|Cardiac Function & Wall Motion|
Balanced Left Ventricular Myocardial SSFP-Tagging at
1.5 and 3 Tesla
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.
Accelerated 3D Tagging for Quantification of Left
Ventricular Dyssynchrony in Patients After Myocardial Infarction
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.
Inverted Left Ventricular Apical Rotation
in Patients Eligible for Cardiac Resynchronization Therapy Assessed by
Tagged MRI Predicts Acute Response to Biventricular Pacing
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.
zHARP with Dumbbells (D-ZHARP): Accelerated True 3-D
Myocardial Regional Function Quantification and Tracking
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.
Externally Calibrated ARC Parallel Imaging
Reconstruction for DENSE Imaging: Initial Experience
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.
Respiratory Triggered DENSE Imaging with Navigator
Echoes: Initial Experience
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.
|Strain-Encoded (SENC) MR Imaging with
Improved Signal-To-Noise Ratio Using Balanced Steady-State Free
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.
Segmental Left Ventricular Function Depends on Gender
and Age: New Findings by High Temporal Resolution Tissue Phase Mapping
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.
Myocardial Acceleration Calculation from Highly Time
Resolved Tissue Phase Mapping
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.
|Non Invasive Measurement of the Volume-Pressure Work
of the Human Heart by Cardiac MR Elastography
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.