Keywords:
Thorax, Lung, Computer applications, CT, CT-High Resolution, CT-Quantitative, Computer Applications-Detection, diagnosis, Computer Applications-3D, Segmentation, Tissue characterisation, Chronic obstructive airways disease
Authors:
R. Sanz-Requena, M. L. Peris Pérez, M. P. Calvillo, G. García-Martí, L. Marti-Bonmati; Valencia/ES
DOI:
10.1594/ecr2018/C-0451
Methods and materials
This IRB-approved retrospective study included 68 patients,
with respiratory functional tests and high-resolution CT scans (slice thickness ≤1.25 mm,
standard reconstruction kernel).
See figure 1 for a description of the patients and the emphysema characteristics.
Initially,
whole lungs were segmented using a -500 HU threshold,
while emphysema was quantified using a standard threshold of -950 HU.
Then the ratio emphysema volume vs.
total lung volume was calculated as a percentage.
Central and peripheral volumes were obtained by applying a set of 3D morphological operations to the CT images (figure 2),
releasing two equal size volumes (50% corresponding to peripheral lung and 50% corresponding to central lung).
Finally,
the ratios of central/peripheral emphysema vs.
total emphysema were obtained.
Pearson’s correlation coefficients were calculated to assess the relationship between DLCO/VA and both total and central/peripheral emphysema volumes.