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Published in: European Radiology 5/2020

Open Access 01-05-2020 | Computed Tomography

Physical evaluation of an ultra-high-resolution CT scanner

Authors: Luuk J. Oostveen, Kirsten L. Boedeker, Monique Brink, Mathias Prokop, Frank de Lange, Ioannis Sechopoulos

Published in: European Radiology | Issue 5/2020

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Abstract

Objectives

To evaluate the technical performance of an ultra-high-resolution CT (UHRCT) system.

Methods

The physico-technical capabilities of a novel commercial UHRCT system were assessed and compared with those of a current-generation multi-detector (MDCT) system. The super-high-resolution (SHR) mode of the system uses 0.25 mm (at isocentre) detector elements (dels) in the in-plane and longitudinal directions, while the high-resolution (HR) mode bins two dels in the longitudinal direction. The normal-resolution (NR) mode bins dels 2 × 2, resulting in a del-size equivalent to that of the MDCT system. In general, standard procedures and phantoms were used to perform these assessments.

Results

The UHRCT MTF (10% MTF 4.1 lp/mm) is twice as high as that of the MDCT (10% MTF 1.9 lp/mm), which is comparable to the MTF in the NR mode (10% MTF 1.7 lp/mm). The width of the slice sensitivity profile in the SHR mode (FWHM 0.45 mm) is about 60% of that of the MDCT (FWHM 0.77 mm). Uniformity and CT numbers are within the expected range. Noise in the high-resolution modes has a higher magnitude and higher frequency components compared with MDCT. Low-contrast visibility is lower for the NR, HR and SHR modes compared with MDCT, but about a 14%, for NR, and 23%, for HR and SHR, dose increase gives the same results.

Conclusions

HR and SHR mode scanning results in double the spatial resolution, with about a 23% increase in dose required to achieve the same low-contrast detectability.

Key Points

• Resolution on UHRCT is up to twice as high as for the tested MDCT.
• With abdominal settings, UHRCT needs higher dose for the same low-contrast detectability as MDCT, but dose is still below achievable levels as defined by current diagnostic reference levels.
• The UHRCT system used in normal-resolution mode yields comparable resolution and noise characteristics as the MDCT system.
Appendix
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Literature
11.
Metadata
Title
Physical evaluation of an ultra-high-resolution CT scanner
Authors
Luuk J. Oostveen
Kirsten L. Boedeker
Monique Brink
Mathias Prokop
Frank de Lange
Ioannis Sechopoulos
Publication date
01-05-2020
Publisher
Springer Berlin Heidelberg
Published in
European Radiology / Issue 5/2020
Print ISSN: 0938-7994
Electronic ISSN: 1432-1084
DOI
https://doi.org/10.1007/s00330-019-06635-5

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