Assessment Of Regional Myocardial Function Research Articles

MulViMotion: Shape-Aware 3D Myocardial Motion Tracking From Multi-View Cardiac MRI.

Recovering the 3D motion of the heart from cine cardiac magnetic resonance (CMR) imaging enables the assessment of regional myocardial function and is important for understanding and analyzing cardiovascular disease. However, 3D cardiac motion estimation is challenging because the acquired cine CMR images are usually 2D slices which limit the accurate estimation of through-plane motion. To address this problem, we propose a novel multi-view motion estimation network (MulViMotion), which integrates 2D cine CMR images acquired in short-axis and long-axis planes to learn a consistent 3D motion field of the heart. In the proposed method, a hybrid 2D/3D network is built to generate dense 3D motion fields by learning fused representations from multi-view images. To ensure that the motion estimation is consistent in 3D, a shape regularization module is introduced during training, where shape information from multi-view images is exploited to provide weak supervision to 3D motion estimation. We extensively evaluate the proposed method on 2D cine CMR images from 580 subjects of the UK Biobank study for 3D motion tracking of the left ventricular myocardium. Experimental results show that the proposed method quantitatively and qualitatively outperforms competing methods.

Evaluation of left ventricular functions by speckle‐tracking echocardiography in coarctation patients

Two-dimensional speckle-tracking echocardiography (2D-STE) is a novel method that allows the assessment of regional myocardial function. The aim of our study was to use 2D-STE to assess left ventricular deformation in patients with coarctation of the aorta (CoA). In this prospective study, patients with CoA (n=42) and healthy controls (n=39) were recruited. Children with CoA who visited the outpatient clinic between 2013 and 2014 were included. The data were compared with those obtained from the sex- and age-matched controls. The mean age of the patients was 5.8±4.5years. Global longitudinal strain based on all three apical views and total global strain values did not appear to be different between the patient and the control groups (P=.59, P=.51, P=.15, P=.38). Hypertension was detected in 14 (33.3%) patients with CoA. There were significant differences between the global longitudinal strain values of the normotensive CoA subgroup and the hypertensive CoA subgroup (P < .05). In our study, we found that 2D-STE total strain analysis of patients with CoA was not different from comparative healthy controls. However, we determined that 2D-STE parameters were lower in the hypertensive CoA subgroup compared to the normotensive CoA subgroup.

Quantification of myocardial strain assessed by cardiovascular magnetic resonance feature tracking in healthy subjects\u2014influence of segmentation and analysis software

ObjectivesQuantification of myocardial deformation by feature tracking is of growing interest in cardiovascular magnetic resonance. It allows the assessment of regional myocardial function based on cine images. However, image acquisition, post-processing, and interpretation are not standardized. We aimed to assess the influence of segmentation procedure such as slice selection and different types of analysis software on values and quantification of myocardial strain in healthy adults.MethodsHealthy volunteers were retrospectively analyzed. Post-processing was performed using CVI42 and TomTec. Longitudinal and radialLong axis (LAX) strain were quantified using 4-chamber-view, 3-chamber-view, and 2-chamber-view. Circumferential and radialShort axis (SAX) strain were assessed in basal, midventricular, and apical short-axis views and using full coverage. Global and segmental strain values were compared to each other regarding their post-processing approach and analysis software package.ResultsWe screened healthy volunteers studied at 1.5 or 3.0 T and included 67 (age 44.3 ± 16.3 years, 31 females). Circumferential and radialSAX strain values were different between a full coverage approach vs. three short slices (− 17.6 ± 1.8% vs. − 19.2 ± 2.3% and 29.1 ± 4.8% vs. 34.6 ± 7.1%). Different analysis software calculated significantly different strain values. Within the same vendor, different field strengths (− 17.0 ± 2.1% at 1.5 T vs. − 17.0 ± 1.7% at 3 T, p = 0.845) did not influence the calculated global longitudinal strain (GLS), and were similar in gender (− 17.4 ± 2.0% in females vs. − 16.6 ± 1.8% in males, p = 0.098). Circumferential and radial strain were different in females and males (circumferential strain − 18.2 ± 1.7% vs. − 17.1 ± 1.8%, p = 0.029 and radial strain 30.7 ± 4.7% vs. 27.8 ± 4.6%, p = 0.047).ConclusionsMyocardial deformation assessed by feature tracking depends on segmentation procedure and type of analysis software. CircumferentialSAX and radialSAX depend on the number of slices used for feature tracking analysis. As known from other imaging modalities, GLS seems to be the most stable parameter. During follow-up studies, standardized conditions should be warranted.Trial registration Retrospectively registeredKey Points• Myocardial deformation assessed by feature tracking depends on the segmentation procedure.• Global myocardial strain values differ significantly among vendors.• Standardization in post-processing using CMR feature tracking is essential.

Assessment of left ventricular regional wall motion abnormalities using regional time-volume curves obtained by real time three-dimensional echocardiography.

BackgroundThree-dimensional echocardiography provides a volumetric measurement of global and regional left ventricular (LV) function. It avoids the subjectivity of 2D echocardiography in the assessment of regional wall motion abnormalities (RWMA).PurposeEvaluate the feasibility and practicality of 3D echocardiography in the evaluation of ischemic patients with abnormal regional LV contractility.MethodsThe study included 40 patients with ischemic heart disease and RWMA as well as 30 control subjects. They underwent routine clinical examination and conventional 2D echocardiographic assessment. Segments were categorized as; normal, hypokinetic; akinetic or dyskinetic. Three-dimensional echocardiographic images were acquired and later on analyzed offline. Global LV function was semi-automatically calculated by the machine using volumetric measurements. Regional LV function was calculated manually for the 17 LV segments by detecting the end-diastolic (EDD) and end-systolic (ESD) points on the specific segment volume curve and the regional ejection fraction (EF) was calculated by the following formula {(EDDx-ESDx)/EDDx}, where x represents the specific segment. Regional EF was compared between patients and control subjects.ResultsThe mean age was 55.0 ± 8.0 and 32.6 ± 8.5 years (P < 0.001) in patients and control groups, respectively. No statistically significant difference in EF between 2D and 3D images (47.3 ± 10.5 vs 48.0 ± 8.0, p = 0.6). There was a good correlation between the 2D-RWMA and 3D-regional EF, and this correlation was consistent in the whole 17 segments.ConclusionThree-dimensional echocardiography is an easy, non-invasive and objective tool to detect regional wall motion abnormalities in ischemic patients. It shows comparable results with conventional 2D images with the advantage of quantitative assessment of regional myocardial function.

Myocardial deformation assessment using cardiovascular magnetic resonance-feature tracking technique.

Cardiovascular magnetic resonance (CMR) imaging is an important modality that allows the assessment of regional myocardial function by measuring myocardial deformation parameters, such as strain and strain rate throughout the cardiac cycle. Feature tracking is a promising quantitative post-processing technique that is increasingly used. It is commonly applied to cine images, in particular steady-state free precession, acquired during routine CMR examinations. To review the studies that have used feature tracking techniques in healthy subjects or patients with cardiovascular diseases. The article emphasizes the advantages and limitations of feature tracking when applied to regional deformation parameters. The challenges of applying the techniques in clinics and potential solutions are also reviewed. Research studies in healthy volunteers and/or patients either applied CMR-feature tracking alone to assess myocardial motion or compared it with either established CMR-tagging techniques or to speckle tracking echocardiography. These studies assessed the feasibility and reliability of calculating or determining global and regional myocardial deformation strain parameters. Regional deformation parameters are reviewed and compared. Better reproducibility for global deformation was observed compared with segmental parameters. Overall, studies demonstrated that circumferential was the most reproducible deformation parameter, usually followed by longitudinal strain; in contrast, radial strain showed high variability. Although feature tracking is a promising tool, there are still discrepancies in the results obtained using different software packages. This highlights a clear need for standardization of MRI acquisition parameters and feature tracking analysis methodologies. Validation, including physical and numerical phantoms, is still required to facilitate the use of feature tracking in routine clinical practice.

Intervendor Differences in the Accuracy of Detecting Regional Functional Abnormalities: A Report From the EACVI-ASE Strain Standardization Task Force

ObjectivesThe purpose of this study was to compare the accuracy of vendor-specific and independent strain analysis tools to detect regional myocardial function abnormality in a clinical setting. BackgroundSpeckle tracking echocardiography has been considered a promising tool for the quantitative assessment of regional myocardial function. However, the potential differences among speckle tracking software with regard to their accuracy in identifying regional abnormality has not been studied extensively. MethodsSixty-three subjects (5 healthy volunteers and 58 patients) were examined with 7 different ultrasound machines during 5 days. All patients had experienced a previous myocardial infarction, which was characterized by cardiac magnetic resonance with late gadolinium enhancement. Segmental peak systolic (PS), end-systolic (ES) and post-systolic strain (PSS) measurements were obtained with 6 vendor-specific software tools and 2 independent strain analysis tools. Strain parameters were compared between fully scarred and scar-free segments. Receiver-operating characteristic curves testing the ability of strain parameters and derived indexes to discriminate between these segments were compared among vendors. ResultsThe average strain values calculated for normal segments ranged from −15.1% to −20.7% for PS, −14.9% to −20.6% for ES, and −16.1% to −21.4% for PSS. Significantly lower values of strain (p < 0.05) were found in segments with transmural scar by all vendors, with values ranging from −7.4% to −11.1% for PS, −7.7% to −10.8% for ES, and −10.5% to −14.3% for PSS. Accuracy in identifying transmural scar ranged from acceptable to excellent (area under the curve 0.74 to 0.83 for PS and ES and 0.70 to 0.78 for PSS). Significant differences were found among vendors (p < 0.05). All vendors had a significantly lower accuracy to detect scars in the basal segments compared with scars in the apex (p < 0.05). ConclusionsThe accuracy of identifying regional abnormality differs significantly among vendors.

Speckle-Tracking Echocardiography to Assess Global and Regional Left Ventricular Function in Acute Myocardial Infarction

Speckle tracking is a useful tool in assessing global &amp; regional myocardial function in patients with acute myocardial infarction undergoing primary PCI. Global Longitudinal Strain (GLS) is a robust parameter to assess regional and global LV function. Global longitudinal strain helps in predicting short term outcomes in these patients and has shown to be better than ejection fraction, and as good as wall motion scoring, wall motion scoring index and myocardial performance index. A Lower global longitudinal strain parallels the rise in troponin T and CPKMB in acute myocardial infarction. Global longitudinal strain may have the potential to be an echocardiographic parameter which is useful in identifying multivessel disease. Assessment of regional myocardial function by speckle tracking echocardiography, particularly GLS, can be useful in ACS patients undergoing PCI in predicting short term recovery of the affected segments. Speckle tracking echocardiography can be used independent of the conventional markers to assess regional and global LV function.

LV mechanical dispersion as a predictor of ventricular arrhythmia in patients with advanced systolic heart failure : A pilot study.

BackgroundMyocardial mechanical dyssynchrony induced by the presence of postinfarction scar and/or conduction abnormalities in patients with a left ventricular ejection fraction (LVEF) of < 35 % may be associated with a greater propensity toward inducing serious ventricular arrhythmia [(ventricular tachycardia (VT), ventricular fibrillation (VF)] and sudden cardiac death. The assessment of regional myocardial function using tissue Doppler echocardiography (TDE) allows for noninvasive analysis of regional mechanical dysfunction (LV mechanical dispersion).AimThe aim of this study was to evaluate the TDE-based mechanical dispersion as a potential echocardiographic predictor of VT/VF.MethodsThe study group consisted of 47 consecutive ambulatory patients with implanted cardiac resynchronization therapy–defibrillator (CRT-D) devices who were divided into two groups: Group 1 (n = 29) comprised patients with recorded episodes of VT/VF, in whom baseline TDE data were available, and group 2 (n = 18) comprised patients without registered VT/VF in the device memory within 4 years after implantation. LV mechanical dispersion was defined as the standard deviation of the time measured from the beginning of the QRS complex to the peak longitudinal strain in apical four-chamber and two-chamber views. A retrospective quantitative assessment of LV regional deformation was based on the color tissue velocity recordings.ResultsThe average time to event after implantation was 345 days. Patients with electrical events demonstrated greater mechanical dispersion: 99.14 ± 33.60 vs. 72.98 ± 19.70, p=0.002.ConclusionDuring the 4-year follow-up, patients with documented VT/VF were characterized by significantly higher LV mechanical dispersion as compared with patients without electrical events. Measurement of LV mechanical dispersion might be helpful in determining the risk of sudden cardiac death.

