Accuracy of speckle tracking in the context of stress echocardiography in short axis view: An in vitro validation study

Ultrafast Myocardial Principal Strain Ultrasound Elastography During Stress Tests: In Vitro Validation and In Vivo Feasibility

Objective myocardial contractility assessment during stress tests aims to improve the diagnosis of myocardial ischemia. Tissue Doppler imaging (TDI) or optical flow (OF) speckle tracking echocardiography (STE) has been used to quantify myocardial contractility at rest. However, this is more challenging during stress tests due to image decorrelation at high heart rates. Moreover, stress tests imply a high frame rate which leads to a limited lateral field of view. Therefore, a large lateral field-of-view robust ultrafast myocardial regularized OF-TDI principal strain estimator has been developed for high-frame-rate echocardiography of coherently compounded transmitted diverging waves. The feasibility and accuracy of the proposed estimator were validated in vitro (using sonomicrometry as the gold standard) and in vivo stress experiments. Compared with OF strain imaging, the proposed estimator improved the accuracy of principal major and minor strains during stress tests, with an average contrast-to-noise ratio improvement of 4.4 ± 2.7 dB ( p -value < 0.01). Moreover, there was a significant correlation and a very close agreement between the proposed estimator and sonomicrometry for tested heart rates between 60 and 180 beats per minute (bpm). The averages ± standard deviations (STD) of R² and biases ± STD between them were 0.96 ± 0.04 ( p -value < 0.01) and 0.01 ± 0.03% in the axial direction, respectively; and 0.94 ± 0.02 ( p -value < 0.01) and 0.04 ± 0.06% in the lateral direction, respectively. These results suggest that the proposed estimator could be useful clinically to provide an accurate and quantitative 2-D large lateral field-of-view myocardial strain assessment at high heart rates during stress echocardiography.

Speckle-tracking Echocardiography in Early Diagnosis of Myocardial Dysfunctions of Women with Hypertension in the Perimenopausal Period

Абстрактный   Цель исследования:  оценить роль спекл-трекинговой эхокардиографии в выявлении ранней дисфункции миокарда у женщин с артериальной гипертензией в перименопаузальном периоде.   Материал и методы. В исследовании приняли участие 50 женщин перименопаузального периода в возрасте от 45 до 55 лет. Перименопауза диагностировалась на основании клинического осмотра, включающего осмотр у гинеколога и исследования гормонального статуса женщины. Выборка женщин была разделена на две группы в зависимости от наличия артериальной гипертензии. В основную группу вошли 24 пациентки с артериальной гипертензией, диагностированной в перименопаузальном периоде. Перечисленные выше методы обследования также включали электрокардиографию, эхокардиографию и спекл-трекинговую эхокардиографию.   Результаты. По данным спекл-трекинговой эхокардиографии выявлены статистически значимые показатели в базально-антеропостероидном и нижнебазальном сегментах (р = 0,016; 0,001). Разница индекса массы миокарда левого желудочка была статистически значимой в сравниваемых группах (р = 0,038). ROC-анализ использовался для оценки качества полученной модели логистической регрессии. Площадь под ROC-кривой составила 0,806 ± 0,065 (95% ДИ: 0,679–0,933, p <0,001). Это указывает на «очень хорошее» прогностическое качество модели.   Заключение: в группе больных с артериальной гипертензией более чувствительны показатели базального переднеперегородочного и базально-нижнего сегментов, что может быть использовано как значимый показатель дисфункции при неизменных показателях стандартной эхокардиографии.

Deformability of ascending thoracic aorta aneurysms assessed using ultrafast ultrasound and a principal strain estimator: In vitro evaluation and in vivo feasibility

BACKGROUND

Noninvasive vascular strain imaging under conventional line-by-line scanning has a low frame rate and lateral resolution, and depends on the coordinate system. It is thus affected by high deformations due to image decorrelation between frames.

PURPOSE

To develop an ultrafast time-ensemble regularized tissue-Doppler optical-flow principal strain estimator for aorta deformability assessment in a long-axis view.

METHODS

This approach alleviated the impact of lateral resolution using image compounding and that of the coordinate system dependency using principal strain. Accuracy and feasibility were evaluated in two aorta-mimicking phantoms first, and then in four age-matched individuals with either a normal aorta or a pathological ascending thoracic aorta aneurysm (TAA).

RESULTS

Instantaneous aortic maximum and minimum principal strain maps and regional accumulated strains during each cardiac cycle were estimated at systolic and diastolic phases to characterize the normal aorta and TAA. In vitro, principal strain results matched sonomicrometry measurements. In vivo, a significant decrease in maximum and minimum principal strains was observed in TAA cases, whose range was respectively 7.9 ± 6.4% and 8.2 ± 2.6% smaller than in normal aortas.

CONCLUSIONS

The proposed principal strain estimator showed an ability to potentially assess TAA deformability, which may provide an individualized and reliable evaluation method for TAA rupture risk assessment. This article is protected by copyright. All rights reserved.

Quantitative Assessment of Myocardial Ischemia in Multi-Vessel Coronary Artery Disease by Multimodal Stress Echocardiography with Semi-Supine Bicycle Ergometry

Stress echocardiography is a modern widely used method of noninvasive diagnosis of coronary heart disease and stratification of the risk of cardiovascular complications. In addition, exercise echocardiography is an important tool to clarify the localization of ischemia and establish a symptomassociated artery for management of patient with known coronary angiography data. This is especially important in multivessel lesions, the presence of an occluded artery or borderline stenosis. Currently, various stress agents are used for stress echocardiography in clinical practice: pharmacological drugs (dobutamine or adenosine), transesophageal or endocardial pacing, treadmill, semi-supine bicycle. To detect signs of ischemia usually used only visual estimation of local contractility in the two-dimensional gray-scale mode. Modern modes of myocardial imaging, such as speckletracking echocardiography or three-dimensional visualization, are practically not used. In the presented clinical case, the possibility of combining standard and modern imaging modes to clarify the localization and quantification of ischemia in multivessel coronary lesions, including chronic artery occlusion, is shown. As a stress agent, a semi-supine bicycle was chosen, the use of which allowed to obtain a qualitative image of the left ventricular myocardium at rest and at peak load, suitable for assessing deformation and threedimensional visualization. Evaluation of left ventricular myocardial deformation by speckle-tracking echocardiography was more accurate than standard diagnosis in detecting signs of ischemia in a patient with multivessel lesions. Three-dimensional imaging was inferior in sensitivity to speckletracking stress echocardiography and, at present, seems to have more research value.