Free ARDMS AB-Abdomen Practice Exam with Questions & Answers | Set: 2

Acute pyelonephritis is a bacterial infection of the renal parenchyma and collecting system. Classic clinical findings include fever, flank pain, leukocytosis (elevated white blood cells), and pyuria (white blood cells in urine). Ultrasound may demonstrate renal enlargement, decreased echogenicity, and loss of corticomedullary differentiation.

Nephrocalcinosis (A) involves calcium deposition without infection.

Staghorn calculus (B) may lead to infection but is primarily characterized by obstructive uropathy.

Renal cell carcinoma (C) presents with hematuria and mass formation rather than infection symptoms.

Reference Extracts:

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

Middleton WD, Kurtz AB, Hertzberg BS.Ultrasound: The Requisites. 3rd ed. Elsevier, 2015.

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The arrow in this Doppler ultrasound image of the kidney is pointing to vessels located at the corticomedullary junction, arching over the bases of the medullary pyramids. This vascular pattern is characteristic of the arcuate arteries.

Renal arterial anatomy follows a specific branching hierarchy:

Segmental arteries branch off the main renal artery.

Interlobar arteries travel between renal pyramids.

Arcuate arteries arch over the base of the pyramids at the corticomedullary junction.

Interlobular arteries extend into the cortex from the arcuate arteries.

Key characteristics of arcuate arteries on ultrasound:

Located at the corticomedullary junction (between the medullary pyramids and renal cortex).

Run perpendicular to the long axis of the kidney, often forming an arching or curving pattern.

Commonly targeted in Doppler studies to assess resistive index (RI) in renal perfusion studies.

Comparison of answer choices:

A. Interlobular arteries are smaller vessels that extend perpendicularly from the arcuate arteries into the cortex—not visible at this level.

B. Arcuate — Correct. The arrow is indicating these vessels arching over the medullary pyramids.

C. Segmental arteries are larger and deeper, branching off the renal artery near the hilum.

D. Interlobar arteries course between the pyramids but do not arch along their base.

Postsurgical breast scarring may appear hypoechoic and irregular but typically shows no internal vascularity on Doppler imaging. In contrast, recurrent tumors generally exhibit increased internal vascular flow due to neovascularization. Therefore, absent Doppler signal helps suggest scar tissue rather than malignancy.

According to Stavros’ Breast Ultrasound:

“The absence of internal Doppler flow favors scar tissue, whereas recurrent malignancy typically demonstrates internal vascularity.”

The normal gallbladder wall measures up to 3 mm. Thickening beyond 3 mm may suggest cholecystitis, heart failure, hepatitis, or hypoalbuminemia. Measurements should be taken with the patient fasting, using the anterior gallbladder wall.

According to Rumack’s Diagnostic Ultrasound:

“The gallbladder wall is considered thickened if it measures greater than 3 mm.”

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.

The normal epididymis typically appears as a homogeneous structure that is either isoechoic or slightly hypoechoic compared to the testis. The most accurate description is "homogeneous compared to the testis," meaning the texture is uniform. It is not anechoic, nor does it typically show irregular borders unless pathology is present.

According to Rumack’s Diagnostic Ultrasound:

"The normal epididymis appears homogeneous and is isoechoic or slightly hypoechoic relative to the testis." (Rumack CM et al., Diagnostic Ultrasound, 5th ed.)

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.

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 correct sequence of renal arterial branching is: renal artery → segmental arteries → interlobar arteries → arcuate arteries → interlobular arteries. This branching pattern is important for understanding renal perfusion and evaluating vascular disorders.

According to Moore’s Clinically Oriented Anatomy:

“Renal arteries divide into segmental branches, which give rise to interlobar arteries, then arcuate arteries, and finally interlobular arteries.”

The ultrasound image demonstrates a classic example of ascites, shown by the anechoic (dark) fluid located between bowel loops or surrounding abdominal organs. In this case, there appears to be a small fluid collection in the peritoneal cavity.

One of the key maneuvers used to differentiate free fluid (such as ascites) from loculated fluid or other structures is to reposition the patient. Asking the patient to “turn from side to side” (Option D) can help in assessing whether the fluid shifts position — a hallmark feature of free intraperitoneal fluid. This positional change is highly useful in confirming the diagnosis and distinguishing ascites from other potential mimics (e.g., cystic masses, lymphoceles, or bowel wall thickening).

In contrast:

Drinking water (A) is often used in imaging the urinary bladder or gastrointestinal tract but not for fluid characterization.

Standing upright (B) may shift fluid but is less practical during real-time ultrasound.

Breathing quietly (C) doesn’t significantly aid in visualizing peritoneal fluid mobility.