FNA Needle Research Articles

Combining Fine-Needle Aspiration (FNA) and Fine-Needle Core Biopsy (FNCB) Using a Standard 22 Gauge EUS Needle Increases Diagnostic Yield: 2011 ACG Presidential Poster

Purpose: EUS guided needle aspiration for cytology has limitations in diagnosis of diseases such as lymphoma and stromal tumors. Core biopsies for histologic information have been traditionally performed using 19 gauge trucut needles but usage of these devices in certain anatomic locations can be challenging. There is paucity in data examining the utility of standard 22 gauge needles in obtaining core biopsies and such method as a supplement to the traditional FNA. Current study explores combining EUS FNA with FNCB to increase the diagnostic yield. Methods: EUS performed between December 2009 and November 2010 in a single community hospital setting were retrospectively reviewed, and cases which used both FNA and FNCB (with standard FNA needles rather than 19 gauge trucut needles) were selected. Cases were reviewed for procedural details, FNA cytology results, FNCB histopathology results, and confirmation of final diagnoses. FNAs were performed with 25 gauge and/or 22 gauge needles. FNCB were performed with 22 gauge needles. Results: Total of 21 cases meeting the criteria were identified. Diagnoses of the lesions sampled were as follows: lymphoma (4), pancreatic carcinoma (5), GIST (5), undifferentiated carcinoma of pancreas with giant cells (1), splenule (1), schwannoma (1), autoimmune pancreatitis (1), benign mass with mixed lymphocytes (1), gastric adenocarcinoma (1), and carcinoid tumor (1). 18/21 (85.7%) cases were accurately diagnosed with the combined method. Sensitivities of FNA, FNCB, and the combined method were 47.4%, 52.6% and 84.2%, respectively. Specificities were 100% for all methods.11 cases revealed nondiagnostic FNA cytology, of which FNCB was able to yield accurate diagnoses in 7 cases (63.6%). Conclusion: FNCB with 22 gauge EUS needles can be employed as a supplement to FNA in diagnosis with high accuracy, especially in cases where usage of traditional 19 gauge trucut needles can be technically difficult. This would be particularly useful when immediate cytological feedback is not available. More studies are needed to prospectively compare the different EUS tissue sampling methods available.

First assessment of needle-based confocal laser endomicroscopy during EUS-FNA procedures of the pancreas (with videos)

Challenges in EUS-guided FNA (EUS-FNA) include sampling error, nondiagnostic cytology, and limited on-site cytological evaluation. A prototype needle-based confocal laser endomicroscopy (nCLE) probe is a submillimeter probe that provides real-time imaging at the microscopic level through the FNA needle. To evaluate the feasibility of nCLE during EUS-FNA of pancreatic lesions. Feasibility study. Multicenter, tertiary care. Eighteen patients presenting for EUS-FNA. Patients were injected with 2.5 mL of 10% fluorescein. The lesion was interrogated with the nCLE probe positioned at the tip of a 19-gauge FNA needle. Device integrity, technical ease, safety, and image acquisition. Cases included 16 cysts and 2 masses. There were no device malfunctions. Technical challenges were encountered in 6 of 18 attempts to image and reflected challenges with a postloading technique, the longer ferule tip, and a transduodenal approach. Technical feasibility to perform imaging with nCLE during a pancreatic EUS-FNA procedure was achieved in 17 of 18 cases. Ten cases had good to very good image quality. Two serious adverse events occurred; both were pancreatitis requiring hospitalization. Limited sample size, small number of patients with confirmed pathological diagnosis, lack of coregistered pathology and images. nCLE in the pancreas is technically feasible via a 19-gauge needle under endosonographic guidance. Future studies will address identification of structures, diagnostic accuracy, and complication profiles. The rate of pancreatitis needs to be further clarified and mitigated.

