| 1. |
- Bacharova, Ljuba, et al.
(författare)
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The Dipolar ElectroCARdioTOpographic (DECARTO)-like method for graphic presentation of location and extent of area at risk estimated from ST-segment deviations in patients with acute myocardial infarction
- 2009
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 42:2, s. 172-180
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Tidskriftsartikel (refereegranskat)abstract
- A graphic method was developed for presentation of the location and extent of the myocardium at risk in patients with acute myocardial infarction (AMI). This method is based on a mathematical processing of ST-segment deviations of standard 12-lead electrocardiogram following the concept of Titomir and Ruttkay-Nedecky in their dipolar electrocardiotopographic method. The center of the location of the area at risk is given by the spatial orientation of the resultant spatial ST vector, and the extent of the area at risk is derived from the Aldrich score. The areas at risk are projected on a spherical image surface, on which a texture of the anatomical quadrants of the ventricular surface and its coronary artery supply are projected. The method was tested in 10 patients with AMI with single-vessel disease, including 6 patients with an occlusion in the proximal left anterior descending coronary artery (LAD), 3 patients with an occlusion in the right coronary artery, and one patient with occlusion in the left circumflex coronary artery. The estimated areas at risk were compared with myocardial perfusion single photon emission computed tomography. Eight (80%) patients of 10 were correctly localized according to the Aldrich decision rules for the location of AMI. The areas at risk in patients with LAD occlusion correctly localized by the Aldrich score were situated in the anteroseptal and anterosuperior quadrants. In the inferior AMI group, the area at risk was localized in the posterolateral and inferior quadrants. The visual comparison with myocardial perfusion single photon emission computed tomography (SPECT) showed best agreement in patients with LAD involvement. The initial testing showed that this method allows a graphic presentation of estimated area at risk using clinically defined diagnostic rules. The area at risk can be displayed in images that are familiar for clinicians and can be compared with or superimposed on results of other imaging methods used in cardiology. (C) 2009 Elsevier Inc. All rights reserved.
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| 2. |
- Carlsson, Marcus, et al.
(författare)
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Myocardium at risk after acute infarction in humans on cardiac magnetic resonance: quantitative assessment during follow-up and validation with single-photon emission computed tomography.
- 2009
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Ingår i: JACC: Cardiovascular Imaging. - : Elsevier BV. - 1876-7591 .- 1936-878X. ; 2:5, s. 569-576
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Our goal was to validate myocardium at risk on T2-weighted short tau inversion recovery (T2-STIR) cardiac magnetic resonance (CMR) over time, compared with that seen with perfusion single-photon emission computed tomography (SPECT) in patients with ST-segment elevation myocardial infarction, and to assess the amount of salvaged myocardium after 1 week. BACKGROUND: To assess reperfusion therapy, it is necessary to determine how much myocardium is salvaged by measuring the final infarct size in relation to the initial myocardium at risk of the left ventricle (LV). METHODS: Sixteen patients with first-time ST-segment elevation myocardial infarction received (99m)Tc tetrofosmin before primary percutaneous coronary intervention. SPECT was performed within 4 h and T2-STIR CMR within 1 day, 1 week, 6 weeks, and 6 months. At 1 week, patients were injected with a gadolinium-based contrast agent for quantification of infarct size. RESULTS: Myocardium at risk at occlusion on SPECT was 33 +/- 10% of the LV. Myocardium at risk on T2-STIR did not differ from SPECT, at day 1 (29 +/- 7%, p = 0.49) or week 1 (31 +/- 6%, p = 0.16) but declined at week 6 (10 +/- 12%, p = 0.0096 vs. 1 week) and month 6 (4 +/- 11%, p = 0.0013 vs. 1 week). There was a correlation between myocardium at risk demonstrated by T2-STIR at week 1 and myocardium at risk by SPECT (r(2) = 0.70, p < 0.001), and the difference between the methods on Bland-Altman analysis was not significant (-2.3 +/- 5.7%, p = 0.16). Both modalities identified myocardium at risk in the same perfusion territory and in concordance with angiography. Final infarct size was 8 +/- 7%, and salvage was 75 +/- 19% of myocardium at risk. CONCLUSIONS: This study demonstrates that T2-STIR performed up to 1 week after reperfusion can accurately determine myocardium at risk as it was before opening of the occluded artery. CMR can also quantify salvaged myocardium as myocardium at risk minus final infarct size.
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| 3. |
- Demidova, Marina, et al.
(författare)
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ST-segment dynamics during reperfusion period and the size of myocardial injury in experimental myocardial infarction.
- 2011
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:1, s. 74-81
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Tidskriftsartikel (refereegranskat)abstract
- Exacerbation of ST elevation associated with reperfusion has been reported in patients with myocardial infarction. However, the cause of the "reperfusion peak" and relation of its magnitude to the size of myocardial damage has not been explored. The aim of our study was to assess the correlation between the ST-dynamics during reperfusion, the myocardium at risk (MaR), and the infarct size (IS).
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| 4. |
- Fransson, Helen, et al.
(författare)
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An Improved Method for Automatic Segmentation of the Left Ventricle in Myocardial Perfusion SPECT.
- 2009
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 50:2, s. 205-213
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Tidskriftsartikel (refereegranskat)abstract
- This study describes and validates a new method for automatic segmentation of left ventricular mass (LVM) in myocardial perfusion SPECT (MPS) images. This is important for estimating the size of a perfusion defect as percentage of the left ventricle. METHODS: A total of 101 patients with known or suspected coronary artery disease underwent both rest and stress MPS and MRI. A new automated algorithm was trained in 20 patients (40 MPS studies) and tested in 81 patients (162 MPS studies). The algorithm, which segmented the left ventricle in the MPS images, is based on Dijkstra's algorithm and finds an optimal mid-mural line through the left ventricular wall. From this line, the endocardium and epicardium are identified on the basis of an individually estimated wall thickness and signal intensity. The algorithm was validated by comparing LVM in both stress and rest MPS, with LVM of the manually segmented left ventricle from MRI as the reference standard. For comparison, LVM was quantified using the software quantitative perfusion SPECT (QPS). RESULTS: The mean difference +/- SD in LVM between MPS and MRI was lower for the new method (6% +/- 15% LVM) than for QPS (18% +/- 19% LVM) for both mean difference (P < 0.001) and SD (P = 0.015). Linear regression analysis of LVM, comparing MPS and MRI, yielded R(2) = 0.83 using the new method and R(2) = 0.80 using QPS. Interstudy variability, measured as the coefficient of variance between rest MPS and stress MPS, was 6% for both the new method and QPS. Both the new algorithm and QPS systematically overestimated LVM in hearts with thin myocardium and underestimated LVM in hearts with thick myocardium. CONCLUSION: The new segmentation algorithm quantifies LVM with a significantly lower bias and variability than does the commercially available QPS software, when compared to manually segmented LVM by MRI. This makes the new algorithm an attractive method to use for estimating the size of the perfusion defect when expressing it as percentage of the left ventricle. This study shows that inaccurate estimation of wall thickness is the main source of error in automatic segmentation.
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| 5. |
- Fransson, Helen, et al.
(författare)
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Development and validation of a new automatic algorithm for quantification of left ventricular volumes and function in gated myocardial perfusion SPECT using cardiac magnetic resonance as reference standard.
- 2011
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1532-6551 .- 1071-3581. ; 18:5, s. 874-885
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: By gating image acquisition in myocardial perfusion SPECT (MPS) to ECG, left ventricular (LV) volumes and function can be determined. Several previous studies have shown that existing MPS software packages underestimate LV volumes compared to cardiac magnetic resonance (CMR). The aim of this study was therefore to develop a new LV segmentation algorithm for gated MPS using CMR as reference standard. METHODS AND RESULTS: A total of 126 patients with suspected coronary artery disease, who underwent both gated MPS and CMR were retrospectively included. The proposed LV segmentation algorithm (Segment) was trained in 26 patients, and tested in 100 patients in comparison to four commercially available MPS software packages (QGS, MyoMetrix, ECTb, and Exini) using CMR as reference standard. Mean bias ± SD between MPS and CMR was for EDV -5% ± 12%, -43% ± 8%, -40% ± 8%, -42% ± 9%, -32% ± 7%, for ESV 0% ± 17%, -41% ± 16%, -34% ± 15%, -54% ± 13%, -41% ± 10%, for EF -2% ± 13%, -1% ± 14%, -7% ± 15%, 17% ± 16%, 10% ± 17% for Segment, QGS, MyoMetrix, ECTb, and Exini, respectively, and for LVM 3% ± 18%, 33% ± 25%, 37% ± 24% for Segment, QGS, and ECTb, respectively. Correlation between MPS by Segment and CMR were for EDV R (2) = 0.89, for ESV R (2) = 0.92, for EF R (2) = 0.69, and for LVM R (2) = 0.72, with no difference compared to the correlation between the other MPS software packages and CMR (EDV R (2) = 0.86-0.92, ESV R (2) = 0.91-0.93, EF R (2) = 0.64-0.65, and LVM R (2) = 0.68-0.70). CONCLUSION: The Segment software quantifies LV volumes and EF by MPS with similar correlation and a low bias compared to other MPS software packages, using CMR as reference standard. Hence, the Segment software shows potential to provide clinically relevant volumes and functional values from MPS.
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| 6. |
- Galeotti, Loriano, et al.
(författare)
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Development of an automated method for display of ischemic myocardium from simulated electrocardiograms.
- 2009
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 42, s. 204-212
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Knowledge of the size and location of ischemic myocardium during acute coronary occlusion could provide decision support before reperfusion therapy. Electrocardiogram (ECG) scores based on the number of leads and the sum of ST-segment elevation have been unreliable in quantifying ischemia. We aimed to develop a new method to graphically display ischemic myocardium from simulated ECGs (DIMS-ECG) associated with known ischemic regions. METHODS: Twenty-one patterns of ischemia based on normal coronary anatomy were programmed into the freely available program ECGSIM (www.ecgsim.org). Minor variations of these patterns and 5 levels of ischemia severity produced 45 455 ECGs; 1000 normal ECGs were also added. Given a de novo ECG (an ECG from a patient), ST-segment and T-wave measurements are compared with ECG measurements in the database. The closest 200 matches are selected, and the corresponding ischemic areas are "averaged" to create a graphical display of the ischemic myocardium. RESULTS: Three patients are presented who underwent elective coronary angioplasty with continuous ECG recording and scintigraphically defined ischemic myocardium. Based on ECG analysis, the program graphically displays the ischemic myocardium with close agreement to the scintigraphic images. The program's source code and the ECG database will be made freely available. CONCLUSIONS: The DIMS-ECG method graphically displays ischemic myocardium from information contained in the 12-lead ECG based on a novel approach to use a large simulated database instead of rule- or score-based method. After further development and testing, the DIMS-ECG method could be used to risk stratify patients with acute myocardial infarction.
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| 7. |
- Jablonowski, Robert, et al.
(författare)
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Infarct quantification using 3D inversion recovery and 2D phase sensitive inversion recovery; validation in patients and ex vivo.
- 2013
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Ingår i: BMC Cardiovascular Disorders. - : Springer Science and Business Media LLC. - 1471-2261. ; 13:Dec 5
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Tidskriftsartikel (refereegranskat)abstract
- Cardiovascular-MR (CMR) is the gold standard for quantifying myocardial infarction using late gadolinium enhancement (LGE) technique. Both 2D- and 3D-LGE-sequences are used in clinical practise and in clinical and experimental studies for infarct quantification. Therefore the aim of this study was to investigate if image acquisitions with 2D- and 3D-LGE show the same infarct size in patients and ex vivo.
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| 8. |
- Knippenberg, Stephanie A. M., et al.
(författare)
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Consideration of the Impact of Reperfusion Therapy on the Quantitative Relationship between the Selvester QRS Score and Infarct Size by Cardiac MRI
- 2010
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Ingår i: Annals of Noninvasive Electrocardiology. - 1082-720X. ; 15:3, s. 238-244
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Tidskriftsartikel (refereegranskat)abstract
- Methods: Twenty-seven patients with acute first-time reperfused MI were studied. Infarct size was determined by delayed contrast-enhanced magnetic resonance imaging (DE-MRI) and estimated with the 50-criteria/31-point Selvester QRS scoring system 1 week after admission. The findings in the present study were compared with previous postmortem studies exploring the quantitative relationship between Selvester QRS score and MI size in nonreperfused patients. Results: The quantitative relationship between QRS score and MI size by DE-MRI in the present study of early reperfused MI was significantly different from previous postmortem histopathology studies of nonreperfused MI (P < 0.0001). In the present study, each QRS point represented approximately 2% of the left ventricle, compared to approximately 3% in previous postmortem histopathology studies of nonreperfused MI. When only considering small to moderate MI sizes, there was no significant difference in the quantitative relationship between QRS score and infarct size (P > 0.05). Conclusions: There is a different quantitative relationship between QRS score and MI size in early reperfused MI compared to nonreperfused MI, partly explained by differences in MI size. Thus, the Selvester QRS scoring system may not be linearly related to MI size. Ann Noninvasive Electrocardiol 2010;15(3):238-244.
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| 9. |
- Pahlm, Ulrika, et al.
(författare)
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Regional wall function before and after acute myocardial infarction; an experimental study in pigs.
- 2014
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Ingår i: BMC Cardiovascular Disorders. - : Springer Science and Business Media LLC. - 1471-2261. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Left ventricular function is altered during and after AMI. Regional function can be determined by cardiac magnetic resonance (CMR) wall thickening, and velocity encoded (VE) strain analysis. The aims of this study were to investigate how regional myocardial wall function, assessed by CMR VE-strain and regional wall thickening, changes after acute myocardial infarction, and to determine if we could differentiate between ischemic, adjacent and remote segments of the left ventricle.
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| 10. |
- Tufvesson, Jane, et al.
(författare)
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Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance
- 2012
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - 1097-6647. ; 14
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Tidskriftsartikel (refereegranskat)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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