Radiographs Flashcards
Air bronchograms on a thoracic radiograph indicate what?
The correct answer is uniform lung consolidation. An air bronchogram is an area of uniform lung consolidation around an air filled bronchus. This is usually referred to as an alveolar pattern. This can occur with inflammatory diseases, severe edema, lung lobe torsions, hemorrhage, or some neoplasms.
A radiograph of a dog shows areas of consolidation with air bronchograms. What radiographic pattern is this?
The correct answer is alveolar. The classic “trees in the fog” appearance on radiographs of airways coursing through consolidated lung is an alveolar pattern.
In an animal with pleural effusion, which radiographic view will give you the best view of the heart?
The correct answer is ventrodorsal. Pleural effusion obscures the heart completely on a dorsoventral radiograph and at least partially on lateral radiographs. Ventrodorsal positioning usually moves the pleural fluid away from the heart and allows for a radiographic view of the heart to be obtained. Of course, in dyspneic animals, it may not be wise to position them ventrodorsally.
A 9-year old male Queensland Heeler presents with a four day history of progressive tetraparesis. Physical exam showed him to be weakly ambulatory with support. As part of your initial workup, you take chest X-rays which are shown below. Which of the following next steps is the most appropriate test to confirm your clinical suspicion about the cause of the dog’s signs?
The correct answer is a Tensilon (edrophonium) response test. Hopefully, you were able to identify the mass in the cranial mediastinum on the chest radiograph, as this was one of the keys to this case. This, in conjunction with the dog’s other signs, are suggestive that this dog has a thymoma and associated secondary myasthenia gravis. Tensilon (edrophonium) is a rapidly acting anticholinesterase that reverses signs of myasthenia within minutes in most dogs.
A chest CT would be a valid test to confirm the presence of the mediastinal mass and might be an appropriate test before surgery but would not bring you closer to a diagnosis if you already have identified the mass. An MRI of the brain would assess a CNS cause of the dog’s signs, which are unlikely, given the other findings. Similarly, a myelogram would assess if a spinal cord lesion caused the dog’s signs, but the rest of the findings in this case should point you in a different direction.
