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Wave intensity wall analysis: a novel noninvasive method to measure wave inntensity
KTH, School of Technology and Health (STH), Medical Engineering.ORCID iD: 0000-0002-5795-9867
KTH, School of Technology and Health (STH), Medical Engineering.
KTH, School of Technology and Health (STH), Medical Engineering.
KTH, School of Technology and Health (STH), Medical Engineering.
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2009 (English)In: Heart and Vessels, ISSN 0910-8327, E-ISSN 1615-2573, Vol. 24, 357-365 p.Article in journal (Refereed) Published
Abstract [en]

Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.

Place, publisher, year, edition, pages
2009. Vol. 24, 357-365 p.
Keyword [en]
Wave intensity; Ultrasound; Speckle tracking; Arterial stiffness
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
URN: urn:nbn:se:kth:diva-11743DOI: 10.1007/s00380-008-1112-3ISI: 000270225400007PubMedID: 19784819Scopus ID: 2-s2.0-70349641505OAI: oai:DiVA.org:kth-11743DiVA: diva2:280820
Note

QC 20100624

Available from: 2009-12-14 Created: 2009-12-11 Last updated: 2017-12-12Bibliographically approved
In thesis
1. New ultrasonographic approaches to monitoring cardiac and vascular function
Open this publication in new window or tab >>New ultrasonographic approaches to monitoring cardiac and vascular function
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Atherosclerotic cardiovascular disease is the leading cause of death worldwide. To decrease mortality and morbidity in cardiovascular disease, the development of accurate, non-invasive methods for early diagnosis of atherosclerotic cardiac and vascular engagement is of considerable clinical interest. Cardiovascular ultrasound imaging is today the cornerstone in the routine evaluation of cardiovascular function and recent development has resulted in two new techniques, tissue velocity imaging (TVI) and speckle tracking, which allow objective quantification of cardiovascular function. TVI and speckle tracking are the basis for three new approaches to cardiac and vascular monitoring presented in this thesis: wave intensity wall analysis (WIWA), two-dimensional strain imaging in the common carotid artery, and the state diagram of the heart.

 

WIWA uses longitudinal and radial strain rate as input for calculations of wave intensity in the arterial wall. In this thesis, WIWA was validated against a commercially available wave intensity system, showing that speckle tracking-derived strain variables can be useful in wave intensity analysis. WIWA was further tested in patients with end stage renal disease and documented high mortality in cardiovascular disease. The latter study evaluated the effects of a single session of hemodialysis using WIWA and TVI variables and showed improved systolic function after hemodialysis. The results also indicated that preload-adjusted early systolic wave intensity obtained by the WIWA system may contribute in the assessment of left ventricular contractility in this patient category. Two-dimensional strain imaging in the common carotid artery is a new approach showing great potential to detect age-dependent differences in mechanical properties of the common carotid artery. Among the measured strain variables, global circumferential strain had the best discriminating performance and appeared to be superior to conventional measures of arterial stiffness such as elastic modulus and β stiffness index. The state diagram is a visualisation tool that provides a quantitative overview of the temporal interrelationship of mechanical events in the left and right ventricles. Case examples and a small clinical study showed that state diagrams clearly visualize cardiac function and can be useful in the detection of non ST-elevation myocardial infarction (NSTEMI).

 

Even though WIWA, two-dimensional strain imaging in the common carotid artery and the state diagram show potential to be useful in the evaluation of cardiovascular function, there still remains a considerable amount of work to be done before they can be used in the daily clinical practice.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. xiv, 47 p.
Series
Trita-STH : report, ISSN 1653-3836 ; 2009:7
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-11760 (URN)978-91-7415-525-9 (ISBN)
Public defence
2010-01-22, 3-221, Alfred nobels alle 10, Huddinge, 13:00 (Swedish)
Opponent
Supervisors
Note
QC 20100705Available from: 2009-12-14 Created: 2009-12-11 Last updated: 2010-07-05Bibliographically approved
2. Quantification and Visualization of Cardiovascular Function using Ultrasound
Open this publication in new window or tab >>Quantification and Visualization of Cardiovascular Function using Ultrasound
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is a large need for accurate methods detecting cardiovascular diseases, since they are one of the leading causes of mortality in the world, accounting for 29.3% of all deaths. Due to the complexity of the cardiovascular system, it is very challenging to develop methods for quantification of its function in order to diagnose, prevent and treat cardiovascular diseases. Ultrasound is a technique allowing for inexpensive, noninvasive imaging, but requires an experienced echocardiographer. Nowadays, methods like Tissue Doppler imaging (TDI) and Speckle tracking imaging (STI), measuring motion and deformation in the myocardium and the vessel walls, are getting more common in routine clinical practice, but without a proper visualization of the data provided by these methods, they are time-consuming and difficult to interpret. Thus, the general aim of this thesis was to develop novel ultrasound-based methods for accurate quantification and easily interpretable visualization of cardiovascular function.

Five methods based on TDI and STI were developed in the present studies. The first study comprised development of a method for generation of bull’s-eye plots providing a color-coded two-dimensional visualization of myocardial longitudinal velocities. The second study proposed the state diagram of the heart as a new circular visualization tool for cardiac mechanics, including segmental color-coding of cardiac time intervals. The third study included development of a method describing the rotation pattern of the left ventricle by calculating rotation axes at different levels of the left ventricle throughout the cardiac cycle. In the fourth study, deformation data from the artery wall were tested as input to wave intensity analysis providing information of the ventricular – arterial interaction. The fifth study included an in-silico feasibility study to test the assessment of both radial and longitudinal strain in a kinematic model of the carotid artery.

The studies showed promising results indicating that the methods have potential for the detection of different cardiovascular diseases and are feasible for use in the clinical setting. However, further development of the methods and both quantitative comparison of user dependency, accuracy and ease of use with other established methods evaluating cardiovascular function, as well as additional testing of the clinical potential in larger study populations, are needed.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. x, 72 p.
Series
Trita-STH : report, ISSN 1653-3836 ; 2009:6
Keyword
Ultrasound, Tissue Doppler imaging, Speckle tracking imaging, cardiovascular function, visualization, quantification
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-11762 (URN)978-91-7415-524-2 (ISBN)
Public defence
2010-01-22, 3-221, Alfred Nobels Alle 10, Huddinge, 08:30 (Swedish)
Opponent
Supervisors
Note
QC 20100727Available from: 2009-12-14 Created: 2009-12-11 Last updated: 2010-10-04Bibliographically approved

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Larsson, Matilda

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