Contrast-enhanced guided endoscopic ultrasound procedures

Abstract

Contrast-enhanced endoscopic ultrasound (CH-EUS) can overcome the limitations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours. Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions, further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS. This review details the knowledge based on the available data on contrast-guided procedures. The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions, which occur in select cases. Additionally, the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage, and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented. Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours, in which case CH-EUS can be used to reveal the incomplete tumour destruction.

Keywords: Biopsy; Contrast-enhanced endoscopic ultrasound; Drainage; Endosonography; Fine needle aspiration; Fine needle biopsy; Pancreas; Pancreatic fluid collections; Tissue acquisition.

Figure 1

Contrast-enhanced endoscopic ultrasound. A and B: Contrast-enhanced endoscopic ultrasound (CE-EUS)-guided fine needle aspiration (FNA). CE-EUS-guided FNA (white arrow) of a pancreatic mass suggestive of adenocarcinoma. A large vessel near the gut wall is more visible during contrast enhancement (orange arrow); C and D: CE-EUS view of perivascular tumour infiltration. CE-EUS view of perivascular tumour infiltration (superior mesenteric artery, orange arrow) as a hypoenhanced rim (white arrow, both images) around the artery in a patient with pancreatic head adenocarcinoma; E and F: Contrast enhanced endoscopic ultrasound-guided FNA from a hyperenhanced mural nodule inside a branch-duct intraductal papillary mucinous neoplasm (IPMN). CHEUSFNA was performed on a hyperenhanced mural nodule inside a branchduct IPMN, revealing carcinoma cells. On the left, a conventional endoscopic ultrasound image of an IPMN with multiple hyperechoic nodules in the wall (white arrows) is shown. On the right, only one of the nodules was hyperenhanced by the contrast agent, so endoscopic ultrasound-guided FNA sampling was performed.