Gradient-echo magnetic resonance imaging during incremental dobutamine infusion for the localization of coronary artery stenoses.

Dobutamine pharmacological stress testing in conjunction with gradient-echo magnetic resonance imaging (MRI) may be a useful tool for the assessment of haemodynamically significant coronary artery stenoses. Therefore, 28 patients without previous myocardial infarction but significant proximal stenoses (> or = 70% diameter stenosis) of one or more coronary arteries were selected for dobutamine-MRI. Each patient underwent MRI at rest and during incremental dobutamine infusion (5, 10, 15 and 20 micrograms.kg-1.min-1). Additionally, all patients were submitted to exercise stress electrocardiography (EST). A total of 72 segments per patient obtained from identical short axis and transverse tomograms at rest and during dobutamine infusion were evaluated by two observers. Each segment was graded as normal, hypokinetic, akinetic or dyskinetic. Dobutamine-MRI was considered pathological if segmental wall motion deteriorated by at least one grade after dobutamine infusion. For comparison with coronary angiography, segmental wall motion gradings were related to the respective coronary artery territories. Peak rate-pressure product during steady-state dobutamine infusion (18.493 +/- 4.315 mmHg.min-1) was significantly lower (P < 0.01) than during EST (21.316 +/- 4.937 mmHg.min-1). Dobutamine-induced wall motion abnormalities were observed in 22/26 (85%) MR studies and 20/26 (77%) patients had a pathological EST. Regional asynergy induced by dobutamine-MRI occurred in 11/15 (73%) patients with single and 11/11 (100%) with multi-vessel disease. Sensitivity and specificity for the detection of a stenosed coronary artery were 87% and 100% for the left anterior descending, 62% and 93% for the left circumflex and 78% and 88% for the right coronary artery respectively.(ABSTRACT TRUNCATED AT 250 WORDS)