NAVLE Diagnostic Imaging Interpretation 2 — Questions and Answers
Question 1: On thoracic radiographs of a dog, you notice the cardiac silhouette occupies more than 75% of the thoracic width on the VD view. What does this most likely indicate?
- Cardiomegaly (Correct answer)
- Pleural effusion
- Pneumothorax
- Pulmonary consolidation
Correct answer: Cardiomegaly
A cardiac silhouette exceeding 75% of thoracic width on the VD view is consistent with cardiomegaly.
Question 2: Which radiographic sign is MOST characteristic of a diaphragmatic hernia in a dog?
- Loss of diaphragmatic outline with abdominal organs in the thorax (Correct answer)
- Increased sternal contact of the cardiac silhouette
- Air bronchograms within the pulmonary parenchyma
- Pleural fissure lines at the lung margins
Correct answer: Loss of diaphragmatic outline with abdominal organs in the thorax
Loss of the normal diaphragmatic outline combined with abdominal viscera (e.g., intestinal loops, stomach) visible in the thoracic cavity is the hallmark of diaphragmatic hernia.
Question 3: On ultrasound, a hypoechoic halo surrounding a hepatic mass in a dog is called:
- Target lesion (Correct answer)
- Acoustic enhancement
- Reverberation artifact
- Comet tail artifact
Correct answer: Target lesion
A hypoechoic halo surrounding a mass on ultrasound is referred to as a target or bull's-eye lesion, often associated with metastatic disease.
Question 4: A cat presents with a 'ground-glass' opacity on thoracic radiographs. Which condition is MOST associated with this finding?
- Pulmonary edema (Correct answer)
- Pneumothorax
- Pleural effusion
- Rib fracture
Correct answer: Pulmonary edema
Ground-glass opacity reflects partial alveolar filling, most commonly seen with pulmonary edema in cats.
Question 5: On a lateral skull radiograph, which structure appears as a radiolucent line running through the calvarium and should not be mistaken for a fracture?
- Sagittal suture (Correct answer)
- Petrous temporal bone
- Cribriform plate
- Foramen magnum
Correct answer: Sagittal suture
The sagittal suture appears as a radiolucent line in the dorsal calvarium and is a normal anatomic finding.
Question 6: In equine radiography, 'rotation' of the distal phalanx relative to the hoof wall is measured by which imaging technique?
- Lateral radiograph with a reference marker on the dorsal hoof wall (Correct answer)
- Dorsopalmar radiograph of the foot
- Ultrasound of the deep digital flexor tendon
- Nuclear scintigraphy of the foot
Correct answer: Lateral radiograph with a reference marker on the dorsal hoof wall
Lateral radiographs with a radio-opaque marker placed on the dorsal hoof wall allow measurement of the palmar angle and rotation of P3 in laminitic horses.
Question 7: On abdominal ultrasound, an anechoic structure with distal acoustic enhancement in the kidney is MOST consistent with:
- Simple renal cyst (Correct answer)
- Nephrolithiasis
- Renal abscess
- Transitional cell carcinoma
Correct answer: Simple renal cyst
Simple cysts are anechoic with a thin wall and show distal acoustic enhancement due to the lack of sound attenuation by fluid.
