We recently introduced a series of articles that dealt with controversies in EUS. In Part I, the authors discussed which clinical information is necessary prior to EUS and whether other imaging modalities are required before embarking on EUS examinations. Part II focuses on technical details and controversies about the use of EUS in special situations. In this article, important practical issues regarding the application of contrast-enhanced EUS in various clinical settings are raised and controversially discussed from different points of view.

Malignant biliary obstruction (MBO) encompasses a variety of malignancies arising from the pancreaticobiliary system. This can be divided into malignant hilar biliary obstruction (MHBO) or malignant distal biliary obstruction (MDBO) biliary obstruction to which clinical outcomes and technical considerations of various biliary drainage methods may differ. EUS biliary drainage (EUS-BD) has been increasingly influential in the management of MBO together with other familiar biliary drainage methods such as ERCP and percutaneous transhepatic biliary drainage (PTBD). Conventionally, ERCP has always been the primary choice of endoscopic biliary drainage in both MHBO and MDBO and that PTBD or EUS-BD is used as a salvage method when ERCP fails for which current guidelines recommends PTBD, especially for MHBO. This review was able to show that with today's evidence, EUS-BD is equally efficacious and possesses a better safety profile in the management of MBO and should be on the forefront of endoscopic biliary drainage. Therefore, EUS-BD could be used either as a primary or preferred salvage biliary drainage method in these cases.

For a definitive diagnosis of fine-needle aspiration (FNA)/biopsy, one of the reliable techniques to determine the adequacy and accuracy rapid on-site evaluation (ROSE) of cytological samples is preferable. Because of the lack of trained pathologists, alternatives have to be explored. This study is primarily conducted to determine the diagnostic sensitivity and specificity of full-field optical coherence tomography (FF-OCT) and secondarily to evaluate the possibility of FF-OCT differentiating different types of pancreatic diseases. The diagnostic coherence of FF-OCT by a trained assistant (endoscopist) and trained pathologist is also compared. This is a single-center, prospective, observation trial. Eighty patients would be enrolled in the study. The tissue samples acquired by endoscopic ultrasound fine-needle biopsy (EUS-FNB) would be imaged by the FF-OCT system, interpreted by a trained endoscopist and a pathologist. The results of the image interpretation would be verified with histological findings. This study determines the diagnostic capability of FF-OCT as a ROSE technique while performing EUS-FNB, and whether endoscopists can implement the assessment.

Background and Objectives: Measuring a visible core length during macroscopic on-site evaluation (MOSE) can be useful for accurate diagnoses during an EUS-guided fine needle biopsy (EUS-FNB). We aimed to estimate visible core cutoff lengths predictive of a correct diagnosis when using 22-gauge Franseen needles for biopsies from pancreatic masses. Materials and Methods: We assessed 77 consecutive patients who underwent EUS-FNB using 22-gauge Franseen needles for pancreatic masses between March 2018 and October 2018. At least two needle passes were performed in all patients, irrespective of the findings on MOSE. The endoscopists measured the visible cores using a ruler during MOSE. The first two passes were analyzed on a per pass basis, and the correlation between visible core lengths and diagnostic accuracy was evaluated. Results: We evaluated 150 needle passes of 75 patients. The accuracy per pass was 92% (138/150). The median length of the visible cores was 15 (range: 0–60) mm and they were significantly longer in the correct diagnosis group than in the incorrect diagnosis group. The accuracy correlated positively with the visible core length. Receiver-operating characteristic curve analysis of the visible core length for accuracy demonstrated an optimal cutoff value of 10 mm. On multivariate logistic regression, visible core lengths >10 mm independently affected the correct diagnosis (odds ratio: 5.1, P= 0.02). Conclusions: Visible cores exceeding 10 mm may be useful for correct diagnosis while using a 22-gauge Franseen needle for EUS-FNB from pancreatic masses.

Background and Objective: EUS-guided-biliary drainage (EUS-BD) is an efficacious and safe option for patients who fail ERCP. EUS-BD is a technically challenging procedure. The aim of this study was to define the learning curve for EUS-BD. Methods: Consecutive patients undergoing EUS-BD by a single operator were included for a prospective registry over 6 years. Demographics, procedural information, adverse events, and follow-up data were collected. Nonlinear regression and CUSUM analyses were conducted for the learning curve. Technical success was defined as successful stent placement. Clinical success was defined as resolution of jaundice and/or at least a 30% reduction in the pretreatment bilirubin level within a week after placement or normalization of bilirubin within 30 days. Results: Seventy-two patients were included in the study (53% male, mean age 67 years). Technical success was achieved in 69 patients (96%). Clinical success was achieved in 59/69 patients (86%). Seven patients (10%) had adverse events including bleeding (n = 6) and liver abscess (n = 1). The median procedural time was 59 min (range 36–138 min). This was achieved at the 32^nd procedure. Procedural durations were further reduced to 50 min and below after the 50^th procedure in a nonlinear pattern. This suggests that procedural durations approach a potential plateau after 100 cases. Conclusion: Endoscopists experienced in EUS-BD are expected to achieve a reduction in procedural time over successive cases, with efficiency reached at 59 min and a learning rate of 32 cases. Continued improvement is demonstrated with additional experience, with mastery suggested after approximately 100 cases.

Background and Objectives: Submucosal nasopharyngeal carcinoma (NPC) is a rare type, which is usually difficult to obtain tissue samples. We aimed to evaluate the diagnostic yield and safety of a new technique of endonasopharyngeal ultrasound-guided transnasopharyngeal needle aspiration (ENUS-TNNA) for submucosal NPC.Subjects and Methods: This was a retrospective study. Between March 2018 and September 2019, 11 patients with submucosal nasopharyngeal neoplasms detected with previously computed tomography or magnetic resonance imaging underwent ENUS-TNNA. All patients had cytological evaluation by smears and tissue evaluation of aspiration specimens. Mean and rate. Results: There were seven males and four females, with ages ranging from 33 to 77 years. Needle puncture biopsies were successfully performed in all cases, and sufficient tissue sample for histopathological examination was obtained from each of the 11 patients. Of the 11 patients, nine of these patients were diagnosed using ENUS-TNNA without on-site cytology assistance, false negative in two cases. The sensitivity of the ENUS-TNNA technique in diagnosing submucosal NPC was 81.82%. In the absence of any major complications, the procedure was uneventful. Conclusions: ENUS-TNNA is a safe and effective method to provide a pathological diagnosis of submucosal growth type of nasopharyngeal neoplasms, which has a great clinical value.

Background and Objective: Pancreatic fluid collections in early phase of illness <4 weeks after onset of acute pancreatitis (AP) are usually treated with percutaneous drainage (PCD). There is a paucity of data comparing early (<4 weeks) endoscopic transluminal drainage (ETD) with PCD in patients with symptomatic pancreatic necrosis (PN). The objective of this study is to compare the safety and efficacy of early ETD with PCD in patients with symptomatic PN. Patients and Methods: Retrospective analysis of database of patients with symptomatic PN treated early (<4 weeks of onset of AP) with either ETD (encapsulated wall on EUS) or PCD. Results: Twenty-three patients (19 M; mean age: 36.1 years) were treated with ETD and 41 patients (29 M; mean age: 39.6 years) were treated with PCD, respectively. ETD and PCD were done 24.2 ± 2.3 and 24.2 ± 2.0 days after onset of AP, respectively (P = 0.84). In the ETD group, 35% of patients were treated with self-expanding metallic stents and 48% of patients required direct endoscopic necrosectomy. In the PCD group, 74% of patients were treated with multiple catheters and 91% of patients with either saline or streptokinase irrigation. As compared to the ETD group, patients in the PCD group took longer time for resolution (61.9 ± 22.9 days vs. 30.9 ± 5.6 days; P < 0.00001), increased need for surgery (30% vs. 4%; P = 0.01), and frequency of formation of external pancreatic fistula (EPF) (22% vs. nil; P = 0.02). Conclusions: ETD of PN in early phase of illness is associated with a shorter duration for resolution and infrequent need of salvage surgery compared to PCD. EPF formation is a significant adverse event with PCD.

Pancreas with heterotopic gastric mucosa is a rare congenital malformation and hardly be detected.In the embryonic stages, primitive gut, including foregut, midgut and hindgut, originated in the gastrula endoderm. Stomach and pancreas were stemed from the ending of foregut. When abnormal differentiation occurred, pancreatic tissue was usually ectopic to the stomach, but heterotopic gastric mucosa of the pancreas was rare. This malformation was usually confirmed by post-operative pathology. We report a case of congenital malformation of heterotopic gastric mucosa of pancreas detected by EUS and contrast enhanced EUS. The manifestations in EUS are different from the pancreatic cyst lesion.