Slide 3 of 16
Notes:
These are the imaging performance parameters for which we expect to see a difference between multi-slice and single-slice scanners operating in helical mode:
- the amount of noise in the image
- the width and shape of the z-axis profile
- and the helical artefacts, as illustrated by this rather extreme example taken from a recent journal, showing image distortion of a phantom containing eight balls.
The present study is restricted to measurements of the first two of these parameters. Image noise and the FWHM of the z-axis profile were measured for the range of pitches available on each of the scanners, using the phantoms and techniques described in the previous talk.
Helical artefacts are thought to be largely dependent on the width and shape of the z-axis profile, and have not been assessed separately in this study. We plan to investigate artefacts in future studies, and also to look in greater detail at the shape of the z-axis profile, since the FWHM studied here only gives part of the picture.