Myocardial motion estimation combining tissue Doppler and B-mode echocardiographic images

International audienceWe present a registration framework that combines both tissue Doppler and B-mode echocardiographic sequences. The estimated spatiotemporal transform is diffeomorphic, and calculated by modeling its corresponding velocity field using continuous B-splines. A new cost function using both B-mode image voxel intensities and Doppler velocities is also proposed. Registration accuracy was evaluated on synthetic data with known ground truth. Results showed that our method allows quantifying wall motion with higher accuracy than when using a single modality. On patient data, both displacement and velocity curves were compared with the ones obtained from widely used commercial software using either B-mode images or TDI. Our method demonstrated to be more robust to image noise while being independent from the beam angle

Assessing left ventricular systolic function in shock: evaluation of echocardiographic parameters in intensive care

Introduction: Assessing left ventricular (LV) systolic function in a rapid and reliable way can be challenging in the critically ill patient. The purpose of this study was to evaluate the feasibility and reliability of, as well as the association between, commonly used LV systolic parameters, by using serial transthoracic echocardiography (TTE). Methods: Fifty patients with shock and mechanical ventilation were included. TTE examinations were performed daily for a total of 7 days. Methods used to assess LV systolic function were visually estimated, "eyeball" ejection fraction (EBEF), the Simpson single-plane method, mean atrioventricular plane displacement (AVPDm), septal tissue velocity imaging (TDIs), and velocity time integral in the left ventricular outflow tract (VTI). Results: EBEF, AVPDm, TDIs, VTI, and the Simpson were obtained in 100%, 100%, 99%, 95% and 93%, respectively, of all possible examinations. The correlations between the Simpson and EBEF showed r values for all 7 days ranging from 0.79 to 0.95 (P < 0.01). the Simpson correlations with the other LV parameters showed substantial variation over time, with the poorest results seen for TDIs and AVPDm. The repeatability was best for VTI (interobserver coefficient of variation (CV) 4.8%, and intraobserver CV, 3.1%), and AVPDm (5.3% and 4.4%, respectively), and worst for the Simpson method (8.2% and 10.6%, respectively). Conclusions: EBEF and AVPDm provided the best, and Simpson, the worst feasibility when assessing LV systolic function in a population of mechanically ventilated, hemodynamically unstable patients. Additionally, the Simpson showed the poorest repeatability. We suggest that EBEF can be used instead of single-plane Simpson when assessing LV ejection fraction in this category of patients. TDIs and AVPDm, as markers of longitudinal function of the LV, are not interchangeable with LV ejection fraction

Echocardiographic evaluation including tissue Doppler imaging in New Zealand white rabbits sedated with ketamine and midazolam

Limited data are available on the use of more recent echocardiographic parameters in the rabbit. Echocardiographic examination, including conventional echocardiography and tissue Doppler imaging (TDI), was performed on 26 male New Zealand white rabbits under ketamine-midazolam sedation. Particular emphasis was placed on the more recent systolic and diastolic parameters, such as myocardial performance index (Tei index) and mitral annular motion (from septal and lateral sides of the left ventricle) obtained using pulsed TDI. Parameters that assessed systolic and diastolic function (fractional shortening, Tei index, and maximal mitral E- and A-wave velocities) were comparable to those reported in the literature for rabbits in the awake state. The less cardiodepressive anaesthetic protocol could offer a good alternative in performing echocardiographic evaluation whenever such caution is necessary. TDI is feasible in healthy rabbits and potentially suitable for the investigation of left ventricle systolic and diastolic function

Novel insights into echocardiographic assessment of cardiac function following heart surgery

