RSNA 2012 

Abstract Archives of the RSNA, 2012


LL-PHS-WE6C

The Use of a New Phantom (WAVE) to Study Aspect of 3-D CT Imaging

Scientific Informal (Poster) Presentations

Presented on November 28, 2012
Presented as part of LL-PHS-WEPM: Physics Afternoon CME Posters

Participants

David John Goodenough PhD, Presenter: Director, The Institute for Radiological Image Sciences, Inc Consultant, The Phantom Laboratory Consultant, Live Radiology, LLC
Jesper Fredriksson, Abstract Co-Author: Employee, Raforninn EHF
Hildur Olafsdottir, Abstract Co-Author: Research funded, The Phantom Laboratory Research funded, Image Owl, Inc
Joshua Levy, Abstract Co-Author: Research funded, The Phantom Laboratory Research funded, Image Owl, Inc President, The Phantom Laboratory
Smari Kristinsson, Abstract Co-Author: Research funded, The Phantom Laboratory Research funded, Image Owl, Inc
Austin Healy, Abstract Co-Author: Nothing to Disclose

PURPOSE

The aim of this work is to explore the use of a new phantom that can be used to sample the radial and 3D properties of a CT image, including in–plane (x,y) and z-axis information.  

METHOD AND MATERIALS

A new “WAVE” phantom (The Phantom Laboratory, Salem, NY) uses a periodic pattern of a pair of opposed angled (30°) ramps to produce a waveform profile across the CT image. This pattern s subsequently analyzed into its harmonic components. The amplitude of these components are influenced by (x,y) and z axis resolution. The waveform profiles from the phantom are visually examined and mathematically analyzed, to demonstrate the effect of Slice Thickness (z axis) and/or changes of in-plane (x,y) Resolution and non-uniformity throughout the image volume. The amplitudes of the harmonics of the waveform are used to study, either the in-plane resolution (MTF), and/or the z-axis MTF as results from the slice thickness. .    

RESULTS

In this particular study it is shown how the relative height of the third harmonic provides a useful metric of slice thickness and slice thickness variability across the image plane (volume). First the general profiles of a given slice thickness are shown, including the expected and typical harmonic amplitudes. Next the slice thickness is varied and the influence of the change is shown on given harmonics amplitudes. It is shown that the amplitude of the third harmonic can provide a sensitive and accurate measure of the slice thickness; moreover, variability of slice plane is shown to be reflected by the harmonics in a local region of the scan plane. These effects will be shown for both simulated and actual scan data. Issues of noise and other wave sampling issues are also addressed in the paper.

CONCLUSION

The WAVE phantom provides a new and useful way to study slice thickness and slice variability in the CT image plane.

CLINICAL RELEVANCE/APPLICATION

 The wave pattern provides the physician a visual and mathematical method to investigate slice thickness variability across the image plane. 

Cite This Abstract

Goodenough, D, Fredriksson, J, Olafsdottir, H, Levy, J, Kristinsson, S, Healy, A, The Use of a New Phantom (WAVE) to Study Aspect of 3-D CT Imaging.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043900.html