Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
  1. Home
  2. Search

Refine search

Refine search

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

3 results

  • 14 - Ischemic heart disease

  • from Section 2 - Practical issues in transesophageal echocardiography
  • Edited by Robert Feneck, John Kneeshaw, Marco Ranucci
  • Book:
    Core Topics in Transesophageal Echocardiography
    Published online:
    10 May 2010
    Print publication:
    15 April 2010, pp 225-246

  • Summary

    Aortic valve (AV) disease is very common in Western populations. Aortic sclerosis is diagnosed when there is an ejection systolic murmur present in the AV region due to calcification in the ascending aorta, with associated turbulent flow. Aortic stenosis (AS) is differentiated from sclerosis when significant restriction of cusp movement and a raised transaortic peak velocity is seen on echocardiography. Transesophageal echocardiography (TEE) evaluation of AS starts with a 2D examination of the mid-esophageal short-axis (ME SAX) and long-axis (LAX) views of the valve. Continuous-wave Doppler (CWD) is applied to measure flow velocity across the valve and then calculate a pressure gradient using the Bernoulli equation. Aortic regurgitation (AR) results from a primary valve lesion, an abnormal aortic root and/or ascending aorta, or a combination of both. TEE is valuable in revealing important aspects of AV disease.

  • 18 - Infective endocarditis

  • from Section 2 - Practical issues in transesophageal echocardiography
  • Edited by Robert Feneck, John Kneeshaw, Marco Ranucci
  • Book:
    Core Topics in Transesophageal Echocardiography
    Published online:
    10 May 2010
    Print publication:
    15 April 2010, pp 294-309

  • Summary

    The long- and short-axis views of the right ventricle (RV) are defined by the corresponding views of the left ventricle (LV), but these two standard echocardiographic imaging planes often transect the RV in an oblique way. Discrete probe manipulations and the proper use of the multiplane capacity of transesophageal echocardiography (TEE) are often necessary to fully visualize the RV. Continuous-wave Doppler plays an important role in the study of pathological conditions of the RV and pulmonary circulation. Abnormalities in the shape and motion of the interventricular septum (IVS) reflect the altered pressure differences between the LV and RV. Tricuspid annular plane systolic excursion (TAPSE) corresponds to wall shortening of the RV free wall along its long axis. The total ejection isovolume (TEI) index or myocardial performance index is a Doppler derived measurement combining systolic and diastolic time intervals as a parameter of global ventricular function.

  • Chapter 9 - Ultrasonography and diagnosis of polycystic ovary syndrome

  • from Section 2: - Ultrasonography in infertility
  • Edited by Botros R. M. B. Rizk, University of South Alabama
  • Book:
    Ultrasonography in Reproductive Medicine and Infertility
    Published online:
    07 September 2011
    Print publication:
    25 March 2010, pp 75-80

  • Summary

    Ultrasound examination is now considered as part of almost every clinic setting. The creation of an image from sound is achieved in three steps: producing a sound wave, receiving echoes, and interpreting those echoes. The four different modes of ultrasound used in medical imaging are: A-mode, B-mode, M-mode and Doppler mode. The Doppler frequency shift information can be displayed graphically in various ways that include color Doppler (directional Doppler), power Doppler, and spectral (pulsed) Doppler. The different modes of Doppler waves include: Continuous-wave Doppler (CW) and Pulsed-wave Doppler (PW). The blood flow measurements are performed by calculation of velocity, calculation of absolute flow and flow waveform analysis. Despite its impressive safety record of ultrasound to date, the intensity (or acoustic output) level of ultrasound used to scan the fetus in utero has increased almost eightfold over the level that was allowed in the early 1990s.