Introduction

Idiopathic interstitial pulmonary fibrosis (IPF) is reported in West Highland White Terriers, with alveolar septal fibrosis resulting in clinical signs including coughing, tachypnoea and dyspnoea. Thoracic auscultation typically demonstrates inspiratory crackles. Chronic bronchial disease is often found in conjunction with IPF, and chronic bronchitis alone may present with a similar clinical history to IPF.

While Computed Tomography (CT) has been demonstrated to allow a degree of staging of the chronic pulmonary disease, availability is limited. The purpose of this study was to determine whether thoracic radiography could reliably determine whether IPF, chronic bronchitis or both diseases were present.

Materials and Methods

Patients undergoing investigation as part of a study into chronic pulmonary disease were selected. Each patient underwent thoracic radiography, thoracic CT, bronchoscopy and bronchoalveolar lavage. The final diagnosis was based on the results of all investigations.

Cases where a complete work-up and final diagnosis were complete were selected. The radiographs were reviewed by two board-certified radiologists blinded to the final diagnosis, and working independently.

Each radiologist classified the status of the patient as one of:

1.  IPF

2.  Chronic Bronchitis

3.  IPF and Chronic Bronchitis

4.  Other pulmonary disease

5.  Normal or ageing changes

Other radiographic changes (e.g., cardiomegaly) were also noted. The radiographic diagnosis was then compared to the final diagnosis.

Results

Both radiologists showed higher sensitivity and lower specificity for IPF than for chronic bronchitis. However, overall accuracy for the diagnosis of both IPF and chronic bronchitis was low for both observers. Where both IPF and chronic bronchitis were present, only one of the diseases was detected on the radiographs. Interobserver agreement was good.

Discussion

These results demonstrate the difficulty in determining the nature of chronic pulmonary disease in West Highland White Terriers based on radiographic appearance alone. In such cases, further investigation such as bronchoscopy or advanced imaging is to be recommended.