End-diastolic Phase Research Articles

Quantification of Mouse Heart Left Ventricular Function, Myocardial Strain, and Hemodynamic Forces by Cardiovascular Magnetic Resonance Imaging.

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations result in pathology, and how myocardial diseases may be treated. Cardiovascular magnetic resonance imaging (CMR) has become an indispensable tool for a comprehensive in vivo assessment of cardiac anatomy and function. This protocol shows detailed measurements of mouse heart left ventricular function, myocardial strain, and hemodynamic forces using 7-Tesla CMR. First, animal preparation and positioning in the scanner are demonstrated. Survey scans are performed for planning imaging slices in various short- and long-axis views. A series of prospective ECG-triggered short-axis (SA) movies (or CINE images) are acquired covering the heart from apex to base, capturing end-systolic and end-diastolic phases. Subsequently, single-slice, retrospectively gated CINE images are acquired in a midventricular SA view, and in 2-, 3-, and 4-chamber views, to be reconstructed into high-temporal resolution CINE images using custom-built and open-source software. CINE images are subsequently analyzed using dedicated CMR image analysis software. Delineating endomyocardial and epicardial borders in SA end-systolic and end-diastolic CINE images allows for the calculation of end-systolic and end-diastolic volumes, ejection fraction, and cardiac output. The midventricular SA CINE images are delineated for all cardiac time frames to extract a detailed volume-time curve. Its time derivative allows for the calculation of the diastolic function as the ratio of the early filling and atrial contraction waves. Finally, left ventricular endocardial walls in the 2-, 3-, and 4-chamber views are delineated using feature-tracking, from which longitudinal myocardial strain parameters and left ventricular hemodynamic forces are calculated. In conclusion, this protocol provides detailed in vivo quantification of the mouse cardiac parameters, which can be used to study temporal alterations in cardiac function in various mouse models of heart disease.

ACTIVE CONTOUR MODELS-BASED SEGMENTATION OF LEFT VENTRICLE IN ULTRASOUND IMAGES FOR DIFFERENT AXES VIEWS

Segmentation of the left ventricle in ultrasound images for viewing through different axes is a critical aspect. This paper proposes the development of novel active contour models with shape constraint to segment the left ventricle in three different axis views of the ultrasound images. The shapes observed in all the axis views of the left ventricle were not similar. According to the cardiac cycle, the valve opening in the end-diastolic phase influenced the left ventricle segmentation; hence, a shape constraint was embedded in the active contour model to keep ventricle’s shape, especially in the Apical long-axis view and Apical four-chamber view. Furthermore, for different axes views, diverse active contour models were proposed to fit each situation. The shape constraint in each function for different views exhibited a specific shape during the function iteration. In order to speed up the algorithm evolution, previous results were used for the initialization of the present active contour. We evaluated the proposed method on 57 patients with three different views: Apical long-axis view, Apical four-chamber view and Short-axis view at the papillary muscle level and obtained the Dice similarity coefficients of [Formula: see text], [Formula: see text] and [Formula: see text] and the Hausdorff distance metrics of [Formula: see text], [Formula: see text] and [Formula: see text], respectively. The qualitative and quantitative evaluations showed an advantage of our method in terms of segmentation accuracy.

Hyperparameter optimisation and validation of registration algorithms for measuring regional ventricular deformation using retrospective gated computed tomography images

Recent dose reduction techniques have made retrospective computed tomography (CT) scans more applicable and extracting myocardial function from cardiac computed tomography (CCT) images feasible. However, hyperparameters of generic image intensity-based registration techniques, which are used for tracking motion, have not been systematically optimised for this modality. There is limited work on their validation for measuring regional strains from retrospective gated CCT images and open-source software for motion analysis is not widely available. We calculated strain using our open-source platform by applying an image registration warping field to a triangulated mesh of the left ventricular endocardium. We optimised hyperparameters of two registration methods to track the wall motion. Both methods required a single semi-automated segmentation of the left ventricle cavity at end-diastolic phase. The motion was characterised by the circumferential and longitudinal strains, as well as local area change throughout the cardiac cycle from a dataset of 24 patients. The derived motion was validated against manually annotated anatomical landmarks and the calculation of strains were verified using idealised problems. Optimising hyperparameters of registration methods allowed tracking of anatomical measurements with a mean error of 6.63% across frames, landmarks, and patients, comparable to an intra-observer error of 7.98%. Both registration methods differentiated between normal and dyssynchronous contraction patterns based on circumferential strain (p_1=0.0065, p_2=0.0011). To test whether a typical 10 temporal frames sampling of retrospective gated CCT datasets affects measuring cardiac mechanics, we compared motion tracking results from 10 and 20 frames datasets and found a maximum error of 8.51pm 0.8%. Our findings show that intensity-based registration techniques with optimal hyperparameters are able to accurately measure regional strains from CCT in a very short amount of time. Furthermore, sufficient sensitivity can be achieved to identify heart failure patients and left ventricle mechanics can be quantified with 10 reconstructed temporal frames. Our open-source platform will support increased use of CCT for quantifying cardiac mechanics.

Cardiovascular magnetic resonance detects microvascular dysfunction in a mouse model of hypertrophic cardiomyopathy

BackgroundHypertrophic cardiomyopathy (HCM) related myocardial vascular remodelling may lead to the reduction of myocardial blood supply and a subsequent progressive loss of cardiac function. This process has been difficult to observe and thus their connection remains unclear. Here we used non-invasive myocardial blood flow sensitive CMR to show an impairment of resting myocardial perfusion in a mouse model of naturally occurring HCM.MethodsWe used a mouse model (DBA/2 J; D2 mouse strain) that spontaneously carries variants in the two most susceptible HCM genes—Mybpc3 and Myh7 and bears the key features of human HCM. The C57BL/6 J (B6) was used as a reference strain. Mice with either B6 or D2 backgrounds (male: n = 4, female: n = 4) underwent cine-CMR for functional assessment at 9.4 T. Left ventricular (LV) wall thickness was measured in end diastolic phase by cine-CMR. Quantitative myocardial perfusion maps (male: n = 5, female: n = 5 in each group) were acquired from arterial spin labelling (cine ASL-CMR) at rest. Myocardial perfusion values were measured by delineating different regions of interest based on the LV segmentation model in the mid ventricle of the LV myocardium. Directly after the CMR, the mouse hearts were removed for histological assessments to confirm the incidence of myocardial interstitial fibrosis (n = 8 in each group) and small vessel remodelling such as vessel density (n = 6 in each group) and perivascular fibrosis (n = 8 in each group).ResultsLV hypertrophy was more pronounced in D2 than in B6 mice (male: D2 LV wall thickness = 1.3 ± 0.1 mm vs B6 LV wall thickness = 1.0 ± 0.0 mm, p < 0.001; female: D2 LV wall thickness = 1.0 ± 0.1 mm vs B6 LV wall thickness = 0.8 ± 0.1 mm, p < 0.01). The resting global myocardial perfusion (myocardial blood flow; MBF) was lower in D2 than in B6 mice (end-diastole: D2 MBFglobal = 7.5 ± 0.6 vs B6 MBFglobal = 9.3 ± 1.6 ml/g/min, p < 0.05; end-systole: D2 MBFglobal = 6.6 ± 0.8 vs B6 MBFglobal = 8.2 ± 2.6 ml/g/min, p < 0.01). This myocardial microvascular dysfunction was observed and associated with a reduction in regional MBF, mainly in the interventricular septal and inferior areas of the myocardium. Immunofluorescence revealed a lower number of vessel densities in D2 than in B6 (D2 capillary = 31.0 ± 3.8% vs B6 capillary = 40.7 ± 4.6%, p < 0.05). Myocardial collagen volume fraction (CVF) was significantly higher in D2 LV versus B6 LV mice (D2 CVF = 3.7 ± 1.4% vs B6 CVF = 1.7 ± 0.7%, p < 0.01). Furthermore, a higher ratio of perivascular fibrosis (PFR) was found in D2 than in B6 mice (D2 PFR = 2.3 ± 1.0%, B6 PFR = 0.8 ± 0.4%, p < 0.01).ConclusionsOur work describes an imaging marker using cine ASL-CMR with a potential to monitor vascular and myocardial remodelling in HCM.

Experimental and numerical investigation of pulsed flows in asevere aortic stenosed model

Steady and pulsatile aortic stenotic flows through stenosis tubes were experimentally and numerically investigated. The objective was the understanding of the fluid dynamics in arterial geometries most relevant in the context of atherosclerosis. Axisymmetric phantoms corresponding to significant artery stenosis of 50% in diameter and severe aortic stenosis of 75% were respectively machined from silicon. A water flow circuit was established, a steady flow was provided by gravity and a pulsed flow by a pulsatile pump. At inlet Reynolds numbers in the range of 85 to 1125, flows at the stenosis region were investigated using two-component Particle Image Velocimetry (PIV). For the unsteady flow, three different heartbeats (60, 69 and 90 beats per minute) were considered. The k-ω shear-stress-transport first-order turbulence model in Computational Fluid Dynamics (CFD) commercial software was adopted for simulations. Experimental measurements of the velocity fields show good agreements with CFD for both steady and pulsed flows. Recirculation regions were found near the stenosis in both cases. Reverse flow through the stenosis was also observed in pulsatile flow during the end diastolic phase of the cycle. CFD simulations allowed us to accurately assess wall shear stress in the stenotic region where the optical measurements are very noisy. High values of wall shear stress (with high variations both in space and time), are observed, which are indicators of possible future aortic wall damage.

Application of a machine learning contouring tool for the evaluation of left ventricular strain in clinical practice

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): AK has been funded by the Egyptian cultural centre and educational bureau of the Egyptian embassy in London and the Ministry of higher education in Egypt. SEP acknowledges support from the “SmartHeart” EPSRC programme grant (www.nihr.ac.uk; EP/P001009/1) and the London Medical Imaging and AI Centre for Value-Based Healthcare. This new centre is one of the UK Centres supported by a £50m investment from the Data to Early Diagnosis and Precision Medicine strand of the government’s Industrial Strategy Challenge Fund, managed and delivered by UK Research and Innovation (UKRI). SEP acknowledges support from the CAP-AI programme, London’s first AI enabling programme focused on stimulating growth in the capital’s AI Sector. CAP-AI is led by Capital Enterprise in partnership with Barts Health NHS Trust and Digital Catapult and is funded by the European Regional Development Fund and Barts Charity. SEP also acts as a paid consultant to Circle Cardiovascular Imaging Inc., Calgary, Canada and Servier onbehalf Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, West Smithfield, London, UK Background Manual contouring of cardiovascular magnetic resonance (CMR) cine images remains common practice and the reference standard for left ventricular (LV) volumes and mass evaluation. However, it is time-consuming and machine learning (ML) may significantly reduce the time required for contouring. Accurate LV contours are the basis for reliable LV strain analysis using tissue tracking. Purpose To assess the impact of a ML contouring tool alone versus expert adjusted contours on LV strain. Methods We retrospectively selected 402 CMR studies with diagnoses of myocardial infarction (n = 108), myocarditis (n = 130) and healthy controls (n = 164) from the Barts BioResource between January 2015 to June 2018. CMR examinations were obtained using 1.5T and 3T scanners (Siemens Healthineers, Germany). We excluded 32 cases due to phase inconsistency between short (SAX) and long axes (LAX) cine images or suboptimal cine image quality. For the remaining 370 cases, steady state free precession cine images for LAX and SAX were analysed by the ML contouring tool (using CVI42 research prototype software 5.11). Manual expert adjustment for the contours was done for each case if considered suboptimal for strain analysis in the reference end-diastolic phase. Strain results from ML and expert adjusted ML methods were compared for strain agreement. Times taken by these methods were recorded and compared against the time taken for standard manual contouring. Results SAX and LAX derived strains by ML and expert adjusted ML methods showed good agreement by Bland-Altman analysis (Figure 1) with excellent coefficient of concordance using Kendall W which is 0.98 for global SAX, radial and circumferential strains (mean difference(MD) = -1.7% (lower and upper limits of agreement (UL,LL) -6.6,3.2), MD = 0.5% (-1.0,2.1)) and is 0.95 for global LAX derived strain (radial and longitudinal, MD = 0.7% (UL,LL -8.7 ,7.4),MD= 0.2% (-1.9,2.5), respectively). Time taken for adjustment of ML contours was significantly shorter than manual contouring (1.35 minutes vs 8.0 minutes, around 590% time saving in ML adjusted method). Conclusions ML contouring compared to expert manual adjustment has a clinically reasonable agreement when used for measuring LV strain. Also, using the ML tool with expert adjustment shows significant time saving for analysis and reporting time compared to entirely manual analysis, favouring its application in routine clinical practice. Abstract Figure.

Novel Resectable Myocardial Model Using Hybrid Three-Dimensional Printing and Silicone Molding for Mock Myectomy for Apical Hypertrophic Cardiomyopathy

ObjectiveWe implemented a novel resectable myocardial model for mock myectomy using a hybrid method of three-dimensional (3D) printing and silicone molding for patients with apical hypertrophic cardiomyopathy (ApHCM).Materials and MethodsFrom January 2019 through May 2020, 3D models from three patients with ApHCM were generated using the end-diastolic cardiac CT phase image. After computer-aided designing of measures to prevent structural deformation during silicone injection into molding, 3D printing was performed to reproduce anatomic details and molds for the left ventricular (LV) myocardial mass. We compared the myocardial thickness of each cardiac segment and the LV myocardial mass and cavity volumes between the myocardial model images and cardiac CT images. The surgeon performed mock surgery, and we compared the volume and weight of the resected silicone and myocardium.ResultsDuring the mock surgery, the surgeon could determine an ideal site for the incision and the optimal extent of myocardial resection. The mean differences in the measured myocardial thickness of the model (0.3, 1.0, 6.9, and 7.3 mm in the basal, midventricular, apical segments, and apex, respectively) and volume of the LV myocardial mass and chamber (36.9 mL and 14.8 mL, 2.9 mL and −9.4 mL, and 6.0 mL and −3.0 mL in basal, mid-ventricular and apical segments, respectively) were consistent with cardiac CT. The volume and weight of the resected silicone were similar to those of the resected myocardium (6 mL [6.2 g] of silicone and 5 mL [5.3 g] of the myocardium in patient 2; 12 mL [12.5 g] of silicone and 11.2 mL [11.8 g] of the myocardium in patient 3).ConclusionOur 3D model created using hybrid 3D printing and silicone molding may be useful for determining the extent of surgery and planning surgery guided by a rehearsal platform for ApHCM.

Dosimetric impact from cardiac motion to heart substructures in thoracic cancer patients treated with a magnetic resonance guided radiotherapy system.

Few studies have examined the cardiac volume and radiation dose differences among cardiac phases during radiation therapy (RT). Such information is crucial to dose reconstruction and understanding of RT related cardiac toxicity. In a cohort of nine patients, we studied the changes in the volume and doses of several cardiac substructures between the end-diastolic and end-systolic phases based on the clinical magnetic resonance-guided RT (MRgRT) treatment plans. Significant differences in the volume and dose between the two phases were observed. Onboard cardiac cine MRI holds promise for patient-specific cardiac sparing treatment designs.

Vein of Marshall visualization in cardiac computed tomography

Abstract The oblique vein of the left atrium (vein of Marshall) is a small vessel that descends obliquely on the back of the left atrium and ends in the coronary sinus near the area where great cardiac vein continues into the coronary sinus. Its cannulation can be useful, e.g. before selected electrophysiology procedures such as paroxysmal focal atrial fibrillation ablation. Because the vein of Marshall should also be avoided at the site of the implantation of the left ventricle lead, knowledge about its existence, position or diameters could be useful. There is a lack of complex data about the possibilities of visualizing the vein of Marshall in cardiac computed tomography. Methods 354 patients were included into the research. Cardiac computed tomography (Aquilion 64, Toshiba: 64 slices, 0.5 mm; retrospective gating; contrast enhanced) was performed for all of the patients. A precise retrospective analysis of the CT data in all phases (every 10%) of the cardiac cycle during post processing was performed including searching for the target vein by using Vitrea workstations (Vital Images). Both multi planar reformatted reconstructions (MPR) and 3D volume renderings were used. The analyses were performed by two experienced researchers (more than 200 coronary venous system analyses previously performed). Results The vein of Marshall was found in 66 of the 354 patients (16.6%). An example of the visualization is presented in the figure below (MPR and 3D volume rendering). Its ostium to coronary sinus was found an average of 42.6±10.8 mm from the coronary sinus ostium to the right atrium. This value was statistically higher (p=0.0082) in the men (45.3±11.2) compared to the women (38.5±9.7). The vein of Marshall is a small vessel; its average diameter was 1.8±0.8 mm and length of the visible vessel that was measured was 8.7±7.5 mm. It was visualized statistically more frequently (p=0.0009) in the end-systolic phases (30–40–50% RR; 68.85% cases) compared to the end-diastolic phases (70–80% RR; 21.31% cases). Occasionally, it was optimally visualized in the other phases (9.83%). Conclusion It is possible to visualize the vein of Marshall using cardiac computed tomography. Because it exists in about 20% of population, during visualization, special attention needs to paid to obtaining quality images in CT especially in the end-systolic phases. Vein of Marshall imaging (VR, MPR) Funding Acknowledgement Type of funding source: None

Feasibility of evaluating the left ventricular function in patients with cardiovascular diseases by fully automatic quantified three-dimensional transthoracic echocardiography

Objective: To investigate the clinical value of left ventricular function assessment in patients with cardiovascular disease by fully automatic quantified three-dimensional transthoracic echocardiography. Methods: One hundred and ninety-seven patients with cardiac diseases were examined by three-dimensional transthoracic echocardiography from September 2017 to May 2019. Data from 61 patients with grade 1 echocardiographic image quality were used to determine the default boundary values of endocardial end-diastolic and end-systolic phases. Clinical features were analyzed based on electronic medical records. The accuracy and repeatability of this strategy was evaluated by comparing left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) measured by automated quantitative three-dimensional echocardiography and those measured by conventional manual transthoracic echocardiography, the latter served as gold standard. Results: The levels of LVEDV, LVESV and LVEF measured by automatic three-dimensional echocardiography were positively correlated with values obtained by manual measurement（r=0.97，0.97, 0.98, 0.97, 0.97, 0.96；P<0.05). The levels of LVEDV and LVESV measured by full-automatic three-dimensional echocardiography were significantly higher than those obtained by manual three-dimensional echocardiography（all P<0.05）. The classification and correlation of systolic dysfunction in patients with abnormal ventricular wall motion by automatic three-dimensional echocardiography were significantly improved after manual calibration (κ=0.74, P=0.00) as compared to without manual calibration (κ=0.63, P=0.00). The inter-observer and intra-observer variability of fully automated three-dimensional echocardiography were significantly smaller than manual three-dimensional echocardiography（both P<0.05）. Conclusion: Fully automatic quantified three-dimensional transthoracic echocardiography possesses excellent accuracy and repeatability in measuring left ventricular volume and function， and it is feasible for clinical application.

