The usefulness of endoscopic ultrasound in the diagnosis of gallbladder lesions

Abstract

Gallbladder tumors are neoplastic lesions; however, it can be difficult to distinguish between benign and malignant gall bladder tumors before surgery, although endoscopic ultrasound (EUS) is useful for differentiation. Fundamental B mode EUS (FB-EUS) and contrast-enhanced harmonic EUS (CH-EUS) are reported to be useful for the diagnosis of gallbladder tumor because they allow evaluation of polypoid lesion and gallbladder wall thickening. Scoring systems based on FB-EUS imaging are available for the diagnosis of malignant gallbladder polypoid lesions. The characteristic findings of malignant gallbladder polypoid lesions on CH-EUS include the presence of irregular intratumoral vessels and perfusion defects. The characteristic findings of malignant gallbladder wall thickening on FB-EUS include wall thickening >12 mm, hypoechoic internal echogenicity, inhomogeneous internal echo pattern, and disrupted wall layer, whereas CH-EUS findings include hypovascular enhancement and inhomogeneous contrast distribution pattern. In addition, FB-EUS and CH-EUS are useful for evaluating the stage of gallbladder carcinoma because they allow the evaluation of the depth of invasion of the gallbladder wall. It is usually difficult to obtain pathological evidence from gallbladder tumors before surgery and chemotherapy, even though the histological diagnosis is necessary for determining treatment policy. EUS-guided fine needle aspiration (EUS-FNA) is useful for obtaining pathological samples from gallbladder tumors before surgery and chemotherapy. The accuracy rate of EUS-FNA for gallbladder tumor is as high as 90%, but complications such as bile leakage and needle track seeding can be a problem, although it was reported that contrast-enhanced harmonic imaging is useful for avoiding them.

Recent Advances in Endoscopic Ultrasound for Gallbladder Disease Diagnosis

“…CH-TUS with second-generation contrast agents makes it easier to detect the target because the microbubbles are not destroyed by continuous observation using low sound pressure [41][42][43]. Previous studies have examined the utility of Sonazoid-based CH-TUS in the characterization of the liver [44,45] and GB lesions [9,[46][47][48][49][50][51][52][53]. Some studies have shown that CH-TUS can overcome the limitations associated with conventional TUS and increase the diagnostic accuracy of GB diseases (the accuracy of CH-TUS and conventional TUS was 95.2% and 88.6%, respectively) [47,52].…”

“…Thus, CH-EUS is a useful approach that addresses the limitations of CH-TUS. The usefulness of CH-EUS in the diagnosis of pancreatic [56][57][58][59][60][61], gastrointestinal [62,63], and GB lesions [9,[46][47][48][49][50][51][52][53] has been reported. CH-EUS is useful for diagnosing GB wall thickening.…”

Practical approach to linear endoscopic ultrasound examination of the gallbladder

“…However, acute cholecystitis[ 53 ] and biliary peritonitis[ 54 ] have been reported following FNA of a GB mass and after bile aspiration, respectively. Tamura et al [ 55 ] have proposed an approach considering the risk of EUS-FNA in cases of GB masses (Figure 8 ): Start by obtaining tissue via an ERCP-guided biopsy, then perform EUS-FNA from metastatic liver lesions or lymph nodes when present, and conclude with EUS-FNA from the GB mass itself. Similarly, during the FNA procedure and puncturing the GB wall, it is essential to gain stroke distance by tangentially puncturing the GB wall, avoiding puncture through the lumen.…”

“…This has limited its application in the diagnosis of GB lesions. Furthermore, even though the few conducted studies have not reported major complications related to the use of this type of EUS in the diagnosis of GB pathologies, the risk of bleeding and tumor seeding are still high with the continuous use of EUS in the diagnosis of GB pathologies such as GB cancer[ 55 , 58 ].…”