Free Practice Questions for ARDMS AB-Abdomen Exam

The ultrasound image demonstrates findings consistent with hypertrophic pyloric stenosis (HPS). This condition typically affects infants between 2 and 8 weeks of age and presents clinically with non-bilious projectile vomiting, weight loss, and dehydration.

In the ultrasound image, the classic “target” or “donut” sign can be seen in the transverse view of the hypertrophied pyloric muscle. Key sonographic criteria for HPS include:

Pyloric muscle thickness ≥3 mm

Pyloric channel length ≥15–18 mm

This imaging appearance strongly correlates with the clinical presentation of projectile vomiting (Choice D), which is the hallmark symptom of HPS.

Comparison of answer choices:

A. Abnormal prenatal ultrasound (Choice A) is not typically associated with HPS, which develops postnatally.

B. Neonatal hyperbilirubinemia (Choice B) is not an indication for a pyloric ultrasound and affects liver/biliary imaging.

C. Red currant jelly stools (Choice C) are indicative of intussusception, not HPS.

D. Projectile vomiting (Choice D) is the most common clinical indication leading to an ultrasound exam that reveals HPS.

The ultrasound image demonstrates a longitudinal view of the right kidney. Within the renal pyramids, there are multiple echogenic foci, some showing posterior acoustic shadowing—findings characteristic of medullary nephrocalcinosis. This sonographic appearance is strongly associated with medullary sponge kidney (MSK).

Medullary sponge kidney is a congenital disorder of the renal tubules that results in ectatic (dilated) collecting ducts in the renal medulla. The dilated ducts frequently become calcified, leading to the "paintbrush" or "bouquet of flowers" appearance seen in the renal pyramids on ultrasound. These calcifications are most often bilateral and symmetrical, further aiding the diagnosis.

Comparison of answer choices:

A. Fungal balls (mycetomas) typically appear as mobile, non-shadowing echogenic masses within the collecting system, often in immunocompromised patients.

B. Renal cell carcinoma usually presents as a solid mass with irregular borders and variable echogenicity—this image does not show a mass.

C. Acute pyelonephritis may show renal enlargement, decreased echogenicity, or loss of corticomedullary differentiation—but not calcification of the pyramids.

D. Medullary sponge kidney is correct due to the punctate echogenic foci within the medullary pyramids, consistent with nephrocalcinosis.

Transudative pleural effusions result from imbalances in hydrostatic and oncotic pressures, most commonly caused by congestive heart failure (CHF). In CHF, elevated hydrostatic pressure in the pulmonary capillaries leads to fluid leakage into the pleural space without significant protein or cellular content (hence, transudate). Exudative effusions (associated with infections, malignancy, and inflammation) are more often seen with pulmonary emboli, lymphoma, or empyema.

According to Light’s criteria (which differentiates transudates from exudates):

"Congestive heart failure remains the leading cause of transudative pleural effusions." (Light RW. Pleural Diseases, 6th ed.).

Angiomyolipomas are benign renal tumors composed of fat, smooth muscle, and blood vessels. They are strongly associated with tuberous sclerosis and may be multiple and bilateral in these patients. While RCC may occur, angiomyolipomas are much more characteristic.

According to Rumack’s Diagnostic Ultrasound:

“Angiomyolipomas are frequently multiple and bilateral in patients with tuberous sclerosis.”

A varicocele is an abnormal dilatation of the pampiniform plexus veins, usually seen on the left side due to the perpendicular insertion of the left testicular vein into the left renal vein, making it more susceptible to elevated venous pressure. Sonographically, varicoceles appear as multiple serpiginous anechoic tubular structures that show venous flow on color Doppler, often accentuated with Valsalva maneuver.

Hydrocele (A) is a fluid collection surrounding the testis.

Hematocele (C) is blood within the tunica vaginalis.

Spermatocele (D) is a cystic lesion arising from the epididymis.

Reference Extracts:

Dogra VS, Bhatt S. "Sonographic evaluation of testicular varicoceles." Journal of Ultrasound in Medicine. 2004;23(6): 829-838.

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

—

Budd-Chiari syndrome is caused by hepatic venous outflow obstruction, resulting in hepatomegaly, ascites, right upper quadrant pain, and liver dysfunction. It may be due to thrombosis or compression of the hepatic veins or IVC.

According to Rumack’s Diagnostic Ultrasound:

“Budd-Chiari syndrome results from hepatic venous outflow obstruction and presents with hepatomegaly, ascites, and right upper quadrant pain.”

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.”

Pancreatic ductal adenocarcinoma is by far the most common pancreatic malignancy, accounting for approximately 85–90% of pancreatic cancers. It typically arises from the exocrine portion of the pancreas, most frequently in the pancreatic head. Islet cell (neuroendocrine) tumors and cystic neoplasms (e.g., mucinous cystadenocarcinoma) are far less common.

According to Rumack’s Diagnostic Ultrasound:

“Adenocarcinoma is the most common malignant neoplasm of the pancreas, representing the vast majority of pancreatic cancers.”

Power Doppler measures the amplitude (strength) of Doppler signals rather than frequency shift, making it more sensitive to low-velocity and small-vessel blood flow. Its primary advantage is an improved signal-to-noise ratio, allowing for better visualization of slow or weak flow.

A: Power Doppler is more sensitive to motion artifacts, not less.

B: It is still angle dependent, though somewhat less so than color Doppler.

D: Power Doppler does not display flow direction (a limitation).

Reference Extracts:

Kremkau FW. Sonography Principles and Instruments. 9th ed. Elsevier, 2015.

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