- Meeting abstract
- Open Access
2120 Prospective correction of trigger delay errors caused by heart rate variability using the electrocardiogram during coronary artery imaging
© Liu and Wright; licensee BioMed Central Ltd. 2008
- Published: 22 October 2008
- Heart Rate Variability
- Imaging Window
- Elevated Heart Rate
- Trigger Delay
- Coronary Artery Imaging
Non-invasive alternatives to X-ray angiography, such as MR and MSCT angiography must acquire sub-image data over multiple heartbeats. The accompanying challenge of avoiding cardiac motion artifacts lies in accurately aligning acquisition windows to a low-motion cardiac phase, typically end-systole or diastasis. Using a subject-specific trigger delay reduces gating errors caused by variations in individual physiology. Intra-subject heart rate variability (HRV), however, is believed to be a significant cause of image degradation. We hypothesize that the effect of HRV on the timing of cardiac imaging windows can be predicted and corrected from the electrocardiogram (ECG). This is done through the prospective adjustment of trigger delay to changes in the RT interval of the ECG (ΔRTn) predicted by changes in the previous cardiac cycle duration (RRn-1) associated with HRV.
To improve the accuracy of cardiac gating to the onset of cardiac low-motion periods (LMPs) for non-invasive coronary artery imaging.
RTn vs. RRn-1 data were acquired from the ECG of 7 volunteers. Heart rate was varied by graded exercise. Subject-specific trigger delays for LMPs at end-systole and diastasis were obtained at baseline and elevated heart rates for the proximal right coronary artery via MR imaging. The use of ΔRTn from the RTn vs. RRn-1 relationship to correct the baseline trigger delays at elevated heart rates was evaluated.
In the presence of HRV, (1) changes in RT represent significant shifts in trigger delay and (2) end-systole provides a more robust imaging window than diastasis. The use of heart rate adaptive trigger delays based on RTn vs. RRn-1 from the ECG improves cardiac gating accuracy and imaging efficiency for a target image quality.
This article is published under license to BioMed Central Ltd.