Diagnostic Value of Endoscopic Ultrasound Elastography and Contrast Enhanced Endoscopic Ultrasound for Differential Diagnosis of Gallbladder Polyp

Diagnostic Value of Endoscopic Ultrasound Elastography and Contrast Enhanced Endoscopic Ultrasound for Differential Diagnosis of Gallbladder Polyp

Gallbladder polyps are often detected incidentally by ultrasonography. The most of gallbladder polyps are non-neoplastic such as cholesterol polyps and do not need further treatments. However, neoplastic polyps, which need additional treatments to prevent malignancy, show the same appearance on ultrasound. Clinically, the differential diagnosis between cholesterol polyps and adenomatous polyps is very important for patient follow-up and treatment. However, differential diagnosis between these two conditions is difficult using conventional trans-abdominal ultrasound.

Endoscopic ultrasound (EUS) is less affected and disturbed by subcutaneous fat or intraabdominal air, so a clearer image of pancreatobiliary system can be obtained. In addition, EUS elastography and contrast enhanced EUS are recently introduced. EUS elastography enables practitioners to evaluate the stiffness of a target lesion and compare it with surrounding tissues (strain ratio). Also, contrast enhanced EUS is used widely with additional information such as presence of vessels and enhancement pattern of soft tissues. Several studies have been published that EUS elastography can help in the differential diagnosis of pancreatic solid lesions.

Although studies have been conducted to confirm the usefulness of transabdomnial ultrasound with elastography or contrast enhancement at differentiating gallbladder polyps, no prospective studies have been conducted to evaluate the usefulness of EUS elastography or contrast enhanced EUS for gallbladder polyp. Therefore, with this prospective study, we would like to evaluate the diagnostic value of EUS elastography and contrast enhanced EUS for differential diagnosis of gallbladder polyps.

1. Inclusion Criteria:

   1. Gallbladder polyp of 8-10mm or more in size confirmed by imaging tests
   2. Must be 19 years old or older
   3. With voluntary agreement to participate in the study after be informed about the necessity of EUS due to the clinical necessity

2. Exclusion Criteria:

   1. Unable to confirm histological diagnosis (ex. Patients did not underwent cholecystectomy)
   2. Younger than 18 year-old
   3. Without agreement with this study or informed consent