Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Prenatal Tisse Velocity Imaging of the Heart: A new approach to assess fetal myocardial function
KTH, School of Technology and Health (STH), Medical Engineering.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The general aim of this thesis has been to evaluate color‐coded tissue velocity imaging (TVI) as an approach to developing a new, non‐invasive assessment method for fetal myocardial function. Such a method could hypothetically give early indications of fetal pathology, as myocardial dysfunction is often the consequence when the circulation tries to adapt to deteriorating situations. This would be beneficial in clinical decision making when evaluating fetal well‐being in a wide range of pregnancy associated conditions, to facilitate risk assessment and to monitor the benefit of therapeutic interventions.

TVI is an ultrasound technique that enables quantification of longitudinal myocardial motion with high temporal resolution, which is essential in the identification of fetal myocardial movements of short duration. Furthermore, the longitudinal motion is mainly determined by subendocardial fibers that usually become abnormal in the very early stages of cardiac dysfunction as they are sensitive to milder degrees of hypoxia. Thus, TVI has the potential to give early indications of impaired fetal myocardial function and hypothetically facilitate the detection of intrauterine hypoxia. Hypoxia is a common phenomenon of many pathological conditions in pregnancy, from which a substantial number of children either die or acquire permanent brain injury during delivery every year.

After having established optimal sampling requirements and ensured an acceptable reproducibility for TVI measurements of the fetal myocardium, normal reference values were determined feasible and sensitive enough to provide insight into maturational changes in myocardial function. This provided a foundation that should enable further investigations and was partly accomplished using the cardiac state diagram (CSD) to accurately time the myocardial events during a cardiac cycle according to the motion shifts of the atrioventricular plane.

The demonstrated results are promising and the general conclusion of this thesis is that TVI contributes to increasing the knowledge and understanding of fetal myocardial function and dysfunction. Used together with CSD this technique has great potential as an assessment method. However, further testing of the clinical potential is needed in larger study populations concerning the pathological or physiological questions at issue, and additional development of the method is required to render the method simple enough to be of potential aid in clinical practice.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. , xiv, 29 p.
Series
Trita-STH : report, ISSN 1653-3836 ; 2013:3
National Category
Medical Image Processing
Identifiers
URN: urn:nbn:se:kth:diva-120982OAI: oai:DiVA.org:kth-120982DiVA: diva2:616414
Public defence
2013-05-07, Sal 4-221, Alfred Nobels allé 12, Huddinge, 13:00 (Swedish)
Opponent
Supervisors
Note

QC 20130419

Available from: 2013-04-19 Created: 2013-04-16 Last updated: 2013-04-19Bibliographically approved
List of papers
1. Temporal frequency requirements for tissue velocity imaging of the fetal heart
Open this publication in new window or tab >>Temporal frequency requirements for tissue velocity imaging of the fetal heart
Show others...
2011 (English)In: Ultrasound in Obstetrics and Gynecology, ISSN 0960-7692, E-ISSN 1469-0705, Vol. 38, no 4, 413-417 p.Article in journal (Refereed) Published
Abstract [en]

Objectives The high velocity and short duration of myocardial motion requires a high sampling rate to obtain adequate temporal resolution; this issue becomes even more important when taking into consideration the high fetal heart rate. In this study we have established optimal sampling requirements for assessing the duration of various cardiac cycle events and myocardial velocities of the fetal heart using color-coded tissue velocity imaging (TVI). Methods Recordings from 30 fetuses were acquired at an initial frame rate of 180-273 frames/s. All TVI recordings were performed from an apical four-chamber view and stored as cineloops of five to 10 consecutive cardiac cycles for subsequent offline analysis using software enabling a reduction in frame rate. Different components of the myocardial velocity curve, obtained from the basal part of the ventricular septum, were measured at the initial frame rate and compared with their equivalents at gradually decreased frame rates. Results As acquisition frame rate was reduced, there was a marked increase in deviation from the initial values, resulting in an underestimation of all systolic and diastolic velocities. For the measured durations, there was a clear tendency to underestimate isovolumetric contraction and relaxation, and a clear tendency to overestimate ventricular ejection and diastolic E-wave and A-wave. An acceptable <= 5% deviation from the value obtained at the highest frame rate corresponded to measurements obtained at above 150-200 frames/s. Conclusions A high sampling rate of at least 200 frames/s is necessary for adequate reconstruction of TVI data for the fetal heart. Frame rates that are too low result in considerable loss of temporal and velocity information.

Keyword
fetal echocardiography, frame rate, sampling frequency, temporal frequency requirements, tissue velocity imaging
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-45593 (URN)10.1002/uog.8872 (DOI)000295727400008 ()2-s2.0-80052006941 (Scopus ID)
Note
QC 20111104Available from: 2011-11-04 Created: 2011-10-31 Last updated: 2017-12-08Bibliographically approved
2. Reproducibility and variability in the assessment of color-coded tissue velocity imaging of the fetal myocardium
Open this publication in new window or tab >>Reproducibility and variability in the assessment of color-coded tissue velocity imaging of the fetal myocardium
Show others...
2013 (English)In: Journal of biomedical graphics and computing, ISSN 1925-4008, Vol. 3, no 2Article in journal (Refereed) Published
Abstract [en]

Objective: The introduction of color-coded tissue velocity imaging (TVI) in fetal medicine is quite recent, and as this method is presently evaluated and developed in regard to diagnostic precision it is of outmost importance to evaluate the reproducibility for adequate clinical use. In this study, reproducibility and intra- and inter-observer variability was assessed for offline analysis as well as echocardiography investigations. Also, we evaluated the importance of exact placement of the region of interest (ROI).

Methods: TVI recordings from 21 fetuses, at a gestational age of 27 to 41 weeks, were acquired at 208-239 frames/s for subsequent offline analysis. All recordings were performed with the transducer positioned to provide an apical four-chamber view and the myocardial velocity data was obtained from basal inferoseptum. The data set was analyzed according to Bland-Altman and reproducibility was expressed as the standard error of a single determination, estimated from duplicate determinations in percentage of the total.

Results: The variation of reproducibility for the echocardiography investigation ranged from 2.0% to 9.8%. The duration of left ventricular ejection, and the peak velocities of early diastolic filling and atrial contraction being the most robust events measured. The variation of inter-observer variability for the echocardiography investigation ranged from 1.5% to 8.4%, and the variation of intra- and inter-observer variability for the offline analysis ranged from 1.2% to 10.4%. Least robust were the events of shortest duration, including isovolumetric contraction and relaxation.

Conclusion: We believe that TVI measurements of the fetal myocardium could be performed in the clinical routine with acceptable reproducibility.

National Category
Medical Image Processing
Identifiers
urn:nbn:se:kth:diva-120776 (URN)10.5430/jbgc.v3n2p16 (DOI)
Note

QC 20130419

Available from: 2013-04-16 Created: 2013-04-16 Last updated: 2017-01-12Bibliographically approved
3. Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study
Open this publication in new window or tab >>Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study
Show others...
2012 (English)In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 10, 19- p.Article in journal (Refereed) Published
Abstract [en]

Background: Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI). Methods: TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201-273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis. Results: Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E'/A' ratio also increased with gestational age, while a longitudinal shortening was demonstrated. Conclusions: Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal-and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.

Keyword
Atrioventricular plane displacement, Longitudinal shortening, Fetal heart contractility, Color-coded tissue velocity imaging, Intrauterine development
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:kth:diva-101133 (URN)10.1186/1476-7120-10-19 (DOI)000306787000001 ()
Note

QC 20120824

Available from: 2012-08-24 Created: 2012-08-23 Last updated: 2017-12-07Bibliographically approved
4. Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function
Open this publication in new window or tab >>Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function
Show others...
2013 (English)In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 11, no 1, 29- p.Article in journal (Refereed) Published
Abstract [en]

Objectives: Myocardial function can be evaluated using color-coded tissue velocity imaging (TVI) to analyze the longitudinal myocardial velocity profile, and by expressing the motion of the atrioventricular plane during a cardiac cycle as coordinated events in the cardiac state diagram (CSD). The objective of this study was to establish gestational age specific reference values for fetal TVI measurements and to introduce the CSD as a potential aid in fetal myocardial evaluation. Methods: TVI recordings from 125 healthy fetuses, at 18 to 42 weeks of gestation, were performed with the transducer perpendicular to the apex to provide a four-chamber view. The myocardial velocity data was extracted from the basal segment of septum as well as the left and right ventricular free wall for subsequent offline analysis. Results: During a cardiac cycle the longitudinal peak velocities of septum increased with gestational age, as did the peak velocities of the left and right ventricular free wall, except for the peak velocity of post ejection. The duration of rapid filling and atrial contraction increased during pregnancy while the duration of post ejection decreased. The duration of pre ejection and ventricular ejection did not change significantly with gestational age. Conclusion: Evaluating fetal systolic and diastolic performance using TVI together with CSD could contribute to increase the knowledge and understanding of fetal myocardial function and dysfunction. The pre and post ejection phases are the variables most likely to indicate fetuses with abnormal myocardial function.

Keyword
Color-coded tissue velocity imaging, Fetus, Myocardium, Normal reference values, Cardiac state diagram, Atrioventricular plane displacement, Myocardial time interval, Longitudinal myocardial peak velocity
National Category
Medical Image Processing
Identifiers
urn:nbn:se:kth:diva-120778 (URN)10.1186/1476-7120-11-29 (DOI)000323452000001 ()2-s2.0-84881513349 (Scopus ID)
Note

QC 20130912. Updated from submitted to published.

Available from: 2013-04-16 Created: 2013-04-16 Last updated: 2017-12-06Bibliographically approved

Open Access in DiVA

fulltext(874 kB)503 downloads
File information
File name FULLTEXT01.pdfFile size 874 kBChecksum SHA-512
909e0c6cebb2325bed877e65c9ad9a208c4190d2928ad0ae73da95d52e8b4875475d3c2eabd439df4d6f96fcc3433c43fff281beb222f0bca84f19ba556dfd44
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Elmstedt, Nina
By organisation
Medical Engineering
Medical Image Processing

Search outside of DiVA

GoogleGoogle Scholar
Total: 503 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 222 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf