VTNE Diagnostic Imaging 3 — Questions and Answers
Question 1: Which of the following contrast agents is used for gastrointestinal studies when perforation is suspected?
- Barium sulfate
- Iohexol (Omnipaque) (Correct answer)
- Iopamidol (Isovue)
- Iodinated oil
Correct answer: Iohexol (Omnipaque)
Water-soluble iodinated contrast such as iohexol is used when GI perforation is suspected because barium causes severe peritonitis if it leaks into the abdomen.
Question 2: A patient requires a myelogram. Which position is typically used for subarachnoid injection at the lumbar cistern (L4-L6)?
- Dorsal recumbency with hindlimbs extended
- Lateral recumbency with the spine flexed (Correct answer)
- Sternal recumbency with the head elevated
- Standing with the back arched
Correct answer: Lateral recumbency with the spine flexed
Lateral recumbency with the spine flexed opens the intervertebral spaces, facilitating accurate needle placement into the subarachnoid space at L4-L6.
Question 3: On thoracic radiographs, which cardiac measurement is used to assess heart size in dogs?
- Cardiothoracic ratio (CTR)
- Vertebral heart score (VHS) (Correct answer)
- Cardiac silhouette index (CSI)
- Thoracic volume ratio (TVR)
Correct answer: Vertebral heart score (VHS)
The vertebral heart score (VHS) compares the sum of the long and short cardiac axes to vertebral body lengths starting at T4, with >10.5 considered enlarged in most dogs.
Question 4: What artifact appears as a dark shadow behind a gallstone on ultrasound examination?
- Edge shadowing
- Reverberation artifact
- Acoustic shadowing (Correct answer)
- Mirror artifact
Correct answer: Acoustic shadowing
Acoustic shadowing occurs when sound waves are completely blocked by a highly reflective or attenuating structure such as a gallstone, creating a shadow distal to it.
Question 5: Fluoroscopy is most appropriate for evaluating which of the following conditions?
- Bone density and cortical integrity
- Real-time swallowing function (esophagram) (Correct answer)
- Static cardiac chamber dimensions
- Renal cortical thickness
Correct answer: Real-time swallowing function (esophagram)
Fluoroscopy provides real-time dynamic imaging, making it ideal for evaluating swallowing mechanics, esophageal motility, and contrast agent movement through the GI tract.
Question 6: Which organ is considered the acoustic window used to visualize the heart during echocardiography in most small animals?
- Liver
- Lung
- Spleen
- Chest wall and intercostal spaces (Correct answer)
Correct answer: Chest wall and intercostal spaces
The ultrasound probe is placed in the intercostal spaces of the chest wall where air-filled lungs are displaced, providing a direct acoustic window to the heart.
Question 7: What is the recommended action if a patient shows signs of a contrast reaction (vomiting, urticaria, hypotension) during an IV urogram?
- Administer more contrast to flush the kidneys
- Continue the study and monitor
- Discontinue contrast administration and treat symptomatically (Correct answer)
- Increase the injection rate to speed up the study
Correct answer: Discontinue contrast administration and treat symptomatically
Signs of contrast reaction require immediate discontinuation of the contrast agent and symptomatic treatment including IV fluids, antihistamines, and epinephrine if anaphylaxis develops.
VTNE Diagnostic Imaging 3
Which of the following contrast agents is used for gastrointestinal studies when perforation is suspected?