Self-tracking of contrast kinetics for automatic triggering of contrast-enhanced whole-heart coronary magnetic resonance angiography.

PURPOSE

To develop a method for automatically triggering centric data acquisition during contrast-enhanced whole-heart coronary magnetic resonance angiography (MRA).

MATERIALS AND METHODS

The hypothesis of this work is that the blood signal changes during contrast infusion can be estimated by obtaining a projection of the heart during inversion-recovery prepared data acquisition. A validation study was performed on seven healthy volunteers to test this hypothesis. The peak blood signal enhancement detected from the projection was then used to automatically trigger the start of central k-space data acquisition. Simulations were performed to compare the signal-to-noise ratio (SNR) of the proposed self-triggering method with the fixed delay method. Six healthy volunteers were scanned on a 3T MR system using the proposed self-triggered method to test its effectiveness on coronary artery visualization.

RESULTS

Based on the validation study, the self-triggering method provides an accurate representation of the contrast enhancement. Based on the simulations, self-triggering with centric ordering is expected to give a 27% higher SNR than linear ordering with a fixed imaging delay. Self-triggering was successfully used in all volunteers and showed excellent depiction of the major coronary arteries.

CONCLUSION

The self-triggering method can be used to automatically determine the optimal delay time for central k-space acquisition, for each individual subject, without the need of any extra setup or user interaction.