Fluoroscopic and radiographic evaluation of tracheal collapse in dogs: 62 cases (2001–2006)

Abstract
Objective—To compare the use of radiography and fluoroscopy for detection and grading of tracheal collapse in dogs. Design—Retrospective case series. Animals—62 dogs with tracheal collapse. Procedures—For each dog, tracheal collapse was confirmed fluoroscopically and lateral cervical and thoracic radiographic views were reviewed. A board-certified radiologist (who was unaware of the dogs' clinical history) evaluated the cervical, thoracic inlet, thoracic, carinal, and main stem bronchial regions in all fluoroscopic videos and radiographic images for evidence of collapse. Cervical, thoracic inlet, thoracic, and carinal regions in both radio-graphic and fluoroscopic studies were graded for collapse (0%, 25%, 50%, 75%, or 100% decrease in diameter). Results—Lateral cervical and thoracic radiographic images were available for 54 dogs, and inspiratory and expiratory lateral cervical and thoracic radiographic images were available for 8 dogs. For detection of tracheal collapse, assessment of radiographic views was sensitive and had the best negative predictive value in the cervical and thoracic inlet regions. Assessment of radiographic views was most specific and had the best positive predictive value in the thoracic inlet, thoracic, carina, and main stem bronchial regions. Radiography underestimated the degree of collapse in all areas. Review of inspiratory and expiratory views improved the accuracy of radiography for tracheal collapse diagnosis only slightly. Conclusions and Clinical Relevance—Compared with fluoroscopy, radiography underestimated the frequency and degree of tracheal collapse. However, radiography appears to be useful for screening dogs with potential tracheal collapse.