Because of its excellent ability to non-invasively assess left ventricular(LV)systolic function,two-dimensional speck-le tracking echocardiography(STE)is increasingly being used in echocardiographic laboratories world...Because of its excellent ability to non-invasively assess left ventricular(LV)systolic function,two-dimensional speck-le tracking echocardiography(STE)is increasingly being used in echocardiographic laboratories worldwide.Two-dimensional STE is the most sought-after method to evaluate LV strain,rotation,twist and torsion.Two dimensional,three-dimensional and four-dimensional(4D)deformation estimation by STE has several intrinsic limitations.For better appraisal of LV contractile properties,a recently introduced updated version of 4D XStrain STE has been used to analyse the various complex multidimensional LV mechanics.This novel technology is a reliable,economical and simple tool for estimating regional and global myocardial function.Furthermore,4D XStrain STE can accurately quan-tify the 4D LV ejection-fraction,LV volume and sphericity index.However,this technology has not been extensively implemented,and its assessment remains limited primarily to research applications.Hence,we aim to promote this innovative technology by comprehensively addressing its technique,advantages and limitations,so that it can be better applied in cardiovascular disease.展开更多
Background: The majority of studies published on rheology of hyaluronic acid (HA) fillers have focused on results from frequency sweeps within the linear viscoelastic region (LVR), i.e. at nearly static conditions. To...Background: The majority of studies published on rheology of hyaluronic acid (HA) fillers have focused on results from frequency sweeps within the linear viscoelastic region (LVR), i.e. at nearly static conditions. To study the properties and behavior of HA fillers at more dynamic conditions, it is necessary to go outside the LVR. Objective: Evaluation of the G’/G’’ cross-over point from the amplitude sweep is suggested as a manner to estimate the flexibility of HA fillers. Materials and methods: Rheological properties of 7 HA fillers were measured in an amplitude sweep from 0.1% to 10000% strain at 1 Hz, using an Anton Paar MCR 301, a PP-25 measuring system with a gap of 1 mm at 25℃ and a 30-min relaxation time. The cross-over point was evaluated for stress, strain and G (G’ and G’’ identical), the values denoted xStrain, xStress and xG. Results: The xStrain values spanned from below 1000% to above 2000% for the products based on the Optimal Balance Technology (OBT)? (in the US, XpresHAn Technology?), compared to below 100% for the products based on the NASHA? technology. Conclusions: Measurement of the flexibility provides a more complete picture of the rheological properties of HA fillers as a complement to firmness measured as G’. The test results show that the Restylane family of products covers a large range in flexibility, and that the flexibility can be estimated using xStrain derived from the amplitude sweep.展开更多
文摘Because of its excellent ability to non-invasively assess left ventricular(LV)systolic function,two-dimensional speck-le tracking echocardiography(STE)is increasingly being used in echocardiographic laboratories worldwide.Two-dimensional STE is the most sought-after method to evaluate LV strain,rotation,twist and torsion.Two dimensional,three-dimensional and four-dimensional(4D)deformation estimation by STE has several intrinsic limitations.For better appraisal of LV contractile properties,a recently introduced updated version of 4D XStrain STE has been used to analyse the various complex multidimensional LV mechanics.This novel technology is a reliable,economical and simple tool for estimating regional and global myocardial function.Furthermore,4D XStrain STE can accurately quan-tify the 4D LV ejection-fraction,LV volume and sphericity index.However,this technology has not been extensively implemented,and its assessment remains limited primarily to research applications.Hence,we aim to promote this innovative technology by comprehensively addressing its technique,advantages and limitations,so that it can be better applied in cardiovascular disease.
文摘Background: The majority of studies published on rheology of hyaluronic acid (HA) fillers have focused on results from frequency sweeps within the linear viscoelastic region (LVR), i.e. at nearly static conditions. To study the properties and behavior of HA fillers at more dynamic conditions, it is necessary to go outside the LVR. Objective: Evaluation of the G’/G’’ cross-over point from the amplitude sweep is suggested as a manner to estimate the flexibility of HA fillers. Materials and methods: Rheological properties of 7 HA fillers were measured in an amplitude sweep from 0.1% to 10000% strain at 1 Hz, using an Anton Paar MCR 301, a PP-25 measuring system with a gap of 1 mm at 25℃ and a 30-min relaxation time. The cross-over point was evaluated for stress, strain and G (G’ and G’’ identical), the values denoted xStrain, xStress and xG. Results: The xStrain values spanned from below 1000% to above 2000% for the products based on the Optimal Balance Technology (OBT)? (in the US, XpresHAn Technology?), compared to below 100% for the products based on the NASHA? technology. Conclusions: Measurement of the flexibility provides a more complete picture of the rheological properties of HA fillers as a complement to firmness measured as G’. The test results show that the Restylane family of products covers a large range in flexibility, and that the flexibility can be estimated using xStrain derived from the amplitude sweep.
