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

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.”

The ultrasound image clearly demonstrates a thickened and elongated pyloric muscle with a visible channel, which is characteristic of hypertrophic pyloric stenosis (HPS). This condition is most commonly seen in male infants between 2 and 8 weeks of age who present with non-bilious projectile vomiting, dehydration, and a palpable “olive-like” mass in the right upper quadrant.

Ultrasound is the imaging modality of choice and is highly sensitive and specific for diagnosing pyloric stenosis.

Key sonographic criteria for HPS:

Muscle thickness >3 mm

Pyloric channel length >15–17 mm

“Target sign” or “doughnut sign” on transverse imaging (concentric rings)

“Cervix” or “railroad track sign” on longitudinal imaging (elongated canal with echogenic center)

Differentiation from other options:

A. Intussusception: Also shows a target sign, but it occurs in the right lower quadrant or periumbilical region, not in the gastric antrum.

C. Hydronephrosis: Refers to dilation of the renal pelvis and calyces — not gastrointestinal.

D. Gastritis: May show gastric wall thickening but lacks the distinct elongated, thickened pyloric muscle seen here.

The ultrasound image shows a transverse section through the upper abdomen. The arrow is pointing to a vascular structure running posterior to the pancreas and anterior to the left kidney. This vessel is the splenic vein.

Anatomically:

The splenic vein runs along the posterior border of the pancreas.

It courses medially to join the superior mesenteric vein (SMV) and form the portal vein.

It receives tributaries from the spleen, short gastric veins (draining the stomach), and the inferior mesenteric vein.

In this case, the question asks which organ is primarily drained via the vessel marked by the arrow. The splenic vein's main tributary is from the spleen.

Comparison of answer choices:

A. Spleen — Correct. The splenic vein is the primary drainage vessel for the spleen.

B. Stomach — Some gastric veins drain into the splenic vein, but the primary drainage is via left and right gastric veins into the portal system.

C. Left kidney — Drains into the left renal vein, not the splenic vein.

D. Duodenum — Drains mainly into the superior mesenteric vein (SMV).

The ultrasound image shows echogenic foci with dirty shadowing and reverberation artifacts within the gallbladder wall and lumen. These features are characteristic of emphysematous cholecystitis, a severe, life-threatening variant of acute cholecystitis caused by gas-forming organisms (e.g., Clostridium or E. coli) infecting the gallbladder wall.

Sonographic features of emphysematous cholecystitis:

Echogenic gas within the gallbladder wall or lumen

Reverberation or "dirty" shadowing artifacts

May show intramural gas bubbles or "ring-down" artifact

Often seen in diabetic or immunocompromised patients

No gallstones may be present ("acalculous cholecystitis")

Clinical context:

More common in elderly men and diabetics

Presents with right upper quadrant pain, fever, and leukocytosis

Surgical emergency due to risk of perforation and sepsis

Differentiation from other options:

A. Adenomyomatosis: Involves gallbladder wall thickening with “comet tail” artifacts due to Rokitansky-Aschoff sinuses, not intramural gas.

B. Porcelain gallbladder: Shows curvilinear calcification of the gallbladder wall — dense echogenic rim with posterior shadowing.

C. Gangrenous cholecystitis: May show wall irregularity, intraluminal membranes, and absence of Doppler flow but lacks intramural gas.

A tumor (such as cholangiocarcinoma, pancreatic head carcinoma, or metastases) is a common cause of biliary duct obstruction. It can compress or invade the bile ducts, leading to intrahepatic and extrahepatic duct dilatation.

Cholecystitis (B) typically affects the gallbladder but may rarely cause duct obstruction if complicated.

Pneumobilia (C) refers to air in the biliary tree, not obstruction.

Hepatitis (D) causes liver inflammation but not mechanical biliary obstruction.

Reference Extracts:

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

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

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Von Hippel-Lindau (VHL) syndrome is a genetic disorder associated with multiple pancreatic cysts, pancreatic neuroendocrine tumors, and other systemic neoplasms. While cystic fibrosis can produce thickened pancreatic secretions, it rarely causes true pancreatic cysts.

According to Rumack’s Diagnostic Ultrasound:

“Multiple pancreatic cysts are strongly associated with Von Hippel Lindau syndrome.”

The ultrasound image shown is a transverse endorectal (transrectal) ultrasound, commonly used to evaluate the prostate and adjacent structures. The two hypoechoic (dark) oval-shaped structures seen superior and posterior to the prostate are characteristic of the seminal vesicles.

The seminal vesicles are paired, elongated glands located superior and posterior to the base of the prostate and are best visualized in transverse planes on endorectal imaging. They appear as hypoechoic or anechoic structures with internal septations, depending on the degree of fluid content.

In contrast:

The urethra appears as a central echogenic linear structure within the prostate.

The prostate base is more inferior in the scan and is visualized just above the urethra.

The ejaculatory ducts are usually not as prominently visualized and are located medial to the seminal vesicles, entering the prostate near the verumontanum.

This image most clearly demonstrates the bilateral seminal vesicles.

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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Downstream from a significant renal artery stenosis, the acceleration time is prolonged due to delayed systolic upstroke (“tardus-parvus waveform”). This is a sensitive Doppler parameter for detecting hemodynamically significant stenosis. Spectral broadening usually occurs at the stenotic site, not distal to it.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Prolonged acceleration time and reduced acceleration index characterize tardus-parvus waveforms distal to renal artery stenosis.”

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.