Mohd Farid

Mohd Farid

Monday, December 30, 2013

Tissue Doppler Imaging : Tissue Velocity Gradient



Tissue Velocity Gradient

TDI can measure the difference in velocities of adjacent myocardial tissues (velocity gradient), and this can be used to assess the viability and deformation (strain) of the myocardium. The velocity of the endocardium is normally higher than that of the epicardium, thus producing a tissue velocity gradient. In akinetic but viable or nontransmurally infracted myocardium, the myocardial velocity gradient persists, but there is no velocity gradient in scarred or transmurally infarcted myocardium. 

Because days to weeks are needed for myocardial contractility to recover after successful reperfusion of an occluded coronary artery, measurements of the tissue velocity gradient can be useful in patients with an acute myocardial infarction. To record or display the myocardial velocity gradient, the direction of myocardial contractility needs to be aligned in parallel with the direction of the ultrasound beam. Therefore, imaging views are limited to the parasternal windows to image anterior or posterior walls.

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