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The constitutive elements of the metabolic syndrome (MetS) are linked with both non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease. Controlled attenuation parameter (CAP), and vibration controlled transient elastography (VCTE), are able to detect and quantify NAFLD, while conventional and two-dimensional speckle tracking echocardiography (2D-STE) is capable to identify subclinical changes in cardiac function. We wanted to evaluate whether there is any correspondence between left ventricular (LV) diastolic dysfunction and different degrees of liver steatosis and fibrosis in MetS subjects with NAFLD. A total of 150 adult subjects having MetS and a normal left ventricular (LV) systolic function were recorded in the study, while 150 age- and sex- matched adults without MetS were enrolled as controls. NAFLD was established by VCTE and CAP. The left heart systolic and diastolic function was evaluated by conventional and 2D-ST echocardiography. Left atrial (LA) stiffness was calculated as the ratio between the E/A ratio and the LA reservoir-strain. In univariate regression analysis, the variables associated with LV diastolic dysfunction in MetS patients were: liver steatosis grade ≥2, liver fibrosis grade ≥2, the longitudinal LA peak strain during the reservoir phase, the LA strain rate during ventricular contraction and the LA stiffness. In multivariate logistic regression, two variables were selected as independent predictors of LV diastolic dysfunction, namely the liver stiffness (P=0.0003) and the LA stiffness (P<0.0001). LA stiffness predicted subclinical LV diastolic dysfunction in MetS patients with a sensitivity of 45% and a specificity of 96% when using a cut-off value >0.38, and was significantly correlated with liver steatosis stage ≥2 and liver fibrosis stage ≥2. The present study confirms the association between liver stiffness, LA stiffness and LV diastolic dysfunction in MetS patients. Our study suggests that liver elastography and 2D-STE should become habitual assessments in MetS patients.

The components of metabolic syndrome (MS) are risk factors for developing both cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). Strain (SI) and strain‑rate imaging (SRI) are able to recognize early changes in cardiac function. Vibration-controlled transient elastography (VCTE) and controlled attenuation parameter (CAP) detect and quantify liver fibrosis and steatosis. We aimed to assess whether there is any correlation between liver fibrosis and steatosis and left ventricular (LV) dysfunction in MS patients. A total of 150 adults with MS were registered in the study. They were compared with a control group of 150 age- and sex-matched adults without MS. After the classic echocardiographic assessment of LV function, two-dimensional speckle echocardiography (2D-STE) was used to evaluate LV peak systolic strain (S) and peak systolic strain rate (SR), while liver steatosis and fibrosis were evaluated by VCTE and CAP. LV diastolic dysfunction was significantly more frequent among the patients with MS. We found significant differences between the two groups regarding the presence of subtle LV systolic dysfunction, detected by reduced values of S and SR. The risk for LV diastolic dysfunction was 3.6 times higher in MS with severe steatosis and 8 times higher in patients with severe fibrosis, P<0.0001. The risk for LV systolic dysfunction was double in MS with severe steatosis and 1.7 times higher in MS with severe fibrosis, P<0.0001. In MS patients with normal LV ejection fraction, conventional echocardiography parameters identified diastolic LV dysfunction, while SI and SRI identified subtle impairment of systolic LV dysfunction. The presence of hepatic steatosis and fibrosis increases significantly the risk for cardiac dysfunction in MS patients (P<0.0001).

Echocardiography is the most common diagnostic method for assessing cardiac functions. However, echocardiographic measures are subjective, semi-quantitative, and relatively insensitive when detecting subtle perturbations in contractility. Furthermore, early detection of abnormalities is crucial and may often influence treatments and establish prognosis. Echocardiographic- and Doppler-derived strain and strain rate imaging are relatively newer and more comprehensive techniques. They characterize the mechanics of myocardial contraction and relaxation (deformation imaging) more precisely and find applications in many cardiac pathologies. They are especially useful for assessing longitudinal myocardial deformation, which is otherwise difficult to assess using standard echocardiographic visual inspection. This review describes the fundamental concepts of strain imaging derived from tissue Doppler and two-dimensional speckle tracking and investigates how these methods can be incorporated into echocardiographic examinations and highlights their clinical applications. The considerable potentiality of imaging modalities for numerous cardiac conditions is thereby shown.

Cardiovascular disease (CVD) is one of the major threats to humanity, accounting for one-third of the world’s deaths. For patients with high-risk CVD, plaque rupture can lead to critical condition. It is therefore important to determine the stability of the plaque and classify the patient’s risk level. Lipid content is an important determinant of plaque stability. However, conventional intravascular imaging methods have limitations in finding lipids. Therefore, new intravascular imaging techniques for plaque risk assessment are urgently needed. In this study, a novel photothermal strain imaging (pTSI) was applied to an intravascular imaging system for detecting lipids in plaques. As a combination of thermal strain imaging and laser-induced heating, pTSI differentiates lipids from other tissues based on changes in ultrasound (US) velocity with temperature change. We designed an optical pathway to an intravascular ultrasound catheter to deliver 1210-nm laser and US simultaneously. To establish the feasibility of the intravascular pTSI system, we experimented with a tissue-mimicking phantom made of fat and gelatin. Due to the difference in the strain during laser heating, we can clearly distinguish fat and gelatin in the phantom. The result demonstrates that pTSI could be used with conventional intravascular imaging methods to detect the plaque lipid.

