Free ARDMS AB-Abdomen Practice Exam with Questions & Answers | Set: 5

The inferior vena cava (IVC) is formed by the confluence of the right and left common iliac veins at the level of approximately L5. The hepatic veins drain into the IVC superiorly but do not form it. The superior mesenteric and splenic veins join to form the portal vein, not the IVC.

According to Moore’s Clinically Oriented Anatomy:

“The IVC begins at the level of L5 by the union of the right and left common iliac veins.”

Portal veins course horizontally within the liver and have echogenic walls due to their fibrous sheath. In contrast, hepatic veins course vertically toward the IVC and lack echogenic walls. Hepatic veins also demonstrate a triphasic waveform.

According to Rumack’s Diagnostic Ultrasound:

“Portal veins course horizontally within the liver and are easily recognized by their echogenic walls.”

Testicular metastases are rare and usually identified in older patients. The most frequent primary site of malignancies metastasizing to the testes is theprostate. Studies (Ulbright and Young, 2008; Mosharafa et al., 2003) indicate that prostatic adenocarcinoma accounts for the highest number of testicular metastases, with lung and gastrointestinal tract malignancies also contributing less frequently. These metastases can be unilateral or bilateral and are often discovered incidentally during surgical intervention for prostate cancer.

The metastatic route involves retrograde venous extension, arterial embolism, or lymphatic dissemination. Histologically, prostatic adenocarcinoma in the testis can be confirmed viaimmunohistochemical markers like prostate-specific antigen (PSA), supporting its prostatic origin.

The main pancreatic duct (duct of Wirsung) runs through the central portion of the pancreas, medial and slightly posterior to the superior mesenteric vein (SMV). It converges with the common bile duct near the ampulla of Vater.

According to Moore’s Clinically Oriented Anatomy:

“The main pancreatic duct runs centrally within the gland and lies medial to the superior mesenteric vein.”

The tunica albuginea is the dense fibrous capsule that directly surrounds the testicular parenchyma. The tunica vaginalis is a serous covering surrounding the testis externally, and the dartos fascia and pampiniform plexus are part of the scrotal wall and spermatic cord, respectively.

According to Rumack’s Diagnostic Ultrasound:

“The tunica albuginea is the fibrous capsule surrounding the testis and forming septa within the gland.”

Chronic rejection presents sonographically as cortical thinning, decreased renal size, and increased echogenicity of the renal sinus fat. Acute rejection typically causes an enlarged, edematous kidney with increased parenchymal echogenicity but preserved size early on.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“In chronic rejection, the allograft becomes smaller with cortical thinning, increased echogenicity, and prominence of the central sinus fat.”

Reducing slice (section) width improves spatial resolution, particularly elevational resolution, which enhances visualization of small, superficial structures. Lower slice width reduces off-axis beam artifacts and blurring. Wavelength depends on transducer frequency, not adjustable directly during scanning.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Reduction in slice thickness improves imaging of small superficial structures by minimizing volume averaging and improving elevational resolution.”

The image demonstrates a characteristic "central dot sign" — a hallmark finding of Caroli disease. This is best appreciated on ultrasound as a cystic dilation of the intrahepatic bile ducts with a central echogenic dot or linear structure (which corresponds to the portal vein and fibrous tissue within the dilated duct). The arrow in the image points to one such dilated duct.

Caroli disease is a rare congenital disorder characterized by segmental, saccular dilation of intrahepatic bile ducts. It is often associated with congenital hepatic fibrosis and may predispose to cholangitis, stone formation, and even cholangiocarcinoma.

Key ultrasound features of Caroli disease:

Cystic or saccular dilations of the intrahepatic bile ducts

The "central dot sign" — echogenic focus in the center of the dilated ducts (representing portal vein radicle or fibrous tissue)

May show associated hepatosplenomegaly or signs of portal hypertension

Differentiation from other options:

A. Sclerosing cholangitis: Typically causes diffuse or segmental biliary ductal wall thickening and stricturing; does not present with cystic dilations.

B. Alagille syndrome: A multisystem disorder often characterized by a paucity of intrahepatic bile ducts, not dilation.

D. Biliary atresia: Presents in infancy with obliteration of extrahepatic bile ducts, echogenic "triangular cord" sign, and absence of a visible gallbladder. It does not cause ductal dilation.

Transitional cell carcinoma (TCC) typically presents as a non-mobile, polypoidal, focal intraluminal mass projecting from the bladder wall. Mobility of the lesion helps differentiate TCC from blood clots or debris.

According to Rumack’s Diagnostic Ultrasound:

“Bladder TCC most often appears as a non-mobile, polypoid mass attached to the bladder wall.”