Super-Resolution Deep Learning Reconstruction for Improved Image Quality of Coronary CT Angiography.

Purpose: To investigate image noise and edge sharpness of coronary CT angiography (CCTA) with super-resolution deep learning reconstruction (SR-DLR) compared with conventional DLR (C-DLR) and to evaluate agreement in stenosis grading using CCTA with that from invasive coronary angiography (ICA) as the reference standard. Materials and Methods: This retrospective study included 58 patients (mean age, 69.0 years ± 12.8 [SD]; 38 men, 20 women) who underwent CCTA using 320-row CT between April and September 2022. All images were reconstructed with two different algorithms: SR-DLR and C-DLR. Image noise, signal-to-noise ratio, edge sharpness, full width at half maximum (FWHM) of stent, and agreement in stenosis grading with that from ICA were compared. Stenosis was visually graded from 0 to 5, with 5 indicating occlusion. Results: SR-DLR significantly decreased image noise by 31% compared with C-DLR (12.6 HU ± 2.3 vs 18.2 HU ± 1.9; P < .001). Signal-to-noise ratio and edge sharpness were significantly improved by SR-DLR compared with C-DLR (signal-to-noise ratio, 38.7 ± 8.3 vs 26.2 ± 4.6; P < .001; edge sharpness, 560 HU/mm ± 191 vs 463 HU/mm ± 164; P < .001). The FWHM of stent was significantly thinner on SR-DLR (0.72 mm ± 0.22) than on C-DLR (1.01 mm ± 0.21; P < .001). Agreement in stenosis grading between CCTA and ICA was improved on SR-DLR compared with C-DLR (weighted κ = 0.83 vs 0.77). Conclusion: SR-DLR improved vessel sharpness, image noise, and accuracy of coronary stenosis grading compared with the C-DLR technique.Keywords: CT Angiography, Cardiac, Coronary Arteries Supplemental material is available for this article. © RSNA, 2023.

Prognostic Impact of Peak Aortic Jet Velocity on Patients With Acute Myocardial Infarction.

BACKGROUND: Aortic valve stenosis (AS) leads to increased cardiovascular mortality and morbidity, and recent studies reported that even mild-to-moderate AS was associated with poor prognosis in the general population. This study investigated the prognostic impact of mild or moderate AS, defined as 2.0 m/s ≤ peak aortic jet velocity (Vmax) ≤3.9 m/s using echocardiography in acute myocardial infarction (AMI) patients.Methods and Results: This study enrolled 3,049 AMI patients using data from the Mie ACS registry. Patients were divided into 2 groups according to Vmax: Group 1: Vmax <2.0 m/s and/or visually intact aortic valve in which all 3 leaflets are fully and evenly open; Group 2: 2.0 m/s ≤ Vmax ≤ 3.9 m/s. There were 2,976 patients in Group 1and 73 patients in Group 2. The Group 2 patients were older, had a higher percentage of males and had lower body mass index and Killip ≥2 than the Group 1 patients. Angiographic data, door-to-balloon time, and mechanical support were not different between the 2 groups. The Group 2 patients demonstrated a significantly higher all-cause mortality rate (P<0.01) and composite of cardiovascular death and heart failure hospitalization (P<0.01), and Kaplan-Meier analysis showed the same tendency in propensity score-matched patients. CONCLUSIONS: The present study revealed that mild or moderate AS based on Vmax is associated with poor prognosis following AMI.

Theoretical study of lithium ionic conductors by electronic stress tensor density and electronic kinetic energy density.

We analyze the electronic structure of lithium ionic conductors, Li3PO4 and Li3PS4, using the electronic stress tensor density and kinetic energy density with special focus on the ionic bonds among them. We find that, as long as we examine the pattern of the eigenvalues of the electronic stress tensor density, we cannot distinguish between the ionic bonds and bonds among metalloid atoms. We then show that they can be distinguished by looking at the morphology of the electronic interface, the zero surface of the electronic kinetic energy density. © 2016 Wiley Periodicals, Inc.

Electronic stress tensor analysis of molecules in gas phase of CVD process for GeSbTe alloy.

We analyze the electronic structure of molecules which may exist in gas phase of chemical vapor deposition process for GeSbTe alloy using the electronic stress tensor, with special focus on the chemical bonds between Ge, Sb, and Te atoms. We find that, from the viewpoint of the electronic stress tensor, they have intermediate properties between alkali metals and hydrocarbon molecules. We also study the correlation between the bond order which is defined based on the electronic stress tensor, and energy-related quantities. We find that the correlation with the bond dissociation energy is not so strong while one with the force constant is very strong. We interpret these results in terms of the energy density on the "Lagrange surface," which is considered to define the boundary surface of atoms in a molecule in the framework of the electronic stress tensor analysis.

Ventricular function and dyssynchrony quantified by speckle-tracking echocardiography in patients with acute and chronic right ventricular pressure overload.

BACKGROUND: The aim of this study was to noninvasively investigate right ventricular and left ventricular (LV) adaptation to right ventricular pressure overload in patients with acute pulmonary thromboembolism (APTE) and chronic pulmonary artery hypertension (CPAH). METHODS: Thirty-seven patients with APTE, 36 patients with CPAH, and 33 controls were retrospectively enrolled. Myocardial deformation and wall motion were analyzed using speckle-tracking strain and displacement imaging echocardiography in the right and left ventricles. The standard deviation of the heart rate-corrected intervals from QRS onset to peak systolic strain and peak systolic displacement (PSD) for the six segments was used to quantify right ventricular and LV mechanical dyssynchrony (peak systolic strain dyssynchrony and PSD dyssynchrony). The myocardial performance index in both ventricles was also evaluated. RESULTS: The APTE and CPAH groups had reduced ventricular performance (LV myocardial performance index, 0.40 ± 0.10, 0.66 ± 0.18 [P < .05 vs controls], and 0.58 ± 0.19 [P < .05 vs controls] in the control, APTE, and CPAH groups, respectively) and large mechanical dyssynchrony (LV longitudinal PSD dyssynchrony, 58 ± 41 msec, 119 ± 49 msec [P < .05 vs controls], and 83 ± 37 msec [P < .05 vs controls and the APTE group] in the control, APTE, and CPAH groups, respectively) in both ventricles. Multiple regression analysis indicated that LV longitudinal PSD dyssynchrony in the APTE group and the LV eccentricity index in the CPAH group were independent determinants of LV myocardial performance index. CONCLUSIONS: Pathophysiologic mechanisms that regulate ventricular performance vary depending on whether the ventricles are exposed to acute or chronic right ventricular pressure overload.

Short-term effects of low-dose tolvaptan on hemodynamic parameters in patients with chronic heart failure.

BACKGROUND: We evaluated the short-term effects of low-dose tolvaptan treatment on hemodynamic parameters in patients with chronic heart failure (HF). METHODS: We studied 22 patients (69 ± 10 years) with chronic HF and excess fluid retention despite receiving appropriate medical therapy, including loop and/or thiazide diuretics. The therapeutic effects of low-dose (7.5mg) once-daily tolvaptan on hemodynamics associated with changes in fluid balance and neurohumoral activations were investigated after a seven day treatment period. RESULTS: After the treatment period, body weight decreased (-2.7 ± 2.3 kg) associated with increases in daily urine output. Whereas plasma arginine-vasopressin levels, serum aldosterone concentration, and plasma renin activity mildly increased, plasma levels of B-type natriuretic peptide and atrial natriuretic peptide significantly decreased after tolvaptan treatment. Serum electrolytes were not adversely affected by tolvaptan treatment. Although cardiac index and systemic vascular resistance index remained unchanged, mean pulmonary artery wedge pressure (22 ± 7 mmHg vs. 17 ± 7 mmHg, p<0.05), mean right atrial pressure (12 ± 5 mmHg vs. 9 ± 5 mmHg, p<0.05), mean pulmonary artery pressure (32 ± 9 mmHg vs. 25 ± 7 mmHg, p<0.05), and pulmonary vascular resistance index (332 ± 207 dynes/cm(-5)/m(2) vs. 245 ± 110 dynes/cm(-5)/m(2), p<0.05) significantly decreased after tolvaptan treatment. The extent of the reduction in pulmonary vascular resistance index after tolvaptan treatment strongly correlated with baseline values. CONCLUSIONS: Short-term treatment with low-dose tolvaptan improved hemodynamic parameters and correlated with significant fluid removal in patients with chronic HF.

Reversible left ventricular regional non-uniformity quantified by speckle-tracking displacement and strain imaging in patients with acute pulmonary embolism.

BACKGROUND: The aim of this study was to investigate the impact of acute right ventricular pressure overload (RVPO) on left ventricular (LV) function and regional uniformity using speckle-tracking displacement and strain analyses in patients with acute pulmonary embolism (PE). METHODS: Twenty-five patients with acute PE (mean age, 59 ± 16 years) and 25 normal subjects were enrolled. Radial, longitudinal, and circumferential LV wall motion and myocardial deformation were analyzed using speckle-tracking displacement and strain imaging echocardiography, respectively, from the mid-LV short-axis and apical four-chamber views. The standard deviation of the heart rate-corrected intervals from QRS onset to peak systolic displacement (PSD) and peak systolic strain for the six segments was used to quantify LV systolic dyssynchrony. The standard deviation of regional PSD and peak systolic strain divided by their global values was used to quantify LV systolic heterogeneity. Mechanical discoordination of LV regional wall motion and myocardial deformation was assessed by averaging the frame-by-frame percentage discordance between segmental and global signal changes in the six segments. RESULTS: Patients with acute PE had reduced radial PSD and peak systolic strain and a large extent of displacement-derived nonuniformities (PSD dyssynchrony, 74 ± 32 vs 40 ± 20 m sec; PSD heterogeneity, 0.39 ± 0.13 vs 0.17 ± 0.08; and PSD discoordination, 23 ± 2% vs 15 ± 3%; P < .05 vs normal subjects for all comparisons) associated with a leftward shift of the interventricular septum. In contrast, all indices of strain-derived radial LV nonuniformities were not augmented by acute RVPO in patients with acute PE. Patients with acute PE also had impaired LV systolic function and regional uniformities in the longitudinal and circumferential directions. After the amelioration of acute RVPO by primary treatment, most of the indices of LV function and regional uniformity were restored to normal values. Multiple regression analysis indicated that only radial LV wall motion discoordination was a significant determinant of cardiac index. CONCLUSIONS: Acute RVPO induces reversal LV regional uniformities, which are closely associated with reduced LV function and abnormal geometry of the left ventricle, and radial LV wall motion coordination plays a key role in the short-term regulation of cardiac output in patients with acute PE.

Role of haemodialytic therapy on left ventricular mechanical dyssynchrony in patients with end-stage renal disease quantified by speckle-tracking strain imaging.

BACKGROUND: Abnormal myocardial loading can contribute to left ventricular (LV) mechanical dyssynchrony in patients with end-stage renal disease (ESRD). The aims of this study were to characterize and quantify LV function and mechanical dyssynchrony in patients with ESRD, and to elucidate the impact of haemodialytic (HD) therapy on these parameters by speckle-tracking strain imaging. METHODS: Twenty-three patients with ESRD (63 ± 11 years) before (pre-dialysis group) and after HD therapy (post-dialysis group) and 28 normal subjects (control group; 60 ± 10 years) were examined by echocardiography. Global and segmental LV peak systolic strain (PSS) were analysed, and LV mechanical dyssynchrony was assessed by calculating the standard deviation of the segmental time-to-PSS over longitudinal, circumferential or radial regions, respectively. RESULTS: Global PSS and LV ejection fraction in the pre-dialysis group were similar to those in the control group, and were not altered by HD therapy. LV mechanical dyssynchronies in the longitudinal and radial directions, but not in the circumferential direction, were significantly greater in the pre-dialysis group than those in the control group [longitudinal direction: 63 ± 15 (P < 0.05 vs. the control group) vs. 49 ± 15 ms, circumferential direction: 44 ± 24 vs. 41 ± 23 ms, and radial direction: 47 ± 29 (P < 0.05 vs. the control group) vs. 16 ± 18 ms]. HD therapy dramatically improved only the radial LV dyssynchrony in the post-dialysis group (23 ± 24 ms, P < 0.05 vs. the pre-dialysis group). CONCLUSIONS: The presence of ESRD was associated with longitudinal and radial LV dyssynchronies. In addition, HD therapy dramatically improved radial LV dyssynchrony, which strongly indicates that only radial LV dyssynchrony is preload dependent among the three LV systolic directions.

Left ventricular contraction-relaxation coupling in normal, hypertrophic, and failing myocardium quantified by speckle-tracking global strain and strain rate imaging.

OBJECTIVE: The aim of this study was to noninvasively quantify global left ventricular (LV) contraction and relaxation, and to investigate their relationship in normal, hypertrophic, and failing myocardium. METHODS: Fifty patients with hypertensive LV hypertrophy (LVH) (LVH group), 50 patients with dilated cardiomyopathy (DCM) (DCM group), and 50 normal subjects (control group) had echocardiographic evaluations. Global LV peak systolic strain (PSS) and peak relaxation rate (PRR) during early diastole were analyzed by speckle-tracking strain and strain rate imaging in the longitudinal and circumferential directions. RESULTS: Both global PSS and PRR were reduced in the LVH group in the longitudinal direction. In the circumferential direction, global PSS was maintained and global PRR was reduced in the LVH group. The reductions in both global PSS and PRR were more pronounced in both directions in the DCM group compared with the other 2 groups. Global PSS correlated strongest with global PRR among the clinical and echocardiographic variables, which exhibited the best fit with exponential regressions in both the longitudinal and circumferential directions in all subjects (longitudinal: y=0.15e(-0.10x), r2=0.75; circumferential: y=0.21e(-0.09x), r2=0.76, P<.01, respectively). Multiple regression analysis indicated that global PSS was the most powerful determinant of global PRR in both longitudinal and circumferential directions. CONCLUSION: Global LV function quantified using speckle-tracking echocardiography revealed strong coupling of LV contraction to relaxation sequentially from normal to failing myocardium, regardless of their heterogeneous pathophysiology. In addition, the extent of myocardial systolic shortening was the most powerful independent contributor of LV relaxation in both the longitudinal and circumferential directions. These results strongly indicate that LV myocardial systolic contraction directly regulates its relaxation.