Visual Assessment Of Wall Motion Research Articles

Assessment of Postsystolic Shortening and Global Longitudinal Strain Improves the Sensitivity of Dobutamine Stress Echocardiography in End-Stage Liver Disease

Dobutamine stress echocardiography (DSE) remains a widely used method for detection of coronary artery disease (CAD) in patients with end stage liver disease (ESLD) despite low sensitivity. Speckle tracking assessment of strain may enhance the sensitivity of DSE in the general population but the value of strain analysis in ESLD is unknown. DSE with two-dimensional speckle tracking and quantitative coronary angiography were performed in 146 patients with ESLD. Thirty-six patients (25%) had CAD (> 50% diameter stenosis of a major vessel). Global longitudinal strain at rest (GLSr) and at peak stress (GLSp) and an index of post-systolic (PSSi) shortening ([maximal extent of shortening - extent of shortening in systole] / [extent of shortening in systole]) were determined. A PSSi of > 0.25 was considered evidence for CAD. ROC analysis was used to determine the optimal thresholds of GLSr and GLSp for CAD and to assess the diagnostic performance of wall motion assessment (WMA) and strain parameters. The sensitivity and specificity of WMA, GLSr, GLSp and PSSi were compared. Thirty-six patients (25%) had significant CAD. The areas under the curve (AUC) for WMA, GLSr, GLSp, and PSSi were 0.60, 0.72, 0.68, and 0.78, respectively. Visual assessment of wall motion (WMA) had a sensitivity of 28%. The sensitivity of each of the strain parameters, GLSr (53%, p =0.016), GLSp (69%, p =0.004), and PSSi (78%, p <0.001), exceeded the sensitivity for WMA. WMA specificity was 92% which exceeded the specificity for each of the strain parameters (GLSr 82%, p =0.037), GLSp 63%, p <0.001), and PSSi (78%, p = 0.009). Of the strain parameters, PSSi had the best balance between sensitivity and specificity (both 78%). Assessment of GLS and PSSi with DSE yields better sensitivity than WMA in ELSD patients. PSSi had the best diagnostic performance of all parameters in this population with a low prevalence of CAD.

Right ventricular ejection fraction with cardiac magnetic resonance using a wall motion score

The volumetric method in cardiac magnetic resonance (CMR), the reference standard for right ventricular ejection fraction (RVEF), requires expertise because of the complex right ventricular geometry and anatomical landmarks. The aim of our retrospective study was to describe a new method to evaluate RVEF based on wall motion score index (WMSI) in CMR. Visual assessment of wall motion was performed using an eight-segment model (normokinesia=1, hypokinesia=2, akinesia=3). Correlation between WMSI (WMS/8) and the reference volumetric RVEF was analysed. A regression equation was derived to convert the WMSI into RVEF. The accuracy of CMR WMSI-derived RVEF compared with CMR volumetric RVEF was evaluated using Bland-Altman analysis. In the 112 patients using the volumetric method, the mean RVEF was 48±14%. Fifty-nine patients had normal RV kinetics (WMSI=1), which corresponded to a volumetric RVEF of 56% (standard deviation 7%; range 43-76%). CMR WMSI showed a strong correlation with CMR volumetric RVEF (Spearman's Rho=-0.69). A regression equation was created: RVEF=80-22×WMSI. Overall, the WMSI-derived RVEF resulted in good agreement with the CMR volumetric RVEF (mean bias-3%, standard deviation±7.5%). In addition, using a WMSI cut-off of≥1.5 was highly accurate (92%) to predict a reference RVEF of˂45%, an important prognostic indicator in CMR. Our results suggest that using the WMS in CMR (eight-segment) to estimate RVEF is accurate, and correlates well with the volumetric method. A WMSI≥1.5 is optimal to categorize patients in the higher-risk subset of CMR RVEF˂45%.

