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  • 1.
    Bjällmark, Anna
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lind, Britta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Peolsson, Michael
    KTH, School of Technology and Health (STH).
    Shahgaldi, Kambiz
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, Jacek
    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 artery2010In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, no 7, p. 630-636Article in journal (Refereed)
    Abstract [en]

    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.

  • 2. Fraser, A G
    et al.
    Payne, N
    Mädler, C F
    Janerot-Sjoberg, B
    Hälsouniversitetet Linköping.
    Lind, B
    Grocott-Mason, R M
    Ionescu, A A
    Florescu, N
    Wilkenshoff, U
    Lancellotti, P
    Wütte, M
    Brodin, L A
    Feasibility and reproducibility of off-line tissue Doppler measurement of regional myocardial function during dobutamine stress echocardiography.2003In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 4, no 1, p. 43-53Article in journal (Refereed)
    Abstract [en]

    AIMS: Off-line post-processing of colour tissue Doppler from digital loops may allow objective quantification of dobutamine stress echocardiography. We assessed the reproducibility of off-line measurements of regional myocardial velocities.

    METHODS AND RESULTS: Nine observers analysed 10 studies, each making 2400 observations. Coefficients of variation in basal segments from apical windows, at rest and maximal stress, were 9-14% and 11-18% for peak systolic velocity, 16-18% and 17-19% for time-to-peak systolic velocity, 9-17% and 18-24% for systolic velocity time integral, and 18-23% and 21-27% for systolic acceleration. Coefficients of variation for diastolic velocities in basal segments at rest were 11-40%. Coefficients of variation for peak systolic velocity were 10-24% at rest and 14-28% at peak in mid segments, and 19-53% and 29-69% in apical segments. From parasternal windows coefficients of variation for peak systolic velocity were 14-16% in basal posterior, and 19-29% in mid-anterior segments. High variability makes measurement unreliable in apical and basal anterior septal segments. The feasibility of obtaining traces was tested in 92 subjects, and >90% in all basal and mid segments apart from the anterior septum.

    CONCLUSION: Quantification of myocardial functional reserve by off-line analysis of colour tissue Doppler acquired during dobutamine stress is feasible and reproducible in 11 segments of the left ventricle. The most reliable measurements are systolic velocities of longitudinal motion in basal segments.

  • 3. Govind, Satish C.
    et al.
    Gopal, Aasha S.
    Netyo, Anita
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Patrianakos, Alexandros
    Ramesh, S. S.
    Saha, Samir
    Quantification of low-dose dobutamine stress using speckle tracking echocardiography in coronary artery disease2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 5, p. 607-612Article in journal (Refereed)
    Abstract [en]

    Aims We sought to evaluate the utility of speckle tracking echocardiography (STE) for detecting left ventricular (LV) mechanical abnormalities during low-dose (20 mu g) dobutamine stress (DSE). Methods and results Twenty-nine patients (56 +/- 12 years) with a history of recent acute coronary events (ACE) underwent STE-DSE. Left ventricular images, sampled at frame rates 70-100 Hz, were analysed off-line (Echopac BT 6.0.0). Velocity, strain, and rotational imaging were performed. Twenty patients had LV ejection fraction (EF) >40% (Group 1) whereas nine patients had LVEF <40% (Group 2). Average heart and frame rates were identical during DSE in the two groups (P = ns). Global circumferential strain (%) was significantly lower in Group 2 compared with Group 1 (10.65 +/- 5.30 vs. 16.82 +/- 6.61; P < 0.05) at rest and during peak stress (14.72 +/- 6.51 vs. 21.13 +/- 7.2; P < 0.05). The global peak rotation rate (degree/s) was, however, higher at rest in Group 2 (70 +/- 97 vs. 19 +/- 67; P < 0.05) and 20 mu g stress. Peak systolic velocity increased in three of the four LV walls at 20 mu g ( in Groups 1 and 2). A global rotational rate increased significantly at 20 mu g during systole in both the groups, but was unchanged in Group 2 during diastole. Conclusions Speckle tracking echocardiography dobutamine stress appears to provide comprehensive information on LV mechanical status in the aftermath of ACE. The modality may help risk stratify such patients.

  • 4.
    Lind, Britta
    et al.
    Karolinska Institutet.
    Nowak, J.
    Cain, P.
    Quintana, M.
    Brodin, Lars-Åke
    Karolinska Institutet.
    Left ventricular isovolumic velocity and duration variables calculated from colour-coded myocardial velocity images in normal individuals2004In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 5, no 4, p. 284-293Article in journal (Refereed)
    Abstract [en]

    Aims: To describe the normal myocardial velocity profile during the isovolumic contraction and relaxation period at four different locations within left ventricular base and to establish normal age and gender related isovolumic time and velocity values. Methods and results: In 49 healthy individuals (26 women/23 men) in age groups 21-49 and 50-76 years, tissue velocity profiles and 2D-data were acquired at high temporal resolution (90-147 frames/s) for a subsequent off-line analysis using software enabling retrieval of myocardial Doppler velocity and 2D/anatomical M-mode information from different cardiac locations during the same cardiac cycle. The obtained velocity curves during the isovolumic contraction and relaxation period were usually biphasic and displayed clear regional differences in their respective positive and negative maximal velocities. Besides some gender related differences, mainly in the duration of the positive and negative velocity wave components during the isovolumic contraction period, a clear age-dependent increase in the duration of the isovolumic relaxation phase and its negative and positive velocity components was observed. Conclusion: Modern tissue Doppler imaging supplemented by anatomical M-mode images of the mitral and aortic valve movements allows a proper analysis of the rapid isovolumic myocardial movements. The presented normal isovolumic time and velocity values may prove useful for studies of myocardial function.

