Current trends in three-dimensional visualization and real-time navigation as well as robot-assisted technologies in hepatobiliary surgery

With the continuous development of digital medicine,minimally invasive precision and safety have become the primary development trends in hepatobiliary surgery.Due to the specificity and complexity of hepatobiliary surgery,traditional preoperative imaging techniques such as computed tomography and magnetic resonance imaging cannot meet the need for identification of fine anatomical regions.Imaging-based three-dimensional(3D)reconstruction,virtual simulation of surgery and 3D printing optimize the surgical plan through preoperative assessment,improving the controllability and safety of intraoperative operations,and in difficult-to-reach areas of the posterior and superior liver,assistive robots reproduce the surgeon’s natural movements with stable cameras,reducing natural vibrations.Electromagnetic navigation in abdominal surgery solves the problem of conventional surgery still relying on direct visual observation or preoperative image assessment.We summarize and compare these recent trends in digital medical solutions for the future development and refinement of digital medicine in hepatobiliary surgery.

Real-time Three-dimensional Echocardiographic Assessment of Left Ventricular Remodeling Index in Patients with Hypertensive Heart Disease and Coronary Artery Disease

Left ventricular remodeling index （LVRI） was assessed in patients with hypertensive heart disease （HHD） and coronary artery disease （CAD） by real-time three-dimensional echocardiography （RT3DE）. RT3DE data of 18 patients with HHD, 20 patients with CAD and 22 normal controis （NC） were acquired. Left ventricular end-diastolic volume （EDV） and left ventricular end-diastolic epicardial volume （EDVepi） were detected by RT3DE and two-dimensional echocardiography Simpson biplane method （2DE）. LVRI （left ventricular mass/EDV） was calculated and compared. The results showed that LVRI measurements detected by RT3DE and 2DE showed significant differences inter-groups （P〈0.01）. There was no significant difference in NC group （P〉0.05）, but significant difference in HHD and CAD intra-group （P〈0.05）. There was good positive correlations between LVRI detected by RT3DE and 2DE in NC and HHD groups （t=0.69, P〈0.01; r=0.68, P〈0.01）, but no significant correlation in CAD group （r=0.30, P〉0.05）. It was concluded that LVRI derived from RT3DE as a new index for evaluating left ventricular remodeling can provide more superiority to LVRI derived from 2DE.

REAL-TIME THREE-DIMENSIONAL ECHOCARDIOGRAPHY FOR QUANTIFYING LEFT VENTRICULAR MASS

To test the accuracy of real-time three-dimensional echocardiography (RT3DE) imaging system for evaluating left ventricular mass (LVM) in phantom and excised canine heart. Methods Ten left ventricular (LV) wall phantoms made of two rubber-bursas, ten excised canine hearts underwent RT3DE and two-dimensional echocardiography (2DE). In RT3DE "full volume" imaging, the myocardial volume was mea-sured using 2,4,8, and 16-plane method with the analysis software of RT3DE. Mass was then calculated by multiplying the resulting myocardial volume by specific density of myocardial tissue. In 2DE the masses were measured by area-length meth-od. The true LV wall phantom mass was measured by water displacement and the canine LVM was weighed by anatomy, which served as a reference standard. We compared RT3DE or 2DE with true mass. Results In LV wall phantoms, RT3DE correlated with true masses strongly (r = 0.813-0.994) and weakly correlated between 2DE and true masses (r = 0.628). In excised canine hearts, there is an excellent correlation between RT3DE and true masses (r = 0.764-0.991), while 2DE value showed a lesser correlation (r = 0.514). There are no difference between RT-3DE and true masses (P > 0.05) but different between 2DE and true masses (P < 0.05). In different planes, there was no difference between 8-plane and 16-plane (P > 0.05) but different between 8-plane and 2, 4-plane (P < 0.05). Conclusion RT3DE can accurately quantify LVM and provide a new tool to evaluate LV function. For LVM by RT3DE, 8-plane measurement method is the best choice for accuracy and convenience.

Evaluation of Right Ventricular Volume and Systolic Function by Real-time Three-dimensional Echocardiography

The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function was assessed. RV “Full volume” images were acquired by RT3DE in 22 healthy subjects. RV end-diastolic volumes (RVEDV) and end-systolic volumes (RVESV) were outlined using apical biplane, 4-plane, 8-plane, 16-plane offline separately. RVSV and RVEF were calculated. Meanwhile tricuspid annual systolic excursion (TASE) was measured by M-mode echo. LVSV was outlined by 2-D echo according to the biplane Simpson's rule. The results showed: (1) There was a good correlation between RVSV measured from series planes and LVSV from 2-D echo (r=0.73; r=0.69; r=0.63; r=0.66, P<0.25—0.0025); (2) There were significant differences between RVEDV in biplane and those in 4-, 8-, 16-plane (P<0.001). There was also difference between RV volume in 4-plane and that in 8-plane (P<0.05), but there was no significant difference between RV volume in 8-plane and that in 16-plane (P>0.05); (3) Inter-observers and intro-observers variability analysis showed that there were close agreements and relations for RV volumes (r=0.986, P<0.001; r=0.93, P<0.001); (4) There was a significantly positive correlation of TASE to RVSV and RVEF from RT3DE (r=0.83; r=0.90). So RV volume measures with RT3DE are rapid, accurate and reproducible. In view of RV's complex shape, apical 8-plane method is better in clinical use. It may allow early detection of RV systolic function.

Real-time three-dimensional echocardiography predicts cardiotoxicity induced by postoperative chemotherapy in breast cancer patients

BACKGROUND The anthracycline chemotherapeutic drugs are cardiotoxic.Studies have found some indicators related to cardiotoxicity.However,there is currently no accurate indicator that can predict cardiac toxicity early.AIM To explore the diagnostic value of real-time three-dimensional echocardiography(RT3DE)in predicting cardiac toxicity in breast cancer patients undergoing chemotherapy.METHODS Female breast cancer patients who underwent radical mastectomy and postoperative chemotherapy at the Affiliated Hanzhou First People’s Hospital,Zhejiang University School of Medicine were recruited.All patients were routinely administered with chemotherapy for four cycles(T1-T4)after surgery.Two-dimensional(2D)echocardiography,RT3DE,and serological examinations were performed after each cycle of chemotherapy.Patients were divided into a toxic group and a non-toxic group based on whether patients hadΔleft ventricular ejection fraction>10%after one year of chemotherapy.Repeated measurement analysis of variance was used to compare the changes in 2D echocardiographic indicators,serological indicators,and RT3DE indicators before independent predictive indicators for cardiac toxicity in postoperative chemotherapy patients.Receiver operating characteristics(ROC)curve analysis was performed to analyze the diagnostic value of potential indicators in the diagnosis of cardiotoxicity.RESULTS A total of 107 female breast cancer patients were included in the study.T4 maximum peak velocity in early diastole(E peak)/mitral annulus lateral tissue Doppler(e'peak)(E/e'),serological indicators[T4 cardiac troponin I(cTnI)and T4 pro-brain natriuretic peptide(Pro-BNP)],T3 minimum left atrial volume(LAV),T4 LAVmin,T3 LAV before the start of the P wave(LAVprep),and T4 LAVprep in the toxicity group were significantly higher than those in the nontoxic group.Multivariate logistic regression found that T4 cTnI,T4 Pro-BNP,T3 LAVmin,T4 LAVmin,T3 LAVprep,and T4 LAVprep had potential predictive value for cardiac toxicity(P<0.05).ROC results showed that T4 LAVmin had the highest accuracy for diagnosing cardiac toxicity[area under the curve(AUC)=0.947;sensitivity=78.57%;specificity=94.62%],followed by T4 LAVprep(AUC=0.899;sensitivity=100%;specificity=66.67%).The accuracies of LAVprep and LAVprep in predicting cardiac toxicity were higher than those of T3 LAVmin and T3 LAVprep.CONCLUSION RT3DE of left atrial volume can be used to predict the cardiotoxicity caused by chemotherapy,and it is expected to guide the clinical adjustment of dose and schedule in time.

Real-time Three-Dimensional Color Doppler Flow Imaging： An Improved Technique for Quantitative Analysis of Aortic Regurgitation

The recently introduced real-time three-dimensional color Doppler flow imaging （RT-3D CDFI） technique provides a quick and accurate calculation of regurgitant jet volume （RJV） and fraction. In order to evaluate RT-3D CDFI in the noninvasive assessment of aortic RJV and regurgitant jet fraction （RJF） in patients with isolated aortic regurgitation, real-time three-dimensional echocardiographic studies were performed on 23 patients with isolated aortic regurgitation to obtain LV end-diastolic volumes （LVEDV）, end-systolic volumes （LVESV） and RJV, and then RJF could be calculated. The regurgitant volume （RV） and regurgitant fraction （RF） calculated by two-dimensional pulsed Doppler （2D-PD） method served as reference values. The results showed that aortic RJV measured by the RT-3D CDFI method showed a good correlation with the 2D-PD measurements （r= 0.93, Y=0.89X＋ 3.9, SEE= 8.6 mL, P〈0.001 ）; the mean （SD） difference between the two methods was - 1.5 （9.8） mL. % RJF estimated by the RT-3D CDFI method was also correlated well with the values obtained by the 2D-PD method （r=0.88, Y=0.71X＋ 14.8, SEE= 6.4 %, P〈0. 001）; the mean （SD） difference between the two methods was -1.2 （7.9） %. It was suggested that the newly developed RT-3D CDFI technique was feasible in the majority of patients. In patients with eccentric aortic regurgitation, this new modality provides additional information to that obtained from the two-dimensional examination, which overcomes the inherent limitations of two-dimensional echocardiography by depicting the full extent of the jet trajectory. In addition, the RT-3D CDFI method is quick and accurate in calculating RJV and RJF.

QUANTITATIVE ASSESSMENT OF MYOCARDIAL PERFUSION DEFECTS WITH REAL-TIME THREE-DIMENSIONAL MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY

Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.

Evaluation of Atrial Septal Defect Using Real-time Three-dimensional Echocardiography:Comparison with Surgical Findings

The present study evaluated the application of three dimensional echocardigraphy （3DE） in the diagnosis of atrial septal defect （ASD） and the measurement of its size by 3DE and compared the size with surgical findings. Two-dimensional and real-time three dimensional echocardiography （RT3DE） was performed in 26 patients with atrial septal defect, and the echocardiographic data were compared with the surgical findings. Significant correlation was found between defect diameter by RT3DE and that measured during surgery （r=0.77, P〈0.001）. The defect area changed significantly during cardiac cycle. Percentage change in defect size during cardiac cycle ranged from 6%-70%. Our study showed that the size and morphology of atrial septal defect obtained with RT3DE correlate well with surgical findings. Therefore, RT3DE is a feasible and accurate non-invasive imaging tool for assessment of atrial septal size and dynamic changes.

Dynamic Characteristic Mechanism of Atrial Septal Defect Using Real-Time Three-Dimensional Echocardiography and Evaluation of Right Ventricular Functions

The dynamic characteristics of the area of the atrial septal defect（ASD） were evaluated using the technique of real-time three-dimensional echocardiography（RT 3DE）, the potential factors responsible for the dynamic characteristics of the area of ASD were observed, and the overall and local volume and functions of the patients with ASD were measured. RT 3DE was performed on the 27 normal controls and 28 patients with ASD. Based on the three-dimensional data workstations, the area of ASD was measured at P wave vertex, R wave vertex, T wave starting point, and T wave terminal point and in the T-P section. The right atrial volume in the same time phase of the cardiac cycle and the motion displacement distance of the tricuspid annulus in the corresponding period were measured. The measured value of the area of ASD was analyzed. The changes in the right atrial volume and the motion displacement distance of the tricuspid annulus in the normal control group and the ASD group were compared. The right ventricular ejection fractions in the normal control group and the ASD group were compared using the RT 3DE long-axis eight-plane（LA 8-plane） method. Real-time three-dimensional volume imaging was performed in the normal control group and ASD group（n=30）. The right ventricular inflow tract, outflow tract, cardiac apex muscular trabecula dilatation, end-systolic volume, overall dilatation, end-systolic volume, and appropriate local and overall ejection fractions in both two groups were measured with the four-dimensional right ventricular quantitative analysis method（4D RVQ） and compared. The overall right ventricular volume and the ejection fraction measured by the LA 8-plane method and 4D RVQ were subjected to a related analysis. Dynamic changes occurred to the area of ASD in the cardiac cycle. The rules for dynamic changes in the area of ASD and the rules for changes in the right atrial volume in the cardiac cycle were consistent. The maximum value of the changes in the right atrial volume occurred in the end-systolic period when the peak of the curve appeared. The minimum value of the changes occurred in the end-systolic period and was located at the lowest point of the volume variation curve. The area variation curve for ASD and the motion variation curve for the tricuspid annulus in the cardiac cycle were the same. The displacement of the tricuspid annulus exhibited directionality. The measured values of the area of ASD at P wave vertex, R wave vertex, T wave starting point, T wave terminal point and in the T-P section were properly correlated with the right atrial volume（P〈0.001）. The area of ASD and the motion displacement distance of the tricuspid annulus were negatively correlated（P〈0.05）. The right atrial volumes in the ASD group in the cardiac cycle in various time phases increased significantly as compared with those in the normal control group（P=0.0001）. The motion displacement distance of the tricuspid annulus decreased significantly in the ASD group as compared with that in the normal control group（P=0.043）. The right ventricular ejection fraction in the ASD group was lower than that in the normal control group（P=0.032）. The ejection fraction of the cardiac apex trabecula of the ASD patients was significantly lower than the ejection fractions of the right ventricular outflow tract and inflow tract and overall ejection fraction. The difference was statistically significant（P=0.005）. The right ventricular local and overall dilatation and end-systolic volumes in the ASD group increased significantly as compared with those in the normal control group（P=0.031）. The a RVEF and the overall ejection fraction decreased in the ASD group as compared with those in the normal control group（P=0.0005）. The dynamic changes in the area of ASD and the motion curves for the right atrial volume and tricuspid annulus have the same dynamic characteristics. RT 3DE can be used to accurately evaluate the local and overall volume and functions of the right ventricle. The local and overall volume loads of the right ventricle in the ASD patients increase significantly as compared with those of the normal people. The right ventricular cardiac apex and the overall systolic function decrease.

The Design of a Three-Dimensional Physical Modeling System for Real-Time Groundwater Flows

In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-dimensional groundwater flows,making it impossible to validate groundwater flows simulated by numerical methods with physical modeling.

Evaluation of Biventricular Volume and Systolic Function in Children with Ventricular Septal Defect and Moderate to Severe Pulmonary Hypertension Using Real-Time Three-Dimensional Echocardiography

Background: Real-time three-dimensional echocardiography (RT-3DE) could obtain ventricular volume andejection fraction rapidly and non-invasively without relying on ventricular morphology. This study aims to useRT-3DE to evaluate the changes in biventricular volume and systolic function in children with ventricular septaldefect (VSD) and moderate to severe pulmonary hypertension (PH) before surgery. Methods: In this study18 children with VSD and moderate to severe PH (VSD + PH Group) and 18 healthy children of the sameage (Control Group) were recruited. Biventricular volume and systolic function were evaluated by RT-3DE.The measurements included: left and right ventricular volume indexed to body surface area (BSA), stroke volume(SV) indexed to BSA, and ejection fraction (EF). Results: The results showed left and right ventricular volumeindexed to BSA and SV indexed to BSA were significantly increased in VSD + PH Group (VSD + PH Groupvs. Control Group), LVEDV/BSA (ml/m2): 48.67 ± 21.46 vs. 25.59 ± 6.96, RVEDV/BSA (ml/m2): 55.98 ±15.35 vs. 27.69 ± 4.37, LVSV/BSA (ml/m2): 24.08 ± 9.30 vs. 15.14 ± 4.29, RVSV/BSA (ml/m2): 26.02 ± 8.87 vs.14.11 ± 2.89, (P < 0.05). While for EF in VSD + PH Group decreased (VSD + PH Group vs. Control Group),LVEF: 50.93 ± 7.50% vs. 59.38 ± 7.24%, RVEF: 45.84 ± 7.71% vs. 51.05 ± 6.90% (P < 0.05). Conclusion: Inchildren with VSD and moderate to severe PH, increased biventricular volume and decreased systolic functionwere observed with RT-3DE, but biventricular systolic function remained within acceptable limits. The childrenin this study recovered well after surgery without serious perioperative complications, suggesting that biventricularsystolic function may help facilitate the surgical decision-making process in children with VSD and moderate-toseverePH.

