Pass the ARDMS RDMS AB-Abdomen Questions and answers with CertsForce

The ultrasound image provided shows the liver and diaphragm imaged in a coronal plane with characteristic rib shadows and costophrenic angles. The orientation of the image and the structures visualized suggest that the transducer is placed in the right mid-axillary line, with the sound beam directed coronally — this is a classic right coronal scanning approach.

Key features supporting this:

The liver appears superiorly in the image.

Multiple echogenic lines (representing the ribs) run obliquely, casting acoustic shadows.

The diaphragm and adjacent lung base are seen clearly, which is commonly imaged through the right intercostal spaces in a coronal plane.

Comparison of answer choices:

A. Anterior: Would show a more transverse view of the liver and not typically image the diaphragm and lung this way.

B. Posterior: Not used for upper abdominal scanning due to shadowing from the spine and posterior ribs.

C. Left coronal: Would show the spleen and left kidney — not the liver as seen here.

D. Right coronal — Correct. This image was obtained using the right coronal (intercostal) approach through the right flank.

The ultrasound image of the thyroid clearly shows posterior shadowing originating from the lateral edges of a rounded structure, which is indicative of edge shadow artifact. Edge shadowing occurs when an ultrasound beam passes tangentially to a rounded or curved structure, such as a cyst or blood vessel. The difference in sound wave refraction and beam divergence at the edges leads to decreased echo signals deep to the edges, creating linear hypoechoic bands — which is exactly what the arrows are pointing to in the image.

Edge shadow artifact is purely a result of beam physics and not a real anatomic or pathologic finding.

Key characteristics of edge shadowing:

Appears as a narrow, linear hypoechoic (dark) shadow extending deep to the edge of a curved interface (e.g., cyst, vessel, thyroid nodule)

Caused by refraction and beam deflection, leading to reduced beam intensity distal to the edges

Most commonly seen adjacent to cysts or fluid-filled structures

Differentiation from other options:

A. Focal enhancement: Appears as increased echogenicity distal to a fluid-filled structure due to lower attenuation of the sound beam through fluid (opposite of shadowing).

C. Speed error: A less common artifact that results in displacement of structures due to variation in assumed sound speed.

D. Comet tail: A reverberation artifact that appears as a series of closely spaced bright echoes, often associated with metallic objects or cholesterol crystals in adenomyomatosis.

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 ultrasound image shows a measured common bile duct (CBD) diameter of 7.9 mm in a postcholecystectomy patient. In patients who have undergone cholecystectomy, mild dilation of the CBD is considered normal and is a well-recognized post-surgical change.

Normal upper limits for CBD diameter:

In patients with a gallbladder: ≤6 mm is generally considered normal.

In postcholecystectomy patients: up to 10 mm is considered within normal limits, as the CBD compensates for the absence of the gallbladder and slightly enlarges over time.

With aging, the CBD may enlarge by approximately 1 mm per decade after age 60.

Therefore, a CBD diameter of 7.9 mm in a patient without a gallbladder is considered normal.

Differentiation from other options:

B. Dilated: This would typically refer to a CBD diameter >10 mm in postcholecystectomy patients, or >6 mm in patients with an intact gallbladder.

C. Inflamed: Inflammation refers to wall thickening or hyperemia, which is not evaluated simply by measuring diameter.

D. Atretic: Describes a congenitally absent or severely narrowed duct — not applicable here.

Patients with liver disease often have coagulopathy due to impaired synthesis of clotting factors. This places them at greater risk for bleeding or hematoma formation after biopsy. While hypertension may increase bleeding risk slightly, liver disease presents a significantly higher risk due to impaired coagulation.

According to the Society of Interventional Radiology (SIR) guidelines:

“Liver dysfunction is a significant risk factor for post-biopsy hemorrhage due to associated coagulopathy.”

The superior mesenteric artery (SMA) is typically visualized surrounded by an echogenic fat pad in the mesentery, producing a characteristic "echogenic ring" appearance on ultrasound. This is a helpful landmark for identifying the SMA in the transverse abdominal aortic plane.

According to Rumack’s Diagnostic Ultrasound:

“The superior mesenteric artery is often seen as a round anechoic structure surrounded by echogenic fat at its origin from the anterior aorta.”

Type I choledochal cyst, characterized by fusiform dilatation of the common bile duct, is the most common form, accounting for 80-90% of cases. Other types are much less frequent.

According to Rumack’s Diagnostic Ultrasound:

“Type I fusiform dilatation of the extrahepatic bile duct is the most common type of choledochal cyst.”

The transverse ultrasound image of the liver shows a solid, hypoechoic mass located in the posterior aspect of the right lobe of the liver. In this view:

The anterior aspect of the liver is at the top of the image (near the transducer).

The posterior aspect is at the bottom (deeper).

The right lobe occupies the majority of the screen on transverse imaging when the probe is placed in the epigastrium or right upper quadrant.

Anatomically, the right lobe of the liver is divided into anterior and posterior segments by the right hepatic vein in the coronal plane. In transverse imaging:

The right anterior segment lies closer to the anterior abdominal wall.

The right posterior segment lies deeper (posteriorly).

Given that the mass is seen deep within the liver on the right side of the image, it is best localized to the right posterior segment (Segment VI or VII depending on the exact craniocaudal level).

Comparison of answer choices:

A. Left lateral is located far to the left of the image and typically appears higher and more anterior on transverse scans.

B. Left medial lies near the midline and would appear adjacent to the ligamentum teres or falciform ligament.

C. Right anterior lies closer to the transducer (top of the image), not posteriorly.

D. Right posterior — Correct. This is the segment shown deep in the right lobe of the liver.

The image demonstrates a gallbladder with a possible echogenic focus (likely a gallstone) and posterior acoustic shadowing. This is suggestive of cholelithiasis. To differentiate uncomplicated gallstones from acute cholecystitis, the most effective technique is to assess for a positive sonographic Murphy sign.

A positive sonographic Murphy sign refers to the presence of focal tenderness over the gallbladder when it is directly palpated with the ultrasound transducer. It is a strong indicator of acute cholecystitis when combined with other features such as gallbladder wall thickening, pericholecystic fluid, and gallstones.

Sonographic Murphy sign — key points:

Assessed during real-time scanning

Localized tenderness when pressure is applied over the gallbladder

Highly sensitive for acute cholecystitis (especially in the presence of stones)

Differentiation from other options:

A. Use compound imaging: Improves image quality by reducing artifacts but does not verify tenderness or confirm acute inflammation.

B. Change the patient’s position: Helpful to confirm mobility of gallstones, but not diagnostic of inflammation.

C. Ask patient to perform Valsalva: Used primarily in vascular studies (e.g., assessing for varicocele or venous reflux), not relevant here.

Splenosis refers to autotransplantation of splenic tissue following splenic trauma or splenectomy. After rupture, splenic fragments may implant throughout the peritoneal cavity and vascularize, forming multiple nodules of functional splenic tissue. Splenosis is typically asymptomatic and discovered incidentally on imaging.

Splenule (A) is a congenital accessory spleen, not related to trauma.

Hamartoma (C) is a benign primary splenic lesion.

Target lesion (D) generally refers to sonographic appearance seen in metastases or infections, not post-trauma.

Reference Extracts:

Mortelé KJ, et al. "Multimodality imaging of splenic lesions and the spleen." Radiographics. 2004;24(4):1137-1163.

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017.

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