Multi-sector reconstruction
Performed using continuous helical scanning, and a pitchd of approx. 1
- Overlapping spirals, each portion of heart imaged four times
Data from multiple rotations combined to reduce effective scan time
- Scanner rotation rate and heart rate are different
- At the same point in subsequent heart cycles, x-ray tube is at a different gantry angle
- Effective scan time improved to ~0.1 s for 4 slice scanner
E.g. on next slide, scanner 0.5 s rotation, heart 80 bpm (0.75 s period)