Diagnostic Imaging Interpretation Flashcards

A 10-year-old West Highland White Terrier is presented for a chronic, non-productive cough. Thoracic radiographs reveal prominent, thickened bronchial walls, which appear as 'doughnuts' on end-on views and 'tramlines' when viewed longitudinally. The lung fields appear mildly hyperinflated, but there is no evidence of an alveolar pattern or cardiomegaly. Which of the following is the most likely diagnosis?

Answer: Chronic bronchitis

The radiographic signs described, including thickened bronchial walls seen as 'doughnuts' and 'tramlines', are classic for a bronchial lung pattern. In an older small breed dog with a chronic cough, this pattern is most consistent with chronic bronchitis. Aspiration pneumonia typically presents with an alveolar pattern in the cranioventral lung fields. Cardiogenic edema usually involves an interstitial to alveolar pattern, often in the perihilar or caudodorsal regions, along with cardiomegaly. Pulmonary neoplasia would more likely present as a distinct mass or a structured interstitial (nodular) pattern.

A 2-year-old domestic shorthair cat is presented with a history of acute vomiting, anorexia, and abdominal pain. A physical exam reveals a string-like object under the tongue. Abdominal radiographs show bunching of the small intestines in the mid-abdomen with multiple, abnormally shaped, comma-like or triangular gas bubbles. What is the classic term for this radiographic appearance?

Answer: Plication

The clinical history of a string under the tongue combined with the radiographic findings of bunched intestines and oddly shaped gas pockets is pathognomonic for a linear foreign body. The bunching or gathering of the intestine along the linear object is termed plication. The 'gravel sign' refers to an accumulation of radiopaque material in the intestine, often seen with partial obstructions. A 'sentinel loop' is a focal, gas-distended segment of intestine indicating nearby inflammation. Ileus describes a general lack of intestinal motility, leading to diffuse gas distention, not the specific bunching pattern seen here.

An 11-year-old Shetland Sheepdog presents with vomiting, lethargy, and icterus. An abdominal ultrasound is performed. The gallbladder is distended and contains immobile, echogenic material arranged in a finely striated, stellate pattern. This ultrasonographic finding is most characteristic of which condition?

Answer: Gallbladder mucocele

The ultrasonographic appearance of a distended gallbladder with immobile, non-gravity dependent, organized material in a stellate or finely striated pattern (often described as a 'kiwi fruit' appearance) is pathognomonic for a gallbladder mucocele. Biliary sludge is gravity-dependent and would shift with patient repositioning. Cholecystitis involves inflammation of the gallbladder wall, which might appear thickened or edematous but doesn't create this intraluminal pattern. Cholelithiasis refers to gallstones, which would appear as discrete, hyperechoic structures with acoustic shadowing.

A 5-year-old Dachshund presents with acute onset of thoracolumbar pain and pelvic limb paresis. Intervertebral disc disease (IVDD) is suspected. Which diagnostic imaging modality is considered the gold standard for visualizing the spinal cord, nerve roots, and the extruded disc material to best determine the exact location and degree of spinal cord compression?

Answer: Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is considered the gold standard for neuroimaging because of its superior soft tissue contrast. It allows for excellent visualization of the spinal cord, nerve roots, and the intervertebral disc itself, making it the most accurate modality for diagnosing IVDD, localizing the lesion, and assessing the severity of spinal cord compression. While CT is excellent for bone, it has lower soft tissue detail and is less sensitive for visualizing the spinal cord without contrast (myelography). Survey radiographs can show secondary signs like narrowed disc spaces but cannot visualize the spinal cord or the extruded disc material.

When evaluating a digital radiograph, a veterinarian notes a thin, black (lucent) line immediately adjacent to the dense cortical bone of the radius, mimicking a periosteal reaction or fracture line. However, upon closer inspection, it is determined to be an artifact. Which of the following artifacts is caused by edge enhancement processing and can create a false lucent line at interfaces of high contrast?

Answer: Uberschwinger (rebound) effect

The Uberschwinger effect, also known as the rebound effect or Mach bands, is a processing artifact in digital radiography. It results from edge enhancement algorithms that create a thin lucent halo adjacent to high-density structures (like bone or metal implants), which can be mistaken for pathology such as a fracture line or periosteal reaction. Planking is a CR-specific artifact causing linear striations. Ghosting is the appearance of a latent image from a previous exposure. Quantum mottle is a grainy appearance resulting from too few x-ray photons reaching the detector.

A dog is presented after being hit by a car and has signs of cranial abdominal pain. Survey abdominal radiographs are inconclusive but suggest a loss of serosal detail. The veterinarian suspects a gastrointestinal rupture and decides to perform a positive contrast study. Which type of contrast medium is most appropriate in this situation?

Answer: Water-soluble iodinated contrast medium

When a gastrointestinal perforation is suspected, barium sulfate is contraindicated. If barium leaks into the peritoneal or thoracic cavity, it is inert and will not be absorbed, leading to severe granulomatous inflammation, adhesions, and potential for delayed healing. A water-soluble iodinated contrast medium is the agent of choice because if it leaks from the GI tract, it will be absorbed from the body cavity and excreted by the kidneys. Room air would not be helpful in identifying the location of a leak.