Parallel imaging and dobutamine stress magnetic resonance imaging in patients with atypical chest pain or equivocal ECG not suitable for stress echocardiography.

The aim of this study was to evaluate the clinical utility of cardiac magnetic resonance imaging (MRI) with dobutamine stress in patients with atypical chest pain or equivocal electrocardiography (ECG) stress test, not suitable for stress echocardiography, using steady-state free-precession and parallel imaging technique. Thirty-three patients (22 men, 11 women; mean age 62.4 years) underwent MRI with a 1.5-Tesla imager (General Electric, HD). We used an eightchannel phase-array dedicated coil. The MRI protocol included short-axis cine steady-state sequences with fourchamber parallel imaging of the left ventricle outflow tract at rest and after stress induction. Images were acquired 3 min after the intravenous injection of 5,10, 20, 30 or 40 mu g/kg/min dobutamine. MRIs were analysed both at rest and at incremental dobutamine doses. Results were considered positive for coronary artery disease (CAD) if any new or worsening wall motion abnormality developed during the stress test. Twenty-two patients underwent coronary angiography; in the remaining ten, survival free from cardiovascular events over at least 9 months was considered as absence of disease. One patient presented severe hypertension at rest and was excluded from our study. We analysed 960 segments and observed appearance or worsening of kinesis in 29 different segments in seven patients. Seven patients were considered positive for CAD on the basis of new or worsening wall motion abnormalities during dobutamine stress, yielding an overall sensitivity of 85% and a specificity of 100% in CAD detection. Dobutamine stress cardiac MRI is an accurate method for assessing myocardial ischaemia in patients with CAD, and it could be useful as a noninvasive tool for excluding the disease. The increase in signal intensity and acquisition speed obtained by using steadystate free precession with parallel imaging proved useful in increasing test specificity with respect to previous similar studies.