Real-time Three-dimensional Echocardiography in Assessment of Congenital Double Orifice Mitral Valve

The application of real-time three-dimensional echocardiography （RT 3DE） in the diagnosis of double orifice mitral valve （DOMV） was explored. Five cases of DOMV were examined by using 2-dimensional echocardiography （2DE） and RT 3DE. The spatial morphology of malformed mitral valve and its change in hemodynamics were observed. DOMV associated with partial atrioventricular septal defect was found in 3 cases （in which 2 cases had cleft mitral valve） and isolated DOMV in 2 cases; and moderate to severe mitral regurgitation was detected in 3 cases, and mild mitral regurgitation in 1, and no regurgitation in 1 case; 1 case had complicated rhumatic heart disease. Three cases were preoperatively discovered by 2DE, while 2 missed （1 case was discovered postoperatively）. Four cases were diagnosed by RT 3DE preoperatively, and 1 case was diagnosed postoperatively （not examined by RT 3DE preoperatively）. It was suggested that RT 3DE is a reliable technique in the diagnosis of DOMV; it permitted comprehensive and noninvasive assessment of mitral valve and may supplement 2D TTE in the assessment of DOMV.

Preliminary Clinical Study of Real-time Three-dimensional Echo-cardiographic Volume-time Curve in Evaluating Left Ventricular Diastolic Function

The volume-time curve change in patients with normal left ventricular （LV） diastolic function and diastolic dysfunction was evaluated by real-time three-dimensional echocardiography （RT3DE）. LV diastolic dysfunction was defined by E＇〈A＇ in pulse-wave tissue Doppler for inter-ventricular septal （IVS） of mitral annulus. In 24 patients with LV diastolic dysfunction, including 12 patients with delayed relaxation （delayed relaxation group） and 12 patients with pseudo-normal function （pseudo-normal group） and 24 normal volunteers （control group）, data of full-volume image were acquired by real-time three-dimensional echocardiography and subjected to volume-time curve analysis. EDV （end-diastolic volume）, ESV （end-systolic volume）, LVEF （left ventricular ejection fraction）, PER （peak ejection rate）, PFR （peak filling rate） from RT3DE were examined in the three groups. Compared to the control group, PFR （diastolic filling index of RT3DE） was significantly reduced in the delayed relaxation group and pseudo-normal group （P〈0.05）. There were no significant differences in EDV, ESV, LVEE PER （P〉0.05）. It is concluded that PFR, as a diastolic filling index of RT3DE, can reflect the early diastolic function and serve as a new non-invasive, quick and accurate tool for clinical assessment of LV diastolic function.

Correlation analysis of real-time three-dimensional ultrasound in diagnosis of left ventricular function, portal hemodynamics and severity of liver function in patients with liver cirrhosis

Objective:To analyze the correlation between real-time three-dimensional ultrasound in diagnosis of left ventricular function, portal hemodynamics and severity of liver function in patients with liver cirrhosis.Methods: 90 patients with cirrhosis admitted to our hospital from January 2017 to December 2018 were enrolled in the cirrhosis group, and the cirrhosis components were group A, B and C according to the Child-Pauh classification criteria. During the same period, 90 healthy subjects who underwent physical examination were selected as the control group;real-time three-dimensional ultrasonography was performed to examine left ventricular function and portal hemodynamic parameters;Pearson correlation was used to analyze left ventricular function, portal hemodynamics and liver. Functional severity relationship.Results: The left heart E and E/A levels in the cirrhosis group were significantly lower than those in the control group (P<0.05), and the A level was significantly higher than the control group (P<0.05). The Dpv and Q levels in the cirrhosis group were significantly higher than those in the healthy control group. The difference was statistically significant (P<0.05), and the level of Vpv was significantly lower than that of healthy controls (P<0.05). There were significant differences in E, A and E/A levels between different Child-Paugh patients (P<0.05). There were significant differences in portal hemodynamics Dpv, Vpv and Q between the different Child-Paugh grades, and the difference was statistically significant (P<0.05);left heart function E and E/A and liver function severity There was a significant negative correlation (P<0.05). There was a significant positive correlation between left cardiac function A and liver function severity (P<0.05). Portal vein hemodynamics Dpv, Vpv and QE were significantly associated with liver function severity. Positive correlation (P<0.05). Conclusion: Real-time three-dimensional ultrasound can effectively detect left ventricular function and portal hemodynamics changes in patients with cirrhosis, and left heart function, portal hemodynamics and liver function severity are significantly correlated.