Segmental strain analysis for the detection of chronic ischemic scars in non-contrast cardiac MRI cine images

Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is considered the gold standard for scar detection after myocardial infarction. In times of increasing skepticism about gadolinium depositions in brain tissue and contraindications of gadolinium administration in some patient groups, tissue strain-based techniques for detecting ischemic scars should be further developed as part of clinical protocols. Therefore, the objective of the present work was to investigate whether segmental strain is noticeably affected in chronic infarcts and thus can be potentially used for infarct detection based on routinely acquired non-contrast cine images in patients with known coronary artery disease (CAD). Forty-six patients with known CAD and chronic scars in LGE images (5 female, mean age 52 ± 19 years) and 24 gender- and age-matched controls with normal cardiac MRI (2 female, mean age 47 ± 13 years) were retrospectively enrolled. Global (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS]) and segmental (segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], segmental peak radial strain [SPRS]) strain parameters were calculated from standard non-contrast balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Visual wall motion assessment of short axis cine images as well as segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) of every patient and control were presented in random order to two independent blinded readers, which should localize potentially infarcted segments in those datasets blinded to LGE images and patient information. Global strain values were impaired in patients compared to controls (GPCS p = 0.02; GPLS p = 0.04; GPRS p = 0.01). Patients with preserved ejection fraction showed also impeded GPCS compared to healthy individuals (p = 0.04). In patients, mean SPCS was significantly impaired in subendocardially (− 5.4% ± 2) and in transmurally infarcted segments (− 1.2% ± 3) compared to remote myocardium (− 12.9% ± 3, p = 0.02 and 0.03, respectively). ROC analysis revealed an optimal cut-off value for SPCS for discriminating infarcted from remote myocardium of − 7.2% with a sensitivity of 89.4% and specificity of 85.7%. Mean SPRS was impeded in transmurally infarcted segments (15.9% ± 6) compared to SPRS of remote myocardium (31.4% ± 5; p = 0.02). The optimal cut-off value for SPRS for discriminating scar tissue from remote myocardium was 16.6% with a sensitivity of 83.3% and specificity of 76.5%. 80.3% of all in LGE infarcted segments (118/147) were correctly localized in segmental circumferential strain calculations based on non-contrast cine images compared to 53.7% (79/147) of infarcted segments detected by visual wall motion assessment (p > 0.01). Global strain parameters are impaired in patients with chronic infarcts compared to controls. Mean SPCS and SPRS in scar tissue is impeded compared to remote myocardium in infarcts patients. Blinded to LGE images, two readers correctly localized 80% of infarcted segments in segmental circumferential strain calculations based on non-contrast cine images, in contrast to only 54% of infarcted segments detected due to wall motion abnormalities in visual wall motion assessment. Analysis of segmental circumferential strain shows a promising method for detection of chronic scars in routinely acquired, non-contrast cine images for patients who cannot receive or decline gadolinium.

Speckle tracking stress echocardiography: A valuable diagnostic technique or a burden for everyday practice?

Non-invasive screening for early diagnosis of coronary artery disease (CAD) represents a key element in the never-ending challenge to reduce cardiac death. Stress/rest electrocardiogram often lacks diagnostic accuracy, especially in asymptomatic patients, in fact the latest guidelines for the diagnosis and management of chronic coronary syndromes (CCS) stated the superiority of functional imaging techniques for the detection of subtle myocardial ischemia and the evaluation of myocardial viability (MV). Stress echocardiography is the most accessible and inexpensive imaging method for the study of CAD, either with pharmacological or with exercise provocative stress, based on visual wall-motion assessment. However, in some cases, such as small coronary lesions or microvascular angina, it loses its diagnostic power, therefore requiring a more sensitive approach. Accordingly, in the last years many authors investigated the possible additive value provided by the integration of an advanced but easy-to-obtain technique, that is speckle tracking imaging, to stress echocardiography, reaching promising results; nevertheless, its use is not included in the latest recommendations for CCS. The present review discusses the potential benefits from using a combination of speckle tracking and stress echocardiography for the early detection of myocardial ischemia and the assessment of MV and its suitability in different clinical scenarios, basing on the available evidence.

Using deep learning to extract novel and quantitative imaging features from perfluoropropane contrast, sulphur hexafluoride contrast and non-contrast stress echocardiography images

