Keywords:
Quality assurance, Biological effects, Physics, Computer Applications-General, Computer Applications-Detection, diagnosis, CT-Quantitative, Lung, Artificial Intelligence
Authors:
C. C. Brussaard1, O. Colsoul2, A. Scafoglieri1, G. Van Gompel2, N. Buls2, J. de Mey1; 1Brussel/BE, 2Brussels/BE
DOI:
10.26044/ecr2019/C-0039
Methods and materials
Equipment: iCT,
IntellispacePortal Workstation with COPD density software (Philips,
Best,
the Netherlands)
Catphan phantom (1) and CT-performance phantom (2): both phantoms are scanned with the scan protocol of the thorax with 100 kV.
The field of view (FOV) in the catphan phantom was 10 cm (goal: optimal resolution) and in the CT-performance phantom 35 cm (standard FOV for CT scan of the thorax).
Reconstructions are made with Filtered Back Projection (FBP),
iterative reconstructions (IR) and model-based IR (MBIR) in combination with a hard filter and a soft one (FBP-L,
FBP-B,
idose4-L,
iDose4-B,
IMR-BodySharpPlus (BSP) and IMR-BodySoftTissue (BST)).
This results in six series.
(1): On the images of the six series,
a line is drawn perpendicular to a transition zone between a solid water compartment and a low-density area (vacuum,
-1024 HU) using the software in the workstation (Fig 1).
A density plot line is asked.
The ideal result should be a horizontal line interrupted by a straight down-positioned block of 10 mm when the vacuum hole is hit.
Identification of the combination of reconstruction type/filter which approaches the ideal result best is being sought.
(2): On the six series,
detection of the minimal size of a detectable cavity with histogram analysis in the section with the holes (0.75-1.00-1.25-1.50-1.75 mm) is made.
Cadavers: CT scan of the thorax is performed.
Reconstructions are made in FBP-B,
iDose4-B,
IMR-BSP,
and IMR-BST.
EI is calculated with COPD density software in the workstation with the COPD density software.