AB-Abdomen Premium Exam Questions

The ultrasound image provided shows a transverse view of the abdominal aorta, with a clearly measured aortic diameter of 5.71 cm. A normal adult abdominal aorta should measure less than 3.0 cm in anterior-posterior diameter. Any measurement exceeding this threshold is defined as an abdominal aortic aneurysm (AAA).

In this case, the dilation is well beyond the 3.0 cm threshold, confirming the presence of an aneurysm. The rounded, anechoic/heterogeneous central lumen surrounded by echogenic arterial wall layers further supports this diagnosis.

Comparison of answer choices:

A. Stenosis: Would show a narrowed lumen with turbulent, aliasing flow on Doppler, not a dilated aorta.

B. Dissection: Typically shows an echogenic intimal flap separating true and false lumens; no flap is visible here.

C. Aneurysm: Correct. The aorta’s transverse diameter (5.71 cm) confirms the presence of an aneurysm.

D. Occlusion: Would appear as a lack of flow with thrombus or echogenic content filling the lumen, not dilation.

The image shows a transverse view of the left lobe of the liver with the portal triads clearly visible. The "parallel channel" or "double barrel" sign is observed—where dilated intrahepatic bile ducts run alongside the portal veins, creating a characteristic sonographic pattern of paired anechoic (black) tubular structures.

This sonographic feature is diagnostic for dilated intrahepatic bile ducts and is typically seen in obstructive jaundice or biliary obstruction from conditions such as:

Choledocholithiasis (stone in the common bile duct)

Stricture or mass compressing the bile ducts

Cholangiocarcinoma

The intrahepatic bile ducts normally are too small to visualize clearly unless dilated. Their dilation gives the liver a "too many tubes" appearance, where bile ducts become as prominent as the portal veins.

Comparison of answer choices:

A. Normal intrahepatic ducts are not usually seen this clearly or prominently on ultrasound.

B. Dilated intrahepatic — Correct. The parallel channel sign supports this diagnosis.

C. Dilated common bile duct would be visualized extrahepatically, typically anterior to the portal vein near the head of the pancreas.

D. Dilated common hepatic duct is also extrahepatic and seen in the porta hepatis, not within the liver parenchyma.

The ultrasound image labeled “SAG RUQ KIDNEY” demonstrates a midline sagittal view showing a renal parenchymal structure that extends across the midline anterior to the aorta and vertebral bodies, suggesting the presence of a horseshoe kidney.

A horseshoe kidney is a congenital renal anomaly in which the lower poles of both kidneys are fused across the midline by a parenchymal or fibrous isthmus. This isthmus typically lies anterior to the aorta and inferior vena cava and can be seen as a hypoechoic band of tissue crossing the midline on ultrasound.

Ultrasound findings characteristic of a horseshoe kidney:

Abnormally low position of the kidneys in the abdomen

Renal tissue (isthmus) bridging the lower poles anterior to the great vessels

Renal axes may be more horizontal than usual

Kidneys may appear closer together or “kissing” the spine anteriorly

Differentiation from other options:

A. Duplicated collecting system: Manifests as two separate collecting systems within one kidney, often with a central renal sinus split into two — not typically midline bridging.

B. Crossed renal ectopia: Involves one kidney crossing midline and fusing with the other on the opposite side, but they do not form a midline isthmus.

D. Pelvic kidney: A single kidney located in the pelvis due to failed ascent — it does not appear as midline fusion of two kidneys.

The normal epididymis typically appears as a homogeneous structure that is either isoechoic or slightly hypoechoic compared to the testis. The most accurate description is "homogeneous compared to the testis," meaning the texture is uniform. It is not anechoic, nor does it typically show irregular borders unless pathology is present.

According to Rumack’s Diagnostic Ultrasound:

"The normal epididymis appears homogeneous and is isoechoic or slightly hypoechoic relative to the testis." (Rumack CM et al., Diagnostic Ultrasound, 5th ed.)