Free ARDMS AB-Abdomen Practice Exam with Questions & Answers

Thyroid adenomas typically present as well-defined nodules surrounded by a thin, hypoechoic peripheral halo representing compressed thyroid parenchyma or fibrous capsule. Irregular margins suggest malignancy.

According to Rumack’s Diagnostic Ultrasound:

“A thin hypoechoic halo is characteristic of benign thyroid adenomas.”

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.).

In biliary obstruction (such as at the ampulla of Vater), dilation begins proximally and progresses peripherally. The intrahepatic peripheral bile ducts are the last to dilate because backpressure takes time to propagate. Early dilation is typically seen in the common bile duct and common hepatic duct.

According to Rumack’s Diagnostic Ultrasound:

“The intrahepatic peripheral bile ducts dilate last in the setting of progressive biliary obstruction.”

Adrenal adenomas are the most common adrenal tumors in adults. They are often discovered incidentally (adrenal incidentalomas) and are usually nonfunctioning, though some may secrete cortisol or aldosterone. Neuroblastoma is common in children, pheochromocytomas are rarer catecholamine-producing tumors, and adrenal cortical carcinoma is malignant but much less common than adenomas.

According to Rumack’s Diagnostic Ultrasound:

“Adrenal adenomas are the most common adrenal masses in adults, frequently identified incidentally on imaging studies.”

The ultrasound image shows the liver in a transverse view with the arrow pointing to the middle hepatic vein (MHV). The MHV is a key sonographic landmark that anatomically divides the right and left lobes of the liver.

According to Couinaud's segmental anatomy, which is the basis for surgical and radiological liver segmentation:

The middle hepatic vein runs within the main lobar fissure.

It separates the right lobe (segments V–VIII) from the left lobe (segments II–IV).

This division is crucial in liver surgery and interventional procedures.

Comparison of answer choices:

A. Right anterior and posterior segments are divided by the right hepatic vein, not the middle hepatic vein.

B. Right and left lobes — Correct. The middle hepatic vein, shown by the arrow, defines this boundary.

C. Left medial and lateral segments are divided by the left hepatic vein or falciform ligament.

D. Left superior and inferior is not a standard anatomic division in liver segmentation.

Ring-down artifact occurs when gas bubbles resonate or oscillate, creating continuous echoes distal to the structure that appear as a vertical, echogenic band extending posteriorly. This is distinct from reverberation, which produces multiple discrete reflections.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Ring-down artifact results from resonance of gas bubbles, producing a continuous, echogenic tail distal to the reflecting interface.”

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 superior mesenteric vein (SMV) lies directly anterior to the uncinate process of the pancreas. The uncinate process wraps around the posterior aspect of the SMV and SMA. The portal vein and IVC lie more posteriorly in relation to the pancreatic head.

According to Moore’s Clinically Oriented Anatomy:

“The superior mesenteric vein crosses anterior to the uncinate process of the pancreas.”

An accessory spleen (splenule) is a congenital variant, commonly located near the splenic hilum, and has identical echogenicity to the native spleen. This finding is benign and often incidental.

According to Rumack’s Diagnostic Ultrasound:

“Accessory spleens are typically found near the splenic hilum and are isoechoic to the normal splenic parenchyma.”

In mild acute pancreatitis, the pancreas often appears diffusely enlarged and slightly hypoechoic due to edema and inflammation. However, in very early or mild cases, the pancreas may still appear normal. Heterogeneous echotexture may develop in more severe or necrotizing pancreatitis.

According to Rumack’s Diagnostic Ultrasound:

“In mild pancreatitis, the pancreas is commonly enlarged and hypoechoic due to inflammatory edema.”