Free Practice Questions for ARDMS AB-Abdomen Exam

The image shows a color Doppler ultrasound of the main portal vein (MPV), which appears irregular and replaced by multiple small, serpiginous vascular channels — a hallmark of cavernous transformation. Cavernous transformation of the portal vein is a late complication of chronic portal vein thrombosis, in which collateral vessels develop around the thrombosed portal vein to bypass the obstruction.

Key Doppler ultrasound features of cavernous transformation:

Absence of a normal portal vein

Multiple tortuous vessels in the porta hepatis

Color Doppler shows hepatopetal flow in these channels

Low velocity, continuous waveform flow in collateral vessels

Differentiation from other options:

B. Portal vein thrombosis: Would show an absence of color flow within the portal vein lumen and possibly echogenic material within the vessel. There would be no serpiginous collateral vessels yet if it's an acute process.

C. Portal hypertension: Often diagnosed with other sonographic findings (e.g., splenomegaly, reversed portal flow, varices) but not characterized by the replacement of the portal vein by collateral vessels.

D. Tumor extension: Typically appears as echogenic intraluminal material within the portal vein with arterial waveforms on Doppler due to neovascularity. Tumor thrombus can be seen in hepatocellular carcinoma or pancreatic cancer, not multiple small collateral vessels.

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.”

The sonographic image shows a complex fluid collection within the liver parenchyma, with internal echoes and possibly septations, consistent with an abscess. In the clinical context of post-procedural fever following a liver biopsy, a liver abscess is the most likely diagnosis.

A liver abscess appears on ultrasound as a hypoechoic or complex fluid collection that may contain internal debris, septations, or gas (which may produce reverberation artifacts). These features distinguish it from other post-procedural complications.

A cyst (Option A) typically appears as an anechoic, well-defined lesion with posterior acoustic enhancement and no internal debris—this does not match the image or clinical setting.

A biloma (Option B) is a bile collection that can appear similar to a cyst or fluid collection but typically occurs due to bile leak; however, fever and internal complexity on ultrasound more strongly suggest abscess.

A hematoma (Option D) may also appear complex but usually presents with pain and not fever unless secondarily infected. Over time, hematomas evolve in appearance but lack septations and gas unless superinfected.

The structure indicated by the arrow in the ultrasound image is the adrenal gland. On ultrasound, the adrenal gland in neonates and infants is relatively large and has a distinctive “Y” or “V” shape in the transverse view. It is located superior and slightly medial to the upper pole of the kidney.

In this image, the arrow is pointing to a hypoechoic, curved structure with a thin echogenic central stripe, representing the fetal adrenal gland. This echogenic stripe corresponds to the adrenal medulla, while the surrounding hypoechoic area represents the cortex.

Differential features:

A. Kidney: While the kidney is visualized posterior to the adrenal gland and shows a reniform shape with a central echogenic sinus and peripheral cortex, it is not the structure being directly pointed to by the arrow.

B. Bowel loop: Bowel has variable echogenicity with peristalsis and shadowing from air. It does not have the consistent morphology or location seen in the image.

C. Diaphragm: Appears as a thin, hyperechoic linear structure separating the thoracic cavity from the abdomen. It is seen more superiorly than the indicated structure and lacks the “Y” or “V” adrenal configuration.

Key Anatomical Landmarks:

The adrenal glands are located in the retroperitoneum, superior to the kidneys, and appear prominent on ultrasound in neonates.

In transverse view, the right adrenal gland is anterior to the crus of the diaphragm and posterior to the inferior vena cava (IVC).

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.”

Splenosis refers to autotransplantation of splenic tissue following splenic trauma or splenectomy. After rupture, splenic fragments may implant throughout the peritoneal cavity and vascularize, forming multiple nodules of functional splenic tissue. Splenosis is typically asymptomatic and discovered incidentally on imaging.

Splenule (A) is a congenital accessory spleen, not related to trauma.

Hamartoma (C) is a benign primary splenic lesion.

Target lesion (D) generally refers to sonographic appearance seen in metastases or infections, not post-trauma.

Reference Extracts:

Mortelé KJ, et al. "Multimodality imaging of splenic lesions and the spleen." Radiographics. 2004;24(4):1137-1163.

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

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The ultrasound image demonstrates a tubular, anechoic structure coursing anterior to the left portal vein and heading toward the anterior abdominal wall. This is consistent with a recanalized umbilical vein, which is an important collateral pathway that reopens in cases of portal hypertension.

Normally, the umbilical vein becomes obliterated after birth and forms the ligamentum teres. However, in the setting of significant portal hypertension, the umbilical vein may recanalize and serve as a collateral route to decompress the portal system.

Sonographic features of a recanalized umbilical vein:

Anechoic, tubular structure in the ligamentum teres fissure

Seen anterior to the left portal vein

Color Doppler confirms hepatofugal venous flow

Associated with signs of portal hypertension (e.g., splenomegaly, varices)

Differentiation from other options:

A. Budd-Chiari syndrome: Involves hepatic vein outflow obstruction; ultrasound shows absent or narrowed hepatic veins and may have caudate lobe hypertrophy.

B. Splenic artery aneurysm: Typically visualized near the splenic hilum as a pulsatile cystic mass; Doppler shows arterial flow.

D. Median arcuate ligament syndrome: Involves compression of the celiac axis; best assessed with Doppler showing elevated velocities on expiration.

Hepatic adenomas are benign liver tumors strongly associated with long-term use of oral contraceptives and are most frequently found in women under 40. Hepatoblastoma is seen in children; hepatoma (HCC) is a malignant tumor typically found in cirrhotic livers. Cavernous hemangioma is unrelated to oral contraceptives.

According to Rumack’s Diagnostic Ultrasound:

“Hepatic adenomas occur predominantly in young women with a history of oral contraceptive use.”

Changing the patient's position allows evaluation of lesion mobility. Blood clots and hematomas are often mobile, while true bladder wall masses remain fixed. This technique helps differentiate between solid masses and non-adherent debris.

According to Rumack’s Diagnostic Ultrasound:

“Changing patient position may distinguish between mobile blood clots and fixed bladder wall masses.”

A normal renal artery waveform demonstrates rapid systolic upstroke (acceleration) with continuous forward flow in diastole due to the kidney's low-resistance vascular bed. Slow acceleration or blunted peaks may indicate significant renal artery stenosis.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Normal renal artery waveforms demonstrate a rapid systolic acceleration with a sharp systolic peak.”