W. Richard Widmer, DVM, MS

Digital radiography is the fastest growing imaging modality in medicine. It is replacing conventional analog imaging in practices across the United States. Eventually all veterinary practices will utilize this modality.

The thorax is traditionally examined by a compartment approach-6 basic compartments or "spaces" plus the thoracic wall should be considered during the radiographic examination. The compartments include the mediastinum, the pleural space and four pulmonary divisions-bronchial, vascular, interstitial and alveolar.

Survey radiography is commonly used to image the urinary tract and provides information on size, shape, opacity, location and, margination of urinary organs. This modality is rapid and cost effective for screening animals with suspected urinary tract disease.

Mistakes are commonly made in radiographic interpretation of the thorax. Errors are due to the various radiopacities normally present, non-uniform thoracic shape, functional changes occurring during the respiratory cycle and occasionally an incomplete knowledge base.

Radiographic assessment of the heart and pulmonary vessels is challenging regardless of the species. This is due to numerous factors including variation between species and breeds, exposure factors, effects of the cardiac and respiratory cycles, radiographic positioning and quality of x-ray equipment.

Diagnosis of emergency-critical care conditions requires the same attention to good radiographic technique as routine conditions. Otherwise serious errors can result which may seriously affect outcome.