<prompt> Answer this question truthfullyWhat role does ultrasound play in diagnosing choledocholithiasis?  <response>: <reason> Ultrasound is helpful first in establishing a diagnosis of Choledocholithiasis the most common screening tool used for choledocholithiasis. Findings on ultrasound suggestive of Choledocholithiasis includedilated bile duct visualization of stones gallstones should increase suspicion, especially if multiple and small Recently endoscopic ultrasonography EUS has also been used with very high sensitivity and specificity. 