AB-Abdomen ARDMS Abdomen Sonography Examination Free Practice Exam Questions (2025 Updated)

The ultrasound image demonstrates a tubular, non-compressible, blind-ending structure located in the right lower quadrant (RLQ) with associated echogenic periappendiceal fat and possibly adjacent fluid or phlegmon. These features are consistent with appendicitis. Given the clinical history of fever and RLQ pain, along with the irregular borders and complex periappendiceal findings, the diagnosis of a ruptured appendix is most likely.

Key sonographic features of ruptured appendicitis include:

Non-visualization or distortion of the normal appendiceal wall architecture

Periappendiceal fluid collection or abscess

Disruption of the echogenic submucosal layer

Surrounding fat stranding (hyperechoic inflammatory changes)

Clinical correlation with fever and peritonitis

Comparison of answer choices:

A. Bowel obstruction typically shows dilated bowel loops with air-fluid levels, not a tubular structure like the appendix.

B. Intussusception presents with a target or “donut” sign in a transverse view, not a linear tubular structure.

C. Enlarged lymph nodes are usually round or oval and hypoechoic with a central echogenic hilum, without a tubular appearance.

D. Ruptured appendix — Correct. The ultrasound features and clinical presentation match.

A wandering spleen occurs when the spleen is not adequately anchored by its supporting ligaments, allowing it to move freely within the abdomen. This increases the risk of splenic torsion, which compromises vascular supply and may result in infarction if not corrected.

According to Rumack’s Diagnostic Ultrasound:

“The most serious complication of a wandering spleen is torsion, which may result in splenic infarction.”

Retroperitoneal fibrosis can encase and compress the ureters, leading to obstructive uropathy and hydronephrosis. It may also involve other retroperitoneal structures but hydronephrosis is the most common significant complication.

According to Rumack’s Diagnostic Ultrasound:

“Retroperitoneal fibrosis frequently results in ureteral obstruction, leading to hydronephrosis.”

Pancreas divisum occurs when the dorsal and ventral pancreatic ducts fail to fuse during embryologic development. This results in most pancreatic secretions draining through the minor papilla via the dorsal duct (duct of Santorini).

According to Rumack’s Diagnostic Ultrasound:

“In pancreas divisum, the dorsal and ventral pancreatic ducts fail to fuse, resulting in separate drainage systems.”

The left lobe of the thyroid is located anterolateral to the esophagus. On transverse ultrasound imaging, the esophagus can often be seen posterior to the left thyroid lobe as a circular structure with echogenic mucosa and hypoechoic muscular layer. The longus colli muscle lies posterior to the thyroid. The thyroid is anterior to the trachea but this refers more to the isthmus or midline portion.

According to Rumack’s Diagnostic Ultrasound:

“The esophagus is seen as a target-shaped structure posterior to the left thyroid lobe; thus, the thyroid lobe is anterolateral to the esophagus.”

The Duct of Santorini is the accessory pancreatic duct that drains the superior portion of the pancreatic head into the minor duodenal papilla. The main pancreatic duct (Duct of Wirsung) drains into the major papilla, often joining the common bile duct at the Ampulla of Vater.

According to Moore’s Clinically Oriented Anatomy:

“The accessory pancreatic duct (Duct of Santorini) may be present and drains into the minor duodenal papilla.”

Intrahepatic biliary dilatation with a normal common bile duct (CBD) is typically caused by obstruction located at or above the level of the hepatic duct confluence. A tumor at the porta hepatis, such as cholangiocarcinoma (Klatskin tumor), is a classic cause of this pattern. The porta hepatis is the site where the right and left hepatic ducts join to form the common hepatic duct. A mass at this location can obstruct the intrahepatic ducts while leaving the distal CBD unaffected and of normal caliber.

By contrast:

Portal vein thrombus (A) affects vascular flow but does not directly obstruct bile ducts.

Choledocholithiasis (C) obstructs the CBD, typically resulting in both intrahepatic and extrahepatic duct dilatation.

Acute pancreatitis (D) may cause distal CBD compression if there is associated inflammation or pseudocyst formation, but typically results in extrahepatic duct dilatation rather than isolated intrahepatic dilation.

Reference Extracts:

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound, 5th ed. Elsevier, 2017. Chapter: Biliary Tract: “Klatskin tumors cause proximal (intrahepatic) biliary dilatation while the distal bile duct remains normal in caliber.”

Gore RM, Levine MS. Textbook of Gastrointestinal Radiology, 4th ed. Saunders, 2015.

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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.