EUS has become a substantial diagnostic and therapeutic modality for many anatomical regions. The extent of endosonographic assessment is wide, and among others, allows for the evaluation of the mediastinal anatomy and related pathologies such as mediastinal lymphadenopathy and staging of central malignant lung lesions. Moreover, EUS assessment has proved more accurate in detecting small lesions missed by standard imaging examinations such as computed tomography or magnetic resonance. Endosonographically, various mediastinal anatomical landmarks and stations can be visualized by transesophageal scanning, thus providing arranged systematic examination of the mediastinum. In addition, the correct position during the examination is crucial for EUS-guided procedures such as tissue sampling and drainage of mediastinal abscesses. The evolution of EUS-guided diagnostic and interventional procedures has contributed to the increasing importance of understanding the mediastinal anatomy during the EUS examination.

We present here a new chapter of the series of papers on how to perform specific EUS techniques. In this manuscript, we discuss on how to perform EUS-guided placement of fiducial markers in gastrointestinal tumors. The aim is to present the scientific evidence of fiducials placement before radiation therapy, including an accurate revision of the literature, to give some advices on the technical approach, and to discuss Pros and Cons from the point of view of gastroenterologists and radiation oncologist.

Background and Objectives: Several studies have demonstrated that EUS-guided fine-needle biopsy (EUS-FNB) is useful for diagnosing gastrointestinal subepithelial lesions (GI SELs). However, there is limited evidence regarding the use of Franseen needles during EUS-FNB for patients with GI SELs. In addition, the optimal approach for diagnosing small SELs is unclear. This study aimed to evaluate whether EUS-FNB using a Franseen needle was effective for diagnosing GI SELs, including small lesions. Methods: Between January 2013 and January 2020, 150 consecutive patients with GI SELs underwent EUS-FNA/FNB to achieve a histological diagnosis. Eighty-six consecutive patients who underwent EUS-FNB using a Franseen needle were compared to 64 patients who underwent EUS-FNA using a conventional needle. Results: The diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (85% vs. 75%, P = 0.006). Furthermore, in cases with SELs that were <20 mm, the diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (81% vs. 45%; P = 0.003). Multivariate analysis revealed that obtaining a sufficient diagnostic sample was independently predicted by Franseen needle use (adjusted odds ratio: 2.8, 95% confidence interval: 1.2–6.3; P = 0.01) and tumor size of >20 mm (adjusted odds ratio: 3.4, 95% confidence interval: 1.4–8.2; P = 0.006). Conclusion: Even when attempting to diagnose small GI SELs, EUS-FNB using a Franseen needle appears to provide a more efficient acquisition of true histological core tissue than using a conventional needle.

Background and Objectives: EUS is widely used in the clinical practice. This study aimed to evaluate the efficacy of a novel echoendoscope regarding image quality, maneuverability, stability of the entire machine system, and safety. Setting and Design: We conducted this open-label, multicenter, randomized, parallel-group, noninferiority clinical trial in three tertiary hospitals between November 2018 and April 2019. Subjects and Methods: One hundred and thirty patients were included. The stratified segment randomization method was employed. Sixty-five patients in the test group received an EUS examination using the new material radial echoendoscope, and 65 patients in the control group received an EUS examination using the existing endoscope. We recorded the image quality, maneuverability, stability of the entire machine system, and safety. For the main outcome, comprehensive image quality, the groups were compared with the noninferiority test, using the confidence interval method and 10% as the noninferiority threshold. The Pearson Chi-square test was used to compare the incidence of adverse events between the groups. Results: Sixty-five patients in the test group and 63 patients in the control group were analyzed. Two patients in control group did not complete an EUS examination due to machine problems. There were no significant differences in image quality, maneuverability of the echoendoscope, stability of the entire machine system, and safety between the groups. Conclusions: This new material radial echoendoscope showed good capabilities for image quality, maneuverability, stability of the entire machine system, and safety. Our data suggest that the new echoendoscope may provide an additional option for endoscopic physicians.

Background and Objectives: There is no clear evidence of a negative impact of biliary stents on the diagnostic yield of EUS-guided fine-needle biopsy (EUS-FNB) for diagnosing pancreatic head lesions. We aimed to evaluate the association between the presence of biliary stents and the diagnostic accuracy of EUS-FNB. Materials and Methods: A multicenter retrospective study including all jaundiced patients secondary to pancreatic head masses was performed. Patients were divided into two groups according to the presence of a biliary stent placed before EUS-FNB. Pathological results were classified according to the Papanicolaou classification and compared against the final diagnosis. Diagnostic measures in the two groups were compared. Multivariate logistic regression analyses including potential factors affecting EUS-FNB accuracy were performed. Results: Overall, 842 patients were included, 495 (58.8%) without and 347 (41.2%) with biliary stent. A plastic or a metal stent was placed in 217 (62.5%) and 130 (37.5%) cases, respectively. Diagnostic sensitivity and accuracy were significantly higher in patients without biliary stent than in those with stent (91.9% and 92.1% vs. 85.9% and 86.4%, P = 0.010 At multivariate analyses, lesion size (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.02–1.09, P = 0.01) and presence of biliary stent (OR: 0.51, 95% CI: 0.32–0.89, P = 0.01) were independently associated with diagnostic accuracy. In the subgroup of patients with biliary stent, the type of stent (plastic vs. metal) did not impact EUS-FNB yield, whereas the use of larger bore needles enhanced diagnostic accuracy (OR: 2.29, 95% CI: 1.28–4.12, P = 0.005). Conclusions: In this large retrospective study, an indwelling biliary stent negatively impacted the diagnostic accuracy of EUS-FNB. Preferably, EUS-FNB should precede endoscopic retrograde cholangiopancreatography, especially in the case of small tumors.

Background and Objectives: EUS-guided gallbladder drainage (GBD) has emerged as an alternative GBD technique, particularly for high-risk surgical patients. To prevent stent migration or to facilitate stent deployment, the lumen-apposing metal stent (LAMS) was recently developed for EUS-GBD. However, LAMS remains unavailable in several countries and is expensive compared with conventional fully covered self-expandable metal stent (FCSEMS). Although several studies have shown the clinical benefits of EUS-GBD using novel FCSEMS or LAMS compared with endoscopic transpapillary GBD (ETGBD), the choice between ETGBD and EUS-GBD using conventional FCSEMS and ETGBD remains controversial. The aim of this study was to evaluate EUS-GBD using conventional FCSEMS compared with ETGBD. Materials and Methods: This comparative retrospective study included consecutive symptomatic AC patients who underwent gallbladder drainage by either EUS-GBD or ETGBD between January 2015 and December 2018.The main outcome measures were technical success, clinical success, procedure-related and stent-related adverse events, and recurrence of AC during follow-up. Results: Fifty-four patients (44.4% female, 55.6% male) who underwent EUS-GBD (n = 25) or ETGBD (n = 29) were enrolled. Initial technical success rates were 100% with EUS-GBD and 82.7% (24/29) with ETGBD. The median procedure time was significantly shorter for the EUS-GBD group than for the ETGBD group (11.0 vs. 24.0 min, P < 0.05). Procedure-related adverse events did not differ significantly between groups (P = 0.283). During follow-up (median 522 days, range 43 – 1892 days), recurrent acute cholecystitis (AC) was only observed in 4 patients from the ETGBD group. Overall survival did not differ significantly between the EUS-GBD group (mean 1070 days) and ETGBD group (mean 1470 days) (P = 0.292). Conclusion: The technical success rate for EUS-GBD using FCSEMS with plastic stent insertion was significantly higher with a shorter procedure time and resulted in a lower rate of recurrent AC.

Background and Objectives: The prevalence of choledocholithiasis in the high-risk group of choledocholithiasis has been reported to be slightly more than 50% when there is no definite cholangitis. Replacement of diagnostic endoscopic retrograde cholangiography (ERC) with an EUS-first approach may be beneficial in these patients. Materials and Methods: In this prospective, multicenter study, patients with dilated common bile duct and serum total bilirubin levels of 1.8–4 mg/dL were randomly allocated to undergo either EUS first, followed by subsequent ERC if necessary (EUS group) or ERC only (ERC group). The primary endpoint was the incidence of negative outcomes associated with a false-negative diagnosis of the choledocholithiasis or the endoscopic procedure. The secondary endpoints were the rate of diagnostic ERC and hospital stay length related to the endoscopic procedure. Results: Of 90 patients who were randomly assigned, the final analysis involved 42 in the EUS group and 44 in the ERC group. The negative outcomes were not significantly different between the EUS and ERC groups (2.4% vs. 6.8%; P = 0.62). The rate of diagnostic ERC was significantly lower in the EUS group (2.4% vs. 47.7%; P < 0.001). The hospital stay length related to the endoscopic procedure was significantly shorter in the EUS group (1.8 ± 1.0 vs. 2.5 ± 1.2 days; P = 0.001). Conclusion: In selected high-risk choledocholithiasis patients, an EUS-first strategy significantly decreased the rate of diagnostic ERC and hospital stay but did not achieve a significant reduction in negative endoscopic procedure outcomes.

Objectives: This study aimed to examine the effects of a training program combining formal cytological curriculum and practical assessments on endosonographers and to determine how many operations were needed for training through learning curves. Methods: A formal cytological curriculum was implemented in November 2019 for four endosonographers. The competency of endosonographers before and after the curriculum was judged by quantitative scores. From December 2019 to October 2020, trainees independently examined the adequacy and atypia grade of pancreatic specimens acquired by EUS-guided-fine-needle biopsy based on specific atypical grading criteria. The accuracy of the adequacy and atypia assessment of each trainee was calculated, and learning curves were drawn to evaluate the improvement. Results: The median posttraining score improved by 87% from 49 to 91.5 out of 100. Ninety patients were enrolled in the practical assessments. The accuracy for specimen adequacy and atypia assessment of each trainee was 91.7%, 92.8%, 91.0%, and 89.3% and 80.0%, 82.1%, 81.0%, and 78.9%. The learning curves of each trainee showed a steady and significant improvement, and ninety cases were sufficient for satisfactory adequacy assessment. Conclusions: Basic knowledge of on-site cytopathologic evaluation can be gained through standardized and systematic training. Practical assessments showed that, at the completion of ninety cases, trained endosonographers reached a satisfactory level of recognizing specimen adequacy, but continue practice was needed for atypia assessment.