Abstract: Methods are described for detecting gallbladder complications, e.g. gallstones, in overweight patients using a contrast agent and computed tomography (CT). The methods are generally used prior to bariatric surgery to reduce possible complications associated with the gallbladder following the surgery. The methods described replace existing ultrasound imaging of the gallbladder as the present methods can image the gallbladder through fatty adipose tissue, which ultrasound cannot.