  • 5.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shahgaldi, Kambiz
    Winter, Reidar
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Comparison between colour-coded and spectral tissue Doppler measurements of systolic and diastolic myocardial velocities: effect of temporal filtering and offline gain setting2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 3, p. 406-413Article in journal (Refereed)
    Abstract [en]

    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.

  • 6.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Evaluation of tissue Doppler-based velocity and deformation imaging: a phantom study of ultrasound systems.2011In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 12, no 6, p. 467-476Article in journal (Refereed)
    Abstract [en]

    AIMS: The objective of this study was to test the accuracy and diagnostic interchangeability of tissue Doppler-based displacement, velocity, strain, and strain rate measurements in commercially used ultrasound (US) systems. METHODS AND RESULTS: Using an in-house made phantom, four different US scanner models were evaluated. Two different scanners of the same model were tested, and one scanner acquisition was tested twice with two generations of the same workstation giving six test results in total. The scanners were in active clinical use and are subject to regular maintenance checks. There were three displacement and four velocity results that stood out from the rest and could be regarded as accurate and interchangeable. Among the deformation measurements, three acceptable strain results were found while there were no acceptable strain rate results. Furthermore, the study showed that measurements from scanners of the same model, same acquisition post-processed on different workstations and repeated measurements from the same scanner, can yield disparate results. CONCLUSION: Measurements that are accurate and of interchangeable use can be found for displacement and velocity measurements, but are less likely to be found for strain and strain rate measurements. It is strongly recommended that the ability of each individual US scanner to measure displacement, velocity, strain, and strain rate is evaluated before it is introduced into clinical practice, and it must always be evaluated together with the workstation the scanner is intended to be used in conjunction with.

  • 7.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Olsson, Mats
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ultrasound transducer function: annual testing is not sufficient2010In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, no 9, p. 801-805Article in journal (Refereed)
    Abstract [en]

    The objective was to follow-up the study 'High incidence of defective ultrasound transducers in use in routine clinical practice' and evaluate if annual testing is good enough to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level. A total of 299 transducers were tested in 13 clinics at five hospitals in the Stockholm area. Approximately 7000-15 000 ultrasound examinations are carried out at these clinics every year. The transducers tested in the study had been tested and classified as fully operational 1 year before and since then been in normal use in the routine clinical practice. The transducers were tested with the Sonora FirstCall Test System. There were 81 (27.1%) defective transducers found; giving a 95% confidence interval ranging from 22.1 to 32.1%. The most common transducer errors were 'delamination' of the ultrasound lens and 'break in the cable' which together constituted 82.7% of all transducer errors found. The highest error rate was found at the radiological clinics with a mean error rate of 36.0%. There was a significant difference in error rate between two observed ways the clinics handled the transducers. There was no significant difference in the error rates of the transducer brands or the transducers models. Annual testing is not sufficient to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level and it is strongly advisable to create a user routine that minimizes the handling of the transducers.

  • 8.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Olsson, Mats
    Segall, Björn
    Fraser, Alan G.
    Winter, Reidar
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    High incidence of defective ultrasound transducers in use in routine clinical practice2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 3, p. 389-394Article in journal (Refereed)
    Abstract [en]

    The objective was to evaluate the function of ultrasound transducers in use in routine clinical practice and thereby estimating the incidence of defective transducers. The study comprised a one-time test of 676 transducers from 7 manufacturers which were in daily use in clinical departments at 32 hospitals. They were tested with the Sonora FirstCall Test System; 39.8% exhibited a transducer error. Delamination was detected in 26.5% and break in the cable was detected in 8.4% of the tested transducers. Errors originating from the piezoelectrical elements were unusual. Delamination and short circuit occurred without significant differences between transducers from all tested manufacturers, but the errors break in the cable, weak and dead element showed a statistically significant higher frequency in transducers from certain manufacturers. The high error frequency and the risk for incorrect medical decisions when using a defective transducer indicate an urgent need for increased testing of the transducers in clinical departments.

  • 9.
    Quintana, M
    et al.
    Karollinska Institutet.
    Gustafsson, T
    Karollinska Institutet.
    Sundblad, Patrik
    Karollinska Institutet.
    Langanger, J
    Karollinska Institutet.
    The effects of heart rate on myocardial velocity and atrio-ventricular displacement during exercise with and without beta-blockade: a tissue Doppler echocardiographic study2005In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 6, no 2, p. 127-133Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Colour tissue Doppler echocardiography (TDE) allows an objective assessment of regional myocardial function. Peak systolic velocity (PSV) and A-V plane displacement (AVPD) obtained from colour TDE correlate well with changes in cardiac wall motion and can discriminate ischemic areas during stress echocardiography. During exercise, the relationship between PSV and AVPD depends on several factors besides ischemia and should be considered when performing exercise stress echocardiography.

    AIMS:

    To investigate the relation between PSV, AVPD and heart rate (HR) during semi-upright exercise with and without beta-blockade.

    SUBJECTS AND METHODS:

    Twelve healthy men underwent semi-upright exercise stress echocardiography with and without beta-blockade on two separate occasions. Standard echocardiographic projections were used for the stress echocardiography. Grey-scale echocardiographic pictures containing colour TDE information were obtained at rest and during a two-stage exercise test, and the images were analyzed off-line. The PSV and AVPD were measured at four points at the base of the left ventricle at the septum and lateral, inferior and anterior walls.

    RESULTS:

    PSV, AVPD and HR gradually increased during exercise. The increases in PSV and AVPD were linearly correlated with the increase in HR. The increases in PSV were significantly lower during exercise with beta-blockade than without beta-blockade (P<0.05). This was not observed in AVPD, as increments were not affected by beta-blockade.

    CONCLUSION:

    These data showing a relationship between HR and PSV, and a significantly lower PSV with beta-blockade at a given HR, suggest that PSV is influenced by HR and myocardial contractility, both of which are augmented by physical exercise-induced sympathetic stimulation.

  • 10. Saha, Samir
    et al.
    Nowak, Jacek
    Storaa, Camilla
    Mädler, C. F.
    Fraser, Alan
    Roumina, Simin
    Lind, Britta
    Department of Clinical Physiology, Karolinska University Hospital, Huddinge.
    Brodin, Lars-Ake
    Department of Clinical Physiology, Karolinska University Hospital, Huddinge.
    Functional diagnosis of coronary stenosis using tissue tracking provides best sensitivity and specificity for left circumflex disease: experience from the MYDISE (myocardial Doppler in stress echocardiography) study.2005In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 6, no 1, p. 54-63Article in journal (Refereed)
    Abstract [en]

    AIMS: To evaluate the diagnostic capacity of quantitative analysis of segmental longitudinal myocardial displacement images (tissue tracking, TT) during dobutamine stress echocardiography for the detection of patients with coronary artery disease (CAD).

    METHODS AND RESULTS: TT-generated colour-coded maps of systolic segmental longitudinal displacement were obtained by post-processing of echocardiographic data from 105 patients with CAD and 90 low risk individuals selected from MYDISE database. Quantitative analysis of the distribution pattern of segmental displacement during dobutamine stress was most successful when a ratio of basal (high amplitude) to apical (low amplitude) colour-coded displacement bands (B/A ratio) was employed. Applied in four different left ventricular sectors, the B/A ratio provided a significant discrimination of patients with CAD (p<0.05 in the anterior and p<0.001 in the inferior wall) as assessed by receiver operating characteristic analysis. The procedure was most sensitive when applied in inferior wall for the detection of left circumflex coronary artery disease, the B/A ratio of 0.8 giving the best combination of sensitivity (77+/-8%) and specificity (77+/-5%) values.

    CONCLUSION: Quantification of dobutamine stress echocardiography using TT is an efficient diagnostic approach and a valuable additional modality in functional cardiac imaging for the initial identification of patients suspected for CAD.

  • 11. Storaa, Camilla
    et al.
    Cain, Peter
    Olstad, Bjørn
    Lind, Britta
    Department of Clinical Physiology, Karolinska University Hosp. Huddinge.
    Brodin, Lars-Ake
    Division of Medical Engineering, Karolinska Institutet.
    Tissue motion imaging of the left ventricle--quantification of myocardial strain, velocity, acceleration and displacement in a single image2004In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 5, no 5, p. 375-385Article in journal (Refereed)
    Abstract [en]

    AIMS: Several methods of parametric imaging of left ventricular function including tissue velocity imaging (TVI) and strain rate imaging (SRI) have previously been presented, however, they have the limitation that they can, respectively, portray only one physiological myocardial parameter. The aims of this pilot study were to implement and validate tissue motion imaging (TMI) for the first time, a visualization technique which permits acceleration, velocity, displacement and strain to be interpreted quantitatively or semi-quantitatively in a single image.

    METHODS AND RESULTS: TMI is achieved by the color coding of temporal tissue velocity integrals. The principles behind this technique are validated, and case examples demonstrating its use in the clinical setting are provided. Limitations of the method as well as future applications and improvements are discussed.

    CONCLUSION: As this method allows representation of a multitude of variables and is visually attractive, it may facilitate more widespread use of myocardial quantitation in everyday practice.

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