Gallbladder cancer can also be detected by ultrasound, which is the preferred imaging method for diagnosing hepatobiliary diseases. Ultrasound can detect space-occupying lesions in hepatobiliary diseases early on. It is sensitive enough to detect lesions as small as one centimeter, or even a few millimeters. In the case of space-occupying lesions of the gallbladder, particularly gallbladder cancer, there are no particularly obvious signals on ultrasound. Ultrasound of the gallbladder is merely used as a screening tool, not as a definitive diagnostic method. If gallbladder cancer is suspected, further investigations such as MRI or enhanced CT are generally required, but the final diagnosis still relies on pathology.