Characterizing Myocardial Injury & Predicting Risk
Wednesday 22 April 2009
Room 313A 13:30-15:30

Moderators:

 W. Patricia Bandettini and Christopher M. Kramer
 
13:30 478. Cardiac Magnetic Resonance (CMR) Evaluation of Patients with ST-Elevated Acute Myocardial Infarction (STEMI): Influence of Time-To-Reperfusion on the Extent of the Area at Risk, Infarct Size and Microvascular Damage
    Iacopo Carbone1, Marco Francone2, Emanuela Algeri2, Ilaria Iacucci2, David Cannata2, Luciano Agati2, Carlo Catalano2, Roberto Passariello2
1La Sapienza University of Rome, Rome, Italy, Italy; 2La Sapienza University of Rome, Italy
    Seventy STEMI patients treated with primary PCI within 12 hours from symptom onset underwent CMR in the first week after hospital admission to assess the influence of time to reperfusion on infarct size, microvascular damage and salvaged myocardium. A progressive increase of infarct size and microvascular damage over time has been observed. However, the new finding of the present study is that salvaged myocardium suddenly decreases after 60 minutes of coronary occlusion confirming the importance to shorten the delay in STEMI treatment.
     
13:42 479. Quantitative Tissue Characterization of Infarct Heterogeneity in Patients with Ischemic Cardiomyopathy by Magnetic Resonance Predicts Future Cardiovascular Events
    Harendra Patel, MD1, Shahriar Heidary, MD2, Hajime Yokota, MD2, Chandra Katikireddy, MD2, Patricia Nguyen, MD2, John M. Pauly, PhD3, Masahiro Terashima, MD, PhD2, Michael V. McConnell, MD, MSEE2, Phillip C. Yang, MD2
1Medicine, Stanford University, Stanford, CA, USA; 2Cardiovascular Medicine, Stanford University, Stanford, CA, USA; 3Electrical Engineering, Stanford University, Stanford, CA, USA
    77 patients with ischemic cardiomyopathy (LVEF < 50%, mean LVEF: 28 ± 15%) considered for revascularization or medications ± ICD were enrolled. Using a 1.5T MRI scanner, the core and border zones of infarcted myocardium were analyzed. Patients were followed for cardiovascular events: VT, VFIB, ICD firing, CHF, hospitalization, MI, repeat revascularization, syncope and death. 39 patients (39%) had events (mean follow-up: 20 ± 16 months). The mass of the border zone rather than the core infarct was associated significantly with events (16.6 ± 13.2 g vs. 10.7 ± 10.1 g, p = 0.017 and 19.2 ± 11.7 g vs. 15.0 ± 11.6 g, p= 0.061, respectively). LVEDV, LVESV, and LVEF were not significantly different in patients with or without events. Quantitative tissue characterization of the border zone mass of infarcts is superior to core infarct mass, LVEDV, LVESV, and LVEF in prognosticating the likelihood of future cardiovascular events in patients with ICM. This CMR-guided technique may assist in clinical management of patients with ICM.
     
13:54 480. Clinical Validation of Multi-Contrast Delayed Enhancement (MCDE) for Wall Motion and Viability Imaging
    Jay Stephen Detsky1,2, Kim A. Connelly1,3, Gideon A. Paul1,4, John J. Graham3, Alexander J. Dick4, Graham A. Wright1,2
1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 3Cardiology, St. Michael's Hospital, Toronto, Ontario, Canada; 4Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
    The clinical accuracy and reproducibility of a new multi-contrast delayed enhancement (MCDE) sequence was tested in 41 patients. MCDE can be used to simultaneously visualize cardiac wall motion and viability; MCDE showed excellent agreement with the conventional wall motion and delayed enhancement sequences in this study. MCDE provides improved visualization of small infarcts and halves the number of breath-holds required wall motion and viability imaging.
     
14:06 481. Papillary Muscle Infarction by Delayed-Enhancement Magnetic Resonance Imaging: Reproducibility and Potential as an Independent Predictor of Ischemic Mitral Regurgitation
    Thananya Boonyasirinant1, Ronan Curtin2, Randolph M. Setser1, Michael L. Lieber3, Scott D. Flamm1
1Radiology, Cleveland Clinic, Cleveland, OH, USA; 2Cardiology, Cleveland Clinic, Cleveland, OH, USA; 3Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH, USA
    Delayed-enhancement MRI (DE-MRI) has been accepted as the high resolution, non-invasive infarction specific imaging for evaluation of myocardial viability. However the prevalence, feasibility, and reproducibility of papillary muscle infarction identification and the relationship between IMR severity and papillary muscle viability have not been established. This study demonstrated the feasibility of papillary muscle infarction identification using DE-MRI with excellent intra-observer and inter-observer reproducibility. The presence of posterior papillary muscle infarction and impaired EF are independent predictors of MR severity in ICM patients. The identification of papillary muscle infarction may provide novel insights into improved surgical strategies for IMR.
     
14:18 482. Elite Olympic Calibre High-Endurance Athletes Have Evidence for Myocardial Fibrosis : A Cardiovascular Magnetic Resonance Study
    Myra Sabene Cocker1, Oliver Strohm1, David J. Smith2, Craig Butler1, Israel Belenkie3, Willem Meeuwisse4, Matthias G. Friedrich1
1Stephenson CMR Centre at the Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; 2Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; 3Cardiac Sciences, University of Calgary, Calgary, Alberta, Canada; 4Sports Medicine Centre, University of Calgary, Calgary, Alberta, Canada
   

Background: Athletes have a greater risk of sudden cardiac death then the rest of the population. Autopsy findings show evidence for myocardial fibrosis in athletes. We speculate that a large proportion of athletes have evidence for myocardial fibrosis.  Methods: 48 elite high-endurance athletes and 8 healthy controls were recruited. Following LV function assessment, contrast enhanced cardiovascular magnetic resonance (CMR) was performed to assess for the presence of myocardial fibrosis.  Results: 77% of athletes had myocardial fibrosis in late enhancement image, compared to 13% of healthy control subjects.

Conclusion: The incidence of myocardial fibrosis in elite athletes is very high, and can be visualized with contrast enhanced CMR.
     
14:30 483. Cardiac T1 Mapping: A Comparison of Methodologies for Quantifying Cardiac T1 Values
    Ting Song1, Maureen N. Hood2, Vincent B. Ho3, Sandeep N. Gupta4, Jeffrey A. Stainsby5
1Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 2Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, MD, USA; 3Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, Bethesda, MD; 4GE Global Research, Niskayuna, NY, USA; 5Applied Science Laboratory, GE Healthcare, Toronto, ON, Canada
    Cardiac T1 mapping provides a quantitative way to characterize tissue abnormalities, such as myocardial infarction and amyloidosis. IR prepared SSFP, CINE-IR, and the modified look-locker saturation-recovery (MLLSR) were evaluated on both phantoms and human studies in this paper. The sensitivity of these techniques to variations in heart rate and flip angle were compared. The MLLSR sequence gave consistent, reliable results across the widest range of T1 values, flip angles and heart rates.
     
14:42 484. Myocardial T2* Mapping Free of Distortion Using Susceptibility Weighted Spin-Echo Based Imaging: A Feasibility Study at 1.5 T and 3.0T
    Uwe Heinrichs1, Jane Francis Utting2, Tobias Frauenrath2, Fabian Hezel2, Gabriele A. Krombach2, Michael AJ Hodenius3, Sebastian Kozerke4, Thoralf Niendorf2,5
1Department of Diagnostic Radiology, RWTH Aachen University , Aachen, Germany; 2Department of Diagnostic Radiology, RWTH Aachen University, Aachen, Germany; 32Department of Applied Medical Engineering, Helmholtz-Institute, RWTH Aachen University, Aachen, Germany; 43Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 5Faculty of Mathematics, Computerscience and Natural Science, RWTH Aachen University , Aachen, Germany
    This study is designed to demonstrate the promise of navigator gated, susceptibility weighted fast spin-echo imaging in conjunction with ventricular blood suppression for anatomically accurate T2*-mapping of the heart. First results of phantom and volunteer studies demonstrate the geometrical integrity and high image quality obtained with UFLARE - even for strong T2*-weighting at 1.5T and 3.0T. T2*-mapping using UFLARE yielded mean T2* values for the inferoseptal myocardium of 29.9±6.6 ms at 1.5T and 22.3±4.8 ms at 3.0T. The results derived with susceptibility weighted UFLARE promise to extend the capabilities of CVMR including mapping and quantification of myocardial iron content.
     
