Magnetic resonance real-time imaging for the evaluation of left ventricular function

New ultrafast gradient systems and hybrid imaging sequences make it possibl e to acquire a complete image in real time, without the need for breathhold ing or electrocardiogram (ECG) triggering. In 21 patients, left ventricular function was assessed by the Else of a turbo-gradient echo technique, an e cho-planar imaging (EPI) technique, and a new real-time imaging technique. End-diastolic and end-systolic volumes, left ventricular muscle mass, and e jection fraction of the ultrafast techniques were compared with the turbo-g radient echo technique. Inter- and intraobserver variability was determined for each technique. image quality was sufficient for automated contour det ection in all but two patients in whom foldover occurred in the real-time i mages. Results of the ultrafast imaging techniques were comparable with con ventional turbo-gradient echo techniques. There was a tendency to overestim ate the end-diastolic volume by 3.9 and 1.3 mi with EPI real-time imaging, the end-systolic volume by 0.9 and 5.0 mi, and the left ventricular mass by 2.6 and 23.8 g. Ejection fraction showed a tendency to be overestimated by 1.1% with EPI and underestimated by 4.5% with real-time imaging. Correlati on between EPI, real-time imaging and turbo-gradient echo were 0.94 and 0.9 5 respectively, for end-diastolic volumes, 0.98 and 0.96 respectively: for end-systolic volumes, and 0.96 and 0.89, respectively, fur left ventricular mass. Inter- and intraobserver variability was low with all three techniqu es. Real-time imaging allows an accurate determination of left ventricular function without ECG triggering. Scan times can be reduced significantly wi th this new technique. Further studies will have to assess the value of rea l-time imaging for the detection of wall motion abnormalities and the imagi ng of patients with atrial fibrillation.