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- Maret, Eva, 1961-, et al.
(författare)
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Feature tracking of cine-MRI identifies left ventricular segments with myocardial scar
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: The aim of the study was to apply a new feature tracking software (Diogenes MRI, Tomtec GmbH, Unterschliessheim, Germany) on cine-MR images to evaluate its utility and ability to detect infarcted myocardium and to assess the transmural extent of scar without the need for administering intravenous gadolinium-based contrast agents. Methods: Thirty patients (3 women and 27 men) were selected based on the presence or absence of extensive myocardial scar in the perfusion area of the left anterior descending coronary artery (LAD) but not in remote areas. Seventeen had a scar transmurality >75% in at least one segment belonging to the LAD area (scar patients) and thirteen had scar <1% in this area or in other parts of the myocardium (non-scar patients). The software tracked the motion of the wall through the entire cardiac cycle using two different techniques. Velocity, displacement and strain were calculated in 48 points in the longitudinal direction, tangential to the endocardial outline, and in the radial direction, perpendicular to the tangent. Results: In the scar patients, LAD segments showed lower functional measures than remote segments. The remote segments in the scar group showed, in turn, lower functional measures than the remote segments in the non-scar group. Receiver-operatorcharacteristic (ROC) curves were constructed for all measurements. Best area-undercurve was for radial strain, 0.89, where a cut-off value of 38.8% had 80% sensitivity and 86% specificity for the detection of a segment with scar transmurality >50% in the LAD distribution. As a percentage of the mean, intraobserver variability was for radial measures 16-14-26% for displacement-velocity-strain and for the corresponding interobserver measurements 13-12-18%. Conclusions: With the presented method, we show for the first time its ability to detect scar segments with various transmurality already from an analysis of cine-MRI, without the need for the administration of gadolinium-based contrast. The accuracy and repeatability of the radial functional measurements is satisfactory and global measures agree with other aspects of global left ventricular function.
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- Maret, Eva, 1961-
(författare)
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Noninvasive Evaluation of Myocardial Ischemia and Left Ventricular Function
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this thesis was, following the path of the ischemic cascade, to evaluate the feasibility of some new non-invasive techniques for the detection of myocardial ischemia, the extent of infarcted myocardium, and for the quantification of systolic left ventricular function.Reduced longitudinal myocardial velocity and displacement may be early signs of ischemia. We evaluated the diagnostic sensitivity and specificity of pulsed tissue Doppler for the detection of ischemia and scar during dobutamine stress testing and compared it with myocardial perfusion scintigraphy (SPECT) in patients with a history of unstable angina. Pulsed tissue Doppler was useful for objective quantification of left ventricular longitudinal shortening and for differentiation between patients with a normal, ischemic or necrotic myocardium.The coronary flow velocity reserve (CFVR) of the left anterior descending artery (LAD) was studied with transthoracic Doppler echocardiography (TTDE) during adenosine stress. Patients with a clinical suspicion of stress induced myocardial ischemia were investigated, and the results were compared with the findings from SPECT. A CFVR >2 in the LAD could exclude significant coronary artery disease in a clinical setting, however, in cases with low CFVR, multiple cardiovascular and metabolic risk factors as well as epicardial coronary artery disease or microvascular dysfunction might be responsible. TTDE is a promising tool, e.g. for follow-up after coronary interventions or for evaluating endothelial function over time.A third study focused on the importance of accurate and reproducible measurements of left ventricular volumes and ejection fraction (LVEF). Patients with known or suspected coronary artery disease with different levels of LVEF were enrolled. We compared the LVEF determined with an automatic echocardiographic method with manual planimetry, visual assessment of LVEF and with quantitative myocardial gated SPECT. The software using learned pattern recognition and artificial intelligence (AutoEF) applied on biplane apical echocardiographic views reduced the variation in measurements without increasing the time required. The method seems to be able to reduce variation in the assessment of LVEF in clinical patients, especially for less experienced readers.We evaluated a new feature tracking software for its ability to detect infarcted myocardium on cine-MR images. Patients were selected based on the presence or absence of myocardial scar in the perfusion area of the LAD. The software tracked myocardial wall motion and allowed the calculation of velocity, displacement and strain in radial and longitudinal directions. Feature tracking of cine-MR images detected scar segments with transmurality >50% within the distribution of the LAD with 80% sensitivity and 86% specificity (radial strain), without the need for the administration of gadolinium-based contrast.In summary, we have evaluated some of the noninvasive techniques in the wide array of diagnostic tools available for the diagnosis of ischemic heart disease. Their availability, low costs, freedom from radiation and repeatability are essential as well as their diagnostic ability.
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