A maximum likelihood approach to diffeomorphic speckle tracking for 3D strain estimation in echocardiography.

The strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle between the myocardial movement and the ultrasound beam should be small to provide reliable measures. This constraint makes it difficult to provide strain measures of the entire myocardium. Alternative non-Doppler techniques such as Speckle Tracking (ST) can provide strain measures without angle constraints. However, the spatial resolution and the noisy appearance of speckle still make the strain estimation a challenging task in EC. Several maximum likelihood approaches have been proposed to statistically characterize the behavior of speckle, which results in a better performance of speckle tracking. However, those models do not consider common transformations to achieve the final B-mode image (e.g. interpolation). This paper proposes a new maximum likelihood approach for speckle tracking which effectively characterizes speckle of the final B-mode image. Its formulation provides a diffeomorphic scheme than can be efficiently optimized with a second-order method. The novelty of the method is threefold: First, the statistical characterization of speckle generalizes conventional speckle models (Rayleigh, Nakagami and Gamma) to a more versatile model for real data. Second, the formulation includes local correlation to increase the efficiency of frame-to-frame speckle tracking. Third, a probabilistic myocardial tissue characterization is used to automatically identify more reliable myocardial motions. The accuracy and agreement assessment was evaluated on a set of 16 synthetic image sequences for three different scenarios: normal, acute ischemia and acute dyssynchrony. The proposed method was compared to six speckle tracking methods. Results revealed that the proposed method is the most accurate method to measure the motion and strain with an average median motion error of 0.42 mm and a median strain error of 2.0 ± 0.9%, 2.1 ± 1.3% and 7.1 ± 4.9% for circumferential, longitudinal and radial strain respectively. It also showed its capability to identify abnormal segments with reduced cardiac function and timing differences for the dyssynchrony cases. These results indicate that the proposed diffeomorphic speckle tracking method provides robust and accurate motion and strain estimation.

Characterization of normal regional myocardial function by MRI cardiac tagging

The aim of this study was to establish reference values for segmental myocardial strain measured by magnetic resonance (MR) cardiac tagging in order to characterize the regional function of the heart. We characterized the left ventricular (LV) systolic deformation in 39 subjects (26 women and 13 men, age 58.8 ± 11.6 years) whose cardiological study had not revealed any significant abnormality. The deformation was measured from MR-tagged (Siemens 1.5T MR) images using an algorithm based on sine wave modeling. Circumferential and radial peak systolic strain values along with the torsion angle and circumferential-longitudinal (CL) shear were determined in 16 LV segments in order to settle the reference values for these parameters. Circumferential strain was highest at the anterior and lateral walls (-20.2 ± 4.0% and -21.8 ± 4.3%, respectively; P < 0.05) and was lowest at the base level (-17.2 ± 3.1% vs. -20.1 ± 3.1% "mid level," P < 0.05; -17.2 ± 3.1% vs. -20.3 ± 3.0% "apical level," P < 0.05). Radial strain highest values were from inferior and lateral walls (13.7 ± 7.4% and 12.8 ± 7.8%, respectively; P < 0.05) and it was lowest medially (9.4 ± 4.1% vs. 13.1 ± 4.1% "base level," P < 0.05; 9.4 ± 4.1% vs. 12.1 ± 4.4% "apical level," P < 0.05). Torsion angle (counterclockwise when viewed from the apex) increased with the distance from the base (7.9 ± 2.4° vs. 16.8 ± 4.4°, P < 0.05), and the highest and lowest values were found at lateral (medial lateral: 12.0 ± 4.4°, apical lateral: 25.1 ± 6.4°, P < 0.05) and septal wall (medial septal: 3.6 ± 2.1°, apical septal: 8.3 ± 5.3°, P < 0.05), respectively. These differences were found again in CL shear values, around the LV circumference. However, CL shear remained constant with increasing distance from the base (9.1 ± 2.6°, medium and 9.8 ± 2.4°, apex). In summary, this study provides reference values for the assessment of regional myocardial function by MR cardiac tagging. Comparison of patient deformation parameters with normal deformation patterns may permit early detection of regional systolic dysfunction.

Imaging Cardiac Sarcoidosis: The Incremental Benefit of Speckle Tracking Echocardiography

Mini‐AbstractEchocardiography is the front‐line investigation for assessment of cardiac morphology and function. Assessment of ventricular systolic function has traditionally been defined by the ejection fraction (EF). However, EF is influenced by preload and after load and is inadequate as a sole indicator of systolic performance. Studies have also shown its inability to detect early myocardial dysfunction.We present images from a patient with pulmonary sarcoidosis referred for echocardiography after developing palpitations. Two‐dimensional‐echocardiography was unremarkable but speckle tracking echocardiography (STE) revealed significantly abnormal regional myocardial strains. The images highlight the potential of STE to reveal early myocardial involvement in sarcoidosis.

Imaging techniques for cardiac strain and deformation: comparison of echocardiography, cardiac magnetic resonance and cardiac computed tomography

Myocardial function assessment is essential for determining the health of the myocardium. Global assessment of myocardial function is widely performed (by estimating the ejection fraction), but many common cardiac diseases initially affect the myocardium on a regional, rather than global basis. Regional myocardial wall motion can be quantified using myocardial strain analysis (a normalized measure of deformation). Myocardial strain can be measured in terms of three normal strains (longitudinal strain, radial strain and circumferential) and six shear strains. Cardiac MRI (cMRI) is usually considered the reference standard for measurement of myocardial strain. The most common cMRI method, termed tagged cMRI, allows full, 3D assessment of regional strain. However, due to its complexity and lengthy times for analysis, tagged cMRI is not usually used outside of academic centers. Tagged cMRI is also primarily used only in research studies. Echocardiography combined with tissue Doppler imaging or a speckle tracking technique is now widely available in the clinical setting. Myocardial strain measurement by echocardiography shows reasonable agreement with cMRI. Limited standardization and differences between vendors represent current limitations of the technique. Cardiac computed tomography (CCT) is the newest and most rapidly growing modality for noninvasive imaging of the heart. While CCT studies are most commonly applied to assess the coronary arteries, CCT is easily adapted to provide functional information for both the left and right ventricles. New methods for CCT assessment of regional myocardial function are being developed. This review outlines the current literature on imaging techniques related to cardiac strain analysis and discusses the strengths and weaknesses of various methods for myocardial strain analysis.

Novel insight into the detailed myocardial motion and deformation of the rodent heart using high-resolution phase contrast cardiovascular magnetic resonance.