P0201ASSOCIATION OF INTRARENAL VEIN FLOW PATTERNS WITH CARDIAC FUNCTION IN OUTPATIENTS WITH CHRONIC KIDNEY DISEASE AND HEART FAILURE

Abstract Background and Aims In patients with chronic kidney disease (CKD) and heart failure (HF), renal venous congestion plays a key role in determining renal dysfunction and a worse prognosis. Αim of this ongoing study is to identify Doppler intrarenal venous flow patterns reflecting renal congestion in patients with CKD and HF and to detect possible associations with cardiac function parameters. Prognostic implications will be evaluated at a next stge. Method We prospectively enroll outpatients affected by CKD stages 3-4 and HF, in stable clinical conditions and in conventional therapy. All patients undergo clinical evaluation, routine biochemistry, transthoracic echocardiogram and renal echo-Doppler. Pulsed Doppler flow recording is performed at the level of the right interlobular renal veins at the end-expiratory phase. The intrarenal venous flow patterns are divided into five types according to the waveforms of the flow. Type A and B are characterized by a continuous flow and considered normal waveforms. Type C is characterized by a short interruption and/or reversal flow during the end-diastolic or protosystolic phase. Type D and E are characterized by a wide interruption and/or reversal flow, respectively. Types C, D and E are considered abnormal and reflect increasing venous pressure within the kidneys. Results Until now, 36 patients (27males / 9 females), 13 (36%) diabetics, aged 69.4±10.6 years old, have been included, and baseline characteristics are presented. Twenty patients (55%) have CKD stage 3, and 16 patients CKD stage 4 (45%). Fifteen (40%) of these patients have HF New York Heart Association (ΝΥΗA) class II, 18 (50%) ΝΥΗΑ class ΙΙΙ and 3 (10%) ΝΥΗΑ class IV. Mean ejection fraction (EF) is 34.5±7.8%, moderately reduced in 9 (25%) and severely reduced in 27 (75%) of these patients. By analyzing the waveforms, we noticed that 27 patients (75%) had venous patterns of continuous flow (type A 18% and type B 57%) and 9 (25%) had venous patterns with not continuous flows (21% type C and 4% type D). The patients with renal venous patterns A and B had higher EF than those with renal venous patterns C and D (36±8% vs. 30±5%, p=0.045). We have also observed that worsening HF according to NYHA classification was significantly associated to more pathological renal venous patterns (rho=0.402, p=0.034) Conclusion In patients with CKD and HF we may observe abnormal intrarenal vein flow patterns, in the context of renal congestion, related to the functional state of the heart. Further studies will indicate the clinical and prognostic significance of these measurements to better characterize patients with cardio-renal syndrome.

Abstract P432: Racial Differences In Endothelial Function And Insulin Sensitivity

Racial disparities in health outcomes continue to be a significant public health concern and African Americans (AA) are disproportionately burdened by several risk factors for cardiovascular disease. Endothelial dysfunction has been shown to be a predictor of CVD and metabolic factors, including insulin resistance, are associated with endothelial dysfunction. Compared to EA, AA have impaired endothelial function and are more insulin resistant (less insulin sensitive). However, it remains unclear how insulin resistance may contribute to endothelial dysfunction in AA and EA. The purpose of the present study was to evaluate the relationship between insulin sensitivity and endothelial function in AA and EA. It was hypothesized that insulin sensitivity would be associated with endothelial function in both AA and EA. Skeletal muscle insulin sensitivity was measured by hyperinsulinemic-euglycemic glucose clamp technique in 112 lean, overweight, and obese AA and EA adults without diabetes. Insulin was infused at 120 mU/m 2 /min for 3 hours and an infusion of 20% dextrose was adjusted to maintain blood glucose at the fasting level. Insulin sensitivity (10 -4 .dL.kg -1 .min -1 /(μU/mL)) was defined as M/(G x ΔI), where M is steady state glucose infusion rate, G is steady state serum glucose concentration, and ΔI is the difference between basal and steady state serum insulin concentrations. M was adjusted for total lean body mass which was measured by dual-energy X-ray absorptiometry (DXA). Endothelial function was assessed by percent change in flow-mediated brachial artery dilatation (FMD). Changes in brachial artery diameter during reactive hyperemia were measured using ultrasound. Increased blood flow was induced via blood pressure cuff around the forearm, with a 5-minute inflation at 50 mmHg above the subject’s systolic blood pressure. Brachial arterial flow was determined using a pulsed-Doppler signal at baseline and 10-15 seconds after cuff release. Arterial diameter was measured at end-diastolic phase from super-VHS recordings. For reactive hyperemia response, measurements with the 5 largest diameters were averaged and the percent increase from baseline was determined as FMD. A total of 55 AA and 57 EA were included in the analysis. Mean insulin sensitivity was 4.89 in AA and 7.97 in EA (p &lt; .0001) and mean FMD was 10.69 in AA and 10.14 in EA (p = .595). Linear regression analysis indicated a significant relationship between insulin sensitivity and endothelial function in AA but not in EA (p= .005 and p= .5, respectively). These results suggest that insulin sensitivity may play a role in determining endothelial function in AA.

Study of novel deformable image registration in myocardial perfusion single-photon emission computed tomography.

In the present study, deformable image registration (DIR) technology was applied to gated myocardial perfusion single-photon emission computed tomography (G-MPS) reconstructed images in distorting all image phases. We aimed to define a new method of end-diastole compatible image registration and verify the clinical usability for any cardiac volume. Projection images were created using the Monte Carlo simulation. All image phases were shifted to fit the end-diastole phase by applying DIR to images that were reconstructed from projection images. Defect ratios were subsequently evaluated using the simulated images of the anterior wall simulated ischemia. Furthermore, receiver operating characteristic (ROC) analysis was performed for the clinical evaluation of DIR and nongated images. To this end, normal volume and small hearts of 33 patients without coronary artery disease and 55 with single vessel disease (coronary stenosis > 70%) were evaluated. Defect ratio analysis for voxel values of 25-100 were 75.7-21.3 for nongated and 74.7-15.6 for DIR images. For normal cardiac volume, the area under the ROC curve was 0.901 ± 0.088 for nongated and 0.925 ± 0.073 for DIR images (P = 0.078). Finally, for small cardiac volume, the area under the ROC curve was 0.651 ± 0.124 for nongated and 0.815 ± 0.119 for DIR (P < 0.01). In the present study, we developed a new registration technique by applying DIR to G-MPS images. When optimal DIR conditions were applied, the resolution of G-MPS images was improved. Furthermore, the diagnostic ability was improved in cases of small cardiac volume.

Ginsenoside Rb1 Ameliorates Age-Related Myocardial Dysfunction by Regulating the NF-[Formula: see text]B Signaling Pathway.

Age-related myocardial dysfunction is a very large healthcare burden. Here, we aimed to investigate whether ginsenoside Rb1 (Rb1) improves age-related myocardial dysfunction and to identify the relevant molecular mechanism. Young mice and aged mice were injected with Rb1 or vehicle for 3 months. Then, their cardiac function was inspected by transthoracic echocardiography. Serum and myocardium tissue were collected from all mice for histological or molecular expression analyses, including aging-related proteins, markers relevant to fibrosis and inflammation, and markers indicating the activation of the nuclear factor-kappa B (NF-[Formula: see text]B) pathway. Compared with the control condition, Rb1 treatment significantly increased the ejection fraction percentage and significantly decreased the internal diameter and volume of the left ventricle at the end-systolic and end-diastolic phases in aged mice. Rb1 treatment reduced collagen deposition and collagen I, collagen III, and transforming growth factor-[Formula: see text]1 protein expression levels in aged hearts. Rb1 also decreased the aging-induced myocardial inflammatory response, as measured by serum or myocardial interleukin-6 and tumor necrosis factor-[Formula: see text] levels. Furthermore, Rb1 treatment in aged mice increased cytoplasmic NF-[Formula: see text]B but decreased nuclear NF-[Formula: see text]B, which indicated the suppression of the NF-[Formula: see text]B signaling pathway by regulating the translocation of NF-[Formula: see text]B. Rb1 could alleviate aging-related myocardial dysfunction by suppressing fibrosis and inflammation, which is potentially associated with regulation of the NF-[Formula: see text]B signaling pathway.

