What is the initial imaging test for suspected biliary colic?

In cases of suspected biliary colic, the initial imaging test of choice is abdominal ultrasound. This is primarily because ultrasound is highly effective for evaluating biliary structures, including the gallbladder and bile ducts. It is a non-invasive, safe, and readily available modality that avoids the use of radiation, making it especially useful in a wide range of patients, including those who may be pregnant.

Ultrasound can effectively identify gallstones, which are the most common cause of biliary colic, and can also reveal any complications associated with gallstone disease, such as inflammation of the gallbladder (cholecystitis) or bile duct obstruction (choledocholithiasis). The ability of ultrasound to visualize these structures helps clinicians diagnose the underlying cause of the patient's symptoms quickly.

Other imaging modalities, like a CT scan, may be used later for more complex cases or if complications are suspected, but they are not typically the first choice for biliary colic due to their higher cost, longer time to perform, and exposure to radiation. X-rays are generally not helpful in diagnosing biliary colic because they do not visualize soft tissues well and are not effective for detecting gallstones. MRI is more specialized and usually reserved for specific cases such