Assessment of the physiologic significance of coronary disease with dipyridamole real-time myocardial contrast echocardiography. Comparison with technetium-99m sestamibi single-photon emission computed tomography and quantitative coronary angiography.
OBJECTIVE
The purposes of this study were to test whether quantitative real-time myocardial contrast echocardiography (RT-MCE) can detect coronary disease during pharmacologic stress and to compare this approach with single-photon emission computed tomography (SPECT).


BACKGROUND
Assessing myocardial perfusion during stress is important for the diagnosis and risk stratification of patients with coronary disease.


METHODS
Thirty-five patients referred for coronary angiography underwent RT-MCE and technetium-99m methoxyisobutylisonitrile (MIBI) SPECT at baseline and after 0.84 mg/kg dipyridamole. The modalities of RT-MCE and SPECT were analyzed both qualitatively and quantitatively. For this purpose, myocardial flow reserve was calculated from microbubble replenishment curves, and regional MIBI uptake was measured on circumferential profiles. Segments and vascular territories were categorized into five groups with increasing stenosis severity by quantitative coronary angiography.


RESULTS
With dipyridamole, beta and A x beta increased in all but the highest stenosis severity group. The increase in beta and A x beta was significantly lower in territories supplied by stenotic arteries than in those supplied by arteries with <50% stenosis. Graded decreases in beta and A x beta reserves were noted with increasing stenosis severity. Using the cutoff value of 2.00 for beta reserve, quantitative RT-MCE correctly identified 97% of the territories supplied by significant stenoses and 82% of those supplied by normal arteries. In contrast, quantitative SPECT correctly identified only 71% of the territories supplied by significant stenoses and 81% of those supplied by normal arteries.


CONCLUSIONS
This study shows that RT-MCE, with dipyridamole, can define the presence and severity of coronary disease in a manner that compares favorably with quantitative SPECT.
Peltier
Marcel
M
Divisions of Cardiology and Nuclear Medicine, Université Catholique de Louvain, Brussels, Belgium.
Vancraeynest
David
D
Pasquet
Agnès
A
Ay
Taniyel
T
Roelants
Véronique
V
D'hondt
Anne Marie
AM
Melin
Jacques A
JA
Vanoverschelde
Jean Louis J
JL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology; D003326:Coronary Circulation / Q000502:physiology; D004176:Dipyridamole; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006334:Heart Function Tests / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014665:Vasodilator Agents
D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi