COMPARISON OF DOBUTAMINE TRANSESOPHAGEAL ECHOCARDIOGRAPHY AND DOBUTAMINE MAGNETIC-RESONANCE-IMAGING FOR DETECTION OF RESIDUAL MYOCARDIAL VIABILITY

A dobutamine-induced contraction reserve in akinetic but viable myocar dium, observed by echocardiography or magnetic resonance imaging (MRI) , is a reliable indicator of myocardial viability. However, the compar ative diagnostic accuracy of these 2 techniques is unknown. Therefore, 43 patients with myocardial infarction (infarct age greater than or e qual to 4 months) and regional akinesia underwent dobutamine transesop hageal echocardiography (TEE) and dobutamine MRI (10 mu g dobutamine/m in/kg). Both imaging techniques were compared with the reference stand ard F-18-fluorodeoxyglucose positron emission tomography (FDG PET). An infarct region was considered viable if a dobutamine contraction rese rve could be assessed visually by TEE or quantitatively by MRI in grea ter than or equal to 50% of segments graded ''a'' or dyskinetic at res t. Infarct regions were graded viable by PET if FDG uptake was greater than or equal to 50% of the maximal FDG uptake in a region with norma l wall motion by left ventriculography. A dobutamine contraction reser ve was found in 21 of 43 patients (49%) by TEE and MRI. A viable infar ct region by FDG PET was diagnosed in 26 of 43 patients (60%). FDG upt ake and dobutamine TEE were concordant in 36 of 43 patients (84%) and dobutamine MRI and FDG PET were concordant in 38 of 43 patients (88%). Sensitivity and specificity of dobutamine TEE and dobutamine MRI for FDG PET-defined myocardial viability were 77% versus 81% and 94% versu s 100%, respectively. Both imaging techniques yielded similar results for the detection of myocardial viability as defined by FDG uptake, wi th a slightly higher sensitivity and specificity for the quantitativel y evaluated dobutamine contraction reserve by MRI.