Comparison of myocardial contrast echocardiography with NC100100 and Tc-99m sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

Objective-To determine whether myocardial contrast echocardiography (MCE) f ollowing intravenous injection of perfluorocarbon microbubbles permits iden tification of resting myocardial perfusion abnormalities in patients who ha ve had a previous myocardial infarction. Patients and interventions-32 patients (mean (SD) age 66 (11) years) underw ent MCE after intravenous injection of NC100100, a novel perfluorocarbon co ntaining contrast agent, and resting Tc-99m sestamibi single photon emissio n computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect. Results-Among the 203 normally contracting segments, 151 (74%) were normall y perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptak e was mainly found among normally contracting segments from the inferior wa ll. By contrast, with MCE poor myocardial opacification was noted essential ly among the normally contracting segments from the anterior and lateral wa lls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects b y SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities we re seen more frequently among akinetic than hypokinetic segments. MCE corre ctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exc lusion of segments with attenuation artefacts (defined as abnormal myocardi al opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of t he detection of SPECT perfusion defects by MCE. Conclusions-The data suggest that MCE allows identification of myocardial p erfusion abnormalities in patients who have had a previous myocardial infar ction, provided that regional wall motion is simultaneously taken into acco unt.