|Cardiac Cine & New Contrast Mechanisms|
Free Breathing and Breath-Held High Temporal
Resolution (< 6 Ms) Cardiac Cine Steady State Free Precession (SSFP)
Imaging for Estimation of Diastolic Function
Ramkumar Krishnamurthy1, 2, Benjamin Y. Cheong2, 3, Raja Muthupillai2, 3
1Rice University, Houston, Texas, USA; 2St. Luke's Episcopal Hospital, Houston, Texas, USA; 3Baylor College of Medicine, Houston, Texas, USA
We describe a navigator-guided free breathing (Nav-SSFP), and a SENSE accelerated (Sen-SSFP) breath-held steady-state free precession (SSFP) cine imaging techniques that provide high temporal resolution (3-6 ms). We demonstrate that images acquired using these techniques can be used to measure various indices such as isovolumic relaxation time, time-to-peak filling rate, time-to-peak ejection rate, etc., for characterizing diastolic function as well as myocardial dyssynchrony. The results from our investigation in 10 normal subjects demonstrate that both techniques yield comparable metrics for quantifying diastolic function.
Real-Time Assessment of Right and Left Ventricular
Volumes and Function in Patients with Congenital Heart Disease Using
High Spatio-Temporal Resolution Radial K-T SENSE
VIvek Muthurangu1, Andrew Taylor1, Philip Lurz1, Michael Hansen1
1UCL Institute of Child Health, London, UK
Study to assess the accuracy of ventricular volumes measured using high spatio-temporal resolution radial real-time imaging accelerated with kt-sense in patients with congenital heart disease. Compared to standard real-time imaging radial kt-SENSE images were of high quality. In addition, using cardiac gated imaging as a reference standard method, radial kt-SENSE was more accurate than standard real-time assessment of cardiac function. This technique offers the possibility of accurate real-time assessment of cardiac function. This may be particularly useful in patients who find breath holding difficult (i.e. children), and patients with irregular heart rhythms.
Real-Time M-Mode MRI Monitoring of
Regional Wall Thickening
Corinna S. Maier1, 2, Michael Bock2, Wolfhard Semmler2, Christine H. Lorenz3
1Siemens Corporate Research, Princeton, New Jersey, USA; 2German Cancer Research Center (dkfz), Heidelberg, Germany; 3Siemens Corporate Research, Baltimore, Maryland, USA
Monitoring the ECG for ischemic changes during dobutamine stress testing or MR-guided interventions is not possible in the MR environment due to the magnetohydrodynamic effect. A real time MR was converted to an m-mode (motion mode) representation analogous to echocardiography for simple continuous display of cardiac function. An active contours segmentation algorithm was developed to detecte the myocardial borders to enable the calculation of regional wall thickening. Preliminary results show that the method may allow semi-automated change detection as a monitoring method for CMR.
High Resolution Retrospective Reconstruction from
Real-Time Acquired Cine MR Images
Peter Kellman1, Christophe Chefd'hotel2, Christine H. Lorenz3, Christine Mancini1, Andrew E. Arai1, Elliot R. McVeigh4
1NIH, Bethesda, Maryland, USA; 2Siemens Corporate Research, Princeton, New Jersey, USA; 3Siemens Corporate Research, Baltimore, Maryland, USA; 4Johns Hopkins University, Baltimore, Maryland, USA
Real-time cardiac cine imaging typically has compromised image quality compared with gated, segmented breath-held studies. The proposed approach produces high quality cine images with high spatial and temporal resolution matching that of conventional segmented cine using fully automated retrospective reconstruction with real-time acquired image data.
Vector Map Visualisation of Phase
Contrast Images Demonstrates Disruption of Intra-Atrial Vortices in
Alan M. Groves1, David J. Larkman1, Stephen T. Goldring1, Giuliana Durighel1, Julie A. Fitzpatrick1, Jo V. Hajnal1, A David Edwards1
1Hammersmith Hospital, Imperial College London, London, UK
Cardiac MR has demonstrated the presence of intra-atrial vortices in the adult heart which are thought to conserve the momentum of inflowing blood during atrial filling. Circulatory changes around the time of birth have potential to disrupt these vortices. In this work preliminary assessment of intracardiac flow in newborn preterm and term infants with phase contrast imaging is described, along with vector map visualisation of intra-atrial flow patterns. The potential mechanism and significance of this deviation from the adult pattern is discussed.
Contrast-Agent Concentration Quantification During
First-Pass MRA Using Susceptibility-Induced Magnetic Field Shifts
Ludovic de Rochefort1, Thanh Nguyen1, Ryan Brown1, Martin R. Prince1, Yi Wang1
1Weill Medical College of Cornell University, New York, New York, USA
Paramagnetic contrast agents (CA) modify tissue susceptibility and distort magnetic fields in proportion to their concentration. The frequency shift is proportionnal to the contrast agent concentration and a shape factor which can be calculated provided that the shape is known. Here, using an inversion method, [CA] was measured continuously in the aortic arch during the first-pass MRA. Cardiac output was measured and compared to phase-contrast data evaluating the ability of the method to quantify susceptibility in vivo and derive physiological parameters.
Observing the Settling of Blood in the
Supine Resting Condition in the Peripheral Vascular System Using SWI
Ewart Mark Haacke1, 2, Jaladhar Neelavalli1, Samuel Barnes1, Zahid Latif1
1Wayne State University, Detroit, USA
The risk for deep vein thrombosis (DVT) increases with age and for travellers who are immobile for more than 4 hrs. In this abstract, using ssusceptibility weighted imaging, we show some evidence that points to the transient settling of blood as a possible cause of DVT.
Multi-Echo Dixon Fat and Water Separation Method for
Detecting Fibro-Fatty Infiltration in the Myocardium
Peter Kellman1, Diego Hernando2, Saurabh Shah3, Sven Zuehlsdorff3, Renate Jerecic3, Christine Mancini1, Zhi-Pei Liang2, Andrew E. Arai1
1NIH, Bethesda, Maryland, USA; 2University of Illinois, Urbana, Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA
A Multi-echo Dixon fat and water separation method for detecting fibro-fatty infiltration in the myocardium can be used before or after contrast administration. The method is easy to use and provides improved contrast compared with conventional fat suppression.
Black-Blood Imaging of the Human Heart Using Rapid
Alexander Karaus1, Dietmar Merboldt1, Joachim Graessner2, Jens Frahm1
1Biomedizinische NMR Forschungs GmbH am MPI fuer biophysikalische Chemie, Goettingen, Germany; 2Siemens Medical Solutions, Hamburg, Germany
Because stimulated echoes dephase signals from moving spins, high-speed STEAM MRI sequences were developed for "black-blood" imaging of the heart that overcome limitations of double inversion-recovery techniques. Multislice images along anatomic orientations and triggered to end diastole were obtained from healthy subjects at 3 T. Optimum SNR and resolution of typically 2.0 × 2.0 mm2 (6 mm section thickness) were achieved by segmented multi-shot sequences with interleaved k-space acquisitions (160 ms each) from several heart beats during a single breathhold. Rapid STEAM MRI emerges as a simple technique for multislice imaging of the myocardial wall with efficient flow suppression.
Isotropic High-Resolution 3D MRI of Carotid Arterial
Wall with Imporved Blood Suppression Using Motion-Sensitized Dephasing
Zhaoyang Fan1, 2, Zhuoli Zhang1, Yiucho Chung3, Peter Weale3, John Sheehan1, Natasha Berg1, Ioannis Koktzoglou1, Mark Morasch1, Timothy Carroll1, 2, Renate Jerecic3, James Carr1, Debiao Li1, 2
1Northwestern University, Chicago, Illinois, USA; 2Evanston, Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA
3D MRI offers advantages over 2D techniques for vessel wall visualization, but blood suppression and imaging time are more challenging. A motion-sensitized dephasing (MSD) preparation was combined with a fast 3D TSE sequence (SPACE), and residual intraluminal blood was suppressed dramatically at 3.0T. It was demonstrated on healthy volunteers and carotid atherosclearotic patients that MSD-SPACE is capable of achieving a superior spatial resolution (0.63 mm isotropic), shorter scan time, and significantly higher wall-lumen CNR efficiency as compared to multi-slice 2D TSE using inflow/outflow saturation band technique. MSD-SPACE is a promising technique for plaque screening in the carotid arteries at 3.0T.