Assessment of left ventricular systolic synchronicity by real-time three-dimensional echocardiography in patients with dilated cardiomyopathy

Background Recent advances in real-time three-dimensional echocardiography （RT3DE） offer the potential to assess the left ventricular （LV） dyssynchrony simultaneously by analyzing the 17 segments time-volume curves. The purpose of this study was to test the feasibility and accuracy of RT3DE for quantitative evaluation of left ventricular systolic synchronicity. Methods Twenty-four patients with dilated cardiomyopathy （DCM） and twenty-ftve healthy volunteers were enrolled in this study. Full volume RT3DE was performed by using Philips IE33 with X3-1 probe. The global and 17-segmental time-volume curves were obtained by the on-line Qlab software （version 4.2）. The time to minimal systolic volume in each segment （Tmsv） was taken to derive the following indexes of systolic asynchrony： Tmsv 16-SD, Tmsv 16-Dif, Tmsv 12-SD, Tmsv 12-Dif, Tmsv 6-SD and Tmsv 6-Dif, which meant the standard deviation or the maximal difference of Tmsv among the 16, 12 and 6 segments of the left ventricle respectively. The software also provided with each of the above parameters as a percentage of the cardiac cycle. Results Tmsv 16-SD, Tmsv 12-SD and Tmsv 6-SD were all significantly larger in the DCM group than those of the control group [Tmsv 16-SD： （52.9±40.6） ms vs （8.8±6.2） ms; Tmsv 12-SD： （29.5＋30.8） ms vs （6.9±4.0） ms; Tmsv 6-SD： （28.9±34.6） ms vs （7.0±4.7）ms, all P≤0.001]. Tmsv 16-Dif, Tmsv 12-Dif and Tmsv 6-Dif were also significantly larger in the DCM group. There were close negative relations between the LVEF determined by RT3DE and each of the indexes of systolic asynchrony, among which the indexes of Tmsv-16-SD% and Tmsv-16-Dif% correlated most closely （r=-0.703 and r=-0.701, respectively）. The DCM patients had significantly larger EDV and ESV, with significantly reduced LVEF compared with the healthy subjects. Conclusion RT3DE provides a simple, useful and unique approach to assess the systolic synchronicity of all the left ventricular segments simultaneously.

Assessment of the morphology and mechanical function of the left atrial appendage by real-time three-dimensional transesophageal echocardiography

Background The left atrial appendage （LAA） is an important source of thrombus formation. We investigated the feasibility of the recently developed real-time three-dimensional transesophageal echocardiography （RT3D-TEE） method in assessment of the morphology and function of the LAA. Methods Ninety-six consecutive patients （58 males with a mean age of （43.4±12.5） years） who were referred for 2-dimensional （2D） transesophageal echocardiography （TEE） underwent additional RT3D-TEE. LAA morphology was visualized in multiple views. Orifice size, depth, volumes and ejection fraction （EF） of the LAA, were measured. Results All the patients underwent RT3D-TEE examination without complications. Ninety-two patients （95.8%） had adequate images for visualization and quantitative analysis of the LAA. The LAA exhibited great variability with respect to relative dimensions and morphology. LAA orifice area was （3.8±1.2） cm^2 with a diameter of （2.4±0.9） cm x （1.4±0.6） cm. The mean depth of the LAA was （2.9±0.7） cm. End-diastolic volume （EDV-LAA）, end-systolic volume （ESV-LAA） and EF of the LAA were （6.2±3.7） ml, （4.1±2.8） ml, and 0.35±0.16, respectively. EDV-LAA, ESV-LAA and the orifice area of the LAA in patients with atrial fibrillation （AF） were larger than those without AF, whereas the EF was smaller in the AF patients. Conclusions Defining LAA morphology and quantitative analysis of the size and function of the LAA with superior quality and resolution of images using RT3D-TEE is feasible. This technique may be an ideal tool for guidance of the LAA occlusion procedure. Determination of LAA volumes and volume-derived EF by RT3D-TEE provides new insights into the analysis of LAA function.

