The Experts below are selected from a list of 79023 Experts worldwide ranked by ideXlab platform
Kim H. Parker - One of the best experts on this subject based on the ideXlab platform.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
Frontiers in Physiology, 2020Co-Authors: Alun D Hughes, Jamil Mayet, Chloe Park, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Background Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics, and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms (pWIA). Methods Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analyzed using custom-written software to derive the excess pressure (Pxs ) which was scaled to peak LVOT velocity and used to calculate Wave Intensity. These data were compared with Wave Intensity calculated using the measured LVOT flow velocity Waveform. In a separate study, repeat measures of pWIA were performed on 34 individuals who attended two clinic visits at an interval of ≈1 month to assess reproducibility and reliability of the method. Results Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and peak aortic velocity agreed closely. Wave Intensity estimated using pWIA showed acceptable agreement with estimates using LVOT velocity tracings and estimates of Wave Intensity were similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusion The Pxs is a surrogate of LVOT flow velocity which, when appropriately scaled, allows estimation of aortic Wave Intensity with acceptable reproducibility. This may enable wider application of Wave Intensity analysis to large studies.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
medRxiv, 2020Co-Authors: Alun D Hughes, C.m. Park, Jamil Mayet, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Abstract Background Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms (pWIA). Methods Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analysed using custom-written software to derive the excess pressure (Pxs) which was scaled to peak LVOT velocity and used to calculate Wave Intensity. These data were compared with Wave Intensity calculated using the measured LVOT flow velocity Waveform. In a separate study, repeat measures of pWIA were performed on 34 individuals who attended 2 clinic visits at an interval of approximately 1 month to assess reproducibility and reliability of the method. Results Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and peak aortic velocity agreed closely. Wave Intensity estimated using pWIA showed acceptable agreement with estimates using LVOT velocity tracings and estimates of Wave Intensity were similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusions The Pxs is a surrogate of LVOT flow velocity which, when appropriately scaled, allows estimation of aortic Wave Intensity with acceptable reproducibility. This may enable wider application of Wave Intensity analysis to large studies.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
medRxiv, 2020Co-Authors: Alun D Hughes, Jamil Mayet, Chloe Park, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Background: Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms, and its reproducibility. Methods: Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analysed using custom-written software to derive the excess pressure (Pxs) which was compared with the LVOT flow velocity Waveform, and used to calculate Wave Intensity. In a separate study, repeat measures of Wave Intensity and other Wave and reservoir parameters were performed on 34 individuals who attended 2 clinic visits at an interval of approximately 1 month to assess reproducibility and reliability of the method. Results: Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and maximum aortic velocity agreed closely (mean difference = 0.00 (limits of agreement -0.02, 0.02)s). Wave Intensity patterns when scaled to peak LVOT velocity gave credible estimates of Wave Intensity similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusions: The Pxs is a surrogate of LVOT flow velocity allowing estimation of aortic Wave Intensity with acceptable reproducibility. This enables widespread application of Wave Intensity analysis to large studies.
-
mechanisms of myocardial ischemia in hypertrophic cardiomyopathy insights from Wave Intensity analysis and magnetic resonance
Journal of the American College of Cardiology, 2016Co-Authors: Claire E Raphael, Kim H. Parker, Robert Cooper, Julian Collinson, Vassilis Vassiliou, Dudley J Pennell, Ranil De Silva, Liyueh Hsu, Anders M Greve, S S NijjerAbstract:Background Angina is common in hypertrophic cardiomyopathy (HCM) and is associated with abnormal myocardial perfusion. Wave Intensity analysis improves the understanding of the mechanics of myocardial ischemia.
-
using Wave Intensity analysis to determine local reflection coefficient in flexible tubes
Journal of Biomechanics, 2016Co-Authors: Ye Li, Kim H. Parker, Ashraf W KhirAbstract:It has been shown that reflected Waves affect the shape and magnitude of the arterial pressure Waveform, and that reflected Waves have physiological and clinical prognostic values. In general the reflection coefficient is defined as the ratio of the energy of the reflected to the incident Wave. Since pressure has the units of energy per unit volume, arterial reflection coefficient are traditionally defined as the ratio of reflected to the incident pressure. We demonstrate that this approach maybe prone to inaccuracies when applied locally. One of the main objectives of this work is to examine the possibility of using Wave Intensity, which has units of energy flux per unit area, to determine the reflection coefficient. We used an in vitro experimental setting with a single inlet tube joined to a second tube with different properties to form a single reflection site. The second tube was long enough to ensure that reflections from its outlet did not obscure the interactions of the initial Wave. We generated an approximately half sinusoidal Wave at the inlet of the tube and took measurements of pressure and flow along the tube. We calculated the reflection coefficient using Wave Intensity (RdI and RdI0.5) and Wave energy (RI and RI0.5) as well as the measured pressure (RdP) and compared these results with the reflection coefficient calculated theoretically based on the mechanical properties of the tubes. The experimental results show that the reflection coefficients determined by all the techniques we studied increased or decreased with distance from the reflection site, depending on the type of reflection. In our experiments, RdP, RdI0.5 and RI0.5 are the most reliable parameters to measure the mean reflection coefficient, whilst RdI and RI provide the best measure of the local reflection coefficient, closest to the reflection site. Additional work with bifurcations, tapered tubes and in vivo experiments are needed to further understand, validate the method and assess its potential clinical use.
Vivek Muthurangu - One of the best experts on this subject based on the ideXlab platform.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Background Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity. Wave Intensity was derived in terms of area and velocity changes. These data were directly derived from PC-CMR using a breath-hold spiral sequence accelerated with sensitivity encoding (SENSE). Image processing was integrated in a plug-in for the DICOM viewer OsiriX, including calculations of Wave speed and Wave Intensity. Ascending and descending aortic data from 15 healthy volunteers (30 ± 6 years) data were used to test the method for feasibility, and intra- and inter-observer variability. Ascending aortic data were also compared with results from 15 patients with coronary heart disease (61 ± 13 years) to assess the clinical usefulness of the method. Rapid image acquisition (11 s breath-hold) and image processing was feasible in all volunteers. Wave speed was physiological (5.8 ± 1.3 m/s ascending aorta, 5.0 ± 0.7 m/s descending aorta) and the Wave Intensity pattern was consistent with traditionally formulated Wave Intensity. Wave speed, peak forward compression Wave in early systole and peak forward expansion Wave in late systole at both locations exhibited overall good intra- and inter-observer variability. Patients with coronary heart disease had higher Wave speed (p <0.0001), and lower forward compression Wave (p <0.0001) and forward expansion Wave (p <0.0005) peaks. This difference is likely related to the older age of the patients’ cohort, indicating stiffer aortas, as well as compromised ventricular function due to their underlying condition. A non-invasive, semi-automated and reproducible method for performing Wave Intensity analysis is presented. Its application is facilitated by the use of a very high temporal resolution spiral sequence. A formulation of Wave Intensity based on area change has also been proposed, involving no assumptions about the cross-sectional shape of the vessel.
Giovanni Biglino - One of the best experts on this subject based on the ideXlab platform.
