Which sonographic feature is most specific for classifying an enlarged lymph node as malignant rather than reactive/inflammatory?

All of the following are valid clinical applications during a gallbladder sonographic or clinical examination EXCEPT:

What is the arrow labeled #1 pointing to? 

Which structure is identified by the letter “F” in this image?  

A neonatal ultrasound reveals a unilateral mass composed of multiple non-communicating cysts of varying sizes with no identifiable renal sinus or normal parenchyma within the right renal fossa. The contralateral kidney is enlarged but normal. What is the likely diagnosis?

Asher’s sign states that splenomegaly is suspected when the spleen extends:

Which anatomy is identified by #4 on this image?

Which technique best differentiates true biliary sludge from pseudosludge caused by slice-thickness artifact?

A patient with a history of a recent ERCP procedure presents for an abdominal scan. The sonographer notes linear hyper-echogenic foci with dirty shadowing tracking along the intrahepatic portal triads. What does this represent?

A 55-year-old female presents with these following findings which are indicative of: