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Three-dimensional segmentation of the left ventricle in late gadolinium enhanced MR images of chronic infarction combining long- and short-axis information. Med Image Anal 2013; 17:685-97. [PMID: 23562069 DOI: 10.1016/j.media.2013.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 02/26/2013] [Accepted: 03/02/2013] [Indexed: 11/22/2022]
Abstract
Automatic segmentation of the left ventricle (LV) in late gadolinium enhanced (LGE) cardiac MR (CMR) images is difficult due to the intensity heterogeneity arising from accumulation of contrast agent in infarcted myocardium. In this paper, we present a comprehensive framework for automatic 3D segmentation of the LV in LGE CMR images. Given myocardial contours in cine images as a priori knowledge, the framework initially propagates the a priori segmentation from cine to LGE images via 2D translational registration. Two meshes representing respectively endocardial and epicardial surfaces are then constructed with the propagated contours. After construction, the two meshes are deformed towards the myocardial edge points detected in both short-axis and long-axis LGE images in a unified 3D coordinate system. Taking into account the intensity characteristics of the LV in LGE images, we propose a novel parametric model of the LV for consistent myocardial edge points detection regardless of pathological status of the myocardium (infarcted or healthy) and of the type of the LGE images (short-axis or long-axis). We have evaluated the proposed framework with 21 sets of real patient and four sets of simulated phantom data. Both distance- and region-based performance metrics confirm the observation that the framework can generate accurate and reliable results for myocardial segmentation of LGE images. We have also tested the robustness of the framework with respect to varied a priori segmentation in both practical and simulated settings. Experimental results show that the proposed framework can greatly compensate variations in the given a priori knowledge and consistently produce accurate segmentations.
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Wei D, Sun Y, Ong SH, Chai P, Teo LL, Low AF. A comprehensive 3-D framework for automatic quantification of late gadolinium enhanced cardiac magnetic resonance images. IEEE Trans Biomed Eng 2013; 60:1499-508. [PMID: 23362243 DOI: 10.1109/tbme.2013.2237907] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) can directly visualize nonviable myocardium with hyperenhanced intensities with respect to normal myocardium. For heart attack patients, it is crucial to facilitate the decision of appropriate therapy by analyzing and quantifying their LGE CMR images. To achieve accurate quantification, LGE CMR images need to be processed in two steps: segmentation of the myocardium followed by classification of infarcts within the segmented myocardium. However, automatic segmentation is difficult usually due to the intensity heterogeneity of the myocardium and intensity similarity between the infarcts and blood pool. Besides, the slices of an LGE CMR dataset often suffer from spatial and intensity distortions, causing further difficulties in segmentation and classification. In this paper, we present a comprehensive 3-D framework for automatic quantification of LGE CMR images. In this framework, myocardium is segmented with a novel method that deforms coupled endocardial and epicardial meshes and combines information in both short- and long-axis slices, while infarcts are classified with a graph-cut algorithm incorporating intensity and spatial information. Moreover, both spatial and intensity distortions are effectively corrected with specially designed countermeasures. Experiments with 20 sets of real patient data show visually good segmentation and classification results that are quantitatively in strong agreement with those manually obtained by experts.
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Affiliation(s)
- Dong Wei
- Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
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Kellman P, Arai AE. Cardiac imaging techniques for physicians: late enhancement. J Magn Reson Imaging 2013; 36:529-42. [PMID: 22903654 DOI: 10.1002/jmri.23605] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Late enhancement imaging is used to diagnose and characterize a wide range of ischemic and nonischemic cardiomyopathies, and its use has become ubiquitous in the cardiac MR exam. As the use of late enhancement imaging has matured and the span of applications has widened, the demands on image quality have grown. The characterization of subendocardial MI now includes the accurate quantification of scar size, shape, and characterization of borders which have been shown to have prognostic significance. More diverse patterns of late enhancement including patchy, mid-wall, subepicardial, or diffuse enhancement are of interest in diagnosing nonischemic cardiomyopathies. As clinicians are examining late enhancement images for more subtle indication of fibrosis, the demand for lower artifacts has increased. A range of new techniques have emerged to improve the speed and quality of late enhancement imaging including: methods for acquisition during free breathing, and fat water separated imaging for characterizing fibrofatty infiltration and reduction of artifacts related to the presence of fat. Methods for quantification of T1 and extracellular volume fraction are emerging to tackle the issue of discriminating globally diffuse fibrosis from normal healthy tissue which is challenging using conventional late enhancement methods. The aim of this review will be to describe the current state of the art and to provide a guide to various clinical protocols that are commonly used.
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Affiliation(s)
- Peter Kellman
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Hennemuth A, Friman O, Huellebrand M, Peitgen HO. Mixture-Model-Based Segmentation of Myocardial Delayed Enhancement MRI. STATISTICAL ATLASES AND COMPUTATIONAL MODELS OF THE HEART. IMAGING AND MODELLING CHALLENGES 2013. [DOI: 10.1007/978-3-642-36961-2_11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Lu Y, Yang Y, Connelly KA, Wright GA, Radau PE. Automated quantification of myocardial infarction using graph cuts on contrast delayed enhanced magnetic resonance images. Quant Imaging Med Surg 2012; 2:81-6. [PMID: 23256065 DOI: 10.3978/j.issn.2223-4292.2012.05.03] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 05/21/2012] [Indexed: 11/14/2022]
Abstract
In this work, we propose a semi-automated myocardial infarction quantification method for cardiac contrast delayed enhancement magnetic resonance images (DE-MRI). Advantages of this method include that it reduces manual contouring of the left ventricle, obviates a remote myocardium region, and automatically distinguishes infarct, healthy and heterogeneous ("gray zone") tissue despite variability in intensity and noise across images. Quantitative evaluation results showed that the automatically determined infarct core and gray zone size have high correlation with that derived from the averaged results of the manual full width at half maximum (FWHM) methods (R(2)=0.99 for infarct core and gray zone size). Compared with the manual method, a much better reproducibility was achieved with the proposed algorithm and it shortens the evaluation time to one second per image, compared with 2-5 min per image for the manual method.
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Affiliation(s)
- Yingli Lu
- Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
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Olimulder MA, Galjee MA, Wagenaar LJ, van Es J, van der Palen J, von Birgelen C. Relationship between infarct tissue characteristics and left ventricular remodeling in patients with versus without early revascularization for acute myocardial infarction as assessed with contrast-enhanced cardiovascular magnetic resonance imaging. Int Heart J 2012; 53:263-9. [PMID: 23038085 DOI: 10.1536/ihj.53.263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Left ventricular (LV) remodeling following myocardial infarction (MI) is the result of complex interactions between various factors, including presence or absence of early revascularization. The impact of early revascularization on the relationship between infarct tissue characteristics and LV remodeling is incompletely known. Therefore, we investigated in patients with versus without successful early revascularization for acute MI potential relations between infarct tissue characteristics and LV remodeling with contrast-enhanced (CE) cardiovascular magnetic resonance (CMR). Patients with versus without successful early revascularization underwent CE-CMR for tissue characterization and assessment of LV remodeling including end-diastolic and end-systolic volumes, LV ejection fraction, and wall motion score index (WMSI). CE-CMR images were analyzed for infarct tissue characteristics including core-, peri- and total-infarct size, transmural extent, and regional scar scores. In early revascularized patients (n = 46), a larger area of infarct tissue correlated significantly with larger LV dimensions and a more reduced LV function (r = 0.39-0.68; all P ≤ 0.01). Multivariate analyses identified peri-infarct size as the best predictor of LV remodeling parameters (R(2 )= 0.44-0.62). In patients without successful early revascularization (n = 47), there was no correlation between infarct area and remodeling parameters; only peri-infarct size versus WMSI (r = 0.33; P = 0.03) and transmural extent versus LVEF (r = -0.27; P = 0.07) tended to be related. A correlation between infarct tissue characteristics and LV remodeling was found only in patients with early successful revascularization. Peri-infarct size was found to be the best determinant of LV remodeling. Our findings stress the importance of taking into account infarct tissue characteristics and success of revascularization when LV remodeling is studied.
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Affiliation(s)
- Marlon A Olimulder
- Department of Cardiology, Thoraxcentrum Twente, Medisch Spectrum Twente, Enschede, The Netherlands
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Arai AE, Leung S, Kellman P. Controversies in cardiovascular MR imaging: reasons why imaging myocardial T2 has clinical and pathophysiologic value in acute myocardial infarction. Radiology 2012; 265:23-32. [PMID: 22993218 DOI: 10.1148/radiol.12112491] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andrew E Arai
- Cardiovascular and Pulmonary Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bldg 10, Room B1D416, MSC 1061, 10 Center Dr, Bethesda, MD 20892-1061, USA.
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Chugh AR, Beache GM, Loughran JH, Mewton N, Elmore JB, Kajstura J, Pappas P, Tatooles A, Stoddard MF, Lima JAC, Slaughter MS, Anversa P, Bolli R. Administration of cardiac stem cells in patients with ischemic cardiomyopathy: the SCIPIO trial: surgical aspects and interim analysis of myocardial function and viability by magnetic resonance. Circulation 2012; 126:S54-64. [PMID: 22965994 DOI: 10.1161/circulationaha.112.092627] [Citation(s) in RCA: 367] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND SCIPIO is a first-in-human, phase 1, randomized, open-label trial of autologous c-kit(+) cardiac stem cells (CSCs) in patients with heart failure of ischemic etiology undergoing coronary artery bypass grafting (CABG). In the present study, we report the surgical aspects and interim cardiac magnetic resonance (CMR) results. METHODS AND RESULTS A total of 33 patients (20 CSC-treated and 13 control subjects) met final eligibility criteria and were enrolled in SCIPIO. CSCs were isolated from the right atrial appendage harvested and processed during surgery. Harvesting did not affect cardiopulmonary bypass, cross-clamp, or surgical times. In CSC-treated patients, CMR showed a marked increase in both LVEF (from 27.5 ± 1.6% to 35.1 ± 2.4% [P=0.004, n=8] and 41.2 ± 4.5% [P=0.013, n=5] at 4 and 12 months after CSC infusion, respectively) and regional EF in the CSC-infused territory. Infarct size (late gadolinium enhancement) decreased after CSC infusion (by manual delineation: -6.9 ± 1.5 g [-22.7%] at 4 months [P=0.002, n=9] and -9.8 ± 3.5 g [-30.2%] at 12 months [P=0.039, n=6]). LV nonviable mass decreased even more (-11.9 ± 2.5 g [-49.7%] at 4 months [P=0.001] and -14.7 ± 3.9 g [-58.6%] at 12 months [P=0.013]), whereas LV viable mass increased (+11.6 ± 5.1 g at 4 months after CSC infusion [P=0.055] and +31.5 ± 11.0 g at 12 months [P=0.035]). CONCLUSIONS Isolation of CSCs from cardiac tissue obtained in the operating room is feasible and does not alter practices during CABG surgery. CMR shows that CSC infusion produces a striking improvement in both global and regional LV function, a reduction in infarct size, and an increase in viable tissue that persist at least 1 year and are consistent with cardiac regeneration. CLINICAL TRIAL REGISTRATION This study is registered with clinicaltrials.gov, trial number NCT00474461.
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Affiliation(s)
- Atul R Chugh
- Division of Cardiovascular Medicine, University of Louisville, Louisville, KY, USA
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Bondarenko O, Beek AM, McCann GP, van Rossum AC. Revascularization in patients with chronic ischaemic myocardial dysfunction: insights from cardiovascular magnetic resonance imaging. Eur Heart J Cardiovasc Imaging 2012; 13:985-90. [PMID: 23034989 DOI: 10.1093/ehjci/jes194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In patients with chronic ischaemic left ventricular dysfunction, revascularization may lead to symptomatic and prognostic improvement. Cardiovascular magnetic resonance (CMR) imaging with its high spatial resolution provides the qualitative and quantitative, global and regional information on myocardial anatomy and function. In combination with a gadolinium-based contrast agent, CMR allows an accurate quantification of the myocardial scar and predicts the likelihood of functional recovery after revascularization. The aim of this review is to summarize our current understanding of the detection of myocardial viability using CMR, and why it may be the preferred technique in the assessment of patients with ischaemic cardiomyopathy.
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Affiliation(s)
- Olga Bondarenko
- Department of Cardiology, VU University Medical Center, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands.
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Vermes E, Childs H, Carbone I, Barckow P, Friedrich MG. Auto-Threshold quantification of late gadolinium enhancement in patients with acute heart disease. J Magn Reson Imaging 2012; 37:382-90. [DOI: 10.1002/jmri.23814] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 08/09/2012] [Indexed: 01/17/2023] Open
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Kadir K, Gao H, Payne A, Soraghan J, Berry C. LV wall segmentation using the variational level set method (LSM) with additional shape constraint for oedema quantification. Phys Med Biol 2012; 57:6007-23. [PMID: 22968138 DOI: 10.1088/0031-9155/57/19/6007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this paper an automatic algorithm for the left ventricle (LV) wall segmentation and oedema quantification from T2-weighted cardiac magnetic resonance (CMR) images is presented. The extent of myocardial oedema delineates the ischaemic area-at-risk (AAR) after myocardial infarction (MI). Since AAR can be used to estimate the amount of salvageable myocardial post-MI, oedema imaging has potential clinical utility in the management of acute MI patients. This paper presents a new scheme based on the variational level set method (LSM) with additional shape constraint for the segmentation of T2-weighted CMR image. In our approach, shape information of the myocardial wall is utilized to introduce a shape feature of the myocardial wall into the variational level set formulation. The performance of the method is tested using real CMR images (12 patients) and the results of the automatic system are compared to manual segmentation. The mean perpendicular distances between the automatic and manual LV wall boundaries are in the range of 1-2 mm. Bland-Altman analysis on LV wall area indicates there is no consistent bias as a function of LV wall area, with a mean bias of -121 mm(2) between individual investigator one (IV1) and LSM, and -122 mm(2) between individual investigator two (IV2) and LSM when compared to two investigators. Furthermore, the oedema quantification demonstrates good correlation when compared to an expert with an average error of 9.3% for 69 slices of short axis CMR image from 12 patients.
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Affiliation(s)
- K Kadir
- Department of Electronic and Electrical, Centre for Excellence in Signal and Image Processing, University of Strathclyde, Glasgow, UK
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Chenoune Y, Pellot-Barakat C, Constantinides C, Berbari RE, Lefort M, Roullot E, Mousseaux E, Frouin F. Methodology for Jointly Assessing Myocardial Infarct Extent and Regional Contraction in 3-D CMRI. IEEE Trans Biomed Eng 2012; 59:2650-9. [DOI: 10.1109/tbme.2012.2205925] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Geelen T, Paulis LEM, Coolen BF, Nicolay K, Strijkers GJ. Contrast-enhanced MRI of murine myocardial infarction - part I. NMR IN BIOMEDICINE 2012; 25:953-968. [PMID: 22308108 DOI: 10.1002/nbm.2768] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/07/2011] [Accepted: 11/29/2011] [Indexed: 05/31/2023]
Abstract
The use of contrast agents has added considerable value to the existing cardiac MRI toolbox that can be used to study murine myocardial infarction, as it enables detailed in vivo visualization of the molecular and cellular processes that occur in the infarcted and remote tissue. A variety of non-targeted and targeted contrast agents to study myocardial infarction are available and under development. Manganese, which acts as a calcium analogue, can be used to assess cell viability. Traditionally, low-molecular-weight Gd-containing contrast agents are employed to measure infarct size in a late gadolinium enhancement experiment. Gd-based blood-pool agents are used to study the vascular status of the myocardium. The use of targeted contrast agents facilitates more detailed imaging of pathophysiological processes in the acute and chronic infarct. Cell death was visualized by contrast agents functionalized with annexin A5 that binds specifically to phosphatidylserine accessible on dying cells and with an agent that binds to the exposed DNA of dead cells. Inflammation in the myocardium was depicted by contrast agents that target cell adhesion molecules expressed on activated endothelium, by contrast agents that are phagocytosed by inflammatory cells, and by using a probe that targets enzymes excreted by inflammatory cells. Cardiac remodeling processes were visualized with a contrast agent that binds to angiogenic vasculature and with an MR probe that specifically binds to collagen in the fibrotic myocardium. These recent advances in murine contrast-enhanced cardiac MRI have made a substantial contribution to the visualization of the pathophysiology of myocardial infarction, cardiac remodeling processes and the progression to heart failure, which helps to design new treatments. This review discusses the advances and challenges in the development and application of MRI contrast agents to study murine myocardial infarction.
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Affiliation(s)
- Tessa Geelen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, the Netherlands
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64
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Ugander M, Bagi PS, Oki AJ, Chen B, Hsu LY, Aletras AH, Shah S, Greiser A, Kellman P, Arai AE. Myocardial edema as detected by pre-contrast T1 and T2 CMR delineates area at risk associated with acute myocardial infarction. JACC Cardiovasc Imaging 2012; 5:596-603. [PMID: 22698528 PMCID: PMC3769169 DOI: 10.1016/j.jcmg.2012.01.016] [Citation(s) in RCA: 255] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 12/16/2011] [Accepted: 01/06/2012] [Indexed: 01/01/2023]
Abstract
OBJECTIVES The aim of this study was to determine whether cardiac magnetic resonance (CMR) in vivo T1 mapping can measure myocardial area at risk (AAR) compared with microspheres or T2 mapping CMR. BACKGROUND If T2-weighted CMR is abnormal in the AAR due to edema related to myocardial ischemia, then T1-weighted CMR should also be able to detect and accurately quantify AAR. METHODS Dogs (n = 9) underwent a 2-h coronary occlusion followed by 4 h of reperfusion. CMR of the left ventricle was performed for mapping of T1 and T2 prior to any contrast administration. AAR was defined as regions that had a T1 or T2 value (ms) >2 SD from remote myocardium, and regions with microsphere blood flow (ml/min/g) during occlusion <2 SD from remote myocardium. Infarct size was determined by triphenyltetrazolium chloride staining. RESULTS The relaxation parameters T1 and T2 were increased in the AAR compared with remote myocardium (mean ± SD: T1, 1,133 ± 55 ms vs. 915 ± 33 ms; T2, 71 ± 6 ms vs. 49 ± 3 ms). On a slice-by-slice basis (n = 78 slices), AAR by T1 and T2 mapping correlated (R(2) = 0.95, p < 0.001) with good agreement (mean ± 2 SD: 0.4 ± 16.6% of slice). On a whole-heart analysis, T1 measurements of left ventricular mass, AAR, and myocardial salvage correlated to microsphere measures (R(2) = 0.94) with good agreement (mean ± 2 SD: -1.4 ± 11.2 g of myocardium). Corresponding T2 measurements of left ventricular mass, AAR, and salvage correlated to microsphere analysis (R(2) = 0.96; mean ± 2 SD: agreement 1.6 ± 9.2 g of myocardium). This yielded a median infarct size of 30% of the AAR (range 12% to 52% of AAR). CONCLUSIONS For determining AAR after acute myocardial infarction, noncontrast T1 mapping and T2 mapping sequences yield similar quantitative results, and both agree well with microspheres. The relaxation properties T1 and T2 both change in a way that is consistent with the presence of myocardial edema following myocardial ischemia/reperfusion.
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Affiliation(s)
- Martin Ugander
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA
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Kadir K, Gao H, Payne A, Soraghan J, Berry C. Automatic quantification and 3D visualisation of edema in cardiac MRI. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:8021-4. [PMID: 22256202 DOI: 10.1109/iembs.2011.6091978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Viability assessment of heart muscle after a myocardial infarction is an important step for diagnosis and therapy planning. It is important to quantify the area of edema because it can differentiate between viable and death myocardial tissues. In this paper an automatic method to quantify cardiac edema is presented. The method is based on a combination of morphological operations and statistical thresholding. Using real MRI data it is demonstrated that the proposed method can delineate edema region comparable to manual segmentation with a linear correlation coefficient r=0.76 and the mean difference is around 9.95%. The quantification result is also used to generate 3D visualisation model showing normal myocardial wall and edema region, which will enhance clinician diagnosis capability with real pattern of edema distribution and quantitative description.
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Affiliation(s)
- Kushsairy Kadir
- Centre for excellence in Signal and Image Processing, Dept of Electronic and Electrical, University of Strathcylde, Glasgow G1 1XW, UK.
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Sjögren J, Ubachs JFA, Engblom H, Carlsson M, Arheden H, Heiberg E. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2012; 14:10. [PMID: 22293146 PMCID: PMC3349606 DOI: 10.1186/1532-429x-14-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND T2-weighted cardiovascular magnetic resonance (CMR) has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR), after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD), full width half maximum intensity (FWHM) or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. METHODS Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. RESULTS MaR was 32.9 ± 10.9% of left ventricular mass (LVM) when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p < 0.001) for Segment MaR, -2.3 ± 4.9%, R = 0.91 (p < 0.001) for inter observer variability of manual delineation, -7.7 ± 11.4%, R = 0.38 (p = 0.008) for 2SD, -21.0 ± 9.9%, R = 0.41 (p = 0.004) for FWHM, and 5.3 ± 9.6%, R = 0.47 (p < 0.001) for Otsu. CONCLUSIONS There is a good agreement between automatic Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a promising, objective method for standardized MaR quantification in T2-weighted CMR.
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Affiliation(s)
- Jane Sjögren
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
- Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden
| | - Joey FA Ubachs
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Henrik Engblom
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Marcus Carlsson
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Håkan Arheden
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Einar Heiberg
- Department of Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden
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Gruszczynska K, Kirschbaum S, Baks T, Moelker A, Duncker DJ, Rossi A, Baron J, de Feyter PJ, Krestin GP, van Geuns RJM. Different algorithms for quantitative analysis of myocardial infarction with DE MRI: comparison with autopsy specimen measurements. Acad Radiol 2011; 18:1529-36. [PMID: 22055796 DOI: 10.1016/j.acra.2011.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 11/15/2022]
Abstract
RATIONALE AND OBJECTIVES To compare two semiautomated methods for measurement of infarcted myocardium area on delayed contrast enhanced magnetic resonance imaging, with histopathology findings as standard of reference. MATERIALS AND METHODS Percentage area of myocardial infarction was measured in 10 Yorkshire landrace pigs manually and using two semiautomated methods. The first (standard deviation method) used two operator-selected regions of interest (ROIs) and nine different cutoff values (one to nine times the standard deviation of signal intensity in normal myocardium) to identify infarction. The second (threshold method) used threshold values based on percentages of maximum signal intensity to identify infarction. Results were compared with histopathology findings. RESULTS Difference between percentage area of infarction obtained with standard deviation method and autopsy specimens was in the range: -13.5% to +13.2%. With threshold method (thresholds from 30% to 90% of signal intensity), difference was -15% to +23%. Manual contouring underestimated infarcted area by 2% comparing to autopsy results. The best agreement between histopathology and semi-automated software was achieved for 4 standard deviations with standard deviation method: difference -0.45%, and for a percentage threshold of 70% (difference +0.67%) with threshold method. However, with standard deviation method, there was statistically significant difference between ROIs based on their location in viable myocardium: mean difference 1.7 ± 4%, P < .0001. CONCLUSION Semiautomated measurement of myocardial infarcted area on delayed enhanced magnetic resonance images performs well compared to autopsy. The threshold method, based on percentages of maximum signal intensity is preferable over standard deviation method, which is more susceptible to variability from location of ROIs within viable myocardium.
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Affiliation(s)
- Katarzyna Gruszczynska
- Department of Radiology, Erasmus MC, Universitair Medisch Centrum, Thoraxcenter, Ba 585, 's-Gravendijkwal 230, 3015 CE Rotterdam, the Netherlands
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68
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Desjardins B. MR Imaging of Myocardial Scar, with Electrophysiology Applications. PET Clin 2011; 6:489-502. [DOI: 10.1016/j.cpet.2011.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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69
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Desch S, Eitel I, de Waha S, Fuernau G, Lurz P, Gutberlet M, Schuler G, Thiele H. Cardiac magnetic resonance imaging parameters as surrogate endpoints in clinical trials of acute myocardial infarction. Trials 2011. [PMID: 21917147 DOI: 10.1186/1745-6215-12 204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cardiac magnetic resonance (CMR) offers a variety of parameters potentially suited as surrogate endpoints in clinical trials of acute myocardial infarction such as infarct size, myocardial salvage, microvascular obstruction or left ventricular volumes and ejection fraction. The present article reviews each of these parameters with regard to the pathophysiological basis, practical aspects, validity, reliability and its relative value (strengths and limitations) as compared to competitive modalities. Randomized controlled trials of acute myocardial infarction which have used CMR parameters as a primary endpoint are presented.
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Affiliation(s)
- Steffen Desch
- University of Leipzig - Heart Center, Department of Internal Medicine/Cardiology, Leipzig, Germany.
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Desch S, Eitel I, de Waha S, Fuernau G, Lurz P, Gutberlet M, Schuler G, Thiele H. Cardiac magnetic resonance imaging parameters as surrogate endpoints in clinical trials of acute myocardial infarction. Trials 2011; 12:204. [PMID: 21917147 PMCID: PMC3182906 DOI: 10.1186/1745-6215-12-204] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 09/14/2011] [Indexed: 12/21/2022] Open
Abstract
Cardiac magnetic resonance (CMR) offers a variety of parameters potentially suited as surrogate endpoints in clinical trials of acute myocardial infarction such as infarct size, myocardial salvage, microvascular obstruction or left ventricular volumes and ejection fraction. The present article reviews each of these parameters with regard to the pathophysiological basis, practical aspects, validity, reliability and its relative value (strengths and limitations) as compared to competitive modalities. Randomized controlled trials of acute myocardial infarction which have used CMR parameters as a primary endpoint are presented.
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Affiliation(s)
- Steffen Desch
- University of Leipzig - Heart Center, Department of Internal Medicine/Cardiology, Leipzig, Germany.
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71
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Welinder A, Hakacova N, Martin T, Engblom H. Importance of standardized assessment of late gadolinium enhancement for quantification of infarct size by cardiac magnetic resonance: implications for comparison with electrocardiogram. J Electrocardiol 2011; 44:538-43. [DOI: 10.1016/j.jelectrocard.2011.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Indexed: 10/17/2022]
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72
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Kirschner R, Varga-Szemes A, Brott BC, Litovsky S, Elgavish A, Elgavish GA, Simor T. Quantification of myocardial viability distribution with Gd(DTPA) bolus-enhanced, signal intensity-based percent infarct mapping. Magn Reson Imaging 2011; 29:650-8. [PMID: 21546192 DOI: 10.1016/j.mri.2011.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Accepted: 02/21/2011] [Indexed: 11/17/2022]
Abstract
INTRODUCTION A substantial, common shortcoming of the currently used semiautomated techniques for the quantification of myocardial infarct with delayed enhancement magnetic resonance imaging is the assumption that the whole myocardial slab that corresponds to the hyperenhanced tomographic area is 100% nonviable. This assumption is, however, incorrect. To resolve this conflict, we have recently proposed the signal intensity percent-infarct mapping method and validated it in an ex vivo, canine experiment. The purpose of the current study has been the validation of the signal intensity percent-infarct mapping method in vivo, using a porcine model of reperfused myocardial infarct. METHODS In swines (n=6), reperfused myocardial infarct was generated occluding for 90 min by an angioplasty balloon either the left anterior descending or the left circumflex coronary artery. To obtain DE images, Gd(DTPA) enhanced inversion-recovery fast gradient-echo acquisitions were carried out on day 28 after myocardial infarction. Scanning started 15 min after intravenous injection of 0.2 mmol/kg Gd(DTPA). At the end of the MRI session, the animal was sacrificed and 2,3,5-triphenyltetrazolium chloride staining was used to validate the existence and to determine the accurate size of the myocardial infarct. Tissue samples were taken and stained with hematoxylin-eosin and Masson's trichrome for histological assessment of the infarct and the periinfarct zone. The signal intensity percent-infarct mapping data were compared with corresponding data from the delayed enhancement images analyzed with SI(remote+2S.D.) thresholding, and with corresponding triphenyltetrazolium-chloride staining data using Friedman's repeated measure analysis of variance on ranks. RESULTS The infarct volume determined by the triphenyltetrazolium chloride, SI(remote+2S.D.) and signal intensity percent-infarct mapping methods was 3.04 ml [2.74, 3.45], 13.62 ml [9.06, 18.45] and 4.27 ml [3.45, 6.33], respectively. Median infarct volume determined by SI(remote+2S.D.) significantly differed from that determined by triphenyltetrazolium chloride (P<.05). The Bland-Altman overall bias was 12.49% of the volume of the left ventricle. Median infarct volume determined by signal intensity percent-infarct mapping, however, did not differ significantly (NS) from that obtained by triphenyltetrazolium chloride. Signal intensity percent-infarct mapping yielded only a 1.99% Bland-Altman overall bias of the left ventricular volume. CONCLUSIONS This in vivo study in the porcine reperfused myocardial infarct model demonstrates that signal intensity percent-infarct mapping is a highly accurate method for the determination of the extent of myocardial infarct. MRI images for signal intensity percent-infarct mapping are obtained with the pulse sequence of conventional delayed enhancement imaging and are acquired within clinically acceptable scanning time. This makes signal intensity percent-infarct mapping a practical method for clinical implementation.
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Affiliation(s)
- Robert Kirschner
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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73
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Goetti R, Kozerke S, Donati OF, Sürder D, Stolzmann P, Kaufmann PA, Lüscher TF, Corti R, Manka R. Acute, subacute, and chronic myocardial infarction: quantitative comparison of 2D and 3D late gadolinium enhancement MR imaging. Radiology 2011; 259:704-11. [PMID: 21467254 DOI: 10.1148/radiol.11102216] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE To assess a late gadolinium enhancement (LGE) single-breath-hold three-dimensional (3D) inversion recovery magnetic resonance (MR) imaging sequence for the quantification of myocardial scar mass and transmurality in comparison with a clinically established two-dimensional (2D) sequence. MATERIALS AND METHODS All patients gave written informed consent to participate in this institutional review board-approved study. Ninety patients (84 men; mean age, 54.4 years ± 10.8 [standard deviation]) with acute (n = 30), subacute (n = 30), or chronic (n = 30) myocardial infarction were included. Imaging was performed by using a 1.5-T clinical MR imaging system. Spatial resolution was identical for 3D and 2D images (1.5 × 1.5 mm(2); section thickness, 8 mm; no section gap). Quantitative comparisons of myocardial mass (in grams), scar mass (in grams), and scar transmurality (on a five-point scale) were performed by using the Pearson correlation and Bland-Altman analysis (for myocardial and scar mass) or κ statistics (for transmurality). RESULTS There were no significant differences between 2D and 3D data sets in terms of mean myocardial mass (2D: 148.3 g ± 35.1; 3D: 148.1 g ± 34.6; P = .76) and scar tissue mass (2D: 31.8 g ± 14.6; 3D: 31.6 g ± 15.5; P = .39), with strong and significant correlation regarding both myocardial mass (r = 0.982; P < .001) and scar tissue mass (r = 0.980; P < .001). Bland-Altman analysis showed a mean difference of 0.21 g ± 6.64 (range, -19.64 to 18.44 g) for myocardial mass and a mean difference of 0.26 g ± 2.88 (range, -7.15 to 7.74 g) for scar mass between the 2D and 3D data sets. Agreement regarding scar transmurality was good (κ = 0.75). Acquisition time was significantly shorter for 3D data sets (26.7 seconds ± 4.4 vs 367.7 seconds ± 56.4; P < .001). CONCLUSION Three-dimensional LGE MR imaging enables quantitative evaluation of scar tissue mass and transmurality in patients with acute, subacute, or chronic myocardial infarction at significantly reduced acquisition times compared with 2D LGE MR imaging.
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Affiliation(s)
- Robert Goetti
- Department of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland
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74
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Comparison of visual scoring and quantitative planimetry methods for estimation of global infarct size on delayed enhanced cardiac MRI and validation with myocardial enzymes. Eur J Radiol 2011; 78:87-92. [DOI: 10.1016/j.ejrad.2009.09.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 09/25/2009] [Indexed: 11/17/2022]
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75
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Payne AR, Casey M, McClure J, McGeoch R, Murphy A, Woodward R, Saul A, Bi X, Zuehlsdorff S, Oldroyd KG, Tzemos N, Berry C. Bright-blood T2-weighted MRI has higher diagnostic accuracy than dark-blood short tau inversion recovery MRI for detection of acute myocardial infarction and for assessment of the ischemic area at risk and myocardial salvage. Circ Cardiovasc Imaging 2011; 4:738-45. [PMID: 21427362 DOI: 10.1161/circimaging.111.965095] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND T2-Weighted MRI reveals myocardial edema and enables estimation of the ischemic area at risk and myocardial salvage in patients with acute myocardial infarction (MI). We compared the diagnostic accuracy of a new bright-blood T2-weighted with a standard black blood T2-weighted MRI in patients with acute MI. METHODS AND RESULTS A breath-hold, bright-blood T2-weighted, Acquisition for Cardiac Unified T2 Edema pulse sequence with normalization for coil sensitivity and a breath-hold T2 dark-blood short tau inversion recovery sequence were used to depict the area at risk in 54 consecutive acute MI patients. Infarct size was measured on gadolinium late contrast enhancement images. Compared with dark-blood T2-weighted MRI, consensus agreements between independent observers for identification of myocardial edema were higher with bright-blood T2-weighted MRI when evaluated per patient (P<0.001) and per segment of left ventricle (P<0.001). Compared with bright-blood T2-weighted MRI, dark-blood T2-weighted MRI underestimated the area at risk compared with infarct size (P<0.001). The 95% limits of agreement for interobserver agreements for the ischemic area at risk and myocardial salvage were wider with dark-blood T2-weighted MRI than with bright-blood T2-weighted MRI. Bright blood enabled more accurate identification of the culprit coronary artery with correct identification in 94% of cases compared with 61% for dark blood (P<0.001). CONCLUSIONS Bright-blood T2-weighted MRI has higher diagnostic accuracy than dark-blood T2-weighted MRI. Additionally, dark-blood T2-weighted MRI may underestimate area at risk and myocardial salvage.
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Affiliation(s)
- Alexander R Payne
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Glasgow, Scotland, United Kingdom
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76
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Johnstone RI, Greenwood JP, Biglands JD, Plein S, Ridgway JP, Radjenovic A. Assessment of tissue edema in patients with acute myocardial infarction by computer-assisted quantification of triple inversion recovery prepared MRI of the myocardium. Magn Reson Med 2011; 66:564-73. [PMID: 21394767 DOI: 10.1002/mrm.22812] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 12/07/2010] [Accepted: 12/12/2010] [Indexed: 01/26/2023]
Abstract
The aim of this study was to design a computer algorithm to assess the extent of cardiac edema from triple inversion recovery MR images of the human left ventricular myocardium. Twenty-one patients presenting with acute myocardial infarction were scanned within 48 h of the onset of symptoms. Eight patients were scanned a second time, 4 weeks after the initial event. Myocardial edema was detected in 27 of 29 studies using visual contour-based manual segmentation. A reference standard, created from the segmentations of three raters by voxel-wise majority voting, was compared to the edema mass estimates obtained using a newly developed computer algorithm. At baseline (n=20), the reference standard yielded an edema mass of 16.4±15.0 g (mean±SD) and the computer algorithm edema mass was 16.4±12.6 g. At follow-up (n=7), the reference standard edema mass was 7.1±4.4 g compared to 16.3±7.7 g at baseline. Computer algorithm estimates showed the same pattern of change with 5.7±5.7 g at follow-up compared to 20.8±13.8 g at baseline. Although there was a significant degree of discrepancy between reference standard and computer algorithm estimates of edema mass in individual patients, their overall agreement was good, with intraclass correlation coefficient ICC(3, 1)=0.753.
