| 1. |
- Bjällmark, Anna, et al.
(författare)
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Ultrasonographic strain imaging is superior to conventional non-invasive measures of vascular stiffness in the detection of age-dependent differences in the mechanical properties of the common carotid artery
- 2010
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 11:7, s. 630-636
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Elastic properties of large arteries have been shown to deteriorate with age and in the presence of atherosclerotic vascular disease. In this study, the performance of ultrasonographic strain measurements was compared to conventional measures of vascular stiffness in the detection of age-dependent differences in the elastic properties of the common carotid artery.Methods and results: In 10 younger (25-28 years, 4 women) and 10 older (50-59 years, 4 women) healthy individuals, global and regional circumferential and radial strain variables were measured in the short-axis view of the right common carotid artery using ultrasonographic two-dimensional (2D) strain imaging with recently introduced speckle tracking technique. Conventional elasticity variables, elastic modulus (Ep) and β stiffness index, were calculated using M-mode sonography and non-invasive blood pressure measurements. Global and regional circumferential systolic strain and strain rate values were significantly higher (p < 0.001, p < 0.01 for regional late systolic strain rate) in the younger individuals, whereas the values of conventional elasticity variables in the same group were lower (p < 0.05). Among all strain and conventional elasticity variables, principal component analysis and its regression extension identified only circumferential systolic strain variables as contributing significantly to the observed discrimination between the younger and older age groups.Conclusion: Ultrasonographic 2D-strain imaging is a sensitive method for the assessment of elastic properties in the common carotid artery, being in this respect superior to conventional measures of vascular elasticity. The method has potential to become a valuable non-invasive tool in the detection of early atherosclerotic vascular changes.
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| 2. |
- Manouras, Aristomenis, et al.
(författare)
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Are measurements of systolic myocardial velocities and displacement with colour and spectral Tissue Doppler compatible?
- 2009
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 7, s. 29-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tissue Doppler (TD) in pulsed mode (spectral TD) and colour TD are the two modalities today available in tissue velocity echocardiography (TVE). Previous studies have shown poor agreement between these two methods when measuring myocardial velocities and displacement. In this study, the concordance between the myocardial velocity and displacement measurements using colour TD and different spectral TD procedures was evaluated. Methods: Left ventricular (LV) longitudinal systolic myocardial velocities and displacement during ejection period were quantified at the basal septal and lateral wall in 24 healthy individuals (4 women and 20 men, 34 +/- 12 years) using spectral TD, colour TD and M-mode recordings. Mean, maximal and minimal spectral TD systolic velocities and the corresponding displacement values were obtained by measurements at the outer and inner borders of the spectral velocity signal. The results were then compared with those obtained with the two other modalities used. Results: Systolic myocardial velocities derived from mean spectral TD frequencies were highly concordant with corresponding colour TD measurements (mean difference 0.10 +/- 0.54 cm/sec in septal and 0.09 +/- 0.97 cm/sec in lateral wall). Similarly, the agreement between spectral and colour TD (mean difference 0.22 +/- 0.74 mm in septal and 0.02 +/- 0.86 mm in lateral wall) as well as M-mode was good when mean spectral velocities were temporally integrated and the results did not differ statistically. Conversely, displacement values from the inner or outer border of the spectral signal differed significantly from values obtained with colour TD and M-mode (p < 0.001, in both cases). Conclusion: LV systolic myocardial measurements based on mean spectral TD frequencies are highly concordant with those provided by colour TD and M-mode. Hence, in order to maintain compatibility of the results, the use of this particular spectral TD procedure should be advocated in clinical praxis.
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| 3. |
- Manouras, Aristomenis, et al.
(författare)
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Comparison between colour-coded and spectral tissue Doppler measurements of systolic and diastolic myocardial velocities : effect of temporal filtering and offline gain setting
- 2009
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 10:3, s. 406-413
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Tidskriftsartikel (refereegranskat)abstract
- Colour tissue Doppler (TD) has been reported to underestimate the longitudinal myocardial motion velocities measured with spectral TD. This study evaluates the effect of temporal smoothing and offline gain settings on the results of velocity measurements with these two methods and the difference between them. In 57 patients, 2D data and left ventricular velocity profiles were acquired using spectral and colour TD for a subsequent offline analysis. Longitudinal myocardial velocities were measured at unsaturated, 50%-saturated and fully saturated gain, and before and after temporal smoothing using 30, 50, and 70 ms filters, respectively. Gain level and filter width altered significantly the measured velocities. Peak systolic and early diastolic velocities were significantly higher (P < 0.001) and E/E' ratio was significantly lower (P < 0.001) with spectral TD than with colour TD, although there was a good correlation between the results of both TD modalities. The differences between the methods increased at increasing filter width and gain level. Despite good correlation of the results, spectral TD produces significantly higher myocardial velocity values and lower E/E' ratio than colour TD modality. Increasing gain and temporal smoothing alter significantly the results of velocity measurements and accentuate the difference between the two TD methods.
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| 4. |
- Manouras, Aristomenis, et al.
(författare)
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Measurements of left ventricular myocardial longitudinal systolic displacement using spectral and colour tissue Doppler : time for a reassessment?
- 2009
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 7, s. 12-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Echocardiographic measurements of left ventricular (LV) myocardial displacement may produce different results depending on the choice of employed modality and subjective adjustments during data acquisition and analysis. Methods: In this study, left ventricular longitudinal systolic displacement was quantified in 57 patients (31 women and 26 men, 50 +/- 16 years) using colour (colour TD) and spectral tissue Doppler (spectral TD) before and after temporal filtering (30 to 70 milliseconds in 20-millisecond steps) and changed offline gain saturation (0%, 50% and 100%), respectively. The results were compared with those obtained with anatomic M-mode. Results: Whereas only minor differences occurred between the results of colour TD and anatomic M-mode measurements, spectral TD significantly overestimated the results obtained with both these methods. However, the limits of agreement between the results produced by all three studied methods were not clinically acceptable in any of the cases. The spectral TD displacement values increased along with increasing offline gain saturation whereas the effect of temporal filtering on colour Doppler measurements was insignificant. Conclusion: Measurements of LV myocardial longitudinal displacement employing spectral TD, colour TD or anatomic M-mode produce different results, thus discouraging interchangeable use of these modalities. Whereas the results of spectral TD measurements can be significantly altered by changing offline gain setting, the effect of temporal filtering on colour TD measurements is insignificant, a fact that increases clinical practicality of the latter method.
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| 5. |
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| 6. |
- Shahgaldi, Kambiz, 1978-
(författare)
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Assessment of Left Ventricular Function and Hemodynamics Using Three-dimensional Echocardiography
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Left ventricular (LV) volumes and ejection fraction (EF) are important predictors of cardiac morbidity and mortality. LV volumes provide valuable prognostic information which isparticularly useful in the selection of therapy or determination of the optimal time for surgery. Two-dimensional (2D) echocardiography is the most widely used non-invasive method forassessment of cardiac function, 2D echocardiography has however several limitations inmeasuring LV volumes and EF since the formulas for quantifications are based on geometricalassumptions. Three-dimensional (3D) echocardiography has been available for almost twodecades, although the use of this modality has not gained wide spread acceptance. 3D echocardiography can overcome the above mentioned limitation in LV volume and EF evaluation since it is not based on geometrical assumption. 3D echocardiography has been shownin several studies to be more accurate and reproducible with low inter- and intraobservervariability in comparison to 2D echocardiography regarding the measurements of LV volumesand EF. The overall aim of the thesis was to evaluate the feasibility and accuracy of 3D echocardiography based-methods in the clinical context. In Study I the feasibility of 3D echocardiography was investigated for determination of LV volumes and EF using parasternal, apical and subcostal approaches. The study demonstrated that the apical 3D echocardiography view offers superior visualization. Study II tested the possibility of creating flow-volume loops to differentiate patients with valvular abnormalities from normal subjects. There were significant differences in the pattern from flow-volume loops clearly separating the groups. In Study III the visual estimation, “eyeballing” of EF was evaluated with two- and tri-plane echocardiography in comparison to quantitative 3D echocardiography. The study confirmed that an experienced echocardiographer can, with a high level of agreement estimate EF both with two- and tri-plane echocardiography. Study IV exposed the high accuracy of stroke volume and cardiac output determination using a3D biplane technique by planimetrically tracing the left ventricular outflow tract and indicating that an assumption of circular left ventricular outflow tract is not reliable. In Study V, two 3D echocardiography modalities, single-beat and four-beat ECG-gated 3D echocardiography were evaluated in patients having sinus rhythm and atrial fibrillation. Thesingle-beat technique showed significantly lower inter-and intraobserver variability in LV volumes and EF measurements in patients having atrial fibrillation in comparison to four-beat ECG-gated acquisition due to absence of stitching artifact. All studies demonstrated good results suggesting 3D echocardiography to be a feasible andaccurate method in daily clinical settings.
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| 7. |
- Shahgaldi, Kambiz, et al.
(författare)
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Direct measurement of left ventricular outflow tract area using three-dimensional echocardiography in biplane mode improves accuracy of stroke volume assessment
- 2010
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Ingår i: Echocardiography. - : Wiley. - 0742-2822 .- 1540-8175. ; 27:9, s. 1078-1085
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The aim of the study was to investigate whether left ventricular stroke volume (LVSV) assessment using direct measurement of left ventricular outflow tract area (LVOTA) is superior to conventional methods for SV calculation. Methods and results: Thirty patients were included in the study (39 +/- 12 years). LVSV was assessed by multiplying LVOT velocity time integral (VTI) by LVOTA provided by direct plani-metrical measurements from real time three-dimensional echocardiography (RT3DE) in biplane mode (SV2). These measurements were compared to conventional methods using either the LVOT diameter for LVOTA multiplied with VTI (SV1) or biplane Simpson (SV3). Direct SV measurements by RT3DE were used as gold standard (SVref). There was an excellent correlation and agreement between SV determined by SV2 and 3DE (r = 0.98, mean difference 0.5 +/- 3.3 mL). However, the concordance of the traditional methods (SV1 and SV3) with 3DE was weaker (r = 0.38, mean difference -2.0 +/- 17.6 mL, r = 0.84, mean difference -7.6 +/- 8.7 mL, respectively). Furthermore, cardiac output (CO) measurements performed by the different modalities were not concordant with wide limits of agreement, except by SV2 the mean difference of CO by SV1 was -0.12 +/- 1.05 L/min, 0.03 +/- 0.20 L/min by SV2, and -0.45 +/- 0.52 L/min by SV3. Conclusions: SV and CO calculations using direct measurement of LVOT area is a feasible, accurate and reproducible method and correlates extremely well with 3DE volume measurements. SV and CO calculation by LVOTA is therefore an appealing method for LVSV assessment in clinical routine.
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| 8. |
- Shahgaldi, Kambiz, et al.
(författare)
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Flow-volume loops derived from three-dimensional echocardiography : a novel approach to the assessment of left ventricular hemodynamics
- 2008
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study explores the feasibility of non-invasive evaluation of left ventricular (LV) flow-volume dynamics using 3-dimensional (3D) echocardiography, and the capacity of such an approach to identify altered LV hemodynamic states caused by valvular abnormalities. Methods: Thirty-one patients with moderate-severe aortic (AS) and mitral (MS) stenoses (21 and 10 patients, respectively) and 10 healthy volunteers underwent 3D echocardiography with full volume acquisition using Philips Sonos 7500 equipment. The digital 3D data were post-processed using TomTec software. LV flow-volume loops were subsequently constructed for each subject by plotting instantaneous LV volume data sampled throughout the cardiac cycle vs. their first derivative representing LV flow. After correction for body surface area, an average flow-volume loop was calculated for each subject group. Results: Flow-volume loops were obtainable in all subjects, except 3 patients with AS. The flow-volume diagrams displayed clear differences in the form and position of the loops between normal individuals and the respective patient groups. In patients with AS, an "obstructive" pattern was observed, with lower flow values during early systole and larger end-systolic volume. On the other hand, patients with MS displayed a "restrictive" flow-volume pattern, with reduced diastolic filling and smaller end-diastolic volume. Conclusion: Non-invasive evaluation of LV flow-volume dynamics using 3D-echocardiographic data is technically possible and the approach has a capacity to identify certain specific types of alteration of LV flow-volume pattern caused by valvular abnormalities, thus reflecting underlying hemodynamic states specific for these abnormalities.
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| 9. |
- Shahgaldi, Kambiz, et al.
(författare)
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Three-dimensional echocardiography using single-heartbeat modality decreases variability in measuring left ventricular volumes and function in comparison to four-beat technique in atrial fibrillation
- 2010
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Three dimensional echocardiography (3DE) approaches the accuracy of cardiac magnetic resonance in measuring left ventricular (LV) volumes and ejection fraction (EF). The multibeat modality in comparison to single-beat (SB) requires breath-hold technique and regular heart rhythm which could limit the use of this technique in patients with atrial fibrillation (AF) due to stitching artifact. The study aimed to investigate whether SB full volume 3DE acquisition reduces inter-and intraobserver variability in assessment of LV volumes and EF in comparison to four-beat (4B) ECG-gated full volume 3DE recording in patients with AF. Methods: A total of 78 patients were included in this study. Fifty-five with sinus rhythm (group A) and 23 having AF (group B). 4B and SB 3DE was performed in all patients. LV volumes and EF was determined by these two modalities and inter-and intraobserver variability was analyzed. Results: SB modality showed significantly lower inter-and intraobserver variability in group B in comparison to 4B when measuring LV volumes and EF, except for end-systolic volume (ESV) in intraobserver analysis. There were significant differences when calculating the LV volumes (p < 0.001) and EF (p < 0.05) with SB in comparison to 4B in group B. Conclusion: Single-beat three-dimensional full volume acquisition seems to be superior to four-beat ECG-gated acquisition in measuring left ventricular volumes and ejection fraction in patients having atrial fibrillation. The variability is significantly lower both for ejection fraction and left ventricular volumes.
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