Effects of various generations of iterative CT reconstruction algorithms on low-contrast detectability as a function of the effective abdominal diameter: A quantitative task-based phantom study.
Phys Med
; 48: 111-118, 2018 Apr.
Article
em En
| MEDLINE
| ID: mdl-29728223
ABSTRACT
PURPOSE:
To investigate how various generations of iterative reconstruction (IR) algorithms impact low-contrast detectability (LCD) in abdominal computed tomography (CT) for different patient effective diameters, using a quantitative task-based approach.METHODS:
Investigations were performed using an anthropomorphic abdominal phantom with two optional additional rings to simulate varying patient effective diameters (25, 30, and 35â¯cm), and containing multiple spherical targets (5, 6, and 8â¯mm in diameter) with a 20-HU contrast difference. The phantom was scanned using routine abdominal protocols (CTDIvol, 5.9-16â¯mGy) on four CT systems from two manufacturers. Images were reconstructed using both filtered back-projection (FBP) and various IR algorithms ASiR 50%, SAFIRE 3 (both statistical IRs), ASiR-V 50%, ADMIRE 3 (both partial model-based IRs), or Veo (full model-based IR). Section thickness/interval was 2/1â¯mm or 2.5/1.25â¯mm, except 0.625/0.625â¯mm for Veo. We assessed LCD using a channelized Hotelling observer with 10 dense differences of Gaussian channels, with the area under the receiver operating characteristic curve (AUC) as a figure of merit.RESULTS:
For the smallest phantom (25-cm diameter) and smallest lesion size (5-mm diameter), AUC for FBP and the various IR algorithms did not significantly differ for any of the tested CT systems. For the largest phantom (35-cm diameter), Veo yielded the highest AUC improvement (8.5%). Statistical and partial model-based IR algorithms did not significantly improve LCD.CONCLUSION:
In abdominal CT, switching from FBP to IR algorithms offers limited possibilities for achieving significant dose reductions while ensuring a constant objective LCD.Palavras-chave
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Assunto principal:
Algoritmos
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Processamento de Imagem Assistida por Computador
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Tomografia Computadorizada por Raios X
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Imagens de Fantasmas
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Abdome
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Razão Sinal-Ruído
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article