Diagnostic Imaging Interpretation Flashcards

A 4-year-old cat with a history of intermittent coughing and wheezing presents for acute respiratory distress. Thoracic radiographs reveal severely thickened bronchial walls, seen as 'donuts' and 'railroad tracks', and a flattened diaphragm. Which pulmonary pattern is most prominent?

Answer: Bronchial pattern

The classic radiographic signs of 'donuts' (thickened bronchi seen end-on) and 'railroad tracks' (thickened bronchi seen longitudinally) are pathognomonic for a bronchial pattern. A flattened diaphragm indicates pulmonary hyperinflation, which is also commonly seen with feline lower airway disease (asthma). An alveolar pattern would show air bronchograms and lobar signs, an interstitial pattern involves the lung parenchyma between the airways and vessels, and a vascular pattern relates to the size of the pulmonary arteries and veins.

A 5-year-old mixed-breed dog presents with acute vomiting and abdominal pain. Radiographs of the abdomen show multiple small intestinal loops gathered in the central abdomen with abnormal, comma-shaped or crescent-shaped gas pockets. There is no obvious radiopaque foreign object. What is the most likely diagnosis?

Answer: Linear foreign body obstruction

The radiographic findings of plicated (bunched or gathered) small intestines and abnormally shaped, sharp-angled gas pockets are classic for a linear foreign body obstruction. The intestine bunches up as peristalsis tries to move the anchored linear object. Simple gastroenteritis does not typically cause this pattern. Intussusception usually appears as a soft tissue mass with concentric rings on ultrasound, and mesenteric volvulus presents with diffuse, severe gas distention of the entire small bowel.

A 10-year-old dog is being evaluated for Cushing's disease (pituitary-dependent hyperadrenocorticism, PDH). Which of the following is the most classic ultrasonographic finding for the adrenal glands in a dog with this condition?

Answer: Bilaterally symmetric and moderately enlarged adrenal glands

In pituitary-dependent hyperadrenocorticism (PDH), the pituitary gland produces excessive ACTH, which symmetrically stimulates both adrenal glands, causing them to hypertrophy. Therefore, the classic finding is bilaterally symmetric, moderately enlarged adrenal glands. A very large gland with a contralateral small gland is typical of an adrenal tumor (adrenal-dependent hyperadrenocorticism). Bilaterally small glands are seen with hypoadrenocorticism (Addison's disease) or iatrogenic Cushing's.

A 5-month-old Great Dane presents with a fever, lethargy, and painful, swollen metaphyses of the long bones. Radiographs of the distal radius and ulna reveal irregular radiolucent lines in the metaphyses, parallel to the physes, sometimes referred to as a 'double physis sign'. What is the most likely diagnosis?

Answer: Hypertrophic osteodystrophy (HOD)

The signalment (young, giant-breed dog), clinical signs (fever, bone pain, swollen metaphyses), and classic radiographic finding of a radiolucent line in the metaphysis parallel to the physis ('double physis sign') are all characteristic of hypertrophic osteodystrophy (HOD). Panosteitis appears as shifting leg lameness with increased intramedullary opacities. Retained ulnar cartilage cores show a persistent radiolucent cone in the distal ulnar metaphysis. OCD involves a cartilage flap or defect, typically on an articular surface.

You are performing a contrast study on a dog with a history of being hit by a car and suspect a gastrointestinal perforation. Which type of contrast agent is the safest and most appropriate choice for this study?

Answer: Non-ionic iodinated contrast medium

If a gastrointestinal perforation is suspected, barium sulfate is contraindicated because its leakage into the peritoneum can cause severe granulomatous inflammation and adhesions. A non-ionic iodinated contrast medium is the agent of choice because it is water-soluble, readily absorbed from the peritoneal cavity, and has lower osmolality than ionic agents, reducing the risk of fluid shifts and pulmonary edema if aspirated. While room air can be used, it provides less detail and may not definitively identify the site of leakage compared to a positive contrast agent.

A 9-year-old Boxer presents with a 2-month history of progressive seizures. To best evaluate the brain parenchyma for a suspected intracranial mass, which imaging modality provides the highest level of soft tissue detail and is considered the gold standard?

Answer: Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is the superior imaging modality for evaluating soft tissues, including the brain parenchyma, due to its excellent contrast resolution. It is considered the gold standard for diagnosing intracranial masses like tumors, inflammation, or infarcts. Computed Tomography (CT) is better for bone and can detect some large masses but provides significantly less detail of the brain's soft tissue structures compared to MRI. Skull radiographs are not useful for viewing the brain itself.