14:54 485. Navigator-Gated T2 and T2*-Weighted Imaging of Myocardial Edema and Hemorrhage Following Primary Coronary Intervention
    Declan Patrick O'Regan1, Rizwan Ahmed2, Giuliana Durighel1, Amy McGuinness1, Jo V. Hajnal1, Stuart A. Cook2
1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 2Molecular Cardiology Group, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK
    We assessed the feasibility of using T2* mapping to quantify regions of myocardial hemorrhage following percutaneous primary coronary intervention (PPCI) for acute myocardial infarction. We also assessed myocardial edema imaging using a T2-weighted asymmetric turbo spin echo with spectrally-selective inversion recovery (SPIR) fat suppression. To reduce respiratory motion artifact and ghosting from the blood pool we used navigator gating and a black blood prepulse in both sequences. Our findings show that hemorrhage is frequently observed following PPCI and is an indicator of poor myocardial salvage.
     
15:06 486. Navigated DENSE Strain Imaging for Post RF-Ablation Lesion Assessment in Swine Left Atria: A Comparison with Delayed Enhancement
    Ehud Jeruham Schmidt1, Maggie M. Fung2, Pelin Aksit3, GodtFred Holmvang4, Ting Song5, Sandeep M. Gupta6, Andre D'Avila7, Vivek Y. Reddy7, Stephan B. Danik8
1Radiology, Brigham and Womens Hospital, Boston, MA, USA; 2MRI, GE Healthcare, Waukesha, WI, USA; 3Radiology, Yale University, New Haven, CT, USA; 4Cardiology, Massachusetts General Hospital, Boston, MA, USA; 5Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 6GE Global Research, Niskayuna, NY, USA; 7Cardiology, University of Miami, Miami, FL, USA; 8Heart Center, Massachusetts General Hospital, Boston, MA, USA
    High-resolution navigated strain imaging is compared to high-resolution Myocardium Delayed Enhancement in the assessment of the completeness of RF ablation of the pulmonary-vein/left-atrial junction in swine models. It is shown that DENSE strain detects ablation as regions of low and disorganized strain, and ablation gaps as regions of organized strain. Strain imaging is a possible method for non-contrast visualization of ablation injury in the thin atrial wall.
     
15:18 487. Simultaneous Three-Dimensional Visualisation of Delayed Enhancement and T2 Weighted MRI for the Characterisation of RF Ablation Lesions
    Benjamin R. Knowles1, Dennis Caulfield1, Aldo Rivaldi2, Michael Cooklin2, Jaswinder S. Gill2, Julian Bostock2, Reza Razavi1, Kawal S. Rhode1, Tobias Schaeffter1
1Division of Imaging Sciences, King's College London, London, UK; 2Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK
    Radiofrequency ablation of the pulmonary veins is a common treatment for atrial fibrillation. The endpoint of the procedure is usually determined by measuring signals within each PV to ensure electrical isolation. Electrical isolation however, may be caused permanently by necrosis of the myocardium, or temporally by oedema formation. In this study we image acute post ablation patients using a combination of delayed enhancement and T2 weighted MRI. We visualise the patterns of enhancement and oedema to characterise the ablation lesions and assess wherever pulmonary veins are permanently isolated by necrosis, or have areas of temporary isolation by oedema.