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Affiliation(s)
- R I Johnstone
- Department of Medical Physics and Engineering, Leeds Teaching Hospitals Trust, and School of Medicine, University of Leeds, Leeds, United Kingdom
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77
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Simor T, Surányi P, Ruzsics B, Tóth A, Tóth L, Kiss P, Brott BC, Varga-Szemes A, Elgavish A, Elgavish GA. Percent infarct mapping for delayed contrast enhancement magnetic resonance imaging to quantify myocardial viability by Gd(DTPA). J Magn Reson Imaging 2011; 32:859-68. [PMID: 20882616 DOI: 10.1002/jmri.22296] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To demonstrate the advantages of signal intensity percent-infarct-mapping (SI-PIM) using the standard delayed enhancement (DE) acquisition in assessing viability following myocardial infarction (MI). SI-PIM quantifies MI density with a voxel-by-voxel resolution in clinically used DE images. MATERIALS AND METHODS In canines (n= 6), 96 hours after reperfused MI and administration of 0.2 mmol/kg Gd(DTPA), ex vivo DE images were acquired and SI-PIMs calculated. SI-PIM data were compared with data from DE images analyzed with several thresholding levels using SI(remote+2SD), SI(remote+6SD), SI full width half maximum (SI(FWHM)), and with triphenyl-tetrazolium-chloride (TTC) staining. SI-PIM was also compared to R1 percent infarct mapping (R1-PIM). RESULTS Left ventricular infarct volumes (IV) in DE images, IV(SIremote+2SD) and IV(SIremote+6SD), overestimated (P < 0.05) TTC by medians of 13.21 mL [10.2; 15.2] and 6.2 mL [3.79; 8.23], respectively. SI(FWHM), SI-PIM, and R1-PIM, however, only nonsignificantly underestimated TTC, by medians of -0.10 mL [-0.12, -0.06], -0.86 mL [-1.04; 1.54], and -1.30 mL [-4.99; -0.29], respectively. The infarct-involved voxel volume (IIVV) of SI-PIM, 32.4 mL [21.2, 46.3] is higher (P < 0.01) than IIVVs of SI(FWHM) 8.3 mL [3.79, 19.0]. SI-PIM(FWHM), however, underestimates TTC (-5.74 mL [-11.89; -2.52] (P < 0.01)). Thus, SI-PIM outperforms SI(FWHM) because larger IIVVs are obtained, and thus PIs both in the rim and the core of the infarcted tissue are characterized, in contradistinction from DE-SI(FWHM), which shows mainly the infarct core. CONCLUSION We have shown here, ex vivo, that SI-PIM has the same advantages as R1-PIM, but it is based on the scanning sequences of DE imaging, and thus it is obtainable within the same short scanning time as DE. This makes it a practical method for clinical studies.
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Affiliation(s)
- Tamás Simor
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA
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Reliability of myocardial salvage assessment by cardiac magnetic resonance imaging in acute reperfused myocardial infarction. Int J Cardiovasc Imaging 2011; 28:263-72. [PMID: 21279689 DOI: 10.1007/s10554-011-9802-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 01/08/2011] [Indexed: 12/23/2022]
Abstract
Myocardial salvage assessed by cardiac magnetic resonance imaging (CMRI) holds promise as a surrogate endpoint in studies comparing different treatment strategies for ST-elevation myocardial infarction (STEMI). The aim of this study was to evaluate the reliability of salvaged myocardium measurements by CMRI. Twenty patients underwent CMRI on 2 consecutive days early after reperfused STEMI to assess the area at risk (AAR) on T2-weighted and final infarct size (IS) on delayed enhancement images. Myocardial salvage index (MSI) was calculated (AAR minus IS). Agreement between scans 1 and 2 for the AAR, IS and MSI were analyzed using Bland-Altman analyses. Inter- and intraobserver reliability were assessed. Paired t testing revealed a trend for a significant difference for MSI between scans 1 and 2 (scan 1: 43.8 ± 22.5; scan 2: 45.5 ± 22.0; P = 0.052). The average difference for AAR and IS between scan 1 and scan 2 was -0.5 (upper limit of agreement 5.4% of left ventricular [LV] volume; lower limit of agreement -6.4%LV) and 0.1%LV (upper limit of agreement 2.3%LV; lower limit of agreement -2.1%LV). The corresponding calculated MSI measurements showed a mean bias of -1.7 (upper limit of agreement 5.5; lower limit of agreement -8.9). Coefficients of repeatability for interobserver variability were 3.6%LV for AAR, 2.4%LV for IS and 5.4 for MSI. Likewise, for intraobserver variability, coefficients of repeatability were 5.0%LV (AAR), 2.4%LV (IS) and 4.8 (MSI). Assessment of myocardial salvage by CMRI shows acceptable reliability. Further validation studies and trials showing the prognostic value of myocardial salvage by CMRI are needed before routine implementation as a surrogate endpoint in STEMI trials.
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Tao Q, Milles J, Zeppenfeld K, Lamb HJ, Bax JJ, Reiber JHC, van der Geest RJ. Automated segmentation of myocardial scar in late enhancement MRI using combined intensity and spatial information. Magn Reson Med 2011; 64:586-94. [PMID: 20665801 DOI: 10.1002/mrm.22422] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Accurate assessment of the size and distribution of a myocardial infarction (MI) from late gadolinium enhancement (LGE) MRI is of significant prognostic value for postinfarction patients. In this paper, an automatic MI identification method combining both intensity and spatial information is presented in a clear framework of (i) initialization, (ii) false acceptance removal, and (iii) false rejection removal. The method was validated on LGE MR images of 20 chronic postinfarction patients, using manually traced MI contours from two independent observers as reference. Good agreement was observed between automatic and manual MI identification. Validation results showed that the average Dice indices, which describe the percentage of overlap between two regions, were 0.83 +/- 0.07 and 0.79 +/- 0.08 between the automatic identification and the manual tracing from observer 1 and observer 2, and the errors in estimated infarct percentage were 0.0 +/- 1.9% and 3.8 +/- 4.7% compared with observer 1 and observer 2. The difference between the automatic method and manual tracing is in the order of interobserver variation. In conclusion, the developed automatic method is accurate and robust in MI delineation, providing an objective tool for quantitative assessment of MI in LGE MR imaging.
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Affiliation(s)
- Qian Tao
- LKEB - Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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81
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Bello D, Einhorn A, Kaushal R, Kenchaiah S, Raney A, Fieno D, Narula J, Goldberger J, Shivkumar K, Subacius H, Kadish A. Cardiac magnetic resonance imaging: infarct size is an independent predictor of mortality in patients with coronary artery disease. Magn Reson Imaging 2010; 29:50-6. [PMID: 20980115 DOI: 10.1016/j.mri.2010.03.031] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/03/2010] [Accepted: 03/05/2010] [Indexed: 01/05/2023]
Abstract
BACKGROUND Cardiac magnetic resonance imaging (CMR) can accurately determine infarct size. Prior studies using indirect methods to assess infarct size have shown that patients with larger myocardial infarctions have a worse prognosis than those with smaller myocardial infarctions. OBJECTIVES This study assessed the prognostic significance of infarct size determined by CMR. METHODS Cine and contrast CMR were performed in 100 patients with coronary artery disease (CAD) undergoing routine cardiac evaluation. Infarct size was determined by planimetry. We used Cox proportional hazards regression analyses (stepwise forward selection approach) to evaluate the risk of all-cause death associated with traditional cardiovascular risk factors, symptoms of heart failure, medication use, left ventricular ejection fraction, left ventricular mass, angiographic severity of CAD and extent of infarct size determined by CMR. RESULTS Ninety-one patients had evidence of myocardial infarction by CMR. Mean follow-up was 4.8±1.6 years after CMR, during which time 30 patients died. The significant multivariable predictors of all-cause mortality were extent of myocardial infarction by CMR, extent of left ventricular systolic dysfunction, symptoms of heart failure, and diabetes mellitus (P<.05). The presence of infarct greater than or equal to 24% of left ventricular mass and left ventricular ejection fraction less than or equal to 30% were the most optimal cut-off points for the prediction of death with bivariate adjusted hazard ratios of 2.11 (95% confidence interval 1.02-4.38) and 4.06 (95% confidence interval 1.73-9.54), respectively. CONCLUSIONS The extent of myocardial infarction determined by CMR is an independent predictor of death in patients with CAD.
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Affiliation(s)
- David Bello
- Division of Cardiology, Orlando Regional Medical Center, Orlando, FL 32806, USA.
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82
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Schelbert EB, Hsu LY, Anderson SA, Mohanty BD, Karim SM, Kellman P, Aletras AH, Arai AE. Late gadolinium-enhancement cardiac magnetic resonance identifies postinfarction myocardial fibrosis and the border zone at the near cellular level in ex vivo rat heart. Circ Cardiovasc Imaging 2010; 3:743-52. [PMID: 20847191 DOI: 10.1161/circimaging.108.835793] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND using a resolution 1000-fold higher than prior studies, we studied (1) the degree to which late gadolinium-enhancement (LGE) cardiac magnetic resonance tracks fibrosis from chronic myocardial infarction and (2) the relationship between intermediate signal intensity and partial volume averaging at distinct "smooth" infarct borders versus disorganized mixtures of fibrosis and viable cardiomyocytes. METHODS AND RESULTS sprague-Dawley rats underwent myocardial infarction by coronary ligation. Two months later, rats were euthanized 10 minutes after administration of 0.3 mmol/kg intravenous gadolinium. LGE images ex vivo at 7 T with a 3D gradient echo sequence with 50×50×50 μm voxels were compared with histological sections (Masson trichrome). Planimetered histological and LGE regions of fibrosis correlated well (y=1.01x-0.01; R(2)=0.96; P<0.001). In addition, LGE images routinely detected clefts of viable cardiomyocytes 2 to 4 cells thick that separated bands of fibrous tissue. Although LGE clearly detected disorganized mixtures of fibrosis and viable cardiomyocytes characterized by intermediate signal intensity voxels, the percentage of apparent intermediate signal intensity myocardium increased significantly (P<0.01) when image resolution was degraded to resemble clinical resolution consistent with significant partial volume averaging. CONCLUSIONS these data provide important validation of LGE at nearly the cellular level for detection of fibrosis after myocardial infarction. Although LGE can detect heterogeneous patches of fibrosis and viable cardiomyocytes as patches of intermediate signal intensity, the percentage of intermediate signal intensity voxels is resolution dependent. Thus, at clinical resolutions, distinguishing the peri-infarct border zone from partial volume averaging with LGE is challenging.
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Affiliation(s)
- Erik B Schelbert
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Md. 20892-1061, USA
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83
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Berry C, Kellman P, Mancini C, Chen MY, Bandettini WP, Lowrey T, Hsu LY, Aletras AH, Arai AE. Magnetic resonance imaging delineates the ischemic area at risk and myocardial salvage in patients with acute myocardial infarction. Circ Cardiovasc Imaging 2010; 3:527-35. [PMID: 20631034 DOI: 10.1161/circimaging.109.900761] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND The area at risk (AAR) is a key determinant of myocardial infarction (MI) size. We investigated whether magnetic resonance imaging (MRI) measurement of AAR would be correlated with an angiographic AAR risk score in patients with acute MI. METHODS AND RESULTS Bright-blood, T2-prepared, steady-state, free-precession MRI was used to depict the AAR in 50 consecutive acute MI patients, whereas infarct size was measured on gadolinium late-contrast-enhancement images. AAR was also estimated by the APPROACH and DUKE angiographic jeopardy scores and ST-segment elevation score. Myocardial salvage was calculated as AAR minus infarct size. Results are mean ± SD unless specified otherwise. Patients were 61 ± 12 years of age, 76% had an ST-segment elevation MI, and 20% had a prior MI. All underwent MRI 4 ± 2 days after initial presentation. The relation between MRI and the APPROACH angiographic estimates of AAR was similar (overall size relative to left ventricular mass was 32 ± 12% vs 30 ± 12%, respectively, P=0.33), correlated well (r = 0.78, P < 0.0001), and had a 2.5% bias on Bland-Altman analysis. The DUKE jeopardy score underestimated AAR relative to infarct size and was correlated less well with MRI (r = 0.39, P = 0.0055). ST-segment elevation score underestimated infarct size in 19 subjects (50%) and was not correlated with MRI (r = 0.27, P = 0.06). Myocardial salvage varied according to Thrombolysis in Myocardial Infarction flow grade at the end of angiography/percutaneous coronary intervention (P = 0.04), and Thrombolysis in Myocardial Infarction flow grade was a univariable predictor of myocardial salvage (P = 0.011). In multivariable analyses, infarct size was predicted by T2-prepared, steady-state, free-precession MRI (P < 0.0001). CONCLUSIONS T2-prepared, steady-state, free-precession MRI delineates the AAR and enables estimation of myocardial salvage when coupled with a measurement of infarct size.
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Affiliation(s)
- Colin Berry
- Department of Health and Human Services, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1061, USA
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84
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Attili AK, Schuster A, Nagel E, Reiber JHC, van der Geest RJ. Quantification in cardiac MRI: advances in image acquisition and processing. Int J Cardiovasc Imaging 2010; 26 Suppl 1:27-40. [PMID: 20058082 PMCID: PMC2816803 DOI: 10.1007/s10554-009-9571-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 12/18/2009] [Indexed: 12/25/2022]
Abstract
Cardiac magnetic resonance (CMR) imaging enables accurate and reproducible quantification of measurements of global and regional ventricular function, blood flow, perfusion at rest and stress as well as myocardial injury. Recent advances in MR hardware and software have resulted in significant improvements in image quality and a reduction in imaging time. Methods for automated and robust assessment of the parameters of cardiac function, blood flow and morphology are being developed. This article reviews the recent advances in image acquisition and quantitative image analysis in CMR.
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Affiliation(s)
- Anil K Attili
- Department of Radiology and Cardiology, University of Kentucky, Lexington, KY, USA
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85
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Doesch C, Huck S, Böhm CK, Michaely H, Fluechter S, Haghi D, Dinter D, Borggrefe M, Papavassiliu T. Visual estimation of the extent of myocardial hyperenhancement on late gadolinium-enhanced CMR in patients with hypertrophic cardiomyopathy. Magn Reson Imaging 2010; 28:812-9. [PMID: 20409668 DOI: 10.1016/j.mri.2010.03.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Revised: 02/15/2010] [Accepted: 03/05/2010] [Indexed: 12/21/2022]
Abstract
AIM So far different approaches have been used to quantify late gadolinium enhancement (LGE) in patients with hypertrophic cardiomyopathy (HCM), but there is no general consensus on the gold standard, since histological data are scarce. The aim of our study was to investigate whether the determination of LGE in patients with HCM using a semiquantitative score based on the 17-segment model is feasible and has comparable accuracy to manual planimetry. METHODS Forty-two patients with HCM underwent LGE cardiovascular magnetic resonance imaging. Determination of LGE by planimetry based on visual assessment was used as reference standard. Then the extent of LGE was assessed using a semiquantitative score based on the standard left ventricular 17-segment model. Each segment was scored for the distribution of LGE. The resulting summed score expressed as percentage of the maximum possible score was thereafter compared with the manual planimetric evaluation of LGE, expressed as a percentage of the left ventricular myocardial area. RESULTS In 28 patients (66%), LGE was present. There was a good correlation between the semiquantitative score and the planimetric approach (r=0.89; y=0.819x+2.45; standard error of estimation=2.327; P<.0001). Additionally, the Bland-Altmann plot showed a high concordance between the two approaches (mean of the difference +1.7%). The inter- and intraobserver limits of agreement and the coefficients of repeatability based on measurements with the semiquantitative score of the extent of LGE were superior to planimetric measurements. Besides, the time requirement for the LGE determination using the semiquantitative score was found to be significantly reduced compared to manual planimetry (median 2 vs. 10 min). CONCLUSIONS Thus, a reliable global index of the size of the LGE is feasible and can easily be obtained from visual assessment with a semiquantitative score of the extent of the hyperenhancement.
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Affiliation(s)
- Christina Doesch
- 1st Department of Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany.
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86
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Kim HW, Farzaneh-Far A, Kim RJ. Cardiovascular magnetic resonance in patients with myocardial infarction: current and emerging applications. J Am Coll Cardiol 2010; 55:1-16. [PMID: 20117357 DOI: 10.1016/j.jacc.2009.06.059] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 05/26/2009] [Accepted: 06/18/2009] [Indexed: 12/18/2022]
Abstract
In patients with known or suspected myocardial infarction (MI), cardiovascular magnetic resonance (CMR) provides a comprehensive, multifaceted view of the heart. The data, including that from a recent multicenter clinical trial, indicate that delayed-enhancement cardiac magnetic resonance imaging (DE-CMR) is a well-validated, robust technique that can be easily implemented on scanners that are commonly available worldwide, with an effectiveness that clearly rivals the best available imaging techniques for the detection and assessment of acute and chronic MI. When patients present outside the diagnostic window of cardiac troponins, DE-CMR may be especially useful. Moreover, because DE-CMR can uniquely differentiate between ischemic and various nonischemic forms of myocardial injury, it may be helpful in cases of diagnostic uncertainty, such as in patients with classical features of MI in whom coronary angiography does not show a culprit lesion. Even after the diagnosis of MI has been made, CMR provides clinically relevant information by identifying residual viability, microvascular damage, stunning, and right ventricular infarction. In addition, post-MI sequelae, including left ventricular thrombus and pericarditis, are easily identified. Given that quantification of infarct size by DE-CMR is highly reproducible, this technique may provide a useful surrogate end point for clinical trials with appreciable reductions in sample size compared with alternative methods.
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Affiliation(s)
- Han W Kim
- Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina 27710, USA
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87
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Peri-infarct dysfunction in post-myocardial infarction: assessment of 3-T tagged and late enhancement MRI. Eur Radiol 2009; 20:1139-48. [PMID: 19915846 DOI: 10.1007/s00330-009-1657-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 09/14/2009] [Accepted: 10/02/2009] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine LV function at different distances from myocardial infarction (MI) by using 3-T tagged MRI and late gadolinium enhancement (LGE). METHODS Cardiac MR images were acquired from 21 patients with previous MI. The harmonic phase (HARP) method was used to calculate radial and circumferential strain (RS, CS). The two strains were synchronised by subtracting the CS from the RS at the same time, and this was defined as the efficient strain (ES). Peak strain (P-RS, P-CS, P-ES) and time to peak strain (T-RS, T-CS, T-ES) were used as estimates of contractile function. Based on the presence of LGE, myocardium was classified into infarct, border zone, adjacent and remote areas. RESULTS P-RS and P-ES were significantly greater for remote than for adjacent and infarct areas. P-CS values were significantly greater for remote and border zone than for infarct areas. T-RS and T-ES were significantly shorter for remote and border zone than for infarct areas. T-CS was significantly shorter for border zone than for infarct areas. CONCLUSION Contractile dysfunction demonstrated by peak strain was correlated with location at different distances from the infarct. In the border zone, contractile deformation was characterised as earlier T-RS, T-CS and T-ES and greater P-CS than in the infarct area.
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88
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Beek AM, Bondarenko O, Afsharzada F, van Rossum AC. Quantification of late gadolinium enhanced CMR in viability assessment in chronic ischemic heart disease: a comparison to functional outcome. J Cardiovasc Magn Reson 2009; 11:6. [PMID: 19272147 PMCID: PMC2657135 DOI: 10.1186/1532-429x-11-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 03/09/2009] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Quantification of late gadolinium enhanced cardiovascular magnetic resonance (LGE CMR) by objective window setting increases reproducibility and facilitates multicenter comparison and cooperation. So far, quantification methods or models have only been validated to postmortem animal studies. This study was undertaken to evaluate quantification of LGE in relation to the clinical standard of viability, i.e. functional outcome after revascularization.Thirty-eight patients with chronic ischemic myocardial dysfunction underwent cine and LGE 1 month before and cine CMR 6 months after coronary revascularization. Enhancement was quantified by thresholding window setting at: 2-8 SD above mean signal intensity of a remote normal region, and according to the full width at half maximum method (FWHM). Dysfunctional segments were divided in 5 groups according to segmental extent of enhancement (SEE): SEE 1--no enhancement to SEE 5--76-100% with each quantification method. RESULTS Quantification methods had a strong influence on SEE and total infarct size. Multilevel analysis showed that thresholding contrast images at 6 SD best predicted segmental functional outcome after revascularization, but the difference with other methods was small and non-significant. CONCLUSION Simple thresholding techniques strongly influence global and segmental extent of LGE, but have relatively little influence on the accuracy to predict segmental functional improvement after revascularization.
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Affiliation(s)
- Aernout M Beek
- Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Olga Bondarenko
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands
| | - Farshid Afsharzada
- Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Albert C van Rossum
- Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands
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Hennemuth A, Seeger A, Friman O, Miller S, Klumpp B, Oeltze S, Peitgen HO. A comprehensive approach to the analysis of contrast enhanced cardiac MR images. IEEE TRANSACTIONS ON MEDICAL IMAGING 2008; 27:1592-1610. [PMID: 18955175 DOI: 10.1109/tmi.2008.2006512] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Current magnetic resonance imaging (MRI) technology allows the determination of patient-individual coronary tree structure, detection of infarctions, and assessment of myocardial perfusion. Joint inspection of these three aspects yields valuable information for therapy planning, e.g., through classification of myocardium into healthy tissue, regions showing a reversible hypoperfusion, and infarction with additional information on the corresponding supplying artery. Standard imaging protocols normally provide image data with different orientations, resolutions and coverages for each of the three aspects, which makes a direct comparison of analysis results difficult. The purpose of this work is to develop methods for the alignment and combined analysis of these images. The proposed approach is applied to 21 datasets of healthy and diseased patients from the clinical routine. The evaluation shows that, despite limitations due to typical MRI artifacts, combined inspection is feasible and can yield clinically useful information.
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Affiliation(s)
- Anja Hennemuth
- Center for Medical Image Computing, MeVis Research, 28359 Bremen, Germany
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90
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Carlsson M, Arheden H, Higgins CB, Saeed M. Magnetic resonance imaging as a potential gold standard for infarct quantification. J Electrocardiol 2008; 41:614-20. [DOI: 10.1016/j.jelectrocard.2008.06.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 06/18/2008] [Accepted: 06/27/2008] [Indexed: 11/16/2022]
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91
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Diagnostic and prognostic value of cardiac magnetic resonance imaging in assessing myocardial viability. Top Magn Reson Imaging 2008; 19:15-24. [PMID: 18690157 DOI: 10.1097/rmr.0b013e31817d550c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Assessment of viability is pivotal to the prognosis of patients with chronic coronary artery disease (CAD) and left ventricular dysfunction. Patients with viable myocardium have a better prognosis with revascularization; however, patients with nonviable myocardium have worse outcomes with higher perioperative morbidity and mortality subsequent to revascularization. Cardiac magnetic resonance (CMR) imaging not only is the current reference standard technique in measuring cardiac chamber size and function and myocardial mass and volume but also provides spatially registered 2- or 3-dimensional data sets in myocardial perfusion and myocardial contrast enhancement in the same imaging session. Late gadolinium enhancement by CMR is the best current technique in discriminating myocardial scar versus viable myocardium. An extensive body of preclinical evidence has validated the detection and characterization of the morphology of infarcted tissue. In clinical studies, infarct characteristics by CMR has demonstrated a strong clinical utility in the prediction of left ventricular functional recovery and patient prognosis. In this paper, we aim to review the current CMR techniques in characterizing the spectrum of myocardial changes because of CAD, in the prediction of myocardial viability, and the current evidence of CMR's role in patient prognosis. In addition, we will also review the current literature comparing the clinical utility of CMR with other established imaging modalities in the assessment of CAD.
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92
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Yang Z, Linden J, Berr SS, Kron IL, Beller GA, French BA. Timing of adenosine 2A receptor stimulation relative to reperfusion has differential effects on infarct size and cardiac function as assessed in mice by MRI. Am J Physiol Heart Circ Physiol 2008; 295:H2328-35. [PMID: 18849340 DOI: 10.1152/ajpheart.00091.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The activation of adenosine 2A receptors before reperfusion following coronary artery occlusion reduces infarct size and improves ejection fraction (EF). In this study, we examined the effects of delaying treatment with the adenosine 2A receptor agonist ATL146e (ATL) until 1 h postreperfusion. The infarct size and EF were serially assessed by gadolinium-diethylenetriaminepentaacetic acid-enhanced MRI in C57BL/6 mice at 1 and 24 h postreperfusion. The infarct size was also assessed by 2,3,5-triphenyltetrazolium chloride staining at 24 h. Mice were treated with ATL (10 microg/kg ip) either 2 min before reperfusion (early ATL) or 1 h postreperfusion (late ATL) following the 45-min coronary occlusion. The two methods used to assess infarct size at 24 h postreperfusion (MRI and 2,3,5-triphenyltetrazolium chloride) showed an excellent correlation (R=0.96). The risk region, determined at 24 h postreperfusion, was comparable between the control and ATL-treated groups. The infarct size by MRI at 1 versus 24 h postreperfusion was 25+/-1 vs. 26+/-1% of left ventricular mass (means+/-SE) in control mice, 16+/-2 versus 17+/-2% in early-ATL mice, and 24+/-2 versus 25+/-2% in late-ATL mice (intragroup, P=not significant; and intergroup, early ATL vs. control or late ATL, P<0.05). EF was reduced in control mice but was largely preserved between 1 and 24 h in both early-ATL and late-ATL mice (P<0.05). In conclusion, after coronary occlusion in mice, the extent of myocellular death due to ischemia-reperfusion injury is 95% complete within 1 h of reperfusion. The infarct size was significantly reduced by ATL when given just before reperfusion, but not 1 h postreperfusion. Either treatment window helped preserve the EF between 1 and 24 h postreperfusion.
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Affiliation(s)
- Zequan Yang
- Department of Surgery, University of Virginia, MR5 Bldg. Rm. 1219, Box 800759, 415 Lane Rd., Charlottesville, VA 22903, USA
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93
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McGann CJ, Kholmovski EG, Oakes RS, Blauer JJE, Daccarett M, Segerson N, Airey KJ, Akoum N, Fish E, Badger TJ, DiBella EVR, Parker D, MacLeod RS, Marrouche NF. New Magnetic Resonance Imaging-Based Method for Defining the Extent of Left Atrial Wall Injury After the Ablation of Atrial Fibrillation. J Am Coll Cardiol 2008; 52:1263-71. [PMID: 18926331 DOI: 10.1016/j.jacc.2008.05.062] [Citation(s) in RCA: 256] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/11/2008] [Accepted: 05/05/2008] [Indexed: 11/29/2022]
Abstract
OBJECTIVES We describe a noninvasive method of detecting and quantifying left atrial (LA) wall injury after pulmonary vein antrum isolation (PVAI) in patients with atrial fibrillation (AF). Using a 3-dimensional (3D) delayed-enhancement magnetic resonance imaging (MRI) sequence and novel processing methods, LA wall scarring is visualized at high resolution after radiofrequency ablation (RFA). BACKGROUND Radiofrequency ablation to achieve PVAI is a promising approach to curing AF. Controlled lesion delivery and scar formation within the LA are indicators of procedural success, but the assessment of these factors is limited to invasive methods. Noninvasive evaluation of LA wall injury to assess permanent tissue injury may be an important step in improving procedural success. METHODS Imaging of the LA wall with a 3D delayed-enhanced cardiac MRI sequence was performed before and 3 months after ablation in 46 patients undergoing PVAI for AF. Our 3D respiratory-navigated MRI sequence using parallel imaging resulted in 1.25 x 1.25 x 2.5 mm (reconstructed to 0.6 x 0.6 x 1.25 mm) spatial resolution with imaging times ranging 8 to 12 min. RESULTS Radiofrequency ablation resulted in hyperenhancement of the LA wall in all patients post-PVAI and may represent tissue scarring. New methods of reconstructing the LA in 3D allowed quantification of LA scarring using automated methods. Arrhythmia recurrence at 3 months correlated with the degree of wall enhancement with >13% injury predicting freedom from AF (odds ratio: 18.5, 95% confidence interval: 1.27 to 268, p = 0.032). CONCLUSIONS We define noninvasive MRI methods that allow for the detection and quantification of LA wall scarring after RF ablation in patients with AF. Moreover, there seems to be a correlation between the extent of LA wall injury and short-term procedural outcome.
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Affiliation(s)
- Christopher J McGann
- Radiology Department, University of Utah School of Medicine, University of Utah, Salt Lake City, Utah, USA
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Robust assessment of the transmural extent of myocardial infarction in late gadolinium-enhanced MRI studies using appropriate angular and circumferential subdivision of the myocardium. Eur Radiol 2008; 18:2140-7. [PMID: 18523773 DOI: 10.1007/s00330-008-0991-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 02/29/2008] [Accepted: 03/08/2008] [Indexed: 10/22/2022]
Abstract
A computer-assisted method is proposed to estimate transmural extent of myocardial infarction. In 40 patients with chronic myocardial infarction and 3 control subjects, late gadolinium enhancement images were acquired with magnetic resonance imaging. Segmental infarct transmural extent was visually assessed by two experts on a 5-point scale. A fuzzy c-means algorithm was applied on both the cavity and myocardium to estimate an enhancement index for 12 sub-regions of each segment. A threshold was defined on a training database (n=29) to establish the transmurality extent of each sub-segment and was applied to the validation database (n=14). Inter-observer reproducibility reached an absolute agreement (Aa) of 85% and a kappa value (kappa) of 0.83 when considering the whole training database; Aa decreased to 62% and kappa to 0.68 when excluding homogeneous segments. On the validation database, segments were subdivided into three angular sub-segments. Then, inter-observer visual reproducibility reached Aa of 93% and kappa of 0.92. Moreover, the absolute comparison of each expert with the computer-assisted method yielded Aa higher than 88% and kappa higher than 0.86. The computer-assisted method quantifies infarct transmurality without defining remote and infarcted regions, and the transmural extent is accurately characterized when dividing each segment into three angular sub-segments.
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95
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de Silva R, Raval AN, Hadi M, Gildea KM, Bonifacino AC, Yu ZX, Yau YY, Leitman SF, Bacharach SL, Donahue RE, Read EJ, Lederman RJ. Intracoronary infusion of autologous mononuclear cells from bone marrow or granulocyte colony-stimulating factor-mobilized apheresis product may not improve remodelling, contractile function, perfusion, or infarct size in a swine model of large myocardial infarction. Eur Heart J 2008; 29:1772-82. [PMID: 18502738 DOI: 10.1093/eurheartj/ehn216] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS In a blinded, placebo-controlled study, we investigated whether intracoronary infusion of autologous mononuclear cells from granulocyte colony-stimulating factor (G-CSF)-mobilized apheresis product or bone marrow (BM) improved sensitive outcome measures in a swine model of large myocardial infarction (MI). METHODS AND RESULTS Four days after left anterior descending (LAD) occlusion and reperfusion, cells from BM or apheresis product of saline- (placebo) or G-CSF-injected animals were infused into the LAD. Large infarcts were created: baseline ejection fraction (EF) by magnetic resonance imaging (MRI) of 35.3 +/- 8.5%, no difference between the placebo, G-CSF, and BM groups (P = 0.16 by ANOVA). At 6 weeks, EF fell to a similar degree in the placebo, G-CSF, and BM groups (-7.9 +/- 6.0, -8.5 +/- 8.8, and -10.9 +/- 7.6%, P = 0.78 by ANOVA). Left ventricular volumes and infarct size by MRI deteriorated similarly in all three groups. Quantitative positron emission tomography (PET) demonstrated significant decline in fluorodeoxyglucose uptake rate in the LAD territory at follow-up, with no histological, angiographic, or PET perfusion evidence of functional neovascularization. Immunofluorescence failed to demonstrate transdifferentiation of infused cells. CONCLUSION Intracoronary infusion of mononuclear cells from either BM or G-CSF-mobilized apheresis product may not improve or limit deterioration in systolic function, adverse ventricular remodelling, infarct size, or perfusion in a swine model of large MI.
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Affiliation(s)
- Ranil de Silva
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
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Heiberg E, Ugander M, Engblom H, Götberg M, Olivecrona GK, Erlinge D, Arheden H. Automated Quantification of Myocardial Infarction from MR Images by Accounting for Partial Volume Effects: Animal, Phantom, and Human Study. Radiology 2008; 246:581-8. [DOI: 10.1148/radiol.2461062164] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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97
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In Vivo T2-Weighted Magnetic Resonance Imaging Can Accurately Determine the Ischemic Area at Risk for 2-Day-Old Nonreperfused Myocardial Infarction. Invest Radiol 2008; 43:7-15. [DOI: 10.1097/rli.0b013e3181558822] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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98
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Rosendahl L, Blomstrand P, Heiberg E, Ohlsson J, Björklund PG, Ahlander BM, Engvall J. Computer-assisted calculation of myocardial infarct size shortens the evaluation time of contrast-enhanced cardiac MRI. Clin Physiol Funct Imaging 2007; 28:1-7. [DOI: 10.1111/j.1475-097x.2007.00765.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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99
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Ligabue G, Fiocchi F, Ferraresi S, Barbieri A, Romagnoli R, Torricelli P. How to quantify infarct size on delayed-enhancement MR images: a comparison between visual and quantitative approach. Radiol Med 2007; 112:959-68. [DOI: 10.1007/s11547-007-0196-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 12/29/2006] [Indexed: 11/28/2022]
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100
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Ledesma-Carbayo MJ, Kellman P, Hsu LY, Arai AE, McVeigh ER. Motion corrected free-breathing delayed-enhancement imaging of myocardial infarction using nonrigid registration. J Magn Reson Imaging 2007; 26:184-90. [PMID: 17659545 DOI: 10.1002/jmri.20957] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To develop and test an automatic free-breathing, delayed enhancement imaging method with improved image signal-to-noise ratio (SNR). MATERIALS AND METHODS The proposed approach uses free-breathing, inversion-recovery single-shot fast imaging with steady precession (FISP) delayed-enhancement with respiratory motion compensation based on nonrigid image registration. Motion-corrected averaging is used to enhance SNR. RESULTS Fully automatic, nonrigid registration was compared to previously validated rigid body registration that required user interaction. The performance was measured using the variance of edge positions in intensity profiles through the myocardial infarction (MI) enhanced region and through the right ventricular (RV) wall. Measured variation of the MI edge was 1.16 +/- 0.71 mm (N = 6 patients; mean +/- SD) for rigid body and 1.08 +/- 0.76 mm for nonrigid registration (no significant difference). On the other hand, significant improvement (P < 0.005) was found in the measurements at the RV edge where the SD was 2.06 +/- 0.56 mm for rigid body and 0.59 +/- 0.22 mm for nonrigid registration. CONCLUSION The proposed approach achieves delayed enhancement images with high resolution and SNR without requiring a breathhold. Motion correction of free-breathing delayed-enhancement imaging using nonrigid image registration may be implemented in a fully automatic fashion and performs uniformly well across the full field of view (FOV).
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Affiliation(s)
- Maria J Ledesma-Carbayo
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, DHHS, Bethesda, Maryland 20892-1061, USA
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