Left Ventricular Global Function Analysis by Multi-Detector CT Threshold Based Three Dimension Segmentation Method in Patients with Coronary Artery Disease: A Comparative Study with Two Dimensional Echocardiography

AbstractBackground: Evaluation of global left ventricular function in patients with Coronary Artery Disease (CAD) is important for clinical diagnosis, risk assessment, therapeutic decisions, and prognosis. Because MDCT is a noninvasive imaging modality frequently used for the assessment of coronary artery disease, its ability to assess the LV volumes and EF has to be evaluated and compared with Two Dimensional Standard Echocardiography (2DSE).Aim of Work: To evaluate the role of MDCT threshold based segmentation method in quantification of global left ventricular function in patients with coronary artery disease and compare MDCT data with 2D-echocardiography as the standard of reference.Patients and Methods: Sixty patients with suspected coronary artery disease underwent contrast enhanced MDCT using retrospective gating. Ten phases of cardiac cycle were processed to assess end-systolic and end-diastolic phase at LV short-axis view. 2DSE was performed within two weeks before MDCT. Left Ventricular Ejection Fraction (LVEF), Left Ventricular End-Diastolic Volume (LVDV) and Left Ventricular End-Systolic Volume (LVSV) were calculated using the three dimensional threshold based segmentation method (in MDCT) and modified Simpson method (in echocar-diography).Results: LVEF, LVDV and LVSV were 51.9±10.9, 182.5± 45.2 and 89.8±40.2 and 51.6±10.5, 175.4±32.3 and 87.2±30.6 on MDCT and echocardiography respectively with excellent correlation between the two modalities (p;0.001) using Pear-son's correlationcoefficient. A Bland-Altman analysis showed that MDCT had slightly higher LVEF, LVDV and LVSV values with mean value of differences of 0.6%, 7ml and 2.5ml respectively, MDCT segmentation method had an accuracy of 91.6%, 95% and 98.3% respectively.Conclusion: MDCT threshold based 3D segmentation method is an accurate method for quantitative evaluation of global left ventricular function compared to 2D echocardiog-raphy.

Assessment of Dynamic Change of Coronary Artery Geometry and Its Relationship to Coronary Artery Disease, Based on Coronary CT Angiography

To investigate the relationship between dynamic changes of coronary artery geometry and coronary artery disease (CAD) using computed tomography (CT). Seventy-one patients underwent coronary CT angiography with retrospective electrocardiographic gating. End-systolic (ES) and end-diastolic (ED) phases were automatically determined by dedicated software. Centerlines were extracted for the right and left coronary artery. Differences between ES and ED curvature and tortuosity were determined. Associations of change in geometrical parameters with plaque types and degree of stenosis were investigated using linear mixed models. The differences in number of inflection points were analyzed using Wilcoxon signed-rank tests. Tests were done on artery and segment level. One hundred thirty-seven arteries (64.3%) and 456 (71.4%) segments were included. Curvature was significantly higher in ES than in ED phase for arteries (p = 0.002) and segments (p < 0.001). The difference was significant only at segment level for tortuosity (p = 0.005). Number of inflection points was significantly higher in ES phase on both artery and segment level (p < 0.001). No significant relationships were found between degree of stenosis and plaque types and dynamic change in geometrical parameters. Non-invasive imaging by cardiac CT can quantify change in geometrical parameters of the coronary arteries during the cardiac cycle. Dynamic change of vessel geometry through the cardiac cycle was not found to be related to the presence of CAD.

Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years.

AimsCardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner.Methods and resultsA total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6–18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters.ConclusionWe report volumetric SSFP CMR imaging reference values for children aged 0–18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paediatric cardiac disease and for research purposes.

A Deep Learning Approach for Assessment of Regional Wall Motion Abnormality From Echocardiographic Images

ObjectivesThis study investigated whether a deep convolutional neural network (DCNN) could provide improved detection of regional wall motion abnormalities (RWMAs) and differentiate among groups of coronary infarction territories from conventional 2-dimensional echocardiographic images compared with that of cardiologists, sonographers, and resident readers. BackgroundAn effective intervention for reduction of misreading of RWMAs is needed. The hypothesis was that a DCNN trained using echocardiographic images would provide improved detection of RWMAs in the clinical setting. MethodsA total of 300 patients with a history of myocardial infarction were enrolled. From this cohort, 3 groups of 100 patients each had infarctions of the left anterior descending (LAD) artery, the left circumflex (LCX) branch, and the right coronary artery (RCA). A total of 100 age-matched control patients with normal wall motion were selected from a database. Each case contained cardiac ultrasonographs from short-axis views at end-diastolic, mid-systolic, and end-systolic phases. After the DCNN underwent 100 steps of training, diagnostic accuracies were calculated from the test set. Independently, 10 versions of the same model were trained, and ensemble predictions were performed using those versions. ResultsFor detection of the presence of WMAs, the area under the receiver-operating characteristic curve (AUC) produced by the deep learning algorithm was similar to that produced by the cardiologists and sonographer readers (0.99 vs. 0.98, respectively; p = 0.15) and significantly higher than the AUC result of the resident readers (0.99 vs. 0.90, respectively; p = 0.002). For detection of territories of WMAs, the AUC by the deep learning algorithm was similar to the AUC by the cardiologist and sonographer readers (0.97 vs. 0.95, respectively; p = 0.61) and significantly higher than the AUC by resident readers (0.97 vs. 0.83, respectively; p = 0.003). From a validation group at an independent site (n = 40), the AUC by the deep learning algorithm was 0.90. ConclusionsThe present results support the possibility of using DCNN for automated diagnosis of RWMAs in the field of echocardiography.

