak acceleration values and corresponding times-to-peak support the feasibility of acceleration to provide valuable information about various pathologies.

Thomas Elgeti¹, Jens Rump¹, Dieter Klatt¹, Uwe Hamhaber¹, Sebastian Papazoglou¹, Jürgen Braun¹, Bernd Hamm¹, Ingolf Sack¹

¹Charité Universitätsmedizin Berlin, Berlin, Germany

Wave amplitude variation MR-Elastography enables non invasive measurement of the volume-pressure work of the human heart in 6 healthy volunteers.