Model-Free Slice Following Using the Cardiac Fat Navigator: Enhanced Gating Efficiency for 3D SSFP Coronary Magnetic Resonance Angiography

Pascal Spincemaille¹, Thanh Dang Nguyen¹, Martin Prince¹, Yi Wang¹

Coronary MRA routinely uses a diaphragm navigator combined with slice tracking to enhance navigator gating efficiency. The actual heart displacement is calculated from a linear model. Any breakdown in this correlation (such as in the case of hysteresis), degrades image quality. The cardiac fat navigator, which tracks epicardial fat, provides a direct measure of heart motion so that slice tracking does not require correction or calibration factors as is needed when cardiac motion is extrapolated from diaphragm motion. In this study, the slice tracking cardiac fat navigator with an enlarged gating window was found to improve scanning efficiency without affecting image quality.