ARDMS AB-Abdomen Exam With Confidence Using Practice Dumps

The ultrasound image shows a measured common bile duct (CBD) diameter of 7.9 mm in a postcholecystectomy patient. In patients who have undergone cholecystectomy, mild dilation of the CBD is considered normal and is a well-recognized post-surgical change.

Normal upper limits for CBD diameter:

In patients with a gallbladder: ≤6 mm is generally considered normal.

In postcholecystectomy patients: up to 10 mm is considered within normal limits, as the CBD compensates for the absence of the gallbladder and slightly enlarges over time.

With aging, the CBD may enlarge by approximately 1 mm per decade after age 60.

Therefore, a CBD diameter of 7.9 mm in a patient without a gallbladder is considered normal.

Differentiation from other options:

B. Dilated: This would typically refer to a CBD diameter >10 mm in postcholecystectomy patients, or >6 mm in patients with an intact gallbladder.

C. Inflamed: Inflammation refers to wall thickening or hyperemia, which is not evaluated simply by measuring diameter.

D. Atretic: Describes a congenitally absent or severely narrowed duct — not applicable here.

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.”

The hallmark feature of focal nodular hyperplasia (FNH) is a central stellate scar seen on imaging. This fibrous scar may not always be seen on ultrasound but is a classic distinguishing feature from hepatic adenomas, which usually lack a central scar.

According to Rumack’s Diagnostic Ultrasound:

“Focal nodular hyperplasia often demonstrates a central stellate scar, which may be echogenic or isoechoic.”