Methodological study on real-time three-dimensional echo-cardiography and its application in the diagnosis of complex congenital heart disease

Background Real-time three-dimensional echocardiography （RT-3DE） has made revolutionized improvements of cardiac imaging during the past few years. However, there is no standard examination method for RT-3DE so far. This study aimed to establish the diagnostic method of RT-3DE and evaluate its application in the diagnosis of complex congenital heart diseases （CHD）. Methods Fifty patients with complex CHD were examined by RT-3DE with modes of Live 3DE and Full Volume. A series of novel volumetric views combined with Van Praagh sequential segmental approach were introduced to reveal the pathological morphology of the hearts, which were compared with the findings of two-dimensional echocardiography （2DE）, angiography and cardiac surgery. Results In 50 patients, 190 image acquisitions of Full Volume were performed at several acoustic windows including subcostal, apical and parasternal regions. Among them, 94.2% （179/190） of image acquisitions were successful. Most sectional volumetric views could be clearly displayed in 92.6% of the successful image acquisitions. However, sectional volumetric views could not be clearly displayed in 7.4%, which was mainly due to poor perspective conditions of examination location, improper instrument multi-parameter setting and insufficient information of whole heart captured in Full Volume acquisitions. As compared with surgical findings and angiography, RT-3DE made correction to the diagnoses in 2 cases including 1 with corrected transposition of the great arteries and the other with single atrium and mitral cleft. The diagnoses initially made by 2DE for these 2 patients were double outlet right ventricle with transposition of the great arteries and complete atrio-ventricular septal defect. Conclusions RT-3DE can clearly display the pathological morphology of complex CHD by a series of novel volumetric views combined with sequential segmental approach through providing more spatial informative cardiovascular structures, which provides a practical method for RT-3DE diagnosis.

Validation of real-time three-dimensional echocardiography for quantifying left and right ventricular volumes:an experimental study

Background Assessment of the left ventricular (LV) and the right ventricular (RV) volumes and their functions is important for prognostic prediction and clinical decision making. We compared the accuracy for quantifying the LV and the RV volumes in vitro between conventional two-dimensional echocardiography (2DE) and real-time three-dimensional echocardiography (RT3DE) Methods The volumes of 37 rubber-models (10 regularly shaped to simulate normal LV, 7 shaped to simulate LV with symmetric aneurysm, 8 shaped to simulate LV with asymmetric aneurysm, and 12 irregularly shaped to simulate normal RV) and 10 excised canine hearts were measured by RT3DE and 2DE On RT3DE 'full volume' imaging, the inner-surfaces of the rubber-models and canine LV and RV were outlined and the volumes were measured using 2-, 4-, 8- and 16-plane methods with the RT3DE analysis software On 2DE imaging, the volumes were measured by the Simpson method The LV and RV volumes measured by drained water were served as reference values, with which we compared RT3DE and 2DE data Results In rubber models mimicking normal LV and LV with symmetric aneurysms, RT3DE results were strongly correlated with reference values ( r =0 795-0 998) and there was a good correlation between 2DE estimates and reference values ( r =0 715-0 729) There were no significant differences between RT3DE estimates, 2DE results and reference values ( P >0 05) In rubber models mimicking the RV and LV with asymmetric aneurysm, RT3DE strongly correlated with reference values ( r =0 765-0 988), but 2DE weakly correlated with reference values ( r =0 518-0 592) There were no differences between RT3DE and reference values ( P >0 05), but a significant difference between 2DE and reference values occurred ( P <0 05) For excised canine hearts, there was a strong correlation between RT3DE and reference values ( r =0 728-0 914), while 2DE showed a less obvious correlation ( r =0 502-0 615) Again, there were no significant differences between RT3DE and reference values ( P >0 05), but there was a significant difference between 2DE and reference values ( P <0 05) Conclusions RT3DE can accurately quantify LV and RV volumes and provides a new tool to evaluate LV and RV function For LV and RV measurements by RT3DE, 8-plane strategy is the optimum choice for accuracy and convenience

Real-time three-dimensional myocardial contrast echocardiography in assessment of myocardial perfusion defects