Successful management of perforation during cystogastrostomy with an esophageal fully covered metallic stent placement

A 49-year-old woman presented for endoscopic treatment of symptomatic pseudocyst refractory to conservative management for the past year. EUS showed a thickwalled 49 39-mm pseudocyst in the pancreatic tail in close opposition to the gastric fundus. The cyst was punctured by using a 19-gauge FNA needle (Fig. 1) followed by guidewire placement and dilation of the fistula with a needle-knife cautery and a 6-mm balloon. Attempted placement of a 10F, 4-cm long double-pigtail stent resulted in dislodgment of the guidewire from the pseudocyst because of extreme angulation of the endoscope required to obtain a satisfactory endoscopic view. The guidewire was re-placed into what appeared to be the pseudocyst cavity under endoscopic control, and balloon dilation was repeated using a 12-mm balloon. Fluoroscopic examination showed possible free air at this point, and thus, the echoendoscope was exchanged for a gastroscope to examine the cystogastrostomy tract. Endoscopy showed a clear perforation next to the true lumen of the cystogastrostomy tract (Fig. 2). We then placed an 18 70-mm esophageal fully covered self-expandable metallic stent (FCMS) (ALIMAXX-ES; Merit Medical Endotek, South Jordan, Utah) by using a stiff guidewire (Savary-Gilliard Wire Guides; Cook Medical Inc, Bloomington, Ind) into the pseudocyst cavity to drain it and to seal the perforation (Fig. 2). Broad-spectrum antibiotics were initiated during the procedure. Abdominal CT after the procedure showed free air and the stent to be in good position (Fig. 3). No pain or other signs of peritonitis developed in the patient, and she was discharged after 48 hours of observation on oral antibiotics. The stent was removed uneventfully 1 month later after repeat CT scan confirmed resolution of the pseudocyst.

VHM10 EUS-Guided Ablation of Pancreatic Insulinomas

VHM10 EUS-Guided Ablation of Pancreatic Insulinomas

Mo1379 Feasibility of Intra-Tumoral Confocal Microscopy Under EUS Guidance (EUS-CM)

2.3 respectively, while the mean number of passes with a standard FNA needle was 3.7. No complications occurred, however 100% of the 19 gauge stylets were difficult to remove once the needle was inserted into a target lesion. Conclusion: Our initial experience with this novel EUS-FNB device demonstrates promising results, with higher overall accuracy using fewer number of passes to achieve a diagnosis, and no additional complications noted. It also can obtain tissue from the periduodenal/pancreatic head region, which has been a limitation of traditional EUS guided trucut biopsy. Ongoing comparative data collection should be pursued to further delineate this device’s capacity to achieve complete histologic diagnosis, and its impact on clinical management/cost and need for onsite cytopathology interpretation.

799 The Diagnostic Accuracy of 22- and 25-Gauge Needles in EUS-FNA of Solid Pancreatic Lesions: A Meta-Analysis

The Diagnostic Accuracy of 22and 25-Gauge Needles in EUSFNA of Solid Pancreatic Lesions: A Meta-Analysis Mohammad Madhoun, Sachin B. Wani, Dayna S. Early, Srinivas Gaddam, Amit Rastogi, William M. Tierney, John T. Maple Internal Medicine/ Digestive Diseases, University of Oklahoma Health Sciences Center, Oklahoma City, OK; Division of Gastroenterology, Washington University School of Medicine, St Louis, MO; Division of Gastroenterology and Hepatology, Veterans Affairs Medical Center and University of Kansas School of Medicine, Kansas City, MO Background: Several studies have assessed the performance characteristics of 22and 25-gauge needles in endoscopic ultrasound with fine needle aspiration (EUS-FNA) of pancreatic mass lesions, but most have failed to demonstrate superiority of either needle. Aim: Use meta-analysis to more robustly define the diagnostic accuracy of EUS-FNA for pancreatic masses using different gauge FNA needles. Methods: Studies were identified by searching ten medical databases including Ovid MEDLINE and the Cochrane Library Database for reports published between 1994 and 2010, using a reproducible search strategy comprised of relevant terms. References from retrieved articles and national meeting abstracts were also manually reviewed. Only studies comparing the overall diagnostic accuracy of 22-g vs 25-g EUS needles that used surgical histology or at least 6 months clinical follow up for a gold standard were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. When required, the original investigators were contacted to provide additional data. Pooling was conducted by both fixed-effects and random-effects models; results are presented from the random effects model when heterogeneity was significant. Diagnostic characteristics (sensitivity, specificity, positive and negative likelihood ratios) with 95% confidence interval (CI) were calculated. Results: Six studies (involving 1064 subjects) met the defined inclusion criteria. Of the 1064 patients, 678 subjects were in the 22-g group and 434 subjects were in the 25-g group (both needles were used in 48 patients). The performance characteristics of the two needles are contrasted in the accompanying table. The bivariate generalized linear random-effect model indicated that the 25-g needle is associated with a higher sensitivity (p 0.001) but comparable specificity (p 0.82) to the 22-g needle. The rate of needle malfunction was similar between the 2 groups (p 0.6). The nature of the data reporting did not allow for evaluation of some variables, such as diagnostic accuracy by anatomic sub-sites (e.g. head, body/ tail) and physician ease of use. Conclusions: This meta-analysis suggests 25gauge needle systems are more sensitive than 22-gauge needles for detecting pancreatic malignancy. Potential explanations include fewer bloody specimens, better needle traversal through firm masses, and technically easier access to lesions in the medial aspect of the pancreatic head and uncinate process while using the smaller caliber needle.

A Comparative Study of Endoscopic Ultrasound Guided Fine Needle Aspiration With and Without a Stylet

Despite lack of evidence, use of a stylet during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is assumed to improve the quality and diagnostic yield of specimens. The purpose of this study was to compare EUS-FNA specimens obtained with stylet (S+) and without stylet (S-) for: (i) cellularity, contamination, adequacy, and amount of blood and (ii) diagnostic yield of malignancy. Patients who underwent EUS-FNA of solid lesions by two experienced endosonographers at a tertiary referral center using a 22-gauge FNA needle with suction were included. Stylet was used for all EUS-FNA procedures performed between January 2006 and September 2007 and no stylet was used between October 2007 and April 2009 allowing comparison between the two techniques. Cytology slides were retrieved, de-identified and evaluated by two experienced cytopathologists blinded to FNA technique. Slides were evaluated for cellularity, degree of contamination, adequacy, amount of blood and cytologic diagnosis. Fisher's exact and unpaired t-test were used for comparative analysis. A total of 162 patients with 228 lesions were included. FNA of 106 and 122 lesions each was performed in the S+ and S- groups, respectively. FNA sites included pancreas [41 (18%)], lymph node [125 (55%)], liver [20 (9%)], adrenal [21 (9%)] and others [21 (9%)]. No significant differences in the cellularity (P=0.37), contamination (P=0.18), significant blood (P=0.42) and adequacy of specimen (P=0.45) were found between S+ and S- specimens. There was no statistically significant difference in the diagnostic yield of malignant lesions (P=0.48). The use of stylet during FNA does not appear to confer any advantage with regards to the adequacy of specimen or diagnostic yield of malignancy.

Intragastric Balloon Extraction Two Years after Placement

Purpose: A 46 year old man presented for removal of a Bioenterics® Intragastric Balloon (BIB®) placed 2 years prior in South America for weight loss. His body mass index decreased from 38 to 34, stable at presentation. Although removal was advised in 180 days, he did not follow-up. After confirming BIB on abdominal Xray, we performed upper endoscopy under conscious sedation revealing a 6” BIB in the fundus. The BIB was punctured multiple times with an injection needle, with larger holes created by EUS FNA needle and sphincterotome. Methylene blue dyed fluid was released and suctioned. Once fully deflated, BIB extraction was attempted using multiple devices but eventually successful with polypectomy snare. Total procedure time was 3 hours. The patient did well post procedure and was asymptomatic at follow-up after 2 months. Discussion: The Inamed BIB system is available in Europe and South America as a temporary treatment of morbid obesity but not FDA approved in the U.S. To our knowledge, this is the 1st reported U.S. case of a BIB lasting 2 years with subsequent uncomplicated removal. The BIB's large rounded shape and slippery pliable surface can make extraction challenging without dedicated BIB removal tools, the Wahlen Needle (special tubing sheath can be advanced over the needle to fully suction balloon contents) and 2-pronged Wahlen wire grasper. Standard injection needle and snare/foreign body grasper may suffice but can increase the procedure time by less efficient balloon emptying and surface grip. Though unavailable at the time, a needle knife papillatome may have permitted direct entry into the balloon for rapid suctioning. Potential complications include ulceration, hemorrhage, obstruction and perforation during removal. In the only other U.S. reported BIB case, a woman presenting with BIB-induced gastric outlet obstruction had extraction performed with use of an overtube, complicated by esophageal perforation that resolved with conservative management. In conclusion, Bioenterics Intragastric Balloons may be safely removed under moderate sedation with standard devices although U.S. physicians should be aware of the challenges and associated complications.Figure: [1378]

Endoscopic Necrosectomy With Self-Expandable Metal Stent (SEMS) Drainage: A Novel Approach in the Treatment of Walled-Off Pancreatic Necrosis (WOPN)

Purpose: Pancreatic necrosis is a feared complication of acute pancreatitis with high morbidity and mortality. Recent literature has suggested the advantages of a minimally-invasive approach. Methods: Patients that had undergone cyst-gastrostomy with a SEMS prior to endoscopic necrosectomy for WOPN were retrospectively evaluated. Using a therapeutic echoendoscope, a 19-gauge FNA needle was used to puncture the WOPN. A 0.035-inch guide wire was advanced under direct visualization either with the aid of fluoroscopy or EUS. The tract was then dilated using a combination of needle-knife, Sohendra dilators (Wilson-Cook), and/or CRE balloon (Boston Scientific). A fully-covered or uncovered 10mm x 40mm SEMS was then deployed across the tract, and the WOPN was aggressively irrigated. After adequate drainage of the WOPN had occurred, a conventional gastroscope was used to remove the SEMS. A CRE balloon was used to dilate the tract up to 18 mm. The gastroscope was then introduced into the necroma and debrided using a combination of irrigation, forceps, Roth nets (US Endoscopy), and stone-retrieval baskets. The goal of each necrosectomy was to debride the walls of the necroma until pink granulation tissue was uncovered. At the conclusion of each necrosectomy, 7 or 10F plastic stents or nasobiliary drain were left in place with repeat necrosectomy performed at the endoscopist's discretion. Results: 11 total necrosectomies were performed on 4 patients. The mean age of the patients was 55 years. 3 of the 4 patients had sterile necrosis; 1 had infected necrosis. The mean size of the WOPN was 13.9cm prior to cyst-gastrostomy with SEMS. The mean time frame from the onset of acute pancreatitis until cyst-gastrostomy drainage was 108 days (range 24-237 days). The first endoscopic necrosectomy was performed a mean of 26 days after initial cyst-gastrostomy SEMS drainage (range 10-46 days). Significant improvement in symptoms was seen in all 4 patients, with 2 patients experiencing complete resolution of symptoms, 1 patient with near-complete resolution of symptoms, and 1 patient with partial resolution of symptoms. Complications from endoscopic necrosectomy included fever (1 patient), tachycardia (1 patient), persistent leukocytosis (1 patient), and prolonged procedure time (4 patients). There were no deaths. Conclusion: In a highly-selective patient population, optimal drainage using SEMS for cyst-gastrostomy may be advantageous to using a smaller diameter plastic stent prior to endoscopic necrosectomy. Prospective, randomized trials must be performed for validation.

Fracture of an EUS-guided FNA needle during an attempted rendezvous for an inaccessible pancreatic duct

Strictures of the pancreaticojejunal anastomosis after pancreaticoduodenectomy may lead to pancreatic duct obstruction. ERCP alone is often technically unsuccessful in these patients, and EUS-guided rendezvous or transenteric pancreatic duct stenting have been performed as rescue techniques.1-8 However, these procedures may be associated with significant morbidity. Herein, we present a case of inadvertent fracturing of an EUS-FNA needle during an attempted EUS-guided rendezvous for an inaccessible main pancreatic duct after pancreaticoduodenectomy.

Coexistent Serous Cystadenoma and Intraductal Papillary Mucinous Neoplasm of Pancreas? Yes, It Can Happen!

Purpose: A 63-year-old white male presented with six week history of intermittent, mild right flank discomfort. His physical examination, apart from moderate obesity, was unremarkable. His serum CA 19-9 and serum amylase levels were normal. A biphasic CT scan of abdomen revealed a 2cm water density lesion located in the posterior pancreatic tail. Endoscopic ultrasound (EUS) revealed three cysts ranging in size from 4mm to 10mm in pancreas body and a multi-loculated cystic lesion measuring 2.1cmx1.4cm (lesion #1) located in the pancreas tail. The sonographic features were suggestive of multiside branch intraductal papillary mucinous neoplasm (MS-IPMN) (Image 1, arrowhead). Immediately inferior to the largest MS-IPMN lesion and adjacent to the left kidney, a well-circumscribed, more solid-appearing lesion with anechoic (microcysts) intervening spaces was seen (lesion# 2) (Image 1, arrow). Lesion #2 measured 22mm in the greatest diameter. Based on sonographic features of lesion #2, a differential diagnosis of likely synchronous serous cystadenoma (SCT) versus other cystic solid lesions (neuroendocrine tumor) was rendered. An EUS guided fine needle aspiration (EUS-FNA) using a 22 G needle of lesion#1 yielded 3cc of clear viscous fluid with elevated CEA 203.7 ng/ml and amylase 17,514 U/L levels. EUS-FNA cytology was consistent with a side branch IPMN. The location of lesion #2 immediately inferior to the MS-IPMN precluded safe and uncontaminated advancement of the FNA needle. A subsequent distal pancreatectomy and splenectomy revealed synchronous SCT and MS-IPMN. This is an unusual case of concomitant SCT and IPMN. This report highlights the clinical impact of EUS and EUS-FNA in evaluation and management of cystic lesions of the pancreas and illustrates the limitation of biphasic pancreas protocol CT to ascertain the presence of multiple MS-IPMN lesions in the pancreas.Figure

Preliminary experience with a new cytology brush in EUS-guided FNA

Despite the high diagnostic yield of EUS-guided FNA, room for technical improvements remains. Recently, the EchoBrush (Cook Endoscopy, Winston-Salem, NC), a disposable cytologic brush, was introduced to the market. To date, only 1 study, limited to 10 pancreatic cyst cases, using this device has been published. To assess the diagnostic yield of the EchoBrush in a cohort of consecutive patients, irrespective of the target lesion. Case series. Tertiary care university hospital (Molinette Hospital, Turin, Italy). Thirty-nine consecutive patients (12 with solid pancreatic masses, 12 with pancreatic cysts, 7 with enlarged lymph nodes, and 8 with submucosal masses) were enrolled. The material collected with the EchoBrush and with a standard FNA needle was double-blind evaluated by 2 cytopathologists. Adequacy of the sample and sensitivity and specificity of the EchoBrush method. Adequate material for cytologic analysis was collected in 17 of 39 patients (43.6%) with a single pass of the EchoBrush. Results were better for pancreatic lesions (for solid and cystic lesions, the adequacy was 58.3% and 50%, respectively); adequacy was low (28.6% and 25%, respectively) for lymph nodes and submucosal masses. The overall sensitivity and specificity were 57.9% and 31.2%, respectively. There were no adverse events with the procedure. Preliminary study. This report suggests that the EchoBrush may provide adequate cellularity to diagnose solid and cystic pancreatic lesions. More extensive studies are needed to compare the EchoBrush and standard needles.

EUS for the management of peripancreatic fluid collections after distal pancreatectomy