Abstract Background Stress echocardiography has become established as the most widely applied non-invasive imaging test for diagnosis of coronary artery disease within the UK. However, stress echocardiography has been substantially qualitative, rather than quantitative, based on visual wall motion assessment. For the first time, we have identified and validated quantitative descriptors of cardiac geometry and motion, extracted from ultrasound images acquired using contrast agents in an automated way. Purpose To establish whether these novel imaging features can be generated in an automated, quantifiable and reproducible way from images acquired with perfluoropropane contrast, as well as investigating how these extracted measures compare to those extracted from sulphur hexafluoride contrast and non-contrast studies. Methods 100 patients who received perfluoropropane contrast during their stress echocardiogram were recruited. Their stress echocardiography images were processed through a deep learning algorithm. Novel feature values were recorded and a subset of 10 studies were repeated. The automated measures of global longitudinal strain (GLS) and ejection fraction (EF) extracted from these images were compared to values previously extracted from sulphur hexafluoride contrast and non-contrast images using the same software. Results A full set of 31 novel imaging features were successfully extracted from 79 studies acquired using the perfluoropropane contrast agent with a dropout rate of 14% (n=92, 8 incomplete image sets). Repeated analysis in a subset of 10 perfluoropropane cases demonstrated excellent reproducibility of the extracted feature values (R2=1). Automated values of GLS and EF, at both rest (GLS = −16.4±4.8%, EF = 63±13%) and stress stages (GLS = −17.7±5.8%, EF = 68±11%), were extracted from 83 perfluoropropane studies, with a dropout rate of 16% (n=99, fewer incomplete sets as short axis view not required). The ranges of GLS and EF measures extracted from the perfluoropropane images were comparable to the other contrast studies (n=222) (Rest GLS = −16.8±5.8%, Rest EF = 63±10%; Stress GLS = −19.1±6.7%, Stress EF = 71±9%) and non-contrast studies (n=86) (Rest GLS = −15.7±5.3%, Rest EF = 57±10%; Stress GLS = −17.3±6.4%, Stress EF = 61±14%). Conclusions Novel features and clinically relevant measures were extracted from images acquired using perfluoropropane contrast for the first time in a fully automated and reproducible way using a deep learning algorithm. The analysis failure rate and generated measures are comparable to those extracted from images using other commonly used sulphur hexafluoride contrast agents and non-contrast stress echocardiography studies. These findings demonstrate that deep learning algorithms can be used for automated quantitative analysis of stress echocardiograms acquired using various contrast agents and in non-contrast studies to improve stress echocardiography practice. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Lantheus Medical Imaging, Inc.

P365 Echocardiographic deformation imaging improves detection of arrhythmogenic right ventricular cardiomyopathy; a head-to-head comparison of deformation imaging and conventional assessment

Abstract Background Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited cardiomyopathy diagnosed by a complex set of tests defined in the 2010 Task Force Criteria (TFC). For echocardiography, right ventricular (RV) dilatation and function are combined with visual wall motion assessment to obtain diagnostic criteria. However, subtle wall motion abnormalities can be missed by visual assessment, thereby limiting detection of disease. Recent studies have shown that echocardiographic deformation imaging has high sensitivity for detection of wall motion abnormalities. However, the performance of deformation imaging within the 2010 TFC for ARVC diagnosis remains unknown. Objectives To perform a head-to-head comparison of the diagnostic value of visual wall motion assessment versus deformation imaging in a real-world cohort of consecutive patients evaluated for ARVC. Methods We included a consecutive cohort of 163 patients who were referred for ARVC evaluation between 2009-2011, of whom 59 patients underwent an echocardiogram with images available for deformation analysis. Patients were diagnosed by consensus of 3 independent ARVC experts with access to all patient data including a median follow-up of 5.9 years IQR[2.7-7.6 yrs]. The original clinical assessment of RV outflow tract (RVOT) dimensions, fractional area change and wall motion was used. In addition, deformation patterns of the subtricuspid area were scored as normal (type I) or abnormal (type II/III), according to the presence of regional mechanical dysfunction (see figure). We evaluated the effect of replacing visual wall motion assessment with deformation imaging on the sensitivity, specificity and balanced accuracy of the echocardiographic TFC. Results Of 59 patients (age 38 ± 17 yrs, 49% male), the expert panel diagnosed 15 (25%) with ARVC. Conventional TFC, either minor or major, were observed in 10 patients; replacing visual wall motion assessment with deformation imaging led to 5 additional detections of ARVC patients, whereas 0 were lost. Consequently, deformation imaging increased sensitivity from 67% to 100%, whereas specificity decreased from 89% to 73%. The balanced accuracy increased from 0.78 to 0.86. Of the 12 patients with false positive TFC by deformation imaging, half were asymptomatic mutation carriers at risk for developing ARVC. Of the other 6 false positives, 3 were diagnosed with ventricular arrhythmia from the RVOT. There were no false negative diagnoses using deformation imaging. Conclusion All definite ARVC patients were detected when deformation imaging patterns were used to evaluate wall motion abnormalities. This increased sensitivity was accompanied by a slight decrease in specificity. Deformation imaging on its own was not able to reliably distinguish ARVC from other RV related disease. Since no ARVC diagnoses were missed, echocardiographic deformation imaging could be of great value to exclude ARVC in patients referred for ARVC evaluation. Abstract P365 Figure. Deformation patterns and % TFC per group

Role of left ventricle deformation analysis in stress echocardiography for significant coronary artery disease detection: A diagnostic study meta-analysis.

We compared the diagnostic accuracy of longitudinal strain (LS) imaging during stress echocardiography with visual assessment of wall motion (WM) for detecting significant coronary artery disease (CAD). Our systematic search included studies reporting diagnostic measures for LS imaging and visual assessment of WM for detecting significant CAD during stress echocardiography. Summary diagnostic accuracy measures including area under the curve (AUC), sensitivity, specificity, diagnostic odds ratio (DOR), and likelihood ratios (LRs) were estimated. In thirteen studies with 978 patients, ten studies used invasive coronary angiography as the reference standard. Pooled AUC for diagnosing significant CAD was 0.92 (95% confidence interval [CI] 0.89-0.94) for LS imaging as compared to 0.83 (95% CI 0.80-0.86), P< 0.001 for visual assessment of WM. LS imaging had higher sensitivity (88% [95% CI 84-92] vs 74% [95% CI 68-80], P< 0.001) and comparable specificity to visual assessment of WM (80% [95% CI 72-87] vs 83% [95% CI 74-90], P=0.592). The DOR for LS imaging and visual assessment of WM was 31 and 15, P=0.254, respectively. The positive LR was 4.5 for both; negative LR was 0.14 and 0.31, P=0.002 for LS imaging and visual assessment of WM, respectively. Longitudinal strain imaging during stress echocardiography has better diagnostic accuracy for detecting significant CAD as compared to visual assessment of WM. Studies using larger sample size and standardized techniques of strain measurement are required to further ascertain the added advantage of strain measurement over visual assessment alone.

Feasibility and accuracy of speckle tracking echocardiography in emergency department patients

BackgroundSpeckle tracking echocardiography (STE) is a novel technology that measures regional wall-motion abnormalities that may speed diagnosis and intervention of acute coronary occlusion in Emergency Department (ED) patients with non-ST elevation ACS (NSTE-ACS). STE provides an objective measurement of myocardial strain that is superior to visual assessment of wall motion when performed as part of a point-of-care (POC) echocardiogram. We determined the feasibility and preliminary accuracy of POC STE operated by emergency providers when compared to comprehensive echocardiography or final diagnosis of ACS. MethodsWe retrospectively reviewed 187 emergency provider POC echocardiograms with STE from 7/2014–5/2016 for suspected ACS at a large academic trauma center. Feasibility of POC STE was determined by calculating the percentage of complete exams (adequate apical 4-chamber and parasternal short axis views) out of all STE exams. We then used two different criterion standards for calculating diagnostic accuracy of STE: comprehensive echocardiograms with wall motion abnormalities or formal diagnosis of ACS based on elevated cardiac troponins, unstable angina, percutaneous coronary intervention, or coronary artery stenosis >70% on catheterization. ResultsOf 187 STE studies performed, 75 (40%) were considered complete. Ultrasound-experienced providers had higher rates of complete exams (65% vs. 35%, P = 0.01). 16 of 75 exams (21%) were positive for myocardial strain, and of these 16 (100%) were admitted, 12 (75%) had positive troponins, 6 (46%) had positive comprehensive echocardiograms, and 3 (19%) had PCI or >70% stenotic lesion on catheterization. Compared with comprehensive echocardiography, POC STE had 35% sensitivity, 70% specificity, 46% positive predictive value (PPV), and 59% negative predictive value (NPV). Compared with formal diagnosis of ACS, POC STE had 29% sensitivity, 88% specificity, 75% positive predictive value (PPV), and 51% negative predictive value (NPV). ConclusionSTE is a potentially feasible adjunct to standard bedside echocardiography in ED patients with suspected ACS when operated by experienced ultrasound-trained physicians in the ED. This data shows STE performed by emergency providers is not yet sensitive enough alone to diagnose ACS, and has low accuracy when compared to comprehensive echocardiography. However, the PPV and specificity improve when performed by expert ultrasound-trained providers. STE should be considered for inclusion in the Emergency Ultrasound Fellowship curriculum.

Improving Visual Detection of Wall Motion Abnormality with Echocardiographic Image Enhancing Methods.

Analysis of wall motion abnormality using echocardiography is an established method for detecting myocardial ischemia. We describe a hybrid approach of enhancing 2D+T echo datasets with border detection and Eulerian motion magnification to improve the visual assessment of wall motion. We implemented a local phase-based approach using the monogenic signal and its derived features, either feature asymmetry (FA) or oriented feature symmetry (OFS), to detect boundaries of the heart structure. We enhanced the 2D+T datasets using either an intensity-based or phase-based Eulerian Motion Magnification (EMM) video processing technique, and identified among eight different types of enhancements the best performing method as OFS with an accuracy of 78% versus the original B-Mode with an accuracy of 71%.

Strain Imaging with a Bull's-Eye Map for Detecting Significant Coronary Stenosis during Dobutamine Stress Echocardiography

Accurate visual assessment of wall motion during dobutamine stress echocardiography (DSE) requires expertise; strain stress echocardiography thus has potential for the objective and reliable evaluation of stress-induced wall motion abnormalities. The aim of this study was to test the hypothesis that strain imaging also requires expertise. Diagnostic accuracy for significant coronary artery disease was compared between visual and strain analysis with a bull's-eye map, and the effect of expertise on readers' accuracy during DSE was determined. Thirty-seven patients who underwent both DSE and coronary angiography within 6months were retrospectively selected. Three experts and two fellows performed visual and two-dimensional speckle-tracking analysis using vendor-dependent (GE) software in three apical views. A bull's-eye map of longitudinal strain and a postsystolic shortening map were generated at baseline and peak stress. Significant coronary stenosis was defined as a >1% reduction in longitudinal strain with an increase in postsystolic shortening of at least two contiguous segments in the specific coronary artery territory at peak stress compared with baseline. Twenty-five patients had significant coronary artery disease (>70% stenosis on coronary angiography), including 17 with left anterior descending coronary artery stenosis and 19 with non-left anterior descending coronary artery stenosis. Overall, strain imaging provided no additional benefit over visual analysis in detecting significant stenosis per patient and per vessel among experts and fellows. Strain analysis by the fellows had significantly lower specificity and accuracy compared with the experts. Expertise affects strain evaluation for detecting significant coronary artery disease during DSE.

Combination of single quantitative parameters into multiparametric model for ischemia detection is not superior to visual assessment during dobutamine stress echocardiography.

BackgroundTo evaluate if the combination of several quantitative parameters into a mathematical model would enhance the detection of myocardial ischemia during dobutamine stress echocardiography (DSE) when compared to conventional wall motion analysis.MethodsIn a prospective study design 151 patients (age 61.8 ± 9.2) in test group and 105 patients (age 64.0 ± 10.6) in validation group were selected and underwent DSE between January 2008 and December 2012. In all patients coronary angiography was performed within 6-8 weeks from DSE, considering at least one stenosis ≥50 % per patient as significant coronary artery disease (CAD). Results of DSE visual assessment and myocardial velocity, strain and strain rate parameters derived from speckle tracking imaging were imported automatically to an originally created software. A mathematical model calculating prognosis of at least one stenosis per patient and stenosis in separate arteries was constructed.ResultsMyocardial ischemia was visually detected in 60 (39.7 %) and in 58 (54.2 %) patients of the test and validation group, respectively. A total of 76 (50.3 %) patients in the test group and 69 patients (65.7 %) in the validation group had ≥50 % coronary stenosis. Sensitivity and specificity of the mathematical model per patient in the test group were 91.6 % and 86.3 % compared to 76.8 % and 89.0 % of the visual assessment, respectively. However, in the validation group the sensitivity, specificity, positive predictive value and negative predictive value dropped down significantly becoming lower to visual assessment.ConclusionsMyocardial deformation imaging may potentially replace visual assessment with an automated predictive model for stress-induced ischemia detection. However, a multiparametric mathematical model based on quantitative deformation markers did not demonstrate incremental value to visual assessment of wall motion.