Assessment of cardiac function is a fundamental in everyday clinical decision making and is essential diagnostic tool for choosing therapy in patients with cardiac disease. Currently, echocardiography is the integral part in management of patients with different cardiac disease and the most established imaging tool in the assessment of cardiac function. Coronary artery bypass grafting (CABG) is an effective treatment in selected patients suffering from advanced coronary artery disease (CAD). Improvement in symptoms, functional status and cardiac function is often used to evaluate the success of CABG. Evaluation of cardiac function often is divided in assessment of systolic and diastolic function. However, systole and diastole are integrated and interconnected parts of cardiac cycle. Thus, a method for quantifying cardiac function which incorporates both systole and diastole is to be preferred. Myocardial performance index (MPI) assessed by pulsed-wave Doppler tissue imaging (PW-DTI) is combining systole and diastole, easy to acquire and is independent of cardiac geometry. The aim of this thesis is to evaluate the feasibility of MPI measured by PW-DTI in assessment of left and right ventricular performance in patients with CAD treated with CABG. In addition, to explore the role of B-type natriuretic peptide (BNP) in predicting long-term major adverse outcomes following CABG and exploring its association with MPI. Finally, this thesis aims to evaluate the impact of conventional aortic valve surgery in comparison to minimally invasive aortic valve surgery (MIAVR) on right ventricular function (RV) assessed by echocardiography. Methods and Results Study I, forty six patients who were accepted for CABG were included. They all were investigated by dobutamine stress-echocardiography (DSE) prior to CABG and 3 month after CABG. Several methods for evaluation of left ventricular systolic and diastolic function had been applied, i.e. EF, longitudinal systolic and diastolic velocities as well as MPI. All the measurements were performed at rest and at peak DSE. The values from pre-CABG were compared to those after CABG. At baseline, MPI was prolonged both at rest (0.61 ±0.13) and at peak DSE (0.78±0.16). Accordingly, ejection fraction (EF) was also impaired at rest (42.7±8%) and at peak DSE (49.2±9). Similarly, wall-motion score index WMSI was impaired at rest (1.1±0.2) and at peak DSE (1.4±0.2). After CABG, MPI improved significantly both at rest (0.45±0.08; P < 0.001) and at peak DSE (0.56±0.1; P < 0.001). On the other hand, EF and WMSI did not improve at rest (43.7±8% and 1.1±0.2, respectively). However, at peak DSE an improvement of both EF (54.2±9; P < 0.05) and WMSI (1.1±0.16; P < 0.001) was observed. Study II: The same patient cohort as in study I was used for analyzing the impact of CABG on RV function. Coronary angiography, DSE and exercise bicycle test were performed 1 month before and 3 months after CABG. Right ventricular index of myocardial performance (RIMP), right ventricular systolic velocity (RVS) and displacement (TAPSE) at the lateral tricuspid annulus were all assessed. The RIMP improved following CABG both at rest (0.45 ± 0.11 vs. 0.38 ± 0.08 CABG, P = 0.013) and during DSE (0.75 ± 0.23 vs. 0.49 ± 0.14, P < 0.001). Compared to baseline, TAPSE reduced substantially after CABG both at rest (23.9 ± 4.46 vs. 14.6 ± 3.67, P < 0.001) and during DSE (20.9 ± 4.16 vs 11.9 ± 3.60, P < 0.001). A significant decline in RVS was also observed following CABG both at rest (11.9 ± 2.40 vs. 8.5 ± 1.93, P < 0.001) and during DSE (15.6 ± 4.30 vs. 10.5 ± 3.21, P < 0.001). On contrary, compared to pre-CABG values exercise capacity improved significantly following CABG (128.4 ± 40.12W vs 142.1 ± 46.73 W, P = 0.014). Study III was a predefined post hoc analysis of CMILE study (Cardiac Function after Minimally Invasive Aortic Valve Implantation including 40 patients with severe aortic stenosis and eligible for isolated aortic valve replacement. The patients were randomized 1:1 either to conventional aortic valve replacement (AVR) or minimally invasive aortic valve replacement (MIAVR). The impact of these two surgical techniques on right ventricular mechanics and contractility was evaluated by echocardiography. Compared to baseline RV strain rate (RV-LSR) was preserved after MIAVR (-1.52±0.5 vs -1.49±0.4 1/s, p=0.84) but declined following AVR (-1.67±0.3 vs -1.38±0.3 1/s, p<0.01). RV longitudinal strain (RV-LS) was deteriorated after AVR (˗27.4±2.9% vs ˗18.8±4.7%, p<0.001) and MIAVR (˗26.5±5.3% vs ˗20.7±4.5%, p<0.01). Peak systolic velocity of the lateral tricuspid annulus (RVS) declined by 18.8% in the MIAVR group (10.1±2.9 vs 8.2±1.4 cm/s, p<0.01) and 36.6% in the AVR group (9.3±2.1 vs 5.9±1.5 cm/s, p<0.01) when values from before surgery were compared to after surgery. In Study IV, 99 patients with CAD who underwent CABG were evaluated by a biomarker BNP and Echocardiography. In a subpopulation of 40 patients DTI and MPI were obtained. Patients were followed-up for 5 years and during this period death, myocardial infarction, stroke and hospitalization due to heart failure were recorded. The role of postoperative BNP for predicting major outcomes was assessed and its association with MPI was determined. Seventeen patients experienced major adverse outcomes during the follow-up. Univariate analysis revealed that creatinine clearance (P<0.01), body mass index (BMI, P<0.01), postoperative BNP (P<0.001) and preoperative LV-MPI (P=0.04) were all significantly associated with major outcomes at follow-up. However, after correcting for cofactors in multivariate analysis only postoperative BNP (P=0.003) and BMI (P=0.025) were associated with major outcomes. CONCLUSIONS: Myocardial performance index and right ventricular index of myocardial performance improved significantly following CABG in patients with CAD both at rest and peak DSE and appear to be a sensitive measure of myocardial function in patients with CAD. Postoperative BNP obtained in a stable clinical condition, 3 month after CABG is a predictive of major outcomes 5 years after CABG. Load-independent contractility is preserved following MIAVR but reduced following AVR. Load-dependent measures of myocardial function all declined following both MIAVR and AVR however, to a much lesser extent following MIAVR

Echocardiography

The book "Echocardiography - New Techniques" brings worldwide contributions from highly acclaimed clinical and imaging science investigators, and representatives from academic medical centers. Each chapter is designed and written to be accessible to those with a basic knowledge of echocardiography. Additionally, the chapters are meant to be stimulating and educational to the experts and investigators in the field of echocardiography. This book is aimed primarily at cardiology fellows on their basic echocardiography rotation, fellows in general internal medicine, radiology and emergency medicine, and experts in the arena of echocardiography. Over the last few decades, the rate of technological advancements has developed dramatically, resulting in new techniques and improved echocardiographic imaging. The authors of this book focused on presenting the most advanced techniques useful in today's research and in daily clinical practice. These advanced techniques are utilized in the detection of different cardiac pathologies in patients, in contributing to their clinical decision, as well as follow-up and outcome predictions. In addition to the advanced techniques covered, this book expounds upon several special pathologies with respect to the functions of echocardiography

Bi-Ventricular Myocardial Performance in Heart Failure: A New Approach to Evaluate Interventricular Dyssynchrony

Aims: Patients with heart failure (HF) exhibit ventricular dyssynchrony with negative effects on ventricular systolic and diastolic performance and poor prognosis. There is no consensus about the best approach for estimating the dyssynchrony and for selecting candidates for resynchronization therapy (CRT). We sought to evaluate whether Myocardial Performance Index (MPI), calculated as differences between left and right ventricle (LV, RV), ΔMPI, represents a marker of interventricular dyssynchrony. Methods: The study included 40 patients (22 males, 18 females, mean age 71±13) with NYHA functional class II-III, chronic heart failure (77% ischaemic), in optimal drug therapy for at least three months. All patients underwent a complete two-dimensional and Tissue Doppler Echocardiography (TDE), including an assessment of MPI in both ventricles. Results: Significant correlations were found between ΔMPI and QRS (r = 0.41, p &lt; 0.001), with NYHA (r = 0.66, p &lt; 0.001), with SPWMD (r = 0.32, p &lt; 0.05), with LV ejection fraction (r = -0.32, p &lt; 0.05), with Spv wave at the septal site of LV (r = -0.32, p &lt; 0.05), and with IVMD (r = 0.44, p &lt; 0.001). Ten patients have been re-evaluated six months after CRT implantation, and ΔMPI significantly correlated with the difference between basal LVEF and six months after CRT implantation (r = 0.43, p &lt; 0.04). Conclusion: The ΔMPI could represent an integrative marker of interventricular dyssynchrony and could be considered as a new parameter in the patient selection process to be undergone CRT