Reference parameters for left ventricular wall thickness, thickening, and motion in stress myocardial perfusion CT: Global and regional assessment

PurposeTo use adenosine-induced stress CT myocardial perfusion imaging (CT-MPI) to determine normal reference values for left ventricle (LV) wall thickness (WT) and motion parameters. MethodsThis study included 106 Korean subjects (52 men and 54 women) who underwent CT-MPI due to chest pain, but were not found to have any detectable mild or severe coronary artery disease or myocardial perfusion defect. The following quantitative parameters were assessed on the CT-MPI according to a 17-segment model: LV myocardial thickness at end-systolic (WTES) and end-diastolic (WTED) phases, systolic wall thickening (SWT), and wall motion (WM). The associations of the measured parameters with the subjects' demographic characteristics and comorbidities were also analyzed. ResultsSeptal wall (7.2 mm) and basal-level (7.7 mm) LV myocardium demonstrated significantly higher WT (p < 0.001). SWT was highest in lateral (77.8%, p < 0.014) and apical (78.9%, p = 0.009) myocardium, while lateral (7.7 mm) and basal (6.7 mm) myocardium exhibited the greatest WM (p < 0.001). WT was significantly higher in men and younger (<60 years) subjects (all, p < 0.001). Hypertensive individuals presented with significantly higher SWT (79.9%, p = 0.024). LV WT exhibited statistically significant correlations (all positive, except for age) with age, height, weight, body surface area, body mass index, and systolic blood pressure (all, p < 0.010). ConclusionsThe present study provides CT-MPI reference values for LV myocardial WT, SWT, and WM measured on an adult Korean population. Knowledge of such normal reference measurements would be beneficial for the efficient interpretation of CT-MPI examinations in populations of Asian ethnicity.

Risk Analysis of Perioperative Death in Lung Transplant Patients With Severe Idiopathic Pulmonary Hypertension

ObjectiveTo investigate the risk factors for perioperative mortality in patients with severe idiopathic pulmonary hypertension (IPAH) undergoing lung transplantation (LTx). MethodsTwenty-two IPAH patients were included in the study and were divided 2 groups: a case group with early death post LTx (n = 5, 22.7%) and the remaining 17 recipients (87.3%), who did not die at perioperative time (the control group). All the preoperative clinical data and surgical procedures were analyzed using an independent t-test and Fisher's exact probability test. ResultsAll the patients had over class III heart function rated by World Health Organization classification. Both groups had significantly reduced capacity of 6-min walking distance (6 MWD), decreased oxygen saturation, increased N-terminal probrain natriuretic peptide (NT-proBNP), certain frequent syncope, hemoptysis, and lower extremity edema. In addition, cardiac catheterization examination demonstrated that all patients had elevated pulmonary artery systolic pressure, mean pulmonary artery systolic pressure, and right atrial pressure. Furthermore, reduced mixed venous oxygen saturation and partial pressure of oxygen were seen in oxygen inhalation in a dose of 5 L/min in both groups. Cardiovascular morphological changes in both groups by cardiac ultrasonography included dilated diameter of the right ventricle and the main pulmonary artery. However, the right ventricular ejection fraction and stroke volume were notedly dropped. Distended inferior vena cava and enhanced frequency of hypertensive tricuspid regurgitation velocity response to stress were seen, and pericardial effusion was developed in both groups of patients. Nevertheless, a paired t-test (n = 5 vs n = 17) showed no significance between groups (P > .05), while there was a significant difference in frequencies of brief loss of consciousness (P < .01). Serum sodium concentration, cardiac index (CI), inner diameter of the left ventricle at end diastolic phase, and inner diameter ratio of RV/LV were 116.80 ± 5.76 mmol/L vs 29.88 ± 7.28 mmol/L (P = .002), 1.30 ± 0.07 L/min/m2 vs 1.58 ± 0.26 L/min/m2 (P = .030), 28.80 ± 3.70 mm vs 34.76 ± 5.43 mm (P = .033) and 1.81 ± 0.28 mmol/L vs 1.43 ± 0.26 (P = .011) between case and control group, respectively. ConclusionsAll patients with IPAH waiting for lung transplantation were in critical condition. The highest death risks at perioperative time in IPAH patients were high frequencies of syncope, hyponatremia, lower CI, inner diameter of the left ventricle, and upward RV/LV ratio.