Task-based quantification of image quality using a model observer in abdominal CT: a multicentre study.

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_8914F1CC532F
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Task-based quantification of image quality using a model observer in abdominal CT: a multicentre study.
Journal
European radiology
Author(s)
Racine D., Ryckx N., Ba A., Becce F., Viry A., Verdun F.R., Schmidt S.
ISSN
1432-1084 (Electronic)
ISSN-L
0938-7994
Publication state
Published
Issued date
12/2018
Peer-reviewed
Oui
Volume
28
Number
12
Pages
5203-5210
Language
english
Notes
Publication types: Journal Article ; Multicenter Study
Publication Status: ppublish
Abstract
We investigated the variability in diagnostic information inherent in computed tomography (CT) images acquired at 68 different CT units, with the selected acquisition protocols aiming to answer the same clinical question.
An anthropomorphic abdominal phantom with two optional rings was scanned on 68 CT systems from 62 centres using the local clinical acquisition parameters of the portal venous phase for the detection of focal liver lesions. Low-contrast detectability (LCD) was assessed objectively with channelised Hotelling observer (CHO) using the receiver operating characteristic (ROC) paradigm. For each lesion size, the area under the ROC curve (AUC) was calculated and considered as a figure of merit. The volume computed tomography dose index (CTDI <sub>vol</sub> ) was used to indicate radiation dose exposure.
The median CTDI <sub>vol</sub> used was 5.8 mGy, 10.5 mGy and 16.3 mGy for the small, medium and large phantoms, respectively. The median AUC obtained from clinical CT protocols was 0.96, 0.90 and 0.83 for the small, medium and large phantoms, respectively.
Our study used a model observer to highlight the difference in image quality levels when dealing with the same clinical question. This difference was important and increased with growing phantom size, which generated large variations in patient exposure. In the end, a standardisation initiative may be launched to ensure comparable diagnostic information for well-defined clinical questions. The image quality requirements, related to the clinical question to be answered, should be the starting point of patient dose optimisation.
• Model observers enable to assess image quality objectively based on clinical tasks. • Objective image quality assessment should always include several patient sizes. • Clinical diagnostic image quality should be the starting point for patient dose optimisation. • Dose optimisation by applying DRLs only is insufficient for ensuring clinical requirements.
Keywords
Abdomen/diagnostic imaging, Humans, Phantoms, Imaging, ROC Curve, Radiation Dosage, Radiation Exposure/analysis, Tomography, X-Ray Computed/methods, Abdominal computed tomography, Image quality, Model observer, Standardisation, Task-based assessment
Pubmed
Web of science
Open Access
Yes
Create date
15/06/2018 16:59
Last modification date
20/08/2019 14:48
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