Real-time myocardial contrast echocardiography for the detection of stress-induced myocardial ischemia. Comparison with 99mTc-sestamibi single photon emission computed tomography.
BACKGROUND
Real-time contrast echocardiography (MCE) is a new promising technique for assessing myocardial perfusion. The purpose of this study was to test whether realtime MCE can be used to detect functionally significant coronary artery stenosis in patients with known or suspected coronary artery disease. Myocardial contrast echocardiographic studies were compared with nearly simultaneous 99mTc-sestamibi single photon emission computed tomography (SPECT) as a clinical standard reference to evaluate regional myocardial perfusion defects.


METHODS
Real-time MCE based on continuous infusion of Optison (8-10 ml/h) was performed in 66 patients during standard 99mTc-SPECT dipyridamole (0.56 mg/kg x 4 min) stress testing. Images were obtained in apical 4- and 2-chamber views, each divided into 6 segments. Tracer uptake and myocardial opacification were visually analyzed for each segment by two pairs of blinded observers and graded as normal, mildly reduced, severely reduced, or absent. In 792 myocardial segments, myocardial opacification by MCE was uninterpretable in 143 (18%) segments and tracer uptake by SPECT was not clearly defined in 92 (12%) segments. Interobserver variability for MCE was good with concordance rates of 83% (kappa=0.72) for rest- and 86% (kappa=0.76) for stress images. Overall concordance between MCE and SPECT was good (83%, kappa=0.63) at a segmental level. In the diagnosis of fixed and reversible defects, and of normal perfusion, concordance rates were 73, 65 and 83%, respectively. When analysis was performed at the regional level, we found comparable levels of concordance rates for LAD (83%, kappa=0.59), LCX (86%, kappa=0.64) and RCA (80%, kappa=0.68) perfusion territories.


CONCLUSIONS
These findings suggest that realtime MCE is a clinically acceptable method to evaluate myocardial perfusion defects during dipyridamole stress testing.
Dubart
A-E
AE
Department of Cardiology, Innere Medizin III, Im Neuenheimer Feld, 69120 Heidelberg, Germany.
Carvalho da Silva
K G
KG
Korosoglou
G
G
Bekeredjian
R
R
Hansen
A
A
Hardt
S
S
Rosenberg
M
M
Ferrari
N
N
Hoerig
B
B
Zehelein
J
J
Kuecherer
H
H
D000418:Albumins / Q000008:administration & dosage; D003287:Contrast Media / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology; D009862:Online Systems; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi