Diagnostic contribution of thoracic ultrasonography in 17 foals with Rhodococcus equi pneumonia

The aim of this retrospective study was to determine the clinical usefulness of thoracic ultrasonography compared to thoracic radiography in evaluation of Rhodococcus equi pneumonia. Criteria for patient inclusion in this study were: (1) isolation of R. equi from transtracheal aspirate, (2) radiographic evaluation of the pulmonary parenchyma, and (3) sonographic evaluation of the pulmonary parenchyma. Seventeen foals met this criteria and their medical records were reviewed. Pyogranulomatous pneumonia was identified radiographically in 13 foals. Severe consolidative pneumonia with no detectable abscessation was identified radiographically in three others. Both consolidation and abscessation were identified radiographically in one. In this foal only consolidation was ultrasonographically identified. Ultrasonographically, pulmonary abscessation was identified in 12 foals and pulmonary consolidation with no detectable abscessation was identified in three others. Sonographic examination allowed detection of only pleural irregularities in one foal, which was subsequently found to have pyogranulomatous pneumonia radiographically. Results indicate that ultrasonography may be an accurate alternative imaging modality for detection of pulmonary pathology attributed to R. equi pneumonia in foals when thoracic radiography is not available.