Free Practice Questions for ARDMS AB-Abdomen Exam

Wooden foreign bodies are often difficult to detect on CT because of their low radiodensity, but they are highly echogenic with posterior shadowing or reverberation on ultrasound, making ultrasound superior for detecting retained wooden objects. Glass, metal, and stones are better visualized with CT due to their high radiodensity.

According to AIUM and musculoskeletal ultrasound literature:

“Wood is poorly visualized on CT but demonstrates high reflectivity and acoustic shadowing on ultrasound.”

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 shows an anechoic (black) fluid collection in the perihepatic and perirenal spaces. The fluid outlines the liver (LIV) and right kidney (RK), which is characteristic of free fluid in the peritoneal cavity — consistent with ascites.

Sonographic features of ascites:

Anechoic (or hypoechoic) fluid in dependent areas of the abdomen

Seen surrounding the liver, spleen, and intestines

Can be free-flowing or loculated

Bowel loops may be floating or displaced centrally

This image is consistent with a typical finding of ascites: free fluid in Morison’s pouch (hepatorenal recess), a common site for fluid accumulation.

Differentiation from other options:

A. Hydropic gallbladder: Refers to an enlarged gallbladder filled with clear bile; not visible in this image.

B. Hemoperitoneum: May appear similar to ascites, but usually has complex echogenicity or layering if acute; clinical context (trauma, bleeding) is essential for diagnosis.

C. Bowel obstruction: Would show dilated, fluid-filled bowel loops with peristalsis or to-and-fro motion, not evident here.

The structure indicated by the arrow is the middle hepatic vein. This is confirmed by both its anatomical location within the liver and its Doppler waveform characteristics.

Key ultrasound and Doppler features:

The middle hepatic vein runs between the right and left hepatic lobes and drains into the inferior vena cava (IVC). On grayscale imaging, it appears as a tubular anechoic structure extending toward the IVC.

On spectral Doppler, hepatic veins (including the middle hepatic vein) demonstrate a characteristic triphasic waveform due to pressure changes in the right atrium. This triphasic pattern is clearly visible in the Doppler tracing below the image.

This differs significantly from the monophasic low-resistance flow of the hepatic artery or the continuous hepatopetal flow of the portal vein.

Differentiation from other options:

A. Left portal vein: Would show continuous, hepatopetal flow (toward the liver) and lies more anterior and medial within the liver.

C. Proper hepatic artery: Small-caliber vessel with low-resistance pulsatile waveform (not triphasic).

D. Inferior vena cava: Lies posterior to the liver and demonstrates phasic flow with respiration, but this vessel is more centrally located and not shown in this field of view.

When the sample volume (gate) is too large, it captures signals from both the vessel and surrounding tissues or adjacent flows. This leads to a broadening of the spectral waveform and produces "spectral noise" or "spectral broadening," reducing the accuracy of velocity measurements and waveform analysis. Aliasing results from high velocity relative to the Nyquist limit, not from gate size.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Increasing the sample volume beyond the vessel size causes spectral broadening, resulting in spectral noise and inaccurate Doppler measurements.”

De Quervain thyroiditis (subacute granulomatous thyroiditis) is often triggered by a viral infection. Patients may present with painful thyroid enlargement, elevated inflammatory markers, and transient hyperthyroidism. Hashimoto’s and Graves' diseases are autoimmune in nature.

According to Braverman’s The Thyroid:

“Subacute (De Quervain) thyroiditis typically follows a viral upper respiratory tract infection and is characterized by thyroid pain and transient thyrotoxicosis.”

The ultrasound image shows a blind-ending, non-compressible, tubular structure in the right lower quadrant with a target or bullseye appearance in transverse section — highly suggestive of the appendix.

Sonographic features of the appendix (especially in suspected appendicitis):

Blind-ending tubular structure arising from the cecum

Non-compressible on graded compression

Diameter >6 mm is suggestive of appendicitis

May demonstrate a “target sign” in transverse view (concentric ring-like appearance)

Increased echogenicity of surrounding fat in cases of inflammation

May contain an appendicolith or show hyperemia on color Doppler if inflamed

The location (right lower quadrant) and appearance in this case are classic for the normal or potentially inflamed appendix.

Differentiation from other options:

A. Fallopian tube: Located more in the adnexal regions and usually not visible unless distended (e.g., hydrosalpinx).

B. Ureter: Usually not visualized on ultrasound unless dilated due to obstruction.

D. Jejunum: Has valvulae conniventes ("keyboard sign") and peristalsis; does not present with a blind-ending tubular appearance from the cecum.

The coronary vein (left gastric vein) is a common collateral pathway in portal hypertension. It often becomes dilated and may demonstrate hepatofugal (reversed) flow as blood diverts from the high-pressure portal system into systemic collaterals.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“The left gastric (coronary) vein is a frequent site of hepatofugal flow in portal hypertension, reflecting collateral development.”

The technique shown in the video is compression. In ultrasound imaging—especially of soft tissue masses, the bowel, or venous structures—compression is used to evaluate the compressibility of structures. The image demonstrates a classic grayscale ultrasound view of a lesion or structure being compressed with the probe.

Compression sonography is particularly important in:

Evaluating venous patency (e.g., for deep vein thrombosis)

Differentiating cystic from solid structures

Evaluating bowel wall abnormalities or intussusception

Assessing lymph nodes and soft tissue masses (as shown here)

When a structure compresses easily under probe pressure, it suggests that the lesion is fluid-filled or soft. In contrast, incompressibility may indicate a solid mass or thrombus.

Differentiation from other options:

B. Valsalva: Involves forced expiration against a closed airway, used primarily to assess venous reflux or inguinal hernias—not what is demonstrated here.

C. Exhalation: A respiratory maneuver that passively alters thoracoabdominal pressure, not actively performed by the operator or causing focal structural change.

D. Deep inspiration: Used to improve visualization of the liver, diaphragm, or gallbladder—not to evaluate the compressibility of soft tissue.

Ring-down artifact occurs when gas bubbles resonate or oscillate, creating continuous echoes distal to the structure that appear as a vertical, echogenic band extending posteriorly. This is distinct from reverberation, which produces multiple discrete reflections.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Ring-down artifact results from resonance of gas bubbles, producing a continuous, echogenic tail distal to the reflecting interface.”