BackgroundPhase contrast velocimetry cardiovascular magnetic resonance (PC-CMR) is a powerful and versatile tool allowing assessment of in vivo motion of the myocardium. However, PC-CMR is sensitive to motion related artifacts causing errors that are geometrically systematic, rendering regional analysis of myocardial function challenging. The objective of this study was to establish an optimized PC-CMR method able to provide novel insight in the complex regional motion and strain of the rodent myocardium, and provide a proof-of-concept in normal and diseased rat hearts with higher temporal and spatial resolution than previously reported.MethodsA PC-CMR protocol optimized for assessing the motion and deformation of the myocardium in rats with high spatiotemporal resolution was established, and ten animals with different degree of cardiac dysfunction underwent examination and served as proof-of-concept. Global and regional myocardial velocities and circumferential strain were calculated, and the results were compared to five control animals. Furthermore, the global strain measurements were validated against speckle-tracking echocardiography, and inter- and intrastudy variability of the protocol were evaluated.ResultsThe presented method allows assessment of regional myocardial function in rats with high level of detail; temporal resolution was 3.2 ms, and analysis was done using 32 circumferential segments. In the dysfunctional hearts, global and regional function were distinctly altered, including reduced global peak values, increased regional heterogeneity and increased index of dyssynchrony. Strain derived from the PC-CMR data was in excellent agreement with echocardiography (r = 0.95, p < 0.001; limits-of-agreement −0.02 ± 3.92%strain), and intra- and interstudy variability were low for both velocity and strain (limits-of-agreement, radial motion: 0.01 ± 0.32 cm/s and −0.06 ± 0.75 cm/s; circumferential strain: -0.16 ± 0.89%strain and −0.71 ± 1.67%strain, for intra- and interstudy, respectively).ConclusionWe demonstrate, for the first time, that PC-CMR enables high-resolution evaluation of in vivo circumferential strain in addition to myocardial motion of the rat heart. In combination with the superior geometric robustness of CMR, this ultimately provides a tool for longitudinal studies of regional function in rodents with high level of detail.

Assessment of Myocardial Contractile Function Using Global and Segmental Circumferential Strain following Intracoronary Stem Cell Infusion after Myocardial Infarction: MRI Feature Tracking Feasibility Study.

Background. Magnetic resonance imaging (MRI) strain analysis is a sensitive method to assess myocardial function. Our objective was to define the feasibility of MRI circumferential strain (ε cc) analysis in assessing subtle changes in myocardial function following stem cell therapy. Methods and Results. Patients in the Amorcyte Phase I trial were randomly assigned to treatment with either autologous bone-marrow-derived stem cells infused into the infarct-related artery 5 to 11 days following primary PCI or control. MRI studies were obtained at baseline, 3, and 6 months. ε cc was measured in the short axis views at the base, mid and apical slices of the left ventricle (LV) for each patient (13 treatments and 10 controls). Mid-anterior LV ε cc improved between baseline −18.5 ± 8.6 and 3 months −22.6 ± 7.0, P = 0.03. There were no significant changes in ε cc at 3 months and 6 months compared to baseline for other segments. There was excellent intraobserver and interobserver agreement for basal and mid circumferential strain. Conclusion. MRI segmental strain analysis is feasible in assessment of regional myocardial function following cell therapy with excellent intra- and inter-observer variability's. Using this method, a modest interval change in segmental ε cc was detected in treatment group.

Exercise‐induced cardiac remodelling: the need for assessment of regional myocardial function

Exercise‐induced cardiac remodelling: the need for assessment of regional myocardial function

MYOCARDIAL MECHANICS FOR THE EARLY DETECTION OF CARDIAC SARCOIDOSIS

Speckle tracking has emerged as valuable tool for a more comprehensive assessment of regional myocardial function, providing angle-independent measurements of strain. The aim of this study was to evaluate left ventricular (LV) function in patients with newly diagnosed sarcoidosis, utilizing the

A New Method for Cardiac Computed Tomography Regional Function Assessment

Background— Quantitative assessment of regional myocardial function has important diagnostic implications in cardiac disease. Recent advances in CT imaging technology have allowed fine anatomic structures, such as endocardial trabeculae, to be resolved and potentially used as fiducial markers for tracking local wall deformations. We developed a method to detect and track such features on the endocardium to extract a metric that reflects local myocardial contraction. Methods and Results— First-pass CT images and contrast-enhanced cardiovascular magnetic resonance images were acquired in 8 infarcted and 3 healthy pigs. We tracked the left ventricle wall motion by segmenting the blood from myocardium and calculating trajectories of the endocardial features seen on the blood cast. The relative motions of these surface features were used to represent the local contraction of the endocardial surface with a metric we call Stretch Quantifier of Endocardial Engraved Zones (SQUEEZ). The average SQUEEZ value and the rate of change in SQUEEZ were calculated for both infarcted and healthy myocardial regions. SQUEEZ showed a significant difference between infarct and remote regions ( P &lt;0.0001). No significant difference was observed between normal myocardium (noninfarcted hearts) and remote regions ( P =0.8). Conclusions— We present a new quantitative method for measuring regional cardiac function from high-resolution volumetric CT images, which can be acquired during angiography and myocardial perfusion scans. Quantified measures of regional cardiac mechanics in normal and abnormally contracting regions in infarcted hearts were shown to correspond well with noninfarcted and infarcted regions as detected by delayed enhancement cardiovascular magnetic resonance images.

