Background: Doppler Tissue Imaging (DTI) is an emerging non-invasive
ultrasound technique, which allows measuring velocities at any point of the
ventricular wall during the cardiac cycle.
Objective: To evaluate the clinical feasibility of DTI as a new method for detection
and quantification of regional Wall Motion Abnormalities (WMA) in patients with
old Myocardial Infarction (MI).
Patients: Fourty patients with old MI who had angiographically-documented
significant stenotic lesion in the infarct-related artery and WMA in the infarcted area
were evaluated in addition to twenty healthy subjects(control group).
Methods: Regional wall motion of each of the anterior and inferior wall segments of
the left ventricle was assessed by conventional 2-D echocardiography and pulsed
wave DTI. The later includes the measurement of Peak Myocardial Velocity (PMV)
and Myocardial Velocity Gradient (MVG).
Results: The peak MV and MVG in the studied myocardial segments of control
subjects ranged between 4 to 15 cm/s and 1 to 3.85 cmsa respectively. In patients
group, Myocardial segments supplied by diseased coronary vessel in the infarcted
area were found to have highly significant reduction of both MV & MVG compared
to the same segments in control subjects (p<0.001). The sensitivity for detection of
WMA was markedly improved by DTI studies (92.5% for MV and 100% for MVG
versus 52.5 % for 2-D echo) with retaining the high specificity inherited by
conventional echocardiography.
Conclusion: Compared to conventional 2-D echo, pulsed wave DTI is an accurate,
highly sensitive non-invasive method to detect and quantify regional WMA induced
by coronary artery disease. It is almost as accurate as contrast ventriculography in this
regard, so it may be the best imaging technique for detection of WMA at rest and with
different cardiovascular stresses. |
