Performance of QRS detection for cardiac magnetic resonance imaging with anovel vectorcardiographic triggering method

In many cardiac patients, image quality and/or scan efficiency is reduced d ue to imprecise R-wave ability to trigger the scan due to noise on the elec trocardiogram (ECG) caused by the magnetic resonance (MR) environment. We d eveloped a triggering system that uses the spatial information of the vecto rcardiogram (VCG) to minimize the effects of MR-related noise on triggering . Fifteen volunteers underwent standard cardiovascular MR exams, and a tota l of 52,474 R-waves were evaluated with the algorithm, giving a performance index of 99.91%. The mean propagation delay of the system was -10.64 +/- 3 .19 msec, which falls within the real-time definition for cardiac MRI trigg ering. Five patients had arrhythmias consisting of premature ventricular de polarizations (PVDs) and supraventricular extra systoles. For those patient s with PVDs, all arrhythmic beats were rejected unless they passed through the algorithm's reference point. The performance index for the arrhythmic p atients approached 100%. VCG-based triggering has been demonstrated to prov ide near 100% triggering performance during cardiac MR examinations. (C) 20 00 Wiley-Liss, Inc.