Strain and Strain Rate Echocardiography and Coronary Artery Disease

The echocardiographic assessment of regional myocardial function plays a critical role in the diagnosis and management of ischemic heart disease and in most laboratories relies on the visual detection of endocardial wall motion abnormalities and assessment of left ventricular (LV) ejection fraction. However, this approach is subjective and operator dependent, demands complete visualization of the endocardium, and is subject to the vicissitudes of cardiac loading and heart rate. Although estimation of myocardial shortening and thickening reflect the radial mechanics of the heart, the contribution of longitudinal (and to a lesser extent circumferential) myocardial deformation is largely neglected. Thus, there is a need for an objective, comprehensive, noninvasive measurement of myocardial performance and contractility with acceptable interpretative variability. Doppler tissue imaging, which measures the velocity of myocardium (in the longitudinal direction from apical windows and in the radial direction from short-axis scans) during systole and diastole is used to quantify ventricular function and is more sensitive to subtle changes in contractility than ejection fraction.1 However, tissue velocities are affected by translational movement and tethering, making it difficult to discriminate akinetic segments that are pulled (or tethered) from actively contracting segments.2 In addition, velocities are not uniformly distributed across the myocardium, decreasing from base to apex, making difficult the establishment of reference values. Measurements of myocardial strain and strain rate (SR) are newer indices that have the potential to overcome these limitations. Strain and SRs represent the magnitude and rate, respectively, of myocardial deformation, which is an energy-requiring process that occurs in both systole and diastole. Abnormalities of myocardial deformation are seen early in the development of many pathophysiologic states, including ischemia, and thus provide a sensitive means for detecting regional myocardial dysfunction. The objective of this report is to review the use of strain and SR echocardiography in patients …

Three-directional acceleration phase mapping of myocardial function

An optimized acceleration encoded phase contrast method termed "acceleration phase mapping" for the assessment of regional myocardial function is presented. Based on an efficient gradient waveform design using two-sided encoding for in vivo three-directional acceleration mapping, echo and repetition times TE = 12-14 ms and TR = 15-17 ms for low accelerations sensitivity aenc = 5-8 m/s(2) were achieved. In addition to phantom validation, the technique was applied in a study with 10 healthy volunteers at 1.5T and 3T to evaluate its feasibility to assess regional myocardial acceleration at 1.5T and 3T. Results of the acceleration measurements were compared with the temporal derivative of myocardial velocities from three-directional velocity encoded standard phase contrast MRI in the same volunteers. The feasibility to assess myocardial acceleration along the radial, circumferential, and longitudinal direction of the left ventricle was demonstrated. Despite improved signal-to-noise-ratio at 3T (34% increase compared with 1.5T), image quality with respect to susceptibility artifacts was better 1.5T compared with 3T. Analysis of global and regional left ventricular acceleration showed characteristic patterns of systolic and diastolic acceleration and deceleration. Comparisons of directly measured and derived myocardial acceleration dynamics over the cardiac cycle revealed good correlation (r = 0.45-0.68, P < 0.01) between both methods.

E0687 The application of vector flow mapping in quantitative assessment of regional myocardial function in CAD patients

BackgroundUntil now, the study of regional infarct and ischaemic myocardial function in patients with coronary atherosclerotic heart disease is still mainly focused on the abnormal wall motion, how the blood...