-
reduced ascending aorta distensibility relates to adverse ventricular mechanics in patients with hypoplastic left heart syndrome noninvasive study using Wave Intensity analysis
The Journal of Thoracic and Cardiovascular Surgery, 2012Co-Authors: Giovanni Biglino, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Hopewell N Ntsinjana, Sachin Khambadkone, Marc R De Leval, Tainyen Hsia, Alessandro GiardiniAbstract:Objective To evaluate the aortic arch elastic properties and ventriculoarterial coupling efficiency in patients with single ventricle physiology, with and without a surgically reconstructed arch. Methods We studied 21 children with single ventricle physiology after bidirectional superior cavopulmonary surgery: 10 with hypoplastic left heart syndrome, who underwent surgical arch reconstruction, and 11 with other types of single ventricle physiology but without arch reconstruction. All children underwent pre-Fontan magnetic resonance imaging. No patient exhibited aortic recoarctation. Data on aortic Wave speed, aortic distensibility and Wave Intensity profiles were all extracted from the magnetic resonance imaging studies using an in-house–written plug-in for the Digital Imaging and Communications in Medicine viewer OsiriX. Results Children with hypoplastic left heart syndrome had significantly greater Wave speed ( P = .002), and both stiffer ( P = .004) and larger ( P Conclusions Using a novel, noninvasive technique based on image analysis, we have demonstrated that aortic arch reconstruction in children with hypoplastic left heart syndrome is associated with reduced aortic distensibility and unfavorable ventricular-vascular coupling compared with those with single ventricle physiology without aortic arch reconstruction.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Background Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity. Wave Intensity was derived in terms of area and velocity changes. These data were directly derived from PC-CMR using a breath-hold spiral sequence accelerated with sensitivity encoding (SENSE). Image processing was integrated in a plug-in for the DICOM viewer OsiriX, including calculations of Wave speed and Wave Intensity. Ascending and descending aortic data from 15 healthy volunteers (30 ± 6 years) data were used to test the method for feasibility, and intra- and inter-observer variability. Ascending aortic data were also compared with results from 15 patients with coronary heart disease (61 ± 13 years) to assess the clinical usefulness of the method. Rapid image acquisition (11 s breath-hold) and image processing was feasible in all volunteers. Wave speed was physiological (5.8 ± 1.3 m/s ascending aorta, 5.0 ± 0.7 m/s descending aorta) and the Wave Intensity pattern was consistent with traditionally formulated Wave Intensity. Wave speed, peak forward compression Wave in early systole and peak forward expansion Wave in late systole at both locations exhibited overall good intra- and inter-observer variability. Patients with coronary heart disease had higher Wave speed (p <0.0001), and lower forward compression Wave (p <0.0001) and forward expansion Wave (p <0.0005) peaks. This difference is likely related to the older age of the patients’ cohort, indicating stiffer aortas, as well as compromised ventricular function due to their underlying condition. A non-invasive, semi-automated and reproducible method for performing Wave Intensity analysis is presented. Its application is facilitated by the use of a very high temporal resolution spiral sequence. A formulation of Wave Intensity based on area change has also been proposed, involving no assumptions about the cross-sectional shape of the vessel.
Alun D Hughes - One of the best experts on this subject based on the ideXlab platform.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
Frontiers in Physiology, 2020Co-Authors: Alun D Hughes, Jamil Mayet, Chloe Park, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Background Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics, and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms (pWIA). Methods Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analyzed using custom-written software to derive the excess pressure (Pxs ) which was scaled to peak LVOT velocity and used to calculate Wave Intensity. These data were compared with Wave Intensity calculated using the measured LVOT flow velocity Waveform. In a separate study, repeat measures of pWIA were performed on 34 individuals who attended two clinic visits at an interval of ≈1 month to assess reproducibility and reliability of the method. Results Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and peak aortic velocity agreed closely. Wave Intensity estimated using pWIA showed acceptable agreement with estimates using LVOT velocity tracings and estimates of Wave Intensity were similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusion The Pxs is a surrogate of LVOT flow velocity which, when appropriately scaled, allows estimation of aortic Wave Intensity with acceptable reproducibility. This may enable wider application of Wave Intensity analysis to large studies.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
medRxiv, 2020Co-Authors: Alun D Hughes, C.m. Park, Jamil Mayet, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Abstract Background Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms (pWIA). Methods Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analysed using custom-written software to derive the excess pressure (Pxs) which was scaled to peak LVOT velocity and used to calculate Wave Intensity. These data were compared with Wave Intensity calculated using the measured LVOT flow velocity Waveform. In a separate study, repeat measures of pWIA were performed on 34 individuals who attended 2 clinic visits at an interval of approximately 1 month to assess reproducibility and reliability of the method. Results Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and peak aortic velocity agreed closely. Wave Intensity estimated using pWIA showed acceptable agreement with estimates using LVOT velocity tracings and estimates of Wave Intensity were similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusions The Pxs is a surrogate of LVOT flow velocity which, when appropriately scaled, allows estimation of aortic Wave Intensity with acceptable reproducibility. This may enable wider application of Wave Intensity analysis to large studies.
-
feasibility of estimation of aortic Wave Intensity using non invasive pressure recordings in the absence of flow velocity in man
medRxiv, 2020Co-Authors: Alun D Hughes, Jamil Mayet, Chloe Park, Anenta Ramakrishnan, Nish Chaturvedi, Kim H. ParkerAbstract:Background: Wave Intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics and energy transfer in the arterial circulation. Widespread use of Wave Intensity analysis is limited by the need for concurrent measurement of pressure and flow Waveforms. We describe a method that can estimate Wave Intensity patterns using only non-invasive pressure Waveforms, and its reproducibility. Methods: Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity Waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure Waveforms were analysed using custom-written software to derive the excess pressure (Pxs) which was compared with the LVOT flow velocity Waveform, and used to calculate Wave Intensity. In a separate study, repeat measures of Wave Intensity and other Wave and reservoir parameters were performed on 34 individuals who attended 2 clinic visits at an interval of approximately 1 month to assess reproducibility and reliability of the method. Results: Pxs Waveforms were similar in shape to aortic flow velocity Waveforms and the time of peak Pxs and maximum aortic velocity agreed closely (mean difference = 0.00 (limits of agreement -0.02, 0.02)s). Wave Intensity patterns when scaled to peak LVOT velocity gave credible estimates of Wave Intensity similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusions: The Pxs is a surrogate of LVOT flow velocity allowing estimation of aortic Wave Intensity with acceptable reproducibility. This enables widespread application of Wave Intensity analysis to large studies.
-
a review of Wave mechanics in the pulmonary artery with an emphasis on Wave Intensity analysis
Acta Physiologica, 2016Co-Authors: Alun D Hughes, Junjing Su, Ole Hilberg, Luke Howard, Ulf SimonsenAbstract:Mean pulmonary arterial pressure and pulmonary vascular resistance (PVR) remain the most common haemodynamic measures to evaluate the severity and prognosis of pulmonary hypertension. However, PVR only captures the non-oscillatory component of the right ventricular hydraulic load and neglects the dynamic compliance of the pulmonary arteries and the contribution of Wave transmission. Wave Intensity analysis offers an alternative way to assess the pulmonary vasculature in health and disease. Wave speed is a measure of arterial stiffness, and the magnitude and timing of Wave reflection provide information on the degree of impedance mismatch between the proximal and distal circulation. Studies in the pulmonary artery have demonstrated distinct differences in arterial Wave propagation between individuals with and without pulmonary vascular disease. Notably, greater Wave speed and greater Wave reflection are observed in patients with pulmonary hypertension and in animal models exposed to hypoxia. Studying Wave propagation makes a valuable contribution to the assessment of the arterial system in pulmonary hypertension, and here, we briefly review the current state of knowledge of the methods used to evaluate arterial Waves in the pulmonary artery.
-
Wave Intensity analysis and its application to the coronary circulation
Global Cardiology Science and Practice, 2015Co-Authors: Christopher Broyd, Justin E. Davies, Javier Escaned, Alun D Hughes, Kim H. ParkerAbstract:Wave Intensity analysis (WIA) is a technique developed from the field of gas dynamics that is now being applied to assess cardiovascular physiology. It allows quantification of the forces acting to alter flow and pressure within a fluid system, and as such it is highly insightful in ascribing cause to dynamic blood pressure or velocity changes. When co-incident Waves arrive at the same spatial location they exert either counteracting or summative effects on flow and pressure. WIA however allows Waves of different origins to be measured uninfluenced by other simultaneously arriving Waves. It therefore has found particular applicability within the coronary circulation where both proximal (aortic) and distal (myocardial) ends of the coronary artery can markedly influence blood flow. Using these concepts, a repeating pattern of 6 Waves has been consistently identified within the coronary arteries, 3 originating proximally and 3 distally. Each has been associated with a particular part of the cardiac cycle. The most clinically relevant Wave to date is the backward decompression Wave, which causes the marked increase in coronary flow velocity observed at the start of the diastole. It has been proposed that this Wave is generated by the elastic re-expansion of the intra-myocardial blood vessels that are compressed during systolic contraction. Particularly by quantifying this Wave, WIA has been used to provide mechanistic and prognostic insight into a number of conditions including aortic stenosis, left ventricular hypertrophy, coronary artery disease and heart failure. It has proven itself to be highly sensitive and as such a number of novel research directions are encouraged where further insights would be beneficial.
Silvia Schievano - One of the best experts on this subject based on the ideXlab platform.
-
reduced ascending aorta distensibility relates to adverse ventricular mechanics in patients with hypoplastic left heart syndrome noninvasive study using Wave Intensity analysis
The Journal of Thoracic and Cardiovascular Surgery, 2012Co-Authors: Giovanni Biglino, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Hopewell N Ntsinjana, Sachin Khambadkone, Marc R De Leval, Tainyen Hsia, Alessandro GiardiniAbstract:Objective To evaluate the aortic arch elastic properties and ventriculoarterial coupling efficiency in patients with single ventricle physiology, with and without a surgically reconstructed arch. Methods We studied 21 children with single ventricle physiology after bidirectional superior cavopulmonary surgery: 10 with hypoplastic left heart syndrome, who underwent surgical arch reconstruction, and 11 with other types of single ventricle physiology but without arch reconstruction. All children underwent pre-Fontan magnetic resonance imaging. No patient exhibited aortic recoarctation. Data on aortic Wave speed, aortic distensibility and Wave Intensity profiles were all extracted from the magnetic resonance imaging studies using an in-house–written plug-in for the Digital Imaging and Communications in Medicine viewer OsiriX. Results Children with hypoplastic left heart syndrome had significantly greater Wave speed ( P = .002), and both stiffer ( P = .004) and larger ( P Conclusions Using a novel, noninvasive technique based on image analysis, we have demonstrated that aortic arch reconstruction in children with hypoplastic left heart syndrome is associated with reduced aortic distensibility and unfavorable ventricular-vascular coupling compared with those with single ventricle physiology without aortic arch reconstruction.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Background Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity.
-
a non invasive clinical application of Wave Intensity analysis based on ultrahigh temporal resolution phase contrast cardiovascular magnetic resonance
Journal of Cardiovascular Magnetic Resonance, 2012Co-Authors: Giovanni Biglino, Kim H. Parker, Jennifer A Steeden, Catriona Baker, Silvia Schievano, Andrew M Taylor, Vivek MuthuranguAbstract:Wave Intensity analysis, traditionally derived from pressure and velocity data, can be formulated using velocity and area. Flow-velocity and area can both be derived from high-resolution phase-contrast cardiovascular magnetic resonance (PC-CMR). In this study, very high temporal resolution PC-CMR data is processed using an integrated and semi-automatic technique to derive Wave Intensity. Wave Intensity was derived in terms of area and velocity changes. These data were directly derived from PC-CMR using a breath-hold spiral sequence accelerated with sensitivity encoding (SENSE). Image processing was integrated in a plug-in for the DICOM viewer OsiriX, including calculations of Wave speed and Wave Intensity. Ascending and descending aortic data from 15 healthy volunteers (30 ± 6 years) data were used to test the method for feasibility, and intra- and inter-observer variability. Ascending aortic data were also compared with results from 15 patients with coronary heart disease (61 ± 13 years) to assess the clinical usefulness of the method. Rapid image acquisition (11 s breath-hold) and image processing was feasible in all volunteers. Wave speed was physiological (5.8 ± 1.3 m/s ascending aorta, 5.0 ± 0.7 m/s descending aorta) and the Wave Intensity pattern was consistent with traditionally formulated Wave Intensity. Wave speed, peak forward compression Wave in early systole and peak forward expansion Wave in late systole at both locations exhibited overall good intra- and inter-observer variability. Patients with coronary heart disease had higher Wave speed (p <0.0001), and lower forward compression Wave (p <0.0001) and forward expansion Wave (p <0.0005) peaks. This difference is likely related to the older age of the patients’ cohort, indicating stiffer aortas, as well as compromised ventricular function due to their underlying condition. A non-invasive, semi-automated and reproducible method for performing Wave Intensity analysis is presented. Its application is facilitated by the use of a very high temporal resolution spiral sequence. A formulation of Wave Intensity based on area change has also been proposed, involving no assumptions about the cross-sectional shape of the vessel.
