- Poster presentation
- Open Access
Retrospective gating leads to more accurate velocity measurements than prospective gating in spiral phase velocity mapping
© Simpson et al.; licensee BioMed Central Ltd. 2014
- Published: 16 January 2014
- Equal Time Interval
- Early Diastole
- Heart Rate Variation
- Myocardial Velocity
- Spiral Path
Spiral phase velocity mapping (PVM) has been used to assess both blood flow  and myocardial velocities . Data is usually acquired over several heartbeats which, will not be exactly the same due to physiological RR interval (RR) variations. The way in which the data from different cycles is combined depends on the method of ECG gating. This simulation study investigates the effect of RR variation on the velocities measured for prospective (pro) and retrospective (retro) gating.
Percentage errors for peak and time to peak S, D and AS velocities for prospective and retrospective gating
These simulations show that for this application retro allows more accurate measurements of peak velocities in the presence of heart rate variation than pro: at 15% RR variation, D and AS are both underestimated by more than 20% with pro but by less than 10% with retro. This is because during the normalisation step retro effectively stretches each heartbeat linearly before combining to produce an image while pro makes no attempt to deal with variation. Pro therefore averages velocities from different parts of the cardiac cycle in the presence of RR variation, while the linear stretching in retro goes some way towards reducing the effect. These results show that incorporation of more physiological stretching algorithms could further improve future retro algorithms.
CBRU Royal Brompton Hospital. HRUK Grant number RG2584.
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