Global and segmental myocardial deformation by 2D speckle tracking compared to visual assessment

To examine the feasibility and reliability of measuring global and segmental longitudinal strain (LS) compared to visual assessment of wall motion (WM). Assessment of segmental (17 left ventricular segments) LS using automatic function imaging (AFI) in 55 patients (60.0 ± 8.7 years, 73% male) divided into 2 groups: group I included 35 patients with WM abnormalities and/or impaired ejection fraction and group II included 20 patients with normal WM and ejection fraction. Visual analysis of WM abnormalities was performed using 2-dimensional echocardiography (2DE) and WM score was calculated. Both modalities were analyzed by one expert reader at 2 different sessions. Analysis of 935 left ventricular segments was completed in 94.1% and 96.3% by visual assessment and AFI, respectively. There was a strong positive linear relationship between the WM score and global LS in all patients. Intra-observer agreement for calculation of WM score was excellent for group I patients (kappa: 0.97) and very good for group II patients (kappa: 0.92). Intra-observer agreement for AFI showed excellent agreement with very small mean difference in both group I and II (-0.0 ± 2.3 and -0.0 ± 1.9, respectively). The interpretation of global and segmental LS using AFI is a more feasible and reliable technique for the quantification of myocardial deformation than visual assessment of WM scores.

Longitudinal peak strain detects a smaller risk area than visual assessment of wall motion in acute myocardial infarction

BackgroundOpening of an occluded infarct related artery reduces infarct size and improves survival in acute ST-elevation myocardial infarction (STEMI). In this study we performed tissue Doppler analysis (peak strain, displacement, mitral annular movement (MAM)) and compared with visual assessment for the study of the correlation of measurements of global, regional and segmental function with final infarct size and transmurality. In addition, myocardial risk area was determined and a prediction sought for the development of infarct transmurality ≥50%.MethodsTwenty six patients with STEMI submitted for primary percutaneous coronary intervention (PCI) were examined with echocardiography on the catheterization table. Four to eight weeks later repeat echocardiography was performed for reassessment of function and magnetic resonance imaging for the determination of final infarct size and transmurality.ResultsOn a global level, wall motion score index (WMSI), ejection fraction (EF), strain, and displacement all showed significant differences (p ≤ 0.001, p ≤ 0.001, p ≤ 0.001 and p = 0.03) between the two study visits, but MAM did not (p = 0.17). On all levels (global, regional and segmental) and both pre- and post PCI, WMSI showed a higher correlation with scar transmurality compared to strain. We found that both strain and WMSI predicted the development of scar transmurality ≥50%, but strain added no significant information to that obtained with WMSI in a logistic regression analysis.ConclusionsIn patients with acute STEMI, WMSI, EF, strain, and displacement showed significant changes between the pre- and post PCI exam. In a ROC-analysis, strain had 64% sensitivity at 80% specificity and WMSI around 90% sensitivity at 80% specificity for the detection of scar with transmurality ≥50% at follow-up.

Speckle tracking echocardiography: A new approach to myocardial function

Echocardiography is the most common diagnostic method for assessing cardiac function but some limitations affect this technique. Until now, visual assessment of wall motion and thickening has allowed only a subjective evaluation of myocardial function and requires long-term training. Recently, new echocardiographic techniques have been introduced to evaluate myocardial mechanics. Tissue Doppler imaging (TDI) technique is limited by angle-dependency such that only deformation along the ultrasound beam can be derived from velocities, while myocardium deforms simultaneously in three dimensions. Speckle tracking echocardiography (STE) is a more recent technique that provides a global approach to left ventricular myocardial mechanics, giving information about the three spatial dimensions of cardiac deformation. In this editorial, we describe the physical and pathophysiological concepts of STE, discussing the differences compared to TDI and underlining the pitfalls of this new technique.

The diagnostic and prognostic value of tissue Doppler imaging during dobutamine stress echocardiography in end-stage renal disease

To determine whether a quantitative measurement of peak systolic velocity (PSV) during dobutamine stress echocardiography (DSE) detects severe coronary artery disease (CAD) and predicts mortality in patients with end-stage renal disease. One hundred and forty renal transplant candidates had DSE and coronary angiography. DSE analysis was performed using conventional visual wall motion assessment, longitudinal PSV, and combining the two modalities. Failure of PSV to rise by more than 50% predicted an ischemic response. Significant CAD was defined as luminal stenosis greater than 70%. The number of positive DSE studies according to conventional, PSV, and combined criteria was 41 (30%), 42 (31%), and 46 (34%) respectively. Forty patients (29%) had significant CAD at angiography. The sensitivity, specificity, positive and negative predictive values for conventional DSE analysis were 84, 91, 86, and 90% respectively. The same values for PSV analysis were 86, 92, 86, and 91%, respectively. The same values for the combination of visual and PSV analysis were 88, 94, 87, and 92% respectively. The differences between the three methods were not statistically significant. Sensitivity for single-vessel CAD (P=0.05) and circumflex artery disease (P=0.05) diagnosis was higher with PSV compared with conventional DSE analysis. Failure of PSV to rise by more than 50% during DSE was associated with significantly increased mortality (P=0.001). A quantitative interpretation of DSE, based on the percentage rise of PSV during stress, accurately detects CAD and predicts prognosis in end-stage renal disease.

611 Surface detection and color-encoding applied to real-time three-dimensional echocardiographic images as a basis for automated assessment of left ventricular wall motion

Purpose: Color encoding of left ventricular (LV) endocardial motion in 2D echo (2DE) has been shown to improve visual detection of regional wall motion abnormalities (RWMA). Our goals were: 1) to extend this technique to color encode detected LV endocardial surfaces from real-time 3D echo (RT3DE) images; 2) to automatically detect systolic RWMA and test its accuracy against visual interpretation of 2DE images. Methods: 19 normal subjects (N), and 14 patients with RWMA (including 7 with global LV dysfunction) underwent RT3DE and 2DE (Philips). 2DE images (apical 2-, 3and 4-chamber) were reviewed by an expert cardiologist, who graded wall motion (18 segments model) as normal or abnormal (AB). RT3DE datasets were analyzed using custom software: frame-by-frame semiautomated LV surface detection was followed by logical operations applied to each pair of consecutive frames, to track and color encode endocardial motion in 3D. Then, regional fractional volume change (RFVC) in % of regional end-diastolic volume was calculated automatically by colored voxels count, and displayed as stacked color-histograms. In RWMA, RFVCs were compared with regional thresholds, derived from RFVC computed in N and optimized using ROC analysis, for automated classification of wall motion. Results: The generation of 3D color-encoded wall-motion and RFVC quantification took <10 sec. In RWMA, 182/252 segments were graded as AB (Figure 1, arrows). The automated technique agreed with the expert reader in 225/252 (89%) segments, with only 8/252 (3%) false positive and 19/252 (8%) false negative detections (sensitivity: 0.91; specificity: 0.80; accuracy: 0.84). Conclusions: The proposed technique could improve the visual assessment of wall motion from RT3DE images, and represent the basis for automated detection of RWMA.

Echocardiographic Strain Imaging for Myocardial Viability

Echocardiographic strain imaging was introduced by Heimdal et al in 19981 as a means to calculate myocardial regional function from tissue Doppler velocity data.2,3 Strain imaging is a variation of the previous concept of tissue Doppler myocardial velocity gradient, which calculates regional thickening independent of passive whole heart motion.4,5 Because routine clinical evaluation of regional function is usually by visual wall-motion assessment, strain imaging has great promise to improve objective quantification of regional function. Strain imaging calculates deformation, which translates clinically to percent shortening in the longitudinal dimension (assessed from apical views) or percent thickening in the radial dimension (assessed from parasternal views).1,6,7 Theoretically, it has the important advantage of differentiating active myocardial motion from passive translational or tethering movements that other echocardiographic-Doppler approaches cannot differentiate. Indeed, there have been literally hundreds of publications over the last 10 years detailing a wide range of experimental and potential clinical applications of strain imaging; however, currently, few centers have adopted strain imaging in their routine clinical practice, preferring visual “eyeball” assessment, even though this is inherently subjective and requires a high level of experience and training.8 An important question remains: Is it now time for strain imaging to be adopted in a widespread clinical sense? Articles pp 3892 and 3901 Two important articles are contained in this issue of Circulation that address the application of strain imaging as a tool to assess myocardial viability: an animal study of experimental ischemia and infarction by Lyseggen et al9 and a clinical study using dobutamine echocardiography with outcome data after revascularization by Hanekom et al.10 The article by Lyseggen et al illustrates the additive value of strain imaging in an elegant open-chest animal model of coronary occlusion and reperfusion. Echocardiographic strain imaging was performed along with simultaneous dimensional …

The feasibility of repeated left ventricular ejection fraction analysis with sequential single-dose radionuclide ventriculography

Repeated left ventricular ejection fraction (LVEF) analyses with sequential single-dose radionuclide ventriculography might be an interesting technique for monitoring the effect of positive inotropic interventions. The aim of the study was to assess the reproducibility of LVEF measurement with planar radionuclide ventriculography within 3 h, using a standard single dose of radioactive tracer. Sixteen patients underwent routine planar radionuclide ventriculography with a standard dose of 500 MBq of [Tc]pertechnetate and returned after 3 h for a repeat planar radionuclide ventriculography without administration of additional tracer. The average initial LVEF was 35.1+/-18.6%-point (range, 12%-point to 68%-point). The mean difference of the LVEF between the initial planar radionuclide ventriculography and the repeat planar radionuclide ventriculography was 2.8%+/-6.3% (range, -11.8% to 13.3%, P=NS). The correlation between both measurements was significant with a correlation coefficient of 0.995 (P<0.01). Bland-Altman analysis revealed a mean LVEF difference of 0.94%-point between the baseline planar radionuclide ventriculography and the repeat planar radionuclide ventriculography (95% confidence interval: -2.7%-point to 4.5%-point). The visual wall motion assessment showed excellent reproducibility, with a kappa-statistic of 0.98. Repeated radionuclide ventriculography with a 3 h interval using a single standard dose of 500 MBq of [Tc]pertechnetate is highly reproducible and will be useful for monitoring the effect of positive inotropic interventions.

1112-141 Determinants of visual 2-D echo assessment of left ventricular wall motion: Comparison with myocardial thickening on cardiac magnetic resonance imaging

Background: left ventricular wall motion on 2d echo (2de) is usually scored visually. we sought to examine the determinants of visually assessed wall motion scoring on 2de by comparison with myocardial thickening quantified on MRI. Methods: using a 16 segment model, we studied 287 segments in 30 patients aged 61+/ -11 years (6 female), with ischaemic LV dysfunction (defined by at least 2 segments dysfunctional on 2de). 2de was performed in 5 views and wall motion scores (WMS) assigned: 1 (normal) 103 segments, 2 (hypokinetic) 93 segments, 3 (akinetic) 87 segments. MRI was used to measure end systolic wall thickness (ESWT), end diastolic wall thickness (EDWT) and percentage systolic wall thickening (SWT%) in the plane of the 2de and to assess WMS in the same planes visually. No patient had a clinical ischemic event between the tests. Results: visual assessment of wall motion by 2de and MRI showed moderate agreement (kappa = 0.425). Resting 2de wall motion correlated significantly (p<0.01) with ESWT(- 0.345), EDWT(-0.379) and SWT%(-0.334). Conclusion: SWT% and ESWT decrease with increasing WMS. However, the distinction between hypo and akinesis appears to correlate better with ESWT than SWT% or EDWT.

Quantification of the Myocardial Response to Low-Dose Dobutamine Using Tissue Doppler Echocardiographic Measures of Velocity and Velocity Gradient

Low-dose dobutamine echocardiography has been clinically useful in myocardial viability studies, although routine visual assessment of wall motion is subjective. The objective was to quantify the incremental myocardial response to low-dose dobutamine infusion using a new semiautomated tissue Doppler (TD) analysis system and to compare these data with routine echocardiographic measures in the same subjects. Twelve subjects had TD and routine echocardiographic studies at baseline and during 10-minute stages of dobutamine infusion at 1, 2, 3, and 5 μg/kg/min. Color TD video data were converted to a digital velocity matrix (4.5 velocity data points/mm at 500 Hz) for analysis of mitral annular velocity, endocardial velocity, and velocity gradient at each stage. Posterior wall percent thickening and ejection fraction were calculated from the routine images. Mitral annular peak systolic velocity significantly increased with only 1 μg/kg/min of dobutamine from 69 ± 9 to 77 ± 7 mm/s (p <0.05 vs baseline), and further incremental increases occurred with each subsequent dose. Anteroseptal and posterior wall peak endocardial velocity increased with 2 μg/kg/min of dobutamine from 33 ± 7 to 46 ± 15 mm/s and 50 ± 9 to 61 ± 10 mm/s, respectively (p <0.01 vs baseline) and further increased with 5 μg/kg/min (p <0.0001 vs 3 μg/kg/min). Posterior wall peak systolic gradient also increased with 2 μg/kg/min of dobutamine from 3.1 ± 0.6 to 5.4 ± 1.6 s −1 (p <0.05 vs baseline). Routine measures of percent wall thickening or ejection fraction did not detect increases until the 3 μg/kg/min dose. TD can detect subtle alterations in contractility induced by low-dose dobutamine and has the potential to quantify regional ventricular function objectively.