NAVLE Diagnostic Imaging Interpretation 3 — Questions and Answers
Question 1: Which radiographic finding is MOST consistent with pyloric outflow obstruction in a dog?
- Markedly distended stomach with delayed gastric emptying (Correct answer)
- Free peritoneal gas on the VD view
- Dilated small intestinal loops > 3x rib width
- Retroperitoneal effusion with loss of serosal detail
Correct answer: Markedly distended stomach with delayed gastric emptying
Pyloric obstruction causes gastric outflow failure, producing marked gastric distension with delayed or absent contrast passage on fluoroscopy.
Question 2: On a lateral thoracic radiograph, 'sternal contact' of the heart is increased in which cardiac condition?
- Right ventricular enlargement (Correct answer)
- Left atrial enlargement
- Pulmonary hypertension
- Pericardial effusion
Correct answer: Right ventricular enlargement
Right ventricular enlargement causes the heart to shift cranioventrally, increasing its contact with the sternum on the lateral view.
Question 3: Which ultrasound artifact is produced when sound reflects between two parallel, highly reflective surfaces and appears as equidistant lines deep to the structure?
- Reverberation artifact (Correct answer)
- Acoustic shadowing
- Acoustic enhancement
- Refraction artifact
Correct answer: Reverberation artifact
Reverberation artifact occurs when the sound beam bounces between two reflective interfaces, producing multiple parallel echogenic lines at regular intervals.
Question 4: On MRI, T2-weighted sequences are MOST useful for identifying:
- Fluid-filled structures and edema (Correct answer)
- Cortical bone detail
- Gas within tissues
- Calcified lesions
Correct answer: Fluid-filled structures and edema
T2-weighted MRI sequences produce high signal (bright) from fluid, making them ideal for identifying edema, effusions, and fluid-filled structures.
Question 5: A 'string of pearls' sign on abdominal radiographs of a cat refers to:
- Small gas bubbles trapped between intestinal folds indicating ileus (Correct answer)
- Mineralization of lymph nodes in the mesentery
- Gas within the portal vasculature
- Multiple uroliths in the ureter
Correct answer: Small gas bubbles trapped between intestinal folds indicating ileus
The 'string of pearls' sign describes small gas bubbles trapped between the valvulae conniventes in paralytic ileus, indicating functional obstruction.
Question 6: In a dog with suspected intervertebral disc disease, which myelographic finding confirms extradural compression?
- Thinning or deviation of the contrast column on one or both sides (Correct answer)
- Complete absence of contrast cranial to the lesion
- Pooling of contrast material within the spinal cord
- Widening of the subarachnoid space at the lesion site
Correct answer: Thinning or deviation of the contrast column on one or both sides
Extradural compression from a disc extrusion causes thinning or lateral deviation of the myelographic contrast column at the lesion level.
Question 7: On CT of the abdomen with IV contrast, hepatic nodules that are hyperattenuating in the arterial phase and isoattenuating in the portal venous phase are MOST suggestive of:
- Hepatocellular carcinoma (Correct answer)
- Hepatic cysts
- Biliary cystadenoma
- Hepatic abscess
Correct answer: Hepatocellular carcinoma
Hepatocellular carcinoma is typically hypervascular, showing arterial phase enhancement that washes out to isoattenuation in the portal venous phase.
NAVLE Diagnostic Imaging Interpretation 3
Which radiographic finding is MOST consistent with pyloric outflow obstruction in a dog?