Editorial
Expert Review of Cardiovascular Therapy Downloaded from informahealthcare.com by 186.14.5.145 on 05/20/14 For personal use only.
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Tissue Doppler and strain-rate imaging in cardiac ultrasound imaging: valuable tools or expensive ornaments? ‘It remains to be proven...whether the associated increased costs can translate into improved patient care.’ Expert Rev. Cardiovasc. Ther. 3(1), 1–4 (2005)
Cristina Pislaru† Patricia A Pellikka † Author for correspondence Mayo Clinic College of Medicine, Department of Physiology and Biomedical Engineering, 200 First Street, SW Rochester, MN 55905, USA Tel.: +1 507 266 0933 Fax: +1 507 266 0361
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10.1586/14779072.3.1.1
Over the last 30 years, with the introduction Strain represents the relative deformation, of anatomic two-dimensional mode and Dop- while strain rate represents the speed of pler hemodynamics, echocardiography has deformation. As TDI appears less noisy than become a central part of cardiac imaging. The SRI, it is generally preferred. However, the novel technologies tissue Doppler imaging assessment of myocardial function is clearly (TDI) and strain-rate imaging (SRI) have more accurately evaluated by measuring recently been brought to the attention of prac- strain and strain rates [1–3,10,11]. On the ticing cardiologists. other hand, tissue veloc‘Current clinical reports Numerous experimental ities could be seen as animal and clinical studies suggest a promising role in having an advantage; for have confirmed the utility quantifying regional and instance, longitudinal of these techniques [1–7]. It global cardiac function.’ mitral and tricuspid annulus velocities repreis now the moment to verify how this information translates to patient sent the composite motion of entire myocarcare. Current clinical reports suggest a promis- dial walls; therefore, they may be better ing role in quantifying regional and global car- indicators of global function. diac function by providing detailed information that is not easily obtainable using other imaging Advantages & disadvantages of tissue modalities. It remains to be proven how much Doppler & strain-rate imaging of this information is really necessary in clinical Both TDI and SRI provide quantitative practice, and whether the associated increased results, a clear improvement over semi-quanticosts can translate into improved patient care. tative or qualitative methods. Moreover, the measurement of wall motion using TDI/SRI What is measured with tissue Doppler & does not require accurate border detection. strain-rate imaging? Minor out-of-plane motion does not pose a TDI allows the measurement of speed of problem, in contrast to the measurement of the motion of the interrogated structure in rela- classic indices of shortening or thickening tion to the transducer. However, tissue using grayscale M-mode or two-dimensional velocities are confounded by velocities of echocardiography. The high temporal resoluadjacent structures. To distinguish wall teth- tion (>200 frames/s) afforded by TDI and SRI ering from true contraction, strain and techniques is higher than any existent nonstrain rate can be derived from tissue veloci- invasive imaging technique (
