Pleural plaques in asbestos-exposed workers: reproducibility of a new high-resolution CT visual semiquantitative measurement method.
OBJECTIVE
To assess the reproducibility of a new high-resolution computed tomography (CT) visual semiquantitative method for pleural plaques in asbestos-exposed workers.


METHODS
We performed thin-section CT in 752 chrysotile asbestos mining workers and ex-workers. Institutional review board approval and signed written informed consent from subjects were obtained. Two readers independently evaluated the 752 CT scans and identified 57 workers (mean age +/- SD, 61.8 years +/- 8.1; range, 37 to 81 years) who had pleural plaques and no other pleural or parenchymal abnormality. Three independent radiologists then quantified the plaque burden in these 57 workers using a scoring system based on the evaluation of the maximum thickness of parietal pleural plaques and percentage of parietal pleural surface involvement. We also calculated the proportion between the number of CT slices with diaphragmatic plaques and the total number of slices in which the diaphragm was seen (pdiaph). The intraobserver and interobserver agreements were analyzed using weighted Kappa coefficient.


RESULTS
Interobserver agreements were good for the pleural plaque score (k = 0.61, 0.75, and 0.79) and ranged from good (k = 0.61) to excellent (k = 0.86) for the pdiaph. Intraobserver agreements ranged from good to excellent for the pleural plaque score (k = 0.79 and 1.00) and for the pdiaph (k = 0.79 and 0.93).


CONCLUSIONS
The method proposed for high-resolution CT pleural plaque quantification in asbestos-exposed workers has a high reproducibility.
Department of Radiology, Federal University of São Paulo, Rua Napoleão de Barros, 800, Vila Clementino, 04023-900, Brazil.
Gustavo Souza Portes
GS
Meirelles
Jorge Issamu
JI
Kavakama
Dany
D
Jasinowodolinski
Luiz Eduardo
LE
Nery
Mário
M
Terra-Filho
Reynaldo Tavares
RT
Rodrigues
José Alberto
JA
Neder
Lara Maris
LM
Napolis
Ericson
E
Bagatin
Giuseppe
G
D'Ippolito
Nestor L
NL
Müller
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001194:Asbestos / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008906:Mining; D015588:Observer Variation; D016273:Occupational Exposure; D010994:Pleura / Q000000981:diagnostic imaging*; D010995:Pleural Diseases / Q000175:diagnosis* / Q000209:etiology; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
D001194:Asbestos