Myocardial strain assessment by cine cardiac magnetic resonance imaging using non-rigid registration.

AIMS: To evaluate a novel post-processing method for assessment of longitudinal mid-myocardial strain in standard cine cardiac magnetic resonance (CMR) imaging sequences. METHODS AND RESULTS: Cine CMR imaging and tagged cardiac magnetic resonance imaging (TMRI) were performed in 15 patients with acute myocardial infarction (AMI) and 15 healthy volunteers served as control group. A second group of 37 post-AMI patients underwent both cine CMR and late gadolinium enhancement (LGE) CMR exams. Speckle tracking echocardiography (STE) was performed in 36 of these patients. Cine CMR, TMRI and STE were analyzed to obtain longitudinal strain. LGE-CMR datasets were analyzed to evaluate scar extent. Comparison of peak systolic strain (PSS) measured from CMR and TMRI yielded a strong correlation (r=0.86, p<0.001). PSS measured from CMR and STE correlated well (r=0.75, p<0.001). A cutoff longitudinal PSS value of -13.14% differentiated non-infarction from any infarcted myocardium, with a sensitivity of 93% and a specificity of 89% (area under curve (AUC) 0.95). PSS value of -9.39% differentiated non-transmural from transmural infarcted myocardium, with a sensitivity of 75% and a specificity of 67% (AUC 0.78). CONCLUSION: The present study showed a novel off-line post-processing method for segmental longitudinal strain analysis in mid-myocardium layer based on cine CMR data. The method was found to be highly correlated with strain measurements obtained by TMRI and STE. This tool allows accurate discrimination between different transmurality states of myocardial infarction.

Reliability of visual assessment of global and segmental left ventricular function: a multicenter study by the Israeli Echocardiography Research Group.

BACKGROUND: The purpose of this multicenter study was to determine the reliability of visual assessments of segmental wall motion (WM) abnormalities and global left ventricular function among highly experienced echocardiographers using contemporary echocardiographic technology in patients with a variety of cardiac conditions. METHODS: The reliability of visual determinations of left ventricular WM and global function was calculated from assessments made by 12 experienced echocardiographers on 105 echocardiograms recorded using contemporary echocardiographic equipment. Ten studies were reread independently to determine intraobserver reliability. RESULTS: Interobserver reliability for visual differentiation between normal, hypokinetic, and akinetic segments had an intraclass correlation coefficient of 0.70. The intraclass correlation coefficient for dichotomizing segments into normal versus other abnormal was 0.63, for hypokinetic versus other scores was 0.26, and for akinetic versus other scores was 0.58. Similar results were found for intraobserver reliability. Interobserver reliability for WM score index was 0.84 and for left ventricular ejection fraction was 0.78. Similar values were obtained for the intraobserver reliability of WM score index and ejection fraction. Compared to angiographic data, the accuracy of segmental WM assessments was 85%, and correct determination of the culprit artery was achieved in 59% of patients with myocardial infarctions. CONCLUSION: Among experienced readers using contemporary echocardiographic equipment, interobserver and intraobserver reliability was reasonable for the visual quantification of normal and akinetic segments but poor for hypokinetic segments. Reliability was good for the visual assessment of global left ventricular function by WM score index and ejection fraction.

A new tool for automatic assessment of segmental wall motion based on longitudinal 2D strain: a multicenter study by the Israeli Echocardiography Research Group.

BACKGROUND: Identification and quantification of segmental left ventricular wall motion abnormalities on echocardiograms is of paramount clinical importance but is still performed by a subjective visual method. We constructed an automatic tool for assessment of wall motion based on longitudinal strain. METHODS AND RESULTS: Echocardiograms of 105 patients (3 apical views) were blindly analyzed by 12 experienced readers. Visual segmental scores (VSS) and peak systolic longitudinal strain were assigned to each of 18 segments per patient. Ranges of peak systolic longitudinal strain that best fit VSS (by receiver operating characteristic analysis) were used to generate automatic segmental scores (ASS). Comparisons of ASS and VSS were performed on 1952 analyzable segments. There was agreement of wall motion scores between both methods in 89.6% of normal, 39.5% of hypokinetic, and 69.4% of akinetic segments. Correlation between methods was r=0.63 (P<0.0001). Interobserver and intraobserver reliability using interclass correlation for scoring segmental wall motion into 3 scores by ASS was 0.82 and 0.83 and by VSS 0.70 and 0.69, respectively. Compared with VSS (majority rule), ASS had a sensitivity, specificity, and accuracy of 87%, 85%, and 86%, respectively. ASS and VSS had similar success rates for correct identification of wall motion abnormalities in territories supplied by culprit arteries. VSS had greater specificity and positive predictive values, whereas ASS had higher sensitivity and negative predictive values for identifying the culprit artery. CONCLUSIONS: Automatic quantification of wall motion on echocardiograms by this tool performs as well as visual analysis by experienced echocardiographers, with a greater reliability and similar agreement to angiographic findings.

Real-time quantitative automatic assessment of left ventricular ejection fraction and regional wall motion by speckle imaging.

BACKGROUND: Echocardiographic assessment of left ventricular function includes calculation of ejection fraction and regional wall motion analysis. Recently, speckle imaging was introduced for quantification of left ventricular function. OBJECTIVES: To assess LVEF by speckle imaging and compare it with Simpson's method, and to assess the regional LV strain obtained by speckle imaging in relation to conventional echocardiographic scores. METHODS: Thirty consecutive patients, 28 with regional LV dysfunction, underwent standard echocardiographic evaluation. LV end-diastolic volume, LV end-systolic volume and EF were calculated independently by speckle imaging and Simpson's rule. The regional peak systolic strain presented by speckle imaging as a bull's-eye map was compared with the conventional visual estimate of echo score. RESULTS: Average EDV obtained by speckle imaging and by Simpson's method was 85.1 vs. 92.7 ml (P = 0.38), average ESV was 49.4 vs. 48.8 ml (P = 0.94), calculated EF was 43.9 vs. 50.5% (P = 0.08). The correlation rate with Simpson's rule was high: 0.92 for EDV, 0.96 for ESV, and 0.89 for EF. The peak systolic strain in two patients without wall motion abnormality was 17.3 +/- 4.7; in normal segments of patients with regional dysfunction, peak systolic strain (13.4 +/- 4.9) was significantly higher than in hypokinetic segments (10.5 +/- 4.5) (P < 0.000001). The strain in hypokinetic segments was significantly higher than in akinetic segments (6.2 +/- 3.6) (P < 0.000001). CONCLUSIONS: Speckle imaging can be successfully used for the assessment of LV volumes and EF. Bull's-eye strain map, created by speckle imaging, can achieve an accurate real-time segmental wall motion analysis.