Myocardial t1 Mapping Techniques for Quantification of Myocardial Fibrosis

Identifying and quantifying diffuse myocardial fibrosis is important to provide insights into the relationship between myocardial fibrosis, diastolic and systolic dysfunction, as well as clinical outcomes. T1 mapping is a promising technique for noninvasively identifying diffuse myocardial fibrosis in heart failure. A quantitative T1 map provides sensitivity to the full range of T1 values and is advantageous over the traditional T1-weighted imaging by reducing the reliance on visual interpretation of the signal intensity in the myocardium. However, in-vivo myocardial T1 quantification is challenging because of cardiac and respiratory motion. During the past few years, a variety of T1 mapping techniques, including the modified Look Locker inversion recovery (MOLLI) sequence, have been developed and optimized to measure the myocardial T1 value. Importantly, there have been significant differences between the T1 values determined by various methods, and several aspects of T1 mapping are incompletely understood. The accuracy of T1 mapping is sensitive to several confounding factors, such as the types of T1 mapping acquisition sequence and individual physiologic parameters. It also remains unclear if myocardial T1 values are constant throughout the cardiac cycle or the cyclic variation from the error of the variable flip angle (VFA) technique. Lastly, it is necessary to validate these techniques against the endomyocardial biopsy. The work intends to validate several aspects of T1 mapping. Firstly, whether there is significant cyclic variation of myocardial T1 at 1.5T was assessed in healthy volunteers and patients without myocardial disease. Secondly, a fast 3D DFA technique with B1 correction was developed to measure T1 comparably with gold standard in a wide range of T1 values, which showed it is necessary to incorporate B1 correction at 3T. Thirdly, Look Locker and MOLLI were compared to evaluate their agreement and difference in 3 patient groups precontrast and postcontrast situations. Finally, the T1 mapping te

Myocardial t1 Mapping Techniques for Quantification of Myocardial Fibrosis

Identifying and quantifying diffuse myocardial fibrosis is important to provide insights into the relationship between myocardial fibrosis, diastolic and systolic dysfunction, as well as clinical outcomes. T1 mapping is a promising technique for noninvasively identifying diffuse myocardial fibrosis in heart failure. A quantitative T1 map provides sensitivity to the full range of T1 values and is advantageous over the traditional T1-weighted imaging by reducing the reliance on visual interpretation of the signal intensity in the myocardium. However, in-vivo myocardial T1 quantification is challenging because of cardiac and respiratory motion. During the past few years, a variety of T1 mapping techniques, including the modified Look Locker inversion recovery (MOLLI) sequence, have been developed and optimized to measure the myocardial T1 value. Importantly, there have been significant differences between the T1 values determined by various methods, and several aspects of T1 mapping are incompletely understood. The accuracy of T1 mapping is sensitive to several confounding factors, such as the types of T1 mapping acquisition sequence and individual physiologic parameters. It also remains unclear if myocardial T1 values are constant throughout the cardiac cycle or the cyclic variation from the error of the variable flip angle (VFA) technique. Lastly, it is necessary to validate these techniques against the endomyocardial biopsy. The work intends to validate several aspects of T1 mapping. Firstly, whether there is significant cyclic variation of myocardial T1 at 1.5T was assessed in healthy volunteers and patients without myocardial disease. Secondly, a fast 3D DFA technique with B1 correction was developed to measure T1 comparably with gold standard in a wide range of T1 values, which showed it is necessary to incorporate B1 correction at 3T. Thirdly, Look Locker and MOLLI were compared to evaluate their agreement and difference in 3 patient groups precontrast and postcontrast situations. Finally, the T1 mapping te

Myocardial t1 Mapping Techniques for Quantification of Myocardial Fibrosis

Identifying and quantifying diffuse myocardial fibrosis is important to provide insights into the relationship between myocardial fibrosis, diastolic and systolic dysfunction, as well as clinical outcomes. T1 mapping is a promising technique for noninvasively identifying diffuse myocardial fibrosis in heart failure. A quantitative T1 map provides sensitivity to the full range of T1 values and is advantageous over the traditional T1-weighted imaging by reducing the reliance on visual interpretation of the signal intensity in the myocardium. However, in-vivo myocardial T1 quantification is challenging because of cardiac and respiratory motion. During the past few years, a variety of T1 mapping techniques, including the modified Look Locker inversion recovery (MOLLI) sequence, have been developed and optimized to measure the myocardial T1 value. Importantly, there have been significant differences between the T1 values determined by various methods, and several aspects of T1 mapping are incompletely understood. The accuracy of T1 mapping is sensitive to several confounding factors, such as the types of T1 mapping acquisition sequence and individual physiologic parameters. It also remains unclear if myocardial T1 values are constant throughout the cardiac cycle or the cyclic variation from the error of the variable flip angle (VFA) technique. Lastly, it is necessary to validate these techniques against the endomyocardial biopsy. The work intends to validate several aspects of T1 mapping. Firstly, whether there is significant cyclic variation of myocardial T1 at 1.5T was assessed in healthy volunteers and patients without myocardial disease. Secondly, a fast 3D DFA technique with B1 correction was developed to measure T1 comparably with gold standard in a wide range of T1 values, which showed it is necessary to incorporate B1 correction at 3T. Thirdly, Look Locker and MOLLI were compared to evaluate their agreement and difference in 3 patient groups precontrast and postcontrast situations. Finally, the T1 mapping te

Chinese Experience with Global G3 Standard-Setting

China’s growth strategy as set out in the 11th 5-year plan in 2005 called for upgrading of product quality, the development of an innovation society, and reduced reliance on foreign intellectual property with high license fees. Consistent with this policy, China has been involved in recent years with the development of a Chinese standard in third generation (3G) mobile phone technology, both in negotiating the standard and seeing it through to commercialization. This is the first case of a developing country both originating and successfully negotiating a telecommunications standard and this experience raises issues for China’s future development strategy based on product and process upgrading in manufacturing. We argue that while precedent setting from an international negotiating point of view, the experience has thus far is unproven commercially. But the lessons learned will benefit future related efforts in follow-on technologies if similar Chinese efforts are made.This paper documents Chinese standard-setting efforts from proposal submission to ITU to the current large-scale trial network deployment in China and overseas trial networks deployment. We discuss the underlying objectives for this initiative, evaluate its effectiveness, and assess its broader implications for Chinese development policy.

On asymptotic stability of discrete-time non-autonomous delayed Hopfield neural networks

AbstractIn this paper, we obtain some sufficient conditions for determining the asymptotic stability of discrete-time non-autonomous delayed Hopfield neural networks by utilizing the Lyapunov functional method. An example is given to show the validity of the results

Resveratrol attenuates chronic pulmonary embolism-related endothelial cell injury by modulating oxidative stress, inflammation, and autophagy

Objectives: Due to Pulmonary Artery Endothelial Cell (PAEC) dysfunction, Pulmonary Hypertension (PH) persists even after the Pulmonary Embolism (PE) has been relieved. However, the mechanism behind this remains unclear. Method: Here, the authors incubated Human PAECs (HPAECs) with thrombin to simulate the process of arterial thrombosis. Results: CCK8 results showed a decrease in the viability of HPAECs after thrombin incubation. In addition, the expression of Tissue Factor (TF), Monocyte Chemoattractant Protein 1 (MCP-1), VCAM-1, ICAM-1, cleaved caspase 3, cleaved caspase 9, and Bax protein were all increased after thrombin incubation, while Bcl-2 was decreased. The effects of 3-MA treatment further suggested that autophagy might mediate the partial protective effects of Resveratrol on HPAECs. To observe the effects of Resveratrol in vivo, the authors established a Chronic Thromboembolic Pulmonary Hypertension (CTEPH) model by repeatedly injecting autologous blood clots into a rat's left jugular vein. The results exhibited that Mean Pulmonary Arterial Pressure (mPAP) and vessel Wall Area/Total Area (WA/TA) ratio were both decreased after Resveratrol treatment. Moreover, Resveratrol could reduce the concentration and activity of TF, vWF, P-selectin, and promote these Superoxide Dismutase (SOD) in plasma. Western blot analysis of inflammation, platelet activation, autophagy, and apoptosis-associated proteins in pulmonary artery tissue validated the results in PHAECs. Conclusions: These findings suggested that reduced autophagy, increased oxidative stress, increased platelet activation, and increased inflammation were involved in CTEPH-induced HPAEC dysfunction and the development of PH, while Resveratrol could improve PAEC dysfunction and PH