VTNE Diagnostic Imaging 5 — Questions and Answers
Question 1: Which of the following best describes the term 'window width' in CT image display?
- The brightness of the monitor displaying the image
- The range of Hounsfield units displayed as shades of gray (Correct answer)
- The field of view diameter during image acquisition
- The slice thickness selected for reconstruction
Correct answer: The range of Hounsfield units displayed as shades of gray
Window width determines the range of HU values mapped to the grayscale display; a narrow window increases contrast while a wide window shows a broader range of densities.
Question 2: A radiograph of a dog's abdomen reveals a 'string of pearls' gas pattern in the small intestine. This is most consistent with:
- Normal bowel gas distribution
- Mechanical small intestinal obstruction (Correct answer)
- Free abdominal air from perforation
- Colonic dilation due to megacolon
Correct answer: Mechanical small intestinal obstruction
A 'string of pearls' pattern occurs when small gas bubbles are trapped between folds in an obstructed, fluid-filled small intestine, indicating mechanical obstruction.
Question 3: During a barium upper GI series, transit time from stomach to ileocecal junction in a healthy dog should be approximately:
- 5–15 minutes
- 30–60 minutes
- 1–3 hours (Correct answer)
- 6–8 hours
Correct answer: 1–3 hours
In dogs, barium typically reaches the ileocecal junction within 1–3 hours of administration; prolonged transit may indicate ileus or obstruction.
Question 4: Which MRI sequence is most useful for detecting fluid (such as edema or joint effusion) due to its bright fluid signal?
- T1-weighted
- T2-weighted (Correct answer)
- STIR (Short Tau Inversion Recovery)
- Proton density
Correct answer: T2-weighted
T2-weighted sequences produce a bright (hyperintense) signal from fluid, making them ideal for identifying edema, joint effusions, spinal cord lesions, and other fluid-containing structures.
Question 5: What is the recommended technique to confirm correct placement of a nasogastric tube before feeding?
- Auscultate the abdomen while injecting air
- Measure the tube length from nose to stomach
- Obtain a lateral thoracic/abdominal radiograph (Correct answer)
- Check for tube condensation during exhalation
Correct answer: Obtain a lateral thoracic/abdominal radiograph
A lateral radiograph is the gold-standard method to confirm NG tube placement, verifying the tube tip is in the stomach rather than accidentally in the trachea or esophagus.
Question 6: Which radiation safety measure is most effective at reducing occupational exposure for the veterinary technician?
- Wearing a lead apron only
- Maximizing distance from the primary beam and using remote positioning aids (Correct answer)
- Holding the patient manually with double gloves
- Increasing kVp to shorten exposure time
Correct answer: Maximizing distance from the primary beam and using remote positioning aids
Distance is the most effective protection because radiation intensity decreases with the square of the distance (inverse square law); combined with positioning aids, it minimizes occupational dose.
Question 7: On an ultrasound exam, a structure that contains no internal echoes and has acoustic enhancement (brighter area behind it) is described as:
- Hyperechoic
- Isoechoic
- Anechoic with posterior acoustic enhancement (Correct answer)
- Heterogeneous
Correct answer: Anechoic with posterior acoustic enhancement
An anechoic structure (no internal echoes, appearing black) with posterior acoustic enhancement indicates a fluid-filled lesion such as a cyst, as fluid transmits sound without attenuation.
VTNE Diagnostic Imaging 5
Which of the following best describes the term 'window width' in CT image display?