POWER DOPPLER VS SUBTRACTED GREY SCALE FOR MYOCARDIAL
CONTRAST ECHO: DIFFERENCES IN SENSITIVITY RELATED TO SPECT DEFECT SEVERITY. B.
Haluska*, C Case, J Anderson, TH
Marwick. Princess
Alexandra Hospital, University of Queensland, Brisbane, Qld. Accuracy of
myocardial contrast echo (MCE) using gray scale (GS) is affected by regional
variations in baseline myocardiac brightness.
Harmonic power Doppler (HPD) and digitally subtracted color coded gray
scale (SCC) images may reduce the influence of baseline images but the relative
sensitivity of these techniques has not been defined. We sought to compare the sensitivities of GS, SCC and HPD based
on the severity of perfusion defect by SPECT. Methods. 49 pts
(age 61±11, 27 women) with known or suspected CAD were studied with
simultaneous MCE and SPECT after standard dipyridamole stress. MCE was performed with a harmonic transducer
(1.8MHz) and standard equipment using end-diastolic triggering at 1:4 and 1:6
after Levovist infusion (Schering).
Perfusion images were obtained in GS and HPD at baseline and during
infusion. MCE in basal, mid and apical
segts (4 chamber view) was scored by 2 expert observers as 0 (absent), 1
(incomplete) or 2 (complete). SPECT was
performed with Tc99m tetrafosmin, scored with the same system and also
quantitated (NIH Image) as %max saturation in the same segts. Results: 205 of
293 segs (70%) were normal. Proportion
of normal MCE (ie score 2) at each perfusion level are shown (*p<0.05 vs
gray scale); SPECT
level <60% 60-69% 70-79% >80% N 26 62 34 Gray
scale 65% 76% 70% 76% Subtracted
color coded 69% 67% 79%* 74% Harmonic
power Doppler 61% 79% 82%* 88%* Conclusion: Harmonic power Doppler appears to have greater
specificity than gray scale imaging and digital subtraction. There does not appear to be a significant
difference between the techniques in the presence of abnormal perfusion, either
with mild or severe defects.
