Absolute myocardial blood flow determination using real-time myocardial contrast echocardiography during adenosine stress: comparison with single-photon emission computed tomography

Abstract

Objective: To assess the feasibility and diagnostic accuracy of real-time myocardial contrast echocardiography (MCE)-derived absolute myocardial blood flow for detection of myocardial perfusion abnormalities compared with simultaneous technetium 99 m sestamibi single-photon emission computed tomography (SPECT).

Design: Prospective study.

Setting: Tertiary-care medical institution.

Patients: 79 patients with known or suspected coronary artery disease.

Interventions: Simultaneous SPECT and real-time MCE during adenosine stress.

Main outcome measures: Absolute myocardial blood flow (MBF, ml/min/g), microbubble velocity (β, min⁻¹), and reserve values. Endpoints included sensitivity, specificity, positive likelihood ratio (LR+) or negative likelihood ratio (LR−) and area under the curve (AUC) of the receiver operating characteristic curve.

Results: Reserve measurements were feasible in 975 of 1343 segments (73%); of these, 130 segments (13%) were abnormal by SPECT. MCE perfusion parameters clearly distinguished abnormal from normal segments for β reserve (1.13 (0.99) vs 2.22 (1.36), p<0.001) and MBF reserve (1.80 (2.29) vs 3.69 (2.79), p<0.001). The β reserve cut-off of 1.60 provided the following: AUC, 0.787; sensitivity, 82%; specificity, 66%; LR+, 2.40; and LR−, 0.28. The MBF reserve cut-off of 1.90 provided the following: AUC, 0.779; sensitivity, 73%; specificity, 72%; LR+, 2.69; and LR−, 0.37. MBF reserve had an AUC of 0.773 for the left anterior descending coronary artery, 0.885 for the left circumflex coronary artery and 0.739 for the right coronary artery.

Conclusions: Real-time MCE-derived absolute MBF, β, and reserve values are feasible and accurate for detecting myocardial perfusion abnormalities as defined by SPECT.