Shear wave echocardiography

In this thesis we demonstrate that the assessment of the diastolic function of the left ventricle withclassical echocardiography remain

Ultrasound studies of dilated cardiomyopathy in Dobermanns and English cocker spaniels

The basic hypothesis tested in this study was that dogs with dilated cardiomyopathy have abnormal ventricular function, and that this can be detected noninvasively using M-mode, two-dimensional (2D), and Doppler echocardiography, and also by measuring myocardial ultrasonic integrated backscatter. An additional hypothesis was that different breeds of dogs affected with DCM have a different clinical course, and that differences in ventricular function between these breeds can be detected by echocardiography or integrated backscatter measurements that might account for the different prognosisThe aims of this study therefore were (1) to identify echocardiographic variables that distinguished normal dogs from dogs with DCM; (2) to identify differences in ventricular function using echocardiography between Dobermanns and English cocker spaniels with DCM; and (3) to measure ultrasonic integrated backscatter in normal dogs and in Dobermanns and Cocker spaniels with DCM.In this group of Dobermanns, median survival time was 98 days (range 16 - 508 days), whereas median survival in the cocker spaniels was 512 days (range 51 to >1388 days), with 6/11 still alive at the time of writing (p < 0.002). All the measured M-mode variables differed significantly between the normal dogs and the dogs with DCM. Compared with the Dobermanns, the cocker spaniels had significantly increased LV free wall thickening and increased LV diastolic diameter when indexed to body surface area. All the 2D echocardiographic variables were significantly different between the normal dogs and dogs with DCM when corrected for body size, but there were no significant differences between Dobermanns and cocker spaniels. Significant differences were found between normal and DCM dogs in some but not all of the Doppler echocardiographic variables. Cocker spaniels had higher mitral A wave velocities than the normal dogs, and decreased mitral E/A ratios compared with both the other groups. Dobermanns had shorter isovolumic relaxation times than the other groupsIn the second part of this study, measurements were made of ultrasonic integrated backscatter in selected regions of the left ventricle in normal dogs and dogs with DCM. Ultrasonic integrated backscatter is a measurement of the power of the ultrasound signal returned from the myocardium to the transducer. This backscattered signal reflects basic tissue properties, and exhibits dynamic variation with contractile function that may represent fundamental alterations in the shape, size and distribution of scatterers within the myocardium. Consistent cyclic variation in integrated backscatter was observed in the LV free wall and septum of the normal dogs, but this pattern was not consistently seen in the DCM dogs. Differences were not seen between the Dobermanns and cocker spaniels, although the number of cocker spaniels measured was small.In conclusion, the DCM dogs had evidence of markedly reduced systolic function compared with the normal dogs. The affected dogs had left atrial and left ventricular dilation with thinner left ventricular walls. Although there was little evidence of any difference in systolic function between the two affected breeds, there was evidence of different diastolic function, with a tendency for Dobermanns to show a restrictive pattern of transmitral filling, and cocker spaniels to show evidence of delayed relaxation. The different pattern of diastolic dysfunction in the two breeds is consistent with the prognostic value ascribed to transmitral flow patterns in human DCM patients: delayed relaxation patterns have been associated with improved survival times in man. Reduced cyclic variation of ultrasonic integrated backscatter was also seen in the dogs affected with DCM, although no differences were found between the two affected breeds