Background：Strain and strain-rate imaging （SRI） have been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies,and identifying early subclinical changes in various pathologies.The aim of this study was to evaluate the regional and global left ventricular （LV） myocardial function in metabolic syndrome （MS） with SRI so that we can provide more myocardial small lesions in patients with MS,which is robust and reliable basis for early detection of LV function.Methods：Thirty-nine adults with MS were enrolled in the study.There was a control group of 39 healthy adults.In addition to classic echocardiographic assessment of LV global functional changes,SRI was used to evaluate regional and global LV function.Including：Peak systolic strain （S）,peak systolic strain-rate （SR-s）,peak diastolic strain-rate （SR-e）.Results：There were no statistically significant differences between MS and controls in all traditional parameters of LV systolic function.On the other hand,significant differences were observed between MS and the control group in most of the parameters of S,SR-s,SR-e in regional LV function.Multiple stepwise regression analyses revealed that S and SR significantly were negatively correlated with blood pressure,waist circumference,fasting plasma glucose,uric acid,suggesting that risk factories were relevant to regional systolic dysfunction.Conclusion：In MS with normal LV ejection fraction,there was regional myocardial dysfunction,risk factors contributed to the impairment of systolic and diastolic function of the regional myocardium.Assessment of myocardial function using SRI could be more accurate in MS patient evaluation than conventional echocardiography alone.

We report on wide-field optically detected magnetic resonance imaging of nitrogen-vacancy centers (NVs) in type IIa polycrystalline diamond. These studies reveal a heterogeneous crystalline environment that produces a varied density of NV centers, including preferential orientation within some individual crystal grains, but preserves long spin coherence times. Using the native NVs as nanoscale sensors, we introduce a three-dimensional strain imaging technique with high sensitivity ( < 10 − 5 Hz-1/2) and diffraction-limited resolution across a wide field of view.

Myocardial deformation is a sensitive marker of sub-clinical myocardial dysfunction that carries independent prognostic significance across a broad range of cardiovascular diseases. It is now possible to perform 3D feature tracking of SSFP cines on cardiac magnetic resonance imaging (FT-CMR). This study provides reference ranges for 3D FT-CMR and assesses its reproducibility compared to 2D FT-CMR. One hundred healthy individuals with 10 men and women in each of 5 age deciles from 20 to 70 years, underwent 2D and 3D FT-CMR of left ventricular myocardial strain and strain rate using SSFP cines. Good health was defined by the absence of hypertension, diabetes, obesity, dyslipidaemia, or any cardiovascular, renal, hepatic, haematological and systemic inflammatory disease. Normal values for myocardial strain assessed by 3D FT-CMR were consistently lower compared with 2D FT-CMR measures [global circumferential strain (GCS) 3D − 17.6 ± 2.6% vs. 2D − 20.9 ± 3.7%, P < 0.005]. Validity of 3D FT-CMR was confirmed against other markers of systolic function. The 3D algorithm improved reproducibility compared to 2D, with GCS having the best inter-observer agreement [intra-class correlation (ICC) 0.88], followed by global radial strain (GRS; ICC 0.79) and global longitudinal strain (GLS, ICC 0.74). On linear regression analyses, increasing age was weakly associated with increased GCS (R2 = 0.15, R = 0.38), peak systolic strain rate, peak late diastolic strain rate, and lower peak early systolic strain rate. 3D FT-CMR offers superior reproducibility compared to 2D FT-CMR, with circumferential strain and strain rates offering excellent intra- and inter-observer variability. Normal range values for myocardial strain measurements using 3D FT-CMR are provided.

Deformations of the atherosclerotic vascular wall induced by the pulsating blood can be estimated using ultrasound strain imaging. Because these deformations indirectly provide information on mechanical plaque composition, strain imaging is a promising technique for differentiating between stable and vulnerable atherosclerotic plaques. This paper first explains 1-D radial strain estimation as applied intravascularly in coronary arteries. Next, recent methods for noninvasive vascular strain estimation in a transverse imaging plane are discussed. Finally, a compounding technique that our group recently developed is explained. This technique combines motion estimates of subsequently acquired focused ultrasound images obtained at various insonification angles. However, because the artery moves and deforms during the multi-angle acquisition, errors are introduced when compounding. Recent advances in computational power have enabled plane wave ultrasound acquisition, which allows 100 times faster image acquisition and thus might resolve the motion artifacts. In this paper the performance of strain imaging using plane wave compounding is investigated using simulations of an artery with a vulnerable plaque and experimental data of a two-layered vessel phantom. The results show that plane wave compounding outperforms 0° focused strain imaging. For the simulations, the root mean squared error reduced by 66% and 50% for radial and circumferential strain, respectively. For the experiments, the elastographic signal-to-noise and contrast-to-noise ratio (SNRe and CNRe) increased with 2.1dB and 3.7dB radially, and 5.6dB and 16.2dB circumferentially. Because of the high frame rate, the plane wave compounding technique can even be further optimized and extended to 3D in future.

Abdominal aortic aneurysms are a degenerative disease of the aorta associated with high mortality. To date, in vivo information to characterize the individual elastic properties of the aneurysm wall in terms of rupture risk is lacking. We have used time-resolved 3D ultrasound strain imaging to calculate spatially resolved in-plane strain distributions characterized by mean and local maximum strains, as well as indices of local variations in strains. Likewise, we here present a method to generate averaged models from multiple segmentations. Strains were then calculated for single segmentations and averaged models. After registration with aneurysm geometries based on CT-A imaging, local strains were divided into two groups with and without calcifications and compared. Geometry comparison from both imaging modalities showed good agreement with a root mean squared error of 1.22 ± 0.15 mm and Hausdorff Distance of 5.45 ± 1.56 mm (mean ± sd, respectively). Using averaged models, circumferential strains in areas with calcifications were 23.2 ± 11.7% (mean ± sd) smaller and significantly distinguishable at the 5% level from areas without calcifications. For single segmentations, this was possible only in 50% of cases. The areas without calcifications showed greater heterogeneity, larger maximum strains, and smaller strain ratios when computed by use of the averaged models. Using these averaged models, reliable conclusions can be made about the local elastic properties of individual aneurysm (and long-term observations of their change), rather than just group comparisons. This is an important prerequisite for clinical application and provides qualitatively new information about the change of an abdominal aortic aneurysm in the course of disease progression compared to the diameter criterion.

Left ventricular myocardial work (LVMW) represents an innovative tool based on echocardiography designed to assess left ventricular (LV) performance in conjunction with LV pressure patterns. Although previous studies have compared differences in LVMW among patients with Fabry disease (FD), cardiac amyloidosis (CA), and hypertension at rest, there is limited research on the characteristics of LVMW in patients with FD during exercise. This study aims to explore the characteristics of LVMW at rest and during exercise in patients with FD and the value of LVMW combined with stress echocardiography for the early detection of impaired cardiac function in subclinical Fabry patients. This cross-sectional study included 54 participants, comprising 23 healthy individuals and 31 patients with FD. All participants underwent comprehensive two-dimensional echocardiography and semi-supine exercise stress echocardiography tests. At rest, individuals with FD exhibited markedly lower LV global longitudinal strain (LVGLS), LV global myocardial constructive work (LVGCW), LV global myocardial work efficiency (LVGWE), and LV global myocardial work index (LVGWI) compared to healthy controls. During exercise, LVGLS, LVGWI, LVGCW, and LV global wasted myocardial work (LVGWW) markedly increased in patients with FD and controls, while LVGWE decreased. However, across the four phases (rest, 25 W, peak, and recovery), patients with FD consistently demonstrated lower LVGLS, LVGWI, LVGWE, and LVGCW compared to controls. Moreover, the rise in LVGWI and LVGCW from the rest phase to the peak stage was markedly smaller in individuals with FD than in controls. A moderate correlation was found between LVGWI and LVGWE with LV mass index (LVMI) in individuals with FD (LVGWI: r = − 0.57, P  < 0.05; LVGWE: r = − 0.68, P  < 0.001). Additionally, individuals with FD with LV hypertrophy (LVH) exhibited lower LVGLS, LVGWE, and LVGCW from the rest to peak than those without LVH. Individuals with FD who had normal LVGLS at rest or those without LVH still showed markedly lower LVGWI than controls during the resting phase. Additionally, at peak exercise, LVGLS, LVGWI, and LVGCW were diminished significantly in the individuals with FD relative to the control cohort. ROC curve analysis in both resting and exercising states showed that LVGWI (rest: AUC 0.86, sensitivity 87%, specificity 74%; peak: AUC 0.94, sensitivity 71%, specificity 96%;) and LVGCW (rest: AUC 0.82, sensitivity 87%, specificity 70%; peak: AUC 0.92, sensitivity 84%, specificity 87%;) than LVGLS (resting: AUC 0.79, sensitivity 61%, specificity 87%; peak: AUC 0.88, sensitivity of 77%, and specificity of 87%) have a higher value in the diagnosis of FD. Patients with FD have markedly lower LVGWI, LVGWE, and LVGCW compared to the healthy controls, and these reductions are more prominent during exercise. Although LVGWI and LVGCW increase during exercise in patients with FD, the rate of increase is reduced, indicating impaired myocardial metabolism and energy utilization efficiency, especially in patients with FD with LVH. Additionally, LVMW combined with Stress Echocardiography allows early detection of impaired cardiac function in Fabry patients.