Background Both real-time three-dimensional echocardi ography (RT3DE) and myocardial contrast echocardiography (MCE) are novel imaging techniques. The purpose of this study was to confirm the feasibility and accuracy of RT3DE combined with MCE for quantitative evaluation of myocardial perfusion defects. Methods Thirteen dogs underwent ligation of the left anterior descending artery (LAD, n=6) or distal branch of the left circumflex artery (LCX, n=7) under general anaesthesia. Three to four ml of a perfluoropropane (C 3F 8) microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with a commercially available Philips SONOS-7500 ultrasound system. After removal of the dog hearts, Evans blue dye was injected via the left and righ t coronary arteries to stain the myocardium at risk. In vitro anatomic measurements of myocardial mass after removal of the animals’ hearts were used as control s. Results Left ventricular (LV) mass determined by RT3DE ranged 36.7-68.9 g [mean, (54.6±9.6) g] before coronary artery ligation, and correlated highly (r=0.99) with in vitro measurement of LV mass [range, 38.9-71.1 g; mean, (55.6±9.3) g]. There was no significant difference between RT3DE and in vitro measurements of LV mass [range, 36.7-68.9 g; mean, (51.3±12.5) g. Or range, 38.9-71. 1 g; mean, (53.7±12.3) g, respectively] and under-perfused mass [range, 0-21.4 g; mean, (12.0±6.9) g. Or range, 0-19.8 g; mean, (10.8±6.3) g, respectively] after th e LAD ligation (P>0.05). Likewise, no significant difference was present between RT3DE and in vitro measurements of LV mass [range, 50.1-65.4 g; mean, (57.5±5.9 ) g. Or range, 51.5-65.8 g; mean, (57.3±6.4) g, respectively] and under-perfused m ass [range, 0-25.6 g; mean, (13.3±9.6) g. Or range, 0-22.7 g; mean, (12.8±8.1 ) g, respectively] after the LCX ligation (P>0.05). For all the animals with coronary ligation, LV mass measured by RT3DE ranged 35.9-68.6 g [mean, (54.8±10.0) g] a nd there was no significant difference between RT3DE and in vitro measurements of LV mass and under-perfused mass (P>0.05, r=0.99). Further, the under-perfused mass derived from RT3DE [range, 0-25.6 g; mean, (12.7±8.2) g] correlate d strongly with the in vitro measurements [range, 0-22.7 g; mean, (11.9±7.2) g] ( r=0.96). Conclusion RT3DE with MCE is a rapid and accurate method for estimating LV myocardial mass and quantifying perfusion defects.

Left atrial minimum volume by real-time three-dimensional echocardiography as an indicator of diastolic dysfunction

Background Left atrial （LA） maximum volume is becoming a prognostic biomarker for left ventricular （LV） diastolic dysfunction. However, we assessed LV diastolic function by measuring LA phasic volumes using real-time threedimensional echocardiography （RT3DE） in patients with stable coronary artery disease （CAD）. Methods Sixty-five stable CAD patients with normal LV ejection fraction （LVEF） were divided into three groups according to degree of coronary stenosis： control （n=15） with 〈50% stenosis as control group, mildS （n=25） with mild stenosis （50%- 70%） and severeS （n=25） with 〉70% stenosis. LA phasic volumes and function were evaluated and compared using RT3DE and two dimensional echocardiography （2DE）. N-terminal pro-B-type natriuretic peptide （NT-proBNP） levels were examined. The correlations of RT3DE-derived parameters with other conventional indices were analyzed. Results Significant correlations between RT3DE and 2DE for LA volume measurements were： control, r=0.93; mildS, 1=0.94; severeS, r=0.90 （all P 〈0.05）. Patients with severe coronary stenosis presented higher NT-proBNP level, indices of LA minimum volume and volume before atrial contraction, but lower LA total emptying fraction （LAEF） and LAEFpass^ve. Significant correlations of RT3DE derived LA volume indices with E/E＇ （r=0.695） and NF-proBNP （r=0.630） level were found. Conclusions RT3DE derived, LA indices correlate well with NT-proBNP level and may be superior to 2DE measurements for the evaluation of LV diastolic dysfunction. Enlargement of LA minimum volume in stable CAD patients without systolic dysfunction appears earlier and may be better correlated with LV diastolic function than that of LA maximum volume.