Linear Array Endoscopic Ultrasound Research Articles

Superiority of Linear-Array EUS over MRCP in Diagnosing Pancreas Divisum: Evidence from a Multicenter Retrospective Study in Oriental Cohorts.

Pancreas divisum (PD) is the most common developmental anatomic variant of pancreatic duct. The published data on the accuracy of the detection of pancreas divisum by linear-array endoscopic ultrasound (L-EUS) is limited. The current study aimed to assess the diagnostic accuracy of L-EUS compared with magnetic resonance cholangiopancreatography (MRCP) for identifying PD. Patients who underwent linear-array EUS for pancreaticobiliary indications and subsequently received endoscopic retrograde pancreatograghy (ERP) treatment were retrospectively evaluated between January 2019 and July 2023. A total of 1378 patients from three tertiary centers were included, out of which 120 were diagnosed with pancreas divisum (PD), as confirmed by ERP, yielding an endoscopic detection rate of 8.7%. L-EUS exhibited a high sensitivity of 90.8% (95% confidence interval [CI], 85.7%-96.0%) and an overall accuracy of 99% (95% CI, 98.5%-99.5%) for the diagnosis of PD. These figures were significantly superior to those of MRCP, which showed a sensitivity of 48.4% (95% CI, 38.1%-58.6%) and an accuracy of 95.4% (95% CI, 93.5%-96.3%) (P < 0.001). Furthermore, the area under the curve (AUC) for PD diagnosis was notably higher for L-EUS (95.7%) compared to MRCP (74.1%) (P < 0.001). Consistency testing revealed that L-EUS had an excellent kappa (κ) value of 0.934, compared to the reference standard of 0.621. Univariate logistic regression analysis identified the presence of pancreatic duct stones, chronic pancreatitis, and severe pancreatitis as potential factors leading to diagnostic failure of in detecting PD with L-EUS. Subsequent multivariate logistic regression analysis confirmed the presence of pancreatic duct stones (odds ratio [OR] 5.627, 95% CI, 1.391-22.765) and severe pancreatitis (OR 12.818, 95% CI, 2.280-72.061) were significantly associated with increased odds of L-EUS diagnostic failure for PD. Our study conclusively demonstrates that L-EUS significantly outperforms MRCP in diagnosing pancreas divisum. L-EUS exhibits markedly higher sensitivity, and area under the curve (AUC) values. However, its diagnostic reliability decreases in the presence of pancreatic duct stones or severe pancreatitis.

EUS-guided hydrogel microparticle injection in a cadaveric model.

Background and AimsA potential method to reduce gastrointestinal toxicity during radiation therapy in pancreatic head cancer is to create a physical space between the head of the pancreas (HOP) and the duodenum. To date, there have been early reports on the feasibility of endoscopic ultrasound (EUS)‐guided hydrogel injection into the interface between the HOP and the duodenum to increase the peri‐pancreatic space for radiotherapy. We aimed to evaluate the technical feasibility of EUS‐guided hydrogel injection for the creation of space at the peri‐pancreatic interface in a cadaveric model.MethodsBaseline abdominal computerized tomography (CT) was performed on three unfixed cadaveric specimens. The hydrogel was injected transduodenally into the interface between the HOP and duodenum using linear‐array EUS and a 19G needle for fine needle aspiration (FNA). This procedure was repeated along the length of the HOP. CT imaging and gross dissection were performed after the procedure to confirm the localization of the hydrogel and to measure the distance between the HOP and the duodenum.ResultsAll cadavers underwent successful EUS‐guided injection of the hydrogel. Cadavers 1, 2, and 3 were injected with 9.5, 27, and 10 cc of hydrogel, respectively; along the HOP, the formation of the peri‐pancreatic space was a maximum size of 11.77, 13.20, and 12.89 mm, respectively. The hydrogel injections were clearly visualized as hyperechoic bullae during EUS and on post‐procedure CT images without any artifacts in all cases.ConclusionsWe demonstrated that EUS‐guided delivery of hydrogel is feasible, and that it increases the peri‐pancreatic space in a cadaveric model. The polyethylene glycol (PEG) hydrogel was clearly visible on EUS and CT, without significant artifacts. This may lead to new treatment approaches for pancreatic carcinomas.

Etiological Diagnosis of Linear-Array Endoscopic Ultrasonography in Distal Common Bile Duct Dilatation.

The etiology of distal common bile duct (CBD) dilatation is complex. Linear-array endoscopic ultrasonography (EUS) can not only visualize the distal and surrounding structures of the bile duct closely but also obtain pathological specimens by fine-needle aspiration, which provides an important basis for the diagnosis and differential diagnosis. The purpose of this study was to evaluate the diagnostic value of linear-array EUS in the etiology of distal CBD dilatation. Patients with distal CBD dilatation underwent linear-array EUS in the endoscopic center of The Second Affiliated Hospital of Soochow University and Traditional Chinese Medicine Hospital of Kunshan were collected from January 2015 to June 2019. The pathology results after surgery, endoscopic pathology, computed tomography (CT), and magnetic resonance imaging (MRI) results were retrospectively analyzed. The diagnostic accuracy of linear-array EUS and CT or MRI was compared. For the diagnosis of choledocholithiasis, the diagnostic accuracy of linear-array EUS was 97.5%, which was significantly higher than that of MRI (86.36%) and CT (89.74) (P < 0.001 and 0.006, respectively). The diagnostic accuracy of linear-array EUS for periampullary tumors was 93.75%, which was higher than MRI and CT with an accuracy of 82.73% and 80.34% (P = 0.004 and 0.001, respectively). Linear EUS was effective for the etiological diagnosis of distal CBD dilatation.

Value of staging information provided by linear-array endoscopic ultrasound for therapeutic response and prognosis prediction in gastric lymphoma.

Currently, positron emission tomography/computed tomography (PET/CT)-based Ann Arbor and Lugano staging systems are widely applied for gastric lymphoma, which majorly focused on the extent of systemic invasion, but there is insufficient assessment in extent of gastric wall invasion. Thus, we aimed to assess the value of linear-array EUS in therapeutic response and prognosis prediction, and provide an endoscopic ultrasound (EUS)-based staging system for gastric lymphoma. Between January 2012 and October 2019, 191 patients with histologically confirmed gastric lymphoma were included. We analyzed patients' clinicopathologic data, white-light appearance, EUS staging, tumor extension, and therapeutic regime to identify the predictors for complete remission (CR) and progression-free survival (PFS). With a median follow-up period of 547days, 136 patients achieved CR. Multivariate regression analysis identified EUS T stage three CR predictors, including T stage (T2-T4 vs. T1, OR=0.271, 95% confidence interval (CI)=0.108-0.683, P=0.0085) was the independent predictor. The Ki67 index, lesion surface, EUS stage, tumor extension, and regime predicted PFS, but tumor extension was the only independent predictor (local vs. system, OR=6.005, 95%CI=2.365-15.236, P<0.001). The concordance index (C-index) was higher for CR rate in the EUS-based staging [0.673; 95% CI=0.628-0.718] than Lugano staging [0.663; 95% CI 0.616-0.710], and for PFS in the EUS-based staging [0.694; 95% CI 0.586-0.802] than Lugano staging [0.684; 95% CI 0.564-0.804]. An EUS-based staging system is suitable for CR and PFS prediction in gastric lymphoma, with highly informative assessment in extent of gastric wall invasion.

Mo1354 CURVED LINEAR ARRAY ENDOSCOPIC ULTRASOUND FINDING CAN SIGNIFICANTLY PREDICT "A DIFFICULT-TO-CANNULATE CASE" ON ERCP

To clarify the curved linear array endoscopic ultrasonography (CLAEUS) findings that would enable prediction of cases with difficult selective biliary cannulation during endoscopic retrograde cholangio-pancreatography (ERCP). In this single-institution retrospective observational study, patients who underwent CLAEUS prior to an initial ERCP were examined. Patients who fulfilled the definition of difficult selective biliary cannulation were placed into a refractory (R) group and patients where biliary cannulation was completed within 20 minutes were placed into a straightforward (S) group. Difficult selective biliary cannulation was defined as when more than 20 minutes were required from the time to view the papilla to successful biliary cannulation, when the bile duct could not be cannulated, when the precut technique was necessary, when a CLAEUS-guided intervention was necessary, or when a transhepatic approach was necessary. We retrospectively compared CLAEUS findings, side-viewing scope findings, and other factors between the R and S groups as following. Variables examined: patient characteristics: 1) age, 2) gender, 3) diagnosis, and 4) gallbladder presence or absence; papillary findings on a side-viewing scope: 1) papillary type, 2) papillary size, and 3) periampullary diverticulum presence or absence; CLAEUS findings: 1) bile duct collapse with probe on regular evaluation at 2nd portion of duodenum (D2), 2) coaxial depiction of the cholangio-pancreatic duct at D2, and 3) background pancreas. A p value of <0.05 was considered statistically significant. The subjects were selected from 986 patients who underwent ERCP in the 36 months from July 1, 2014, to June 30, 2017. From these, 98 patients were selected who underwent naïve ERCP after CLAEUS. Of these, 17 and 81 were placed in the R (10 men, mean age 73.0±13.2 years, median 74 years) and S (42 men, mean age 67.6±15.1 years, median 70 years) groups, respectively (p=0.15). A significant difference was observed for bile duct collapse (p=0.02) and coaxial depiction of the cholangio-pancreatic duct (p<0.0001) on univariate analysis. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.71, 0.87, 0.54, and 0.93, respectively. A significant difference was observed between ROC curves to predict difficult biliary cannulation by using bile duct collapse (AUC=0.55), and the factor plus coaxial depiction of the cholangio-pancreatic duct (AUC=0.81; p<0.0001). A finding of coaxial depiction of the cholangio-pancreatic duct on CLAEUS can be used to predict difficult ERCP cannulation.

Growth rate of small pancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1: results from an endoscopic ultrasound based cohort study.

Background and aims In multiple endocrine neoplasia type 1 (MEN1), endoscopic ultrasound (EUS) is used for identification and follow-up of pancreatic neuroendocrine tumors (PNETs). The role of EUS in surveillance of small ( < 20 mm) PNETs is unclear, mostly because the natural course of these lesions is largely unknown. We aimed to determine annual growth and incidence rate of small PNETs in patients with MEN1 using EUS-based surveillance. Patients and methods Linear array EUS procedures in patients with MEN1 between 2002 and 2015 were identified. Number, size, and location of PNETs were recorded. Annual growth of PNETs < 20 mm identified at the initial EUS ("prevalent" PNETs) and during follow-up ("incident" PNETs) was calculated using mixed model linear regression analysis. Results A total of 54 patients were identified and 38 patients were included. In all, 226 PNETs were identified (median size 5.0 mm, interquartile range 3.7 - 7.5) of which 124 (55 %) were prevalent and 102 (45 %) were incident PNETs. Annual incidence rate was 0.79 PNETs/year (95 % confidence interval [CI] 0.73 to 0.87). Overall growth rate was 0.10 mm/year (95 %CI 0.02 to 0.19; P = 0.01); PNETs < 10 mm (n = 198) did not grow (P = 0.23), whereas PNETs ≥ 10 mm (n = 28) grew 0.44 mm/year (95 %CI 0.10 to 0.78; P = 0.01). Prevalent PNETs grew 0.21 mm/year (95 %CI 0.10 - 0.32; P < 0.001), whereas incident PNETs did not grow (P = 0.26). Conclusions The annual growth rate of small, solid PNETs in patients with MEN1 is lower than previously thought. Surveillance intervals could probably be prolonged without compromising safety.

WEO Newsletter.

WEO Newsletter.

Imaging of pancreas divisum by linear-array endoscopic ultrasonography.

Pancreas divisum (PD) is the most common developmental anatomic variant of pancreatic duct. Endoscopic ultrasound (EUS) is often performed to evaluate idiopathic pancreatitis and has been shown to have high accuracy in diagnosis of PD. The different techniques to identify PD by linear EUS have been described differently by different authors. If EUS is done with a proper technique it can be a valuable tool in the diagnosis of PD. The anatomical and technical background of different signs has not been described so far. This article summarizes the different techniques of imaging of pancreatic duct in a suspected case of PD and gives a technical explanation of various signs. The common signs seen during evaluation of pancreatic duct in PD are stack sign of linear EUS, crossed duct sign on linear EUS, the dominant duct and ventral dorsal duct (VD) transition. Few other signs are described which include duct above duct, short ventral duct /absent ventral duct, separate opening of ducts with no communication, separate opening of ducts with filamentous communication, stacking of duct of Santorini and indirect signs like santorinecele. The principles of the sign have been explained on an anatomical basis and the techniques and the principles described in the review will be helpful in technical evaluation of PD during EUS.

Prior radial-scanning endoscopic ultrasonography training did not contribute to subsequent linear-array endoscopic ultrasonography study performance in the stomach of a porcine model.

Background/AimsThe optimal training mode for linear array endoscopic ultrasonography (EUS) has not been established. Prior radial-scanning EUS training seems to improve subsequent linear array EUS learning. The objective of this randomized controlled trial was to evaluate its value in linear array EUS training.MethodsIn total, 18 freshman trainees conducted hands-on EUS operations on a live pig model. The training contents consisted of visualization and tracking of the pancreas and splanchnic vasculature and performing fine-needle aspiration of the body or tail of the pancreas and celiac plexus neurolysis through the stomach. The trainees were randomized into two groups: group A received linear array EUS training after receiving radial-scanning EUS training, whereas group B conducted linear array EUS training alone. Two teachers assessed the competence of each trainee using a scoring system and relevant parameters before and after the training process.ResultsGroups A and B showed significant improvement between the pretests and posttests in terms of diagnostic and interventional procedures. There was no intergroup difference in terms of improvement.ConclusionsPrior radial-scanning EUS training did not contribute to subsequent linear array EUS study performance in the pig stomach model; thus, this training mode may need to be changed.

Extraesophageal saline enhances endoscopic ultrasonography to differentiate esophagus and adjacent organs.

To distinguish between the esophagus and adjacent organs using extraesophageal saline injection (ESI) in a canine model. ESI was performed through the esophagus under the guidance of linear-array endoscopic ultrasonography (EUS). Approximately 15 mL of methylene blue saline (0.5%) was then injected through each of the extraesophageal puncture points using a 22 G needle. Radial EUS examinations were conducted before and after ESI. EUS images of the trachea, tracheal bifurcation, arcus aortae and thoracic aorta were recorded. Vital signs were monitored during the ESI procedure and EUS examination. The dogs were then sacrificed for exploratory thoracotomy. No obvious fluctuation in vital signs or serious adverse events occurred during the ESI procedure. On EUS imaging, an apparent hypoechoic area outside the esophagus, which separated the esophagus and adjacent organs, was visualized. The adventitious of the esophagus and adjacent organs were easily distinguished. The findings of subsequent exploratory thoracotomy confirmed the EUS findings: obvious accumulation of a blue liquid in the extraesophageal tissues, as well as in the esophageal-thoracic aorta space, esophageal-arcus aortae space and esophageal-tracheal space. The esophagus and adjacent organs were successfully separated by ESI, and extraesophageal saline acted as an effective ultrasonic contrast agent.

Therapeutic Endoscopic Ultrasonography

The development of linear sectorial array EUS scopes in the early 1990s brought a new approach to diagnostic and therapeutic dimensions on EUS capabilities, opening the possibility to perform punction over direct EUS guidance. Endoscopic ultrasound (EUS) has evolved from a purely diagnostic imaging modality to an interventional procedure that provides a minimally invasive alternative to interventional radiologic and surgical techniques. This evolution was catalyzed by the introduction of linear echoendoscopes that provide continuous imaging and observation of needles and by therapeutic devices that pass through large-caliber working channels. The spectrum of EUS-guided interventions is today quite large including drainage of the pancreas, gallbladder, and other fluid collections; access to the pancreatic and biliary systems; celiac plexus interventions; vascular and ablative therapies. Some new indications for interventional and therapeutic endoscopic procedures performed under EUS control have been developed in areas that have been purely surgical for many years. Indications, procedures, and related tools for EUS-guided endosurgery are described, all of which are experimental but may open a new corridor for endoscopists to enter a variety of transluminal procedures in real time without soiling the peritoneal or mediastinal cavity. In this current issue, the readers can have emerging technologies applied to the endoluminal interventions made by using EUS view and another endoscopic resources. On the other hand, the procedures in the therapeutic EUS give us the possibility of having new access through the gastrointestinal wall to closed organs. Beside new EUS-guided therapies, other authors in this collection have made a thorough review of the therapeutic capabilities of EUS. The application of EUS-guided therapy is especially appealing in oncological diseases, offering accurate and effective palliative treatment. This is possible mainly due to two EUS characteristics which are: firstly, its ability to deliver direct treatment to lesions unreachable by other means and secondly, the minimal invasiveness of EUS which allows outstanding results with low complication rate. EUS-guided vascular therapy is a new promising field, because the variety of vascular pathology and the proximity of the vascular structures to the GI tract walls call for EUS-guided vascular procedures. Some reports have suggested that EUS-guided vascular procedure might offer benefits for refractory bleeding, and further development of this technique could potentially replace the interventional radiology in the abdominal vessels. A paper in this issue describes the literature review about EUS-guided vascular procedures, such as EUS-guided management of nonvariceal upper GI bleeding, and EUS-guided management of pseudoaneurysms, giving the reader a quick overview of the current state of research of EUS-guided vascular interventions. Pancreatic cancer is a significant cause of morbidity and mortality. Current therapies, however, are of limited benefit in most patients. Recently, several studies have shown initial success with injection of various medications and therapies into pancreatic tumors under the EUS guidance. This issue carries articles on EUS-guided injection of AdV-tk into the pancreatic tumor, which provide the ability to treat pancreatic cancer in a relatively minimally invasive manner, with a very low incidence of procedural-related complications. The latest cutting-edge technique might provide hope in treating the lethal disease in the foreseeable future. In the articles included in this issue, the reader can find new endoscopic approaches by means of EUS to clinical problems or even complications derived from endoscopic maneuvers. These new technical solutions represent one step ahead in therapeutic endosonography. The clinical benefit and safety profile of some of these approaches must be confirmed in new studies, but they open new fields for clinical and experimental research. The minimal invasive concept is an appropriate nomination to the therapeutic procedures that have been made by endoscopy. The endoscopic ultrasound offers to the endoscopy area a new technological eye to reach nonanatomic trajects creating fistulas or determining cytoreduction of masses. Otherwise, therapeutic endoscopic ultrasound or T-EUS is a new tool to those patients who are not operative candidates and in which we can offer a high quality of life (QOL) during a short survival. Everson L. A. Artifon Marc Giovannini Siyu Sun Juan J. Vila

Endoscopic ultrasound-guided gold fiducial marker placement for intraoperative identification of insulinoma

Insulinomas are the most common functioning pancreatic neuroendocrine neoplasm, comprising 30%–45% of these tumors. Although laparoscopic resection is safe, minimally invasive, and is associated with shorter length of hospital stay, tumor localization at surgery can be challenging. We describe endoscopic ultrasound (EUS)-guided fiducial placement as a new technique for intraoperative localization of pancreatic insulinoma. A 36-year-old woman with episodes of confusion that resolved with intake of glucose and whose laboratory tests were suggestive of insulinoma was referred for laparoscopic distal pancreatectomy. Linear-array EUS (GF-UCT 240; Olympus Corp., Center Valley, Pennsylvania, USA) confirmed a tail mass (Fig.1). After retracting the stylet of the fine-needle aspiration (FNA) needle (Expect 19-gauge Flex needle; Boston Scientific Corp., Natick, Massachusetts, USA) by 2cm, one gold fiducial (3 × 0.8mm; Best Medical International, Springfield, Virginia, USA) was back-loaded into the lumen of the needle and sealed with bone wax. At EUS, the fiducials were deployed within the tumor by advancing the stylet forward (Fig.2). Overall, two fiducials were deployed (Fig.3), and a preoperative computed tomography (CT) scan confirmed their position. At laparoscopy, the fiducials were identified using cross-table fluoroscopy (Fig.4), and distal pancreatectomy with splenectomy was performed. A frozen section confirmed negative tumor margins, and the explant specimen revealed the tumor with fiducials in place (Fig.5). Final pathological analysis revealed T1 N0 grade II pancreatic neuroendocrine neoplasm (Fig.6). Fig.1 Linear-array endoscopic ultrasound (EUS) image of the isoechoic mass lesion in the tail of pancreas, superior to the left kidney. Fig.2 Fluoroscopic image showing the linear-array echoendoscope with the 19-gauge fine-needle aspiration (FNA) needle and the first fiducial. Fig.3 Endoscopic ultrasound (EUS) image showing the markers within the lesion casting an acoustic shadow (arrow). Fig.4 Intraoperative fluoroscopic image with the stapler gun in place. The two fiducial markers can be easily visualized. Fig.5 Postoperative specimen of the pancreas, showing the fiducial marker within the lesion. Fig.6 Postoperative histological specimen showing uniform sheets of polyhedral cells with hyperchromatic nuclei and abundant eosinophilic cytoplasm, consistent with a neuroendocrine neoplasm (hematoxylin and eosin stain, ×40). Preoperative injection of India ink [1] or indocyanine green [2] under EUS guidance was developed to facilitate quick tumor localization and to decrease operative time and blood transfusion requirements [3]. However, the disadvantages of dyes include peritonitis, infection, allergic reactions, and reabsorption within tissue planes [4]. In this report, we have described the use of fiducials as an alternative technique for this indication. The fiducials are inexpensive ($80 for five fiducials), easy to deploy, can be identified readily using fluoroscopy or intraoperative ultrasound, and (unlike dyes) do not extravasate into surrounding tissue. Endoscopy_UCTN_Code_TTT_1AS_2AD

THE ROLE OF LINEAR ARRAY EUS FOR DIAGNOSIS OF PANCREATIC MALIGNANCIES IN THE CURRENT SITUATION

Over the last few decades, the role of endoscopic ultrasound (EUS) in the diagnosis of pancreatic malignancies has greatly increased by allowing earlier diagnosis and appropriate staging. The development of linear array EUS also allows fine needle aspiration (FNA) to be carried out under real-time EUS guidance and offers definitive diagnosis, which has fundamentally changed the diagnostic approach to pancreatic malignancies. Moreover, linear array EUS with the EUS-FNA technique has a therapeutic application that has expanded the role of this procedure in the management of pancreatic malignancies. This review will focus on the features of linear array EUS and discuss the current role of linear array EUS in the diagnosis of pancreatic malignancies.

Detection of Celiac Ganglia with Radial Scanning Endoscopic Ultrasonography

Background/AimsIt has been recently reported that celiac ganglia can be identified by linear-array endoscopic ultrasonography (EUS). Still, there has been no report on the detection rate of celiac ganglia with radial scanning EUS. The aim of this study was to evaluate the detection rate of celiac ganglia by radial scanning echoendoscopy during a routine examination.MethodsWe prospectively enrolled 57 consecutive patients (23 men, 34 women; mean age 54 years, range 21-78 years) who were referred for EUS examination from September 2006 to December 2006. EUS was performed using a radial scanning echoendoscope. The size, location and EUS appearance of the celiac ganglia were recorded for each patient.ResultsCeliac ganglia were identified in 51 out of 57 patients (89.4%). They were identified at the left side of the celiac trunk and aorta and between the celiac artery and the left adrenal gland. They appeared as hypoechoic, oblong or lobulated structures, often with an irregular edge, and they often contained a hyperechoic focus or strand. The mean size was 18 mm by 4 mm. Structures corresponding to the visualized celiac ganglia were retrospectively identified on CT scans in 33 among the 37 patients (89.2%).ConclusionsThe results of this study showed that celiac ganglia could be identified, with radial scanning EUS, in the majority of subjects.

Endoscopic Ultrasound (EUS)-Guided Portal Vein CO2 Angiography: A Pilot Study in a Porcine Model

Background: Direct portal vein (PV) angiography can provide valuable clinical information but is not performed due to high risk of complications. Aim: To assess feasibility of endoscopic ultrasound (EUS)-guided PV angiography with a small caliber fine needle aspiration (FNA) needle using carbon dioxide (CO2) in a porcine model. Methods: We performed acute experiments under general anesthesia on 50-kg pigs. Under linear array EUS guidance, an intrahepatic PV branch was punctured with 25g FNA needle. Portal venography was performed injecting iodinated contrast (Hypaque®) and then medical grade CO2 under fluoroscopy. A visualization scoring system was used to assess angiography results. After portography the needle was removed and the animals were observed for 30 minutes and then sacrificed for necropsy. Results: 6 animal experiments were performed without complications. EUS-guided PV puncture with 25g FNA needle was technically straightforward. Injection of ionic iodinated contrast through 25g FNA needles (table 1) was arduous (pressure 76.7 ± 5.2 PSI) resulting in short (6.02 ± 1.15 seconds) and poor opacification of the PV (visualization score 1.33 ± 0.52). CO2 injection through 25g needles was simple and easy (pressure 20.8 ± 2.0 PSI) producing prolonged (19.83 ± 1.68 seconds) opacification of the entire portal system (visualization score 4.33 ± 0.52). There was a statistically significant difference in all compared parameters (P < 0.0001) favoring injection of CO2 over viscous iodinated contrast during portal angiography through 25g FNA needles. Postmortem examination revealed no active bleeding or damage to the liver, other intraabdominal organs or blood vessels. Conclusions: EUS-guided portal venography with CO2 using small (25g) FNA needles appears feasible, technically simple and safe. Tabled 1Comparison of PV angiography with iodinated contrast (IC) and CO2: Subjective score Subjective score Pressure on injection (PSI) Pressure on injection (PSI) Time of opacification Time of opacification Animal IC CO2 IC CO2 IC CO2 Pig#1 1 4 70 20 7.14 21.17 Pig#2 2 4 80 20 5.20 20.23 Pig#3 1 5 80 20 4.19 18.15 Pig#4 2 4 70 20 6.23 18.10 Pig#5 1 4 80 25 6.18 22.25 Pig#6 1 5 80 20 7.15 19.13 Mean 1.33 ± 0.52 4.33 ± 0.52 76.7 ± 5.2 20.8 ± 2.0 6.02 ± 1.15 19.83 ± 1/68 P value p < 0.0001 p < 0.0001 p < 0.0001 Open table in a new tab

Changing Trends in Endosonography: Linear Imaging and Tissue are Increasingly the Issue

The indications and uses of endoscopic ultrasound (EUS) are expanding. The role of EUS-guided fine needle aspiration (EUS-FNA) is considered an essential aspect of EUS practice. A significant change in the indications and technology used for EUS has occurred. This study was designed to compare the use of radial, linear, and miniprobe endosonography equipment during a 10-year period in a single, large, EUS practice. A retrospective review of an EUS experience at a single high-volume center was performed. In this single-center experience, there has been an increase in the volume of EUS and EUS-FNA. For luminal cancer-staging cases, the radial echoendoscope is the predominant scope used for examination and has not changed significantly. In contrast, for pancreaticobiliary and mediastinal indications, the use of the linear array echoendoscope alone has increased and currently is the preferred scope for examination (33% vs. 76%, P < 0.001; 46% vs. 96%, P < 0.001). In these cases requiring EUS-FNA, the use of the linear array scope alone has increased from 17% to 73%. In this single-center experience, EUS has shifted from an imaging technology to an image-guided biopsy and therapeutic technology. The use of the linear array EUS alone has increased, especially in the evaluation of pancreatobiliary and mediastinal disease and when fine-needle aspiration is performed.

Endoscopic Ultrasound in Pediatric Gastroenterology

Purpose: The value of endoscopic ultrasound (EUS) in the evaluation and diagnosis of gastrointestinal disorders in adults is well recognized. Although the number of publications and reports of EUS applications in pediatric patients has been increasing in recent years, the medical literature is still limited. We describe our initial experience with EUS as a diagnostic tool in pediatric patients. Methods: We reviewed all EUS procedures performed at our institution between Sept 2002 and May 2006. EUS was performed using conventional adult echoendoscopes (Pentax EG-3630 UR and EG-3630 U models) by a single endosonographer (AAG). Patients younger than 18 years of age were included in the study. We obtained demographic data, indications and EUS findings as well as follow-up information and outcomes of these patients. Results: A total of seven pediatric patients underwent EUS in the period reviewed. The mean age was 11.7 years (range 7–17), 3 male and 4 female. All patients were >18 kg in weight. EUS was performed with a pediatric anesthesiologist providing IV sedation in all cases. All patients had radial endosonography, two undergoing linear array EUS for FNA of abnormal lesions found during the study. The indications for the procedure included recurrent pancreatitis of unknown origin (4 patients), submucosal lesions of the stomach (2 patients), and an apparent rectal adenocarcinoma for staging (1 patient). All procedures were performed safely without immediate or long-term complications. EUS findings included gallstone disease (2 patients), chronic pancreatitis (1 patient), non-obstructive jaundice (1 patient), and UC in the patient with apparent malignancy of the rectum. The two submucosal gastric masses undergoing EUS-FNA were reported as benign lesions. EUS provided valuable information and had a direct impact in the management decisions made for all patients. Conclusions: In experienced hands, EUS and EUS-FNA can be safely performed in pediatric patients who weigh more than 18 kg using regular adult echoendoscopes, always under assistance of a pediatric anesthesiologist. Our most common indications for EUS in pediatric patients included the evaluation of recurrent pancreatitis of unknown etiology and the presence of submucosal lesions of the GI tract found during routine endoscopy. EUS and EUS-FNA, when indicated, can provide useful information in the decision-making process for the evaluation and treatment of selected pediatric patients.

PARAESOPHAGEAL VARICES MIMICKING A MEDIASTINAL MASS MADE APPARENT BY ENDOSCOPIC ULTRASOUND

A 77 year old male with alcoholic cirrhosis was admitted for progressive dyspnea. A chest x-ray showed a large right pleural effusion. Percutaneous catheter drainage was performed confirming a transudative effusion consistent with hepatic hydrothorax. Computed tomography (CT) scan of the chest with intravenous contrast demonstrated a large, lobulated, mediastinal mass extending from the superior mediastinum to the peri-aortic retroperitoneal space. CT-guided core needle biopsy obtained only bloody material. Cytology was hypocellular, consisting mainly of blood. No malignancy was seen and no clonality was demonstrated on flow cytometry. Due to suspicion of lymphoma referral was made for endoscopic ultrasound (EUS)-guided sampling of the mass. Radial array EUS revealed multiple round and oval anechoic masses in the posterior mediastinum extending inferiorly to the retroperitoneum. Using linear array EUS with doppler it became apparent the described masses were of vascular origin and biopsy was aborted. Subsequent CT of the chest and abdomen revealed large paraesophageal, mesenteric and splenic varices, superior mesenteric vein thrombosis and dilatation and a nodular liver consistent with cirrhosis. The inferior vena cava (IVC) was uninterrupted and without thrombosis. The hemiazygous and azygous veins were markedly dilated at their origins. The large paraesophageal varices enhanced with contrast on venous phase imaging. In the setting of portal hypertension, dilatation of vascular anomolies, the normal azygous vein or paraesophageal varices can mimic mediastinal masses. Observational studies have shown the azygos vein is often significantly dilated in patients with varices. However, periazygos collaterals are only occasionally observed. A variety of mediastinal venous anomalies have also been described. One uncommon anomaly, azygos continuation, involves interruption of the IVC with absence of it's hepatic portion and hepatic vein drainage directly to the right atria. Our patient had large paraesophageal varices and no obvious vascular anomaly. The presence of vascular structures mimicking mediastinal masses highlights the importance of using delayed venous phase CT imaging or EUS with doppler flow to evaluate mediastinal masses in patients with portal hypertension. Percutaneous or transbronchial biopsy without the use of doppler may subject these patients to an unnecessary and high-risk procedure.

Accurate diagnosis of pancreas divisum by linear-array endoscopic ultrasonography.

During linear-array endoscopic ultrasonography (EUS), the main pancreatic duct can be followed continuously from the major papilla into the pancreatic body in most patients. Often, the duct can also be seen crossing a sonographic border between the ventral and dorsal pancreatic anlagen. It was hypothesized that the presence of either feature excludes pancreas divisum, whereas the absence of these features suggests complete pancreas divisum. Pancreas divisum was sought during all linear-array EUS examinations conducted between July 1999 and June 2003. Charts were reviewed retrospectively, and patients who underwent endoscopic retrograde pancreatography after, but not before, EUS were included in the study. A total of 162 patients had EUS before ERCP. Adequate evaluation of the pancreatic duct was possible in 78 % of the patients. The prevalence of pancreas divisum was 13.6 %. In patients with adequate duct visualization, the sensitivity, specificity, and positive and negative predictive values for EUS were 95 %, 97 %, 86 %, and 99 %, respectively. The overall accuracy of EUS for identifying pancreas divisum was 97 % in this subgroup. Adequate EUS evaluation of pancreas divisum was possible in most cases. Linear-array EUS is a promising diagnostic test for pancreas divisum.

EUS: An Ideal Initial Test for Elderly Patients with Idiopathic Pancreatitis

Methods: We reviewed 67 cases of patients who underwent cholecystectomies and who also showed thickened gallbladder wall in their preoperative EUS. According to the post-surgical pathologic diagnosis, the cases were classified into malignant and benign diseases, and then they were statistically compared with several findings of EUS of thickened gallbladder wall such as thickness, extent of wall thickening, associations of gallstones, loss or preservation of layered structure of wall, internal echo pattern within thickened wall, associations of microcyst or echogenic nodule within thickened wall, and irregularity of inner surface of thickened wall. Results: Pathologic diagnoses included 10 cancers and 57 benign gallbladder diseases. The sensitivity and specificity of EUS examination for diagnosis of the gallbladder cancer were 90% and 98% respectively, and especially in the specificity, EUS was superior to that of abdominal ultrasonography or abdominal CT scan that were also performed to enrolled patients preoperatively. Through statistical analyses, EUS findings of thickened wall such as thickness, associations of gallstones, loss or preservation of layered structure, and irregularity of inner surface of thickened wall were turned out to be the statistically significant variables in the differential diagnosis between malignant and benign causes of thickened gallbladder wall. On the multivariate analyses, loss or preservation of layered structure, and irregularity of inner surface of thickened wall were finally remained as independent variables, odds ratio (OR) 12.10: 95% CI (1.2, 137.6), OR 15.80: 95% CI (1.5, 167.0). Conclusion: EUS is useful to diagnose gallbladder cancer when gallbladder shows thickened wall and EUS findings of thicker wall, absence of gall stones, loss of normal layered structure, and irregular internal surface of thickened wall are predictive factor of gallbladder cancer. *T1603 EUS: An Ideal Initial Test for Elderly Patients with Idiopathic Pancreatitis Karin M. Rettig, Allan G. Halline, Russell D. Brown, Rama P. Venu Background: Current standard of care for patients with idiopathic pancreatitis (IP) involves an extensive evaluation including ERCP with possible sphincter manometry to identify an etiology. ERCP carries a significant risk of pancreatitis in comparison to endoscopic ultrasound (EUS). Furthermore, EUS identifies malignancy, stones, sludge, and chronic pancreatitis as well as or better than ERCP. Older patients may have a higher risk of malignancy and a lower incidence of sphincter dysfunction (SD), making EUS an attractive method for initial endoscopic evaluation in this group. Aim: To determine if EUS should be used as the initial investigation of choice in older patients with IP. Methods: Patients >55 years old referred with IP were evaluated with history, physical, amylase, lipase, triglyceride, calcium, liver enzymes, ultrasound and CT. Patients in whom the etiology was unknown after noninvasive evaluation were included in this study. Each patient had EUS, followed by helical CT and ERCP +/sphincterotomy (ES). Radial array EUS was done first followed by linear array EUS with possible fine needle aspirate (FNA). CT, ERCP with brush cytology and/or SOM was performed in all patients. ES, stone extraction, stent placement, laparotomy, or Whipple operation was done based on ERCP results. Results: Of 20 patients, an etiology was identified in 7 (35%). Four of 20 patients had a malignancy (3 pancreas, 1 periampullary). One patient each had choledocholithiasis, pancreas divisum, SD, and early chronic pancreatitis. EUS demonstrated a mass in all 4 patients withmalignancy, andFNAof eachmasswas positive for adenocarcinoma in 3. ERCP showed PD stricture suggestive ofmalignancy in 3 patients, with brush cytology positive for adenocarcinoma in one. Both EUS and ERCP identified a common bile duct stone in one patient, while SD (1) and pancreas divisum (1) were diagnosed exclusively by ERCP. EUS established a diagnosis in 6/7 (84%), while ERCP did so in 4/7 (56%). CT scanning revealed a mass in only one of four cancer patients and an enlarged pancreas due to pancreatitis in 17/20 patients. Three of four patients with cancer underwent Whipple surgery, and all three were correctly staged by EUS. One patient had metastasis to the liver and was treated with endoprosthesis. Conclusion: EUS should be considered as the initial endoscopic study of choice in older patients with IP. EUS has an overall higher yield and can accurately establish a tissue diagnosis, enable staging of malignancy, and aid in appropriate planning for therapy.