©Walter Rasmussen, R.D.C.S.
Mitral Valve Annulus Tissue Doppler Imaging (TDI)
Mitral Valve Annulus Tissue Velocity Imaging (TVI)
PW Doppler of Doppler Tissue Imaging (TDI or TVI) of the lateral mitral annulus.
Spectral Doppler recording of TDI
Mitral valve tissue Doppler imaging is a technique for recording the axial (apex to base) movement of the left ventricle from the apical window. This recording mode is used to help assess the systolic and diastolic motion of the left ventricular myocardium and to characterize left ventricular diastolic function.
The tissue Doppler imaging application can be started by pressing a button labeled either “TDI” or “TVI”, depending upon the manufacturer.
In the apical four-chamber view, the mitral annulus is located where the mitral valve leaflet inserts at the atrio-ventricular junction (on the right side of the image). It is important that the PW Doppler cursor is aligned with the long axis of the heart in order to produce the maximum Doppler shift.
Start the Doppler tissue application and place the PW Doppler sample volume at the lateral mitral annulus. Initialize pulsed Doppler and adjust the scale on the strip chart to include the full systolic and diastolic amplitude of the recording. Make adjustments to the gain, dynamic range and compression so that its edge is clearly seen. If the patient is in normal sinus rhythm or is A-V paced, there should be two distinct, narrow, negative peaks visible on the recording, called E prime and A prime and one broad positive peak, called the S wave.
The first negative peak, E’ (“E prime”) is seen in early to mid-diastole and the second negative peak, A’ (“A prime”), is seen in late-diastole, is concurrent with the P wave on the ECG. Record the highest velocities of the E’ and A’ portions of the cardiac cycle. This may require careful adjustments to the sample volume position. As with all Doppler recordings, it is important to record at least two serial beats that both demonstrate the highest velocities obtainable and look identical to one another. If patient respiration makes consistent recording difficult, have the patient suspend breathing so that the annulus does not drift in and out of the sample volume area.
For patients with a heart rhythm other than sinus or paced, the primary goal should be to record the highest velocities and the most regular sections of irregular rhythms. Do not record beats caused by premature ventricular contractions because the altered contraction patterns they cause will not be useful for assessment of diastolic function.
The above steps for recording E’ and A’, can be repeated with the sample volume placed at the septal aspect of the mitral annulus, if required.
Correct placement of the sample volume is important for accurate assessment of diastolic function because a convincing recording can be produced even when the sample volume is placed incorrectly. Careful adjustment of the sample volume size or position can help to eliminate interference caused by atrial flutter or fibrillation.
Some ultrasound machines can display Doppler and imaging simultaneously (Duplex Doppler), which should be switched to live Doppler only if a poorly defined PW DTI signal it is present.