Keywords:
Lung, Digital radiography
Authors:
K. Vult von Steyern, I. Björkman-Burtscher, P. Höglund, G. C. Bozovic, M. Wiklund, M. Geijer; Lund/SE
DOI:
10.1594/ecr2012/B-0417
Methods and Materials
The tomosynthesis scoring system
A scoring system dedicated for tomosynthesis in pulmonary cystic fibrosis (CF) was created,
based on established CF scoring systems for radiography and computed tomography.
The scoring system was designed to evaluate the whole spectrum of mild to severe CF pulmonary disease. The subscores of five well-recognized pathologic changes in CF lung disease (overinflation,
bronchial wall thickening,
parenchymal lesions,
bronchiectases and mucus plugging) were defined in a scoring form illustrated with reference images,
and the lesions were scored for severity and extent. The total tomosynthesis score had a maximum of 100 and was easily calculated by the sum of the subscores.
Validation of the scoring system
Three radiologists scored independently 88 pairs of radiographs and tomosynthesis examinations of the chest in 29 children and 31 adults with cystic fibrosis and 7 paediatric oncology patients.
The chest tomosynthesis examination consisted of an AP tomosynthesis scan,
with approximately 60 contiguous slices of a nominal thickness of 3 mm for children and 4 mm for adults,
an AP radiograph (which is automatically generated in the examination) and a lateral radiograph (as part of the clinical routine). Radiographs were scored first according to the Brasfield scoring system [2] and then the corresponding tomosynthesis examinations were scored using the new scoring system.
Statistics
Cohen´s kappa with quadratic weighting [3] together with per cent agreement were used for assessment of agreements between observers for the total disease severity scores and subscores of the tomosynthesis score.
To quantify the disagreement between two observers a method by Svensson and Holm [4,5] for paired ordered categorical classifications was used.
Kendall´s rank correlation tau was used to assess the correlation between the total disease severity scores for tomosynthesis and radiography.