Peripancreatic fluid collections (PFCs) are a common complication after distal pancreatectomy and are usually managed by percutaneous drainage. The role of EUS in the management of postoperative PFCs has not been previously reported. To evaluate the role of EUS in the management of PFCs after distal pancreatectomy. Case series. Academic tertiary referral center. Symptomatic patients with PFCs after a distal pancreatectomy. At EUS, the PFCs were accessed transgastrically by using a 19-gauge FNA needle and after passage of a 0.035-inch guidewire; sequential dilation of the transgastric tract was performed up to 8 mm and multiple 7F or 10F double-pigtail stents were deployed. Nasocystic drainage catheters were deployed in those with poor drainage at the time of endoscopy. To evaluate the technical and treatment success and safety profile of the EUS-based approach for management of PFCs after distal pancreatectomy. Ten patients (6 men, 4 women; mean age, 56.8 years [range 20-76 years]) underwent EUS-guided drainage of PFCs after distal pancreatectomy over a 30-month period. Indications for distal pancreatectomy were neuroendocrine tumor in 5 patients, focal chronic pancreatitis in 2, cyst neoplasm in 1, adenocarcinoma in 1, and trauma in 1. The mean size of the PFCs (largest dimension) was 91.4 mm (range 45-140 mm). EUS-guided drainage was technically successful in all 10 patients; 1 patient underwent EUS-guided drainage of 2 large noncommunicating PFCs in the same endoscopy session. Treatment was successful in 9 (90%) of 10 patients; 1 patient had persistent symptoms requiring reoperation. No procedural complications were encountered. At a mean follow-up of 151 days (range 96-280 days), all 9 patients were doing well without any evidence of symptom recurrence. Small number of patients and lack of a comparative treatment group. EUS-guided drainage is a minimally invasive, safe, and highly effective technique for the management of symptomatic PFC after distal pancreatectomy.

EUS-guided radiofrequency ablation with a prototype electrode array system in an animal model (with video)

Although previously reported in an animal model, the development of EUS-guided radiofrequency ablation (EUS-RFA) has been impeded because of a lack of a retractable needle electrode array that could safely and effectively ablate large areas. To evaluate the feasibility and safety of performing EUS-RFA with a 19-gauge FNA needle fitted with an umbrella-shaped retractable needle electrode array. Endoscopic experimental study in a porcine survival model at a tertiary referral center animal laboratory. Evaluate the safety and efficacy of the retractable needle electrode array for performing EUS-RFA. A 19-gauge EUS-FNA needle was modified and fitted with a retractable echogenic umbrella-shaped monopolar electrode array at its tip. The FNA needle was connected to a 200-W generator that has an impedance-based feedback system. EUS-RFA of the liver was attempted on 5 Yorkshire pigs. Although 1 pig was euthanized immediately after RFA to assess for immediate complications and pathological examination, the 4 others were kept alive for 7 days. At EUS, the needle electrode was well visualized and could be deployed in the liver without technical difficulty. During ablation, a round hyperechoic focus gradually surrounded the electrode tip. Tissue ablation was attained within 7 minutes, and the electrode array could be easily withdrawn into the needle assembly. The vital signs of all pigs remained stable throughout the procedure and until they were euthanized. Histopathology in all pigs revealed a discrete, well-demarcated spherical focus of complete coagulation necrosis measuring 2.6 cm in diameter and without damage to the surrounding liver parenchyma or vasculature. In this experimental study, EUS-RFA of the liver was performed safely by using the retractable umbrella-shaped electrode array with effective coagulation necrosis of large areas.

Retrospective analysis of the utility of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in pancreatic masses, using a 22-gauge or 25-gauge needle system: a multicenter experience

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is now performed routinely in many advanced endoscopy centers and has enhanced the ability to diagnose pancreatic masses. However, there is uncertainty about which needle size is optimal for EUS-FNA of pancreatic masses. We aimed to evaluate the performance of the 22-gauge and 25-gauge needles in obtaining cytologic diagnosis of pancreatic masses. All cases that were referred for EUS-FNA for pancreatic masses between February 2001 and June 2007 were reviewed, and patients who underwent EUS-FNA using the 22-gauge and 25-gauge needle system were identified. In patients who underwent surgery, operative histopathological findings were compared with the cytopathological findings from EUS-FNA. A total of 842 patients with pancreatic masses detected on computed tomography (CT) and/or magnetic resonance imaging (MRI) and confirmed by EUS underwent EUS-FNA with the 22-gauge needle (n = 540) or the 25-gauge needle (n = 302). Results of EUS-FNA cytology findings were compared with the gold standard of surgical histopathological findings or long-term clinical follow-up. The sensitivity, specificity, PPV, and NPV of FNA were respectively 84%, 100%, 100%, and 73% [corrected] for the 22-gauge needle compared with 92%, 97%, 98%, and 87%, [corrected] respectively for the 25-