Keywords:
Lung, CT, Screening, Occupational / Environmental hazards
Authors:
J. Teh, P. Wong, C. P. Murray, Y.-J. Kuok, N. de Klerk, H. Alfonso, A. Reid, A. W. Musk, F. J. Brims; Perth/AU
DOI:
10.1594/ranzcr2015/R-0062
Methods and materials
Study population:
This retrospective study examined 143 randomly selected subjects participating in the ARP between September 2012 and September 2013.
All subjects had a baseline chest ultra-LDCT and PFTs as part of their routine annual assessment.
Participants were previous Wittenoom workers,
former residents of the Wittenoom township and other workers with at least three months occupational asbestos exposure and/or those with radiographically confirmed pleural plaques.
CT scanning:
The ultra-LDCT was performed at a single site using a 128-slice CT scanner with iterative reconstruction software.
All studies were performed as a single scan on full inspiration in the prone position without intravenous contrast.
The estimated radiation dose length products ranged from 20 to 120 mGycm (approximately 0.3 - 1.5 mSv).
Image review:
Two thoracic radiologists independently interpreted the LDCT images.
Images were scored as follows:
- Score of 0 - no evidence of ILD
- Score of 1 - equivocal for ILD
- Score of 2 - ILD
A third radiologist provided an opinion on images with discordant scores.
Readers were blinded to all clinical information,
including PFT results.
ILD was defined as non-dependent ground glass opacities (GGO) that affected more than 5% of any lung zone,
non-dependent reticular abnormality,
diffuse centrilobular nodularity with GGO,
honeycombing,
traction bronchiectasis or architectural distortion.
Statistical analysis:
Kappa agreement test was used to calculate the agreement between first and second readers.
Inter-observer agreement was classified as poor (k = 0-0.20),
fair (k = 0.21-0.40),
moderate (k = 0.41-0.60),
good (k = 0.61-0.80),
or excellent (k = 0.81-1).
The correlation between the LDCT fibrosis score and DLCO was tested with Spearman's rank correlation.