Comparison of two-dimensional speckle and tissue Doppler strain measurement during dobutamine stress echocardiography: an angiographic correlation.

AIMS: Two-dimensional (2D)-strain derived from speckle-tracking is an alternative to tissue velocity imaging (TVI)-based strain. We compared their feasibility and accuracy in 150 patients undergoing dobutamine stress echocardiography (DSE) and coronary angiography. METHODS AND RESULTS: 2D- and TVI-strain were obtained in three apical views at rest and peak stress. Peak systolic strain rate (SR), endsystolic strain (epsilon(end-sys)), and peak strain (epsilon(peak)) were measured off-line at rest and peak stress, and results were compared with wall motion analysis and significant coronary artery disease (CAD > or = 70% diameter stenosis). Optimal cut-offs were derived from receiver operating characteristic (ROC) curves for sentinel segments. The most feasible method was 2D-strain at rest, and TVI-strain at peak stress. The average peak SR and epsilon(end-sys) at peak stress in segments of patients with significant CAD was less than in segments of patients without CAD (P < 0.0001) and mean PSI at peak stress was higher (P < 0.0001) with both 2D- and TVI-strain. Peak systolic SR at peak stress had the best area under the ROC for both 2D- (AUC 0.67) and TVI-strain (AUC 0.71) for the diagnosis of CAD. The accuracy of WMS (75%) for diagnosis of CAD per patient was similar to 2D-SR (69%) and TVI-SR (74%). The accuracy of 2D-SR and TVI-SR at peak stress was 78 vs. 79% (P = NS) for LAD, 67 vs. 73% (P = NS) for LCX, and 59 vs. 74% (P = 0.008) for RCA disease. CONCLUSION: Measurement of speckle tracking strain during DSE is feasible and similar in accuracy to TVI-strain in the anterior, but not in the posterior circulation.

Comparison of two- and three-dimensional echocardiography with sequential magnetic resonance imaging for evaluating left ventricular volume and ejection fraction over time in patients with healed myocardial infarction.

Echocardiographic follow-up of left ventricular (LV) volumes is difficult because of the test-retest variation of 2-dimensional echocardiography (2DE). We investigated whether the accuracy and reproducibility of real-time 3-dimensional echocardiography (RT3DE) would make this modality more feasible for serial follow-up of LV measurements. We performed 2DE and RT3DE and cardiac magnetic resonance imaging (MRI) in 50 patients with previous infarction and varying degrees of LV function (44 men; 61 +/- 11 years of age) at baseline and after 1-year follow-up. Images were obtained during breath-hold and measurements of LV volumes and ejection fraction were made offline. Over follow-up, end-diastolic volume decreased from 192 +/- 53 to 187 +/- 60 ml (p <0.01), end-systolic volume decreased from 104 +/- 51 to 95 +/- 53 ml (p <0.01), and ejection fraction increased from 48 +/- 12% to 51 +/- 12% (p <0.01). MRI showed that LV mass shrank from 183 +/- 39 to 182 +/- 37 g (p <0.01). The correlation between change in RT3DE and change in MRI was greater than the correlations of 2DE with MRI for measurement of end-diastolic volume (r = 0.47 vs 0.02, p <0.01), end-systolic volume (r = 0.44 vs 0.17, p <0.01), and ejection fraction (r = 0.58 vs -0.03, p <0.01). The change in end-diastolic volume between baseline and follow-up with RT3DE (-4 +/- 20, p <0.01) was similar to that with MRI but was unrecognized by 2DE (4 +/- 19, p = 0.09). There was good test-retest and inter- and intraobserver correlation within RT3DE for volumes, ejection fraction, and mass. In conclusion, if sequential measurement of LV volumes is used to guide management decisions, 3DE appears preferable to 2DE.

Differentiation of subendocardial and transmural infarction using two-dimensional strain rate imaging to assess short-axis and long-axis myocardial function.

OBJECTIVES: This study sought to differentiate the transmural extent of infarction (TME) by assessment of the short-axis and long-axis function of the left ventricle (LV) using 2-dimensional (2D) strain. BACKGROUND: The differentiation of subendocardial infarction from transmural infarction has significant prognostic and clinical implications. METHODS: Contrast-enhanced magnetic resonance imaging (CE-MRI) and dobutamine stress echocardiography (DBE) were performed in 80 patients (age 63 +/- 10 years) with chronic ischemic LV dysfunction. Myocardial function was assessed in the short axis at the midventricular level using peak strain rate (SR) and strain (S) in circumferential and radial dimensions, and was assessed in the long axis using longitudinal SR and S. Wall motion analysis was performed during DBE to assess for contractile reserve. RESULTS: Transmural infarct segments had lower circumferential S (-10.7 +/- 6.3) and SR (-1.0 +/- 0.4) than subendocardial infarcts (S: -15.4 +/- 7.0, p < 0.0001; SR: -1.4 +/- 0.8, p = 0.02) and normal myocardium (S: p < 0.0001; SR: p < 0.0001). Transmural and subendocardial infarct segments had similar radial S and SR. Subendocardial infarct segments showed significant reduction of longitudinal S (-13.2 +/- 5.6) and SR (-0.91 +/- 0.45) compared with normal myocardium (S: -17.8 +/- 5.4, p < 0.0001; SR: -1.1 +/- 0.41, p < 0.0001), but there were no significant differences between subendocardial and transmural infarct segments (p = 0.09). Wall motion analysis by DBE could not identify subendocardial infarction on CE-MRI (TME 1% to 50%: DBE scar 38%, DBE viable 38%, DBE ischemic 24%, p = NS). CONCLUSIONS: The combined assessment of long-axis and short-axis function using 2D strain may be used to identify TME.

Accuracy and feasibility of online 3-dimensional echocardiography for measurement of left ventricular parameters.

BACKGROUND: The availability of automated online software may increase the feasibility of real-time 3-dimensional (3D) echocardiography (3DE) for left ventricular (LV) volume calculation in clinical practice. We sought to compare offline and online approaches with magnetic resonance imaging (MRI). METHODS: Patients who presented to the clinical laboratory for evaluation of LV parameters (n = 110, 94 men, age 63 +/- 10 years) were studied with 2-dimensional echocardiography, online and offline 3DE, and MRI. The 3DE measurements were obtained by a semiautomated LV border detection based on tracing (online) and edge detection (offline). MRI images were obtained using true free induction steady-state precession during breath hold, with measurement of 3D volumes and ejection fraction (EF). RESULTS: All echocardiographic techniques underestimated LV volumes, but EF estimations were similar. The best correlation was between MRI versus offline 3DE. The correlation of online 3DE with MRI was significantly better than 2-dimensional echocardiography (end-diastolic volume (EDV) z = 4.2, end-systolic volume (ESV) z = 4.44, EF z = 4.32; all P < .01). However, correlation of offline 3DE with MRI was significantly better than online 3DE (EDV z = 2.57, P < .05; ESV z = 2.42, P < .05; EF z = 3.82, P < .01). Images were considered to be good quality (endocardium visualized in all walls) in 49 patients; discrepancies between online and offline 3DE and MRI were similar in good- and poor-quality images. Wall-motion abnormalities were present in 98 patients; discrepancies with MRI were similar in patients with and without abnormal wall motion. CONCLUSIONS: Online measurement of LV volumes is feasible and more accurate than with 2-dimensional echocardiography. Although the offline approach is more accurate, it is also more time-consuming.

Incremental value of strain rate analysis as an adjunct to wall-motion scoring for assessment of myocardial viability by dobutamine echocardiography: a follow-up study after revascularization.

BACKGROUND: Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear. METHODS AND RESULTS: DbE and SRI were performed in 55 stable patients (mean age, 64+/-10 years; mean ejection fraction, 36+/-8%) with previous myocardial infarction. Viability was predicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (DeltaSR), ESS, and ESS increment (DeltaESS) (each P<0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, P=0.3), DeltaSR (80%, P=0.1), ESS (75%, P=0.6), and DeltaESS (74%, P=0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, P=0.015; area under the curve=0.88 versus 0.73, P<0.001), although specificities were comparable (80% versus 77%, P=0.2). CONCLUSIONS: The measurement of low-dose DbE SR and DeltaSR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE.

Optimisation of strain rate imaging for application to stress echocardiography.

We sought to improve the feasibility of strain rate imaging (SRI) during dobutamine stress echocardiography (DSE) in 56 subjects at low risk of coronary disease. The impact of several SRI changes during acquisition were studied, including: (1) changing from fundamental to harmonic imaging; (2) parallel beamforming; (3) alteration of spatial resolution and (4) narrow sector acquisition. We assessed SR signal quality, a quantitative measure of signal noise and measurements of SRI. Of 1462 segments evaluated, 6% were uninterpretable at rest and 8% at peak stress. Signal quality was optimised by increasing temporal (p = 0.01) and spatial resolution (p < 0.0001 vs. baseline imaging) at rest and peak. Increasing spatial resolution also minimised signal noise (p < 0.0001). Inter-observer variability of time to peak SR and peak SR were less with high temporal and spatial resolution. SRI quality can be improved with harmonic imaging and higher temporal resolution but optimisation of spatial resolution is critical.

Prediction of subclinical left ventricular dysfunction with strain rate imaging in patients with asymptomatic severe mitral regurgitation.

This study sought the ability of strain rate imaging to detect subclinical left ventricular dysfunction, as evidenced by reduced contractile reserve (CR) in 32 asymptomatic patients with isolated severe mitral regurgitation. Compared with CR- patients (n = 10), CR+ patients (n = 22) had significantly higher end-systolic strain and peak systolic strain rate, but these parameters were not significantly different between CR+ patients and matched normal controls.

Reproducibility and accuracy of echocardiographic measurements of left ventricular parameters using real-time three-dimensional echocardiography.

OBJECTIVES: We sought to determine whether assessment of left ventricular (LV) function with real-time (RT) three-dimensional echocardiography (3DE) could reduce the variation of sequential LV measurements and provide greater accuracy than two-dimensional echocardiography (2DE). BACKGROUND: Real-time 3DE has become feasible as a standard clinical tool, but its accuracy for LV assessment has not been validated. METHODS: Unselected patients (n = 50; 41 men; age, 64 +/- 8 years) presenting for evaluation of LV function were studied with 2DE and RT-3DE. Test-retest variation was performed by a complete restudy by a separate sonographer within 1 h without alteration of hemodynamics or therapy. Magnetic resonance imaging (MRI) images were obtained during a breath-hold, and measurements were made off-line. RESULTS: The test-retest variation showed similar measurements for volumes but wider scatter of LV mass measurements with M-mode and 2DE than 3DE. The average MRI end-diastolic volume was 172 +/- 53 ml; LV volumes were underestimated by 2DE (mean difference, -54 +/- 33; p < 0.01) but only slightly by RT-3DE (-4 +/- 29; p = 0.31). Similarly, end-systolic volume by MRI (91 +/- 53 ml) was underestimated by 2DE (mean difference, -28 +/- 28; p < 0.01) and by RT-3DE (mean difference, -3 +/- 18; p = 0.23). Ejection fraction by MRI was similar by 2DE (p = 0.76) and RT-3DE (p = 0.74). Left ventricular mass (183 +/- 50 g) was overestimated by M-mode (mean difference, 68 +/- 86 g; p < 0.01) and 2DE (16 +/- 57; p = 0.04) but not RT-3DE (0 +/- 38 g; p = 0.94). There was good inter- and intra-observer correlation between RT-3DE by two sonographers for volumes, ejection fraction, and mass. CONCLUSIONS: Real-time 3DE is a feasible approach to reduce test-retest variation of LV volume, ejection fraction, and mass measurements in follow-up LV assessment in daily practice.