Measurement of myocardial blood flow velocity reserve with myocardial contrast echocardiography in patients with suspected coronary artery disease: comparison with quantitative gated Technetium 99m sestamibi single photon emission computed tomography.
BACKGROUND
The ability of high and low mechanical index (MI) imaging methods during myocardial contrast echocardiography (MCE) to assess the physiologic significance of coronary stenoses were compared with technetium 99m sestamibi single photon emission computed tomography (SPECT) in patients.


METHODS
Intermittent ultraharmonic imaging (high MI) and power modulation angio (low MI) were performed during continuous infusions of the echo-enhancing contrast agent, Optison, at rest and after dipyridamole stress in 39 patients. Technetium 99m sestamibi SPECT was performed simultaneously. Images from the 3 apical windows were divided into 6 walls. Myocardial blood flow (MBF) velocity and MBF velocity reserve were quantified from pulsing interval versus acoustic intensity MCE curves in each wall using postprocessed images.


RESULTS
Approximately 25% of the myocardial walls could not be analyzed from MCE because of artifacts. MBF velocity and MBF derived from both MCE methods increased significantly after dipyridamole in healthy patients (n = 143 and 129 walls for high and low MI, respectively), compared with those with either reversible (n = 11 and 10 walls for high and low MI, respectively) or fixed defects (n = 18 and 14 walls for high and low MI, respectively) on SPECT. Consequently, MBF velocity and MBF reserve were significantly greater for patients with normal perfusion. Receiver operator characteristic curves obtained for MBF velocity reserve provided a sensitivity and specificity of 82% and 87%, respectively, for high MI; versus 64% and 96%, respectively, for low MI imaging after uninterpretable images were excluded from analysis.


CONCLUSIONS
Both high and low MI MCE imaging techniques can be used to determine the presence of perfusion defects as identified by technetium 99m sestamibi SPECT. Low MI imaging methods have a number of drawbacks that limit its sensitivity compared with high MI techniques.
Dawson
Dana
D
Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, Virgina 22908-0158, USA.
Rinkevich
Diana
D
Belcik
Todd
T
Jayaweera
Ananda R
AR
Rafter
Patrick
P
Kaul
Sanjiv
S
Wei
Kevin
K
D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology*; D004176:Dipyridamole / Q000008:administration & dosage; D004452:Echocardiography; D025401:Echocardiography, Stress; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006346:Heart Septum / Q000000981:diagnostic imaging / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000737:chemistry*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents / Q000008:administration & dosage
D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi