Radiographic scoring lacks predictive value in inflammatory airway disease.
BACKGROUND
Diagnosis of inflammatory airway disease (IAD) currently rests upon the results of bronchoalveolar lavage (BAL) cytology, lung function testing and histamine bronchoprovocation (HBP), none of which provides direct information about structural change in the lung.


OBJECTIVE
That thoracic radiography might better portray structural change in the lungs and therefore offer a good clinical assessment of IAD.


METHODS
A radiographic scoring system was developed to assess the extent of bronchial and interstitial pattern on thoracic radiographs in the dorsocaudal, dorsocranial and caudoventral regions in 16 control horses and 33 horses with IAD. Mean scores were compared to ascertain whether thoracic radiographs could distinguish between the 2 groups. In order to determine whether independent observers reliably scored radiographs similarly, an inter-rater reliability score was employed for each radiographic observation. Correlations between radiographic scores, BAL cytology, lung function testing using the forced oscillatory technique and HBP were examined.


RESULTS
Inter-rater reliability was only moderate. Radiographic scoring demonstrated no differences between the 2 groups. There were no correlations among BAL cytology, lung function testing, HBP and radiographic scores.


CONCLUSIONS
Thoracic radiographs are a low-yield diagnostic modality in horses with a clinical history compatible with IAD. In the absence of clinical evidence of more extensive, infectious disease, thoracic radiographs neither refine nor improve diagnosis of IAD, but increase diagnostic costs.
Mazan
M R
MR
Lung Function Laboratory, Tufts University School of Veterinary Medicine, 200 Westboro Road, North Grafton, Massachusetts 01536, USA.
Vin
R
R
Hoffman
A M
AM
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D016022:Case-Control Studies; D005540:Forced Expiratory Flow Rates; D006734:Horse Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging*; D006736:Horses; D008168:Lung / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic / Q000191:economics / Q000379:methods / Q000662:veterinary*; D012129:Respiratory Function Tests / Q000662:veterinary; D012140:Respiratory Tract Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000662:veterinary*; D012680:Sensitivity and Specificity