NAVLE Small Animal Diagnostic Imaging 3 — Questions and Answers
Question 1: A dog's abdominal ultrasound reveals a splenic mass with a 'target' or 'bull's-eye' lesion appearance (hypoechoic halo around a hyperechoic center). This pattern is most associated with:
- Splenic hematoma
- Nodular hyperplasia
- Metastatic neoplasia (Correct answer)
- Splenic abscess
Correct answer: Metastatic neoplasia
A target or bull's-eye lesion pattern in the spleen is classically associated with metastatic disease, where a necrotic center is surrounded by viable tumor tissue.
Question 2: On a ventrodorsal thoracic radiograph, the cardiac silhouette of a healthy dog should not exceed what percentage of the thoracic width at the level of the 8th rib?
- 50%
- 60% (Correct answer)
- 70%
- 75%
Correct answer: 60%
The cardiac silhouette on a VD projection normally occupies no more than 60% of the thoracic width at the level of the 8th intercostal space.
Question 3: Which MRI sequence best demonstrates hemorrhage of varying ages due to its sensitivity to paramagnetic effects of blood breakdown products?
- T1-weighted with contrast
- T2-weighted FLAIR
- Gradient echo (GRE/T2*) (Correct answer)
- Diffusion-weighted imaging (DWI)
Correct answer: Gradient echo (GRE/T2*)
Gradient echo sequences are highly sensitive to susceptibility effects caused by hemosiderin and deoxyhemoglobin, making them ideal for detecting hemorrhage.
Question 4: A radiograph of a cat's elbow shows periarticular soft tissue swelling and subchondral bone lysis without significant new bone production. This pattern is most consistent with:
- Degenerative joint disease
- Septic arthritis (Correct answer)
- Osteochondrosis dissecans
- Hypertrophic osteodystrophy
Correct answer: Septic arthritis
Septic arthritis characteristically causes joint space narrowing, subchondral bone lysis, and periarticular soft tissue swelling with minimal productive bone response.
Question 5: During abdominal ultrasound, the normal feline adrenal gland has which characteristic appearance?
- Oval homogeneous hyperechoic structure, 5-10mm length
- Bilobed hypoechoic structure with a hyperechoic medulla, less than 4.3mm width (Correct answer)
- Round anechoic structure adjacent to the kidney, 3-5mm diameter
- Elongated hyperechoic structure parallel to the aorta, 15-20mm length
Correct answer: Bilobed hypoechoic structure with a hyperechoic medulla, less than 4.3mm width
Normal feline adrenal glands are bilobed (peanut-shaped) with a hypoechoic cortex and hyperechoic medulla, measuring less than 4.3mm in width.
Question 6: Which radiographic sign on a lateral thoracic view indicates right-sided cardiomegaly in a dog?
- Increased sternal contact (more than 3 sternal segments) (Correct answer)
- Dorsal displacement of the trachea
- Widening of the caudal vena cava shadow
- Loss of the cranial waist on the VD view
Correct answer: Increased sternal contact (more than 3 sternal segments)
Right heart enlargement causes the cardiac silhouette to contact more sternal segments than normal (typically more than 3), displacing the apex ventrally.
Question 7: On ultrasound, a dog's liver shows hyperechoic parenchyma compared to the spleen and falciform fat. This finding is most consistent with:
- Hepatic lipidosis (Correct answer)
- Acute hepatitis
- Hepatic congestion
- Portal hypertension
Correct answer: Hepatic lipidosis
Diffuse hepatic hyperechogenicity compared to the spleen and falciform fat is the classic ultrasound pattern of hepatic lipidosis (fatty liver).
NAVLE Small Animal Diagnostic Imaging 3
A dog's abdominal ultrasound reveals a splenic mass with a 'target' or 'bull's-eye' lesion appearance (hypoechoic halo around a hyperechoic center).
This pattern is most associated with: