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- Saha, Samir, et al.
(författare)
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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.
- 2005
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 6:1, s. 54-63
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Storaa, Camilla, 1976-
(författare)
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Reproducibility and interpretation in tissue Doppler echocardiography
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As cardiovascular disease is the single most common cause ofdeath in the western world, and since there is a closeconnection between cardiovascular disease and left ventricular(LV) function, good methods for the assessment of LV functionis highly needed. A widely used tool for the diagnosis of LVdisease is echocardiography, a technique which today faces twodi_culties; the low reproducibility and the subjectiveinterpretation. The present dissertation aims to quantifyreproducibility, to study the factors that influencereproducibility and to provide tools for simplifying theinterpretation of tissue velocities measured by Dopplerultrasound.The reproducibility has been studied by letting twoindependent observers measure tissue Doppler velocities toinvestigate how well their measurements agree. To improvereproducibility an algorithm for the automatic detection ofpre-defined echocardiographic localizations is presented. Oneof the most difficult skills for the sonographer to master,thus leading to reduced reproducibility, is the transducermanipulation. The effect of poor transducer manipulation hasbeen modeled, and we show that even a poorly placed transducermay yield images which are easily mistaken for good, however,when scanning in two orthogonal planes the transducermisplacement is easily detected.Interpretation of the echocardiograms is influenced byseveral parameters. As the tissue velocities are measured byutilizing the Doppler effect, only the velocity componentdirected towards the transducer can be measured, thus thealignment of the heart within the view of the transduceraffects the tissue velocity measurements. The effect of thishas been investigated, and it is demonstrated that since themyocardium primarily has longitudinal motion and thus thevelocity vectors are mainly longitudinal, imaging in the apicalview will give little error in the velocity measurements.Filtering of the tissue velocity signals have becomecommercially available with the hope that it will improvereproducibility and simplify interpretation. One set of lowpass filters has been tested, and it is seen that there is arisk of overdoing the filtering and cause an underestimation oftissue velocity parameters. A similar effect to low passfiltering is seen when using too low sample rate when recordingthe tissue velocities.Finally a new imaging modality, tissue motion imaging, ispresented, where myocardial displacement, velocity, strain andacceleration may be interpreted from one single image, insteadof the situation today where several measurements must beperformed to get an overview of all these parameters.The thesis concludes that reproducibility can be improved bycurve smoothing and that interpretation can be simplified usingadvanced methods of parametric imaging.
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| 4. |
- Storaa, Camilla, et al.
(författare)
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Tissue motion imaging of the left ventricle--quantification of myocardial strain, velocity, acceleration and displacement in a single image
- 2004
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 5:5, s. 375-385
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Tidskriftsartikel (refereegranskat)abstract
- 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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