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

The inferior vena cava (IVC) is formed by the confluence of the right and left common iliac veins at the level of approximately L5. The hepatic veins drain into the IVC superiorly but do not form it. The superior mesenteric and splenic veins join to form the portal vein, not the IVC.

According to Moore’s Clinically Oriented Anatomy:

“The IVC begins at the level of L5 by the union of the right and left common iliac veins.”

Lipase is the most sensitive and specific laboratory marker for diagnosing acute pancreatitis. It rises earlier, remains elevated longer (up to 14 days), and is more pancreas-specific than amylase. Amylase may normalize within 48-72 hours and may also be elevated in non-pancreatic conditions.

According to ACG (American College of Gastroenterology) Guidelines:

“Serum lipase is preferred over amylase due to its higher sensitivity, specificity, and prolonged elevation in pancreatitis.”

The ultrasound image demonstrates multiple parallel echogenic lines within the gallbladder lumen, extending distally and diminishing in intensity. These equidistant lines are classic for a reverberation artifact.

Reverberation occurs when the ultrasound beam reflects multiple times between two strong reflectors (such as the anterior gallbladder wall and the transducer), creating repeating echoes that appear as equally spaced lines. This is frequently seen in:

The gallbladder (especially when collapsed or near the wall)

Near air-filled structures

With metallic objects or surgical clips

Reverberation does not represent a true anatomical structure and should be distinguished from real pathology.

Comparison of answer choices:

A. Banding refers to speed displacement or slice-thickness artifacts and typically does not appear as repetitive lines.

B. Shadowing is a dark band posterior to highly attenuating structures like gallstones or bone, not present here.

C. Attenuation is a general term for the reduction in sound energy as it travels—posterior acoustic shadowing is one type.

D. Reverberation — Correct. The characteristic bright, parallel lines within the gallbladder lumen confirm this artifact.

When measuring the abdominal aorta (or any vessel diameter for aneurysm evaluation), calipers should be placed from outer wall to outer wall to ensure inclusion of the full vessel diameter, including any mural thrombus. This is the standard method accepted by professional societies.

According to AIUM and SRU Guidelines:

“Vessel diameter measurements should be performed from outer wall to outer wall to avoid underestimation of aneurysm size.”

Pancreatic pseudocysts most commonly develop in the lesser sac, which lies between the posterior wall of the stomach and the anterior surface of the pancreas. This space allows for the accumulation of pancreatic fluid collections following pancreatitis or pancreatic ductal disruption.

The left anterior pararenal space (B) is a secondary location.

The right subdiaphragmatic space (C) and left pericolic gutter (D) are less common sites.

Reference Extracts:

Mortele KJ, Wiesner W, et al."Pancreatic pseudocysts: imaging features and diagnostic difficulties." Radiographics. 2004;24(4):1005-1020.

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

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In hepatic steatosis (fatty liver), increased echogenicity can obscure visualization of deeper structures like the common bile duct. Lowering the transducer frequency increases sound wave penetration, allowing better visualization of deep structures despite increased liver echogenicity. Decreasing gain or increasing dynamic range primarily adjusts image brightness and contrast but does not improve penetration.

According to Rumack’s Diagnostic Ultrasound:

“Lower frequency transducers are used to improve penetration and visualization of deeper structures in patients with fatty liver.”

The arcuate arteries are located at the corticomedullary junction, arching over the base of the renal pyramids. They form as the interlobar arteries reach the boundary between the cortex and medulla. The arcuate arteries give rise to the interlobular arteries, which supply the renal cortex.

Segmental arteries (A) branch directly from the renal artery.

Interlobar arteries (B) course between the renal pyramids.

Interlobular arteries (D) extend into the cortex from the arcuate arteries.

Reference Extracts:

Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy. 7th ed. Lippincott Williams & Wilkins, 2013.

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

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Direct inguinal hernias protrude through Hesselbach's triangle, which lies medial to the inferior epigastric artery. In contrast, indirect inguinal hernias pass lateral to the inferior epigastric artery via the deep inguinal ring.

According to Moore’s Clinically Oriented Anatomy:

“Direct inguinal hernias occur medial to the inferior epigastric vessels, within Hesselbach's triangle.”

The mucosa is the innermost layer of the gastrointestinal wall, consisting of epithelium, lamina propria, and muscularis mucosae. It is responsible for absorption and secretion. The submucosa lies just outside the mucosa.

According to Moore’s Clinically Oriented Anatomy:

“The mucosa is the innermost layer of the gastrointestinal tract, responsible for nutrient absorption and secretion.”

The ultrasound image demonstrates a dilated duodenum with a hypoechoic soft tissue structure encircling it. This is a classic sonographic appearance suggestive of an annular pancreas. In annular pancreas, pancreatic tissue completely or partially encircles the second portion of the duodenum, which can lead to duodenal narrowing or obstruction.

Annular pancreas is a congenital anomaly that results from failure of the ventral pancreatic bud to rotate properly during embryologic development. As a result, pancreatic tissue encircles the duodenum. It may present in neonates with symptoms of duodenal obstruction or in adults with abdominal pain, pancreatitis, or vomiting.

Ultrasound Findings:

Hypoechoic pancreatic tissue encircling the duodenum

Evidence of duodenal dilatation proximal to the obstruction

“Double bubble” sign may be seen in neonates

Differentiation from other options:

A. Supernumerary kidney: Refers to an accessory kidney. It would be seen in the retroperitoneum and is unrelated to the duodenum or pancreas.

B. Pancreas divisum: A ductal anomaly best diagnosed on MRCP or ERCP. It is not typically visible on conventional ultrasound.

D. Horseshoe kidney: A renal fusion anomaly where the lower poles of the kidneys are fused. It is seen in the pelvis or lower abdomen and does not involve the duodenum or pancreas.