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In patients with small solid pancreatic lesions, EUS elastography can rule out malignancy with a high level of certainty if the lesion appears soft. A stiff lesion can be either benign or malignant.

Background and Objectives:Imaging of the pancreas for detection of neuroendocrine tumors is indicated as surveillance in multiple endocrine neoplasia type 1 (MEN1) or if typical clinical symptoms combined with hormone production raise the suspicion of a neuroendocrine tumor. Endoscopic ultrasound (EUS) is considered the best imaging modality to detect small pancreatic tumors. However, little is known about how small pancreatic neuroendocrine tumors (pNETs) present on EUS.Patients and Methods:In this multicenter study, we retrospectively analyzed the endosonographic characteristics of small pNETs which had been detected due to typical biochemistry and clinical symptoms or during surveillance of MEN 1. Only small pancreatic tumors ≤15 mm with histological confirmation as pNET were included. B-mode and contrast-enhanced ultrasound- and EUS patterns were analyzed.Results:Among 32 patients with histologically proven small pNETs, 7 patients had known MEN1. Among the pNETs, 20 were insulinoma, 2 gastrinoma, 3 glucagonoma, 6 nonfunctional in MEN1, and one PPoma. 94% of the pNET appeared hypoechogenic, only 1 isoechogenic and 1 hyperechogenic. After contrast injection, 90% of the pNETS showed hyperenhancement compared to the surrounding pancreatic parenchyma.Conclusion:The high spatial resolution of EUS allows detection and even cytological confirmation of pNET <7 mm diameter. Hypoechogenicity in B-mode and hyperenhancement after injection of contrast agents are endosonographic characteristics of small pNET and present in >90% of pNETs.

Endoscopic ultrasound-guided biopsies have proven to be of significant value in the diagnostic evaluation of benign and malignant diseases, as well as in the staging of malignant tumours of the gastrointestinal tract and adjacent organs. The high prognostic and therapeutic relevance of the resulting cytopathological diagnoses necessitates a shared responsibility of endosonographer and cytopathologist. Quality control programs are required. The diagnostic yield of endoscopic ultrasound-guided biopsies depends on the location, size and characteristics of target tissues, and technical factors (i. e., type of needle used, biopsy technique, and material processing). Other weighing factors include training, expertise and interaction of the endosonographer with cytopathologists. On-site cytological evaluation, which has proven to be successful in optimising the diagnostic efficiency of endoscopic ultrasound-guided fine-needle aspiration biopsy, is notably practiced in Northern American and French academic institutions. It seems to be a sensible alternative to collect specimens for histological and immunohistochemical investigations in addition to the cytological smears in consideration of the economic and structural terms in the German health-care system. Endoscopic ultrasound-guided fine-needle aspiration succeeds in harvesting core biopsies in 3 out of 4 cases with 22-gauge needles. Therefore the use of 19-gauge needles for endoscopic ultrasound-guided aspiration or trucut biopsy may be necessary only in selected cases.

Direct referral of patients for EUS – instead of preprocedural consultation with the endosonographer – has become standard practice (like for other endoscopic procedures) as it is time- and cost-effective. To ensure appropriate indications and safe examinations, the endosonographer should carefully consider what information is needed before accepting the referral. This includes important clinical data regarding relevant comorbidities, the fitness of the patient to consent and undergo the procedure, and the anticoagulation status. In addition, relevant findings from other imaging methods to clarify the clinical question may be necessary. Appropriate knowledge and management of the patients’ anticoagulation and antiplatelet therapy, antibiotic prophylaxis, and sedation issues can avoid unnecessary delays and unsafe procedures. Insisting on optimal preparation, appropriate indications, and clear clinical referral questions will increase the quality of the outcomes of EUS. In this paper, important practical issues regarding EUS preparations are raised and discussed from different points of view.

In “What should be known prior to performing EUS exams, Part I,” the authors discussed the need for clinical information and whether other imaging modalities are required before embarking EUS examinations. Herewith, we present part II which addresses some (technical) controversies how EUS is performed and discuss from different points of view providing the relevant evidence as available. (1) Does equipment design influence the complication rate? (2) Should we have a standardized screen orientation? (3) Radial EUS versus longitudinal (linear) EUS. (4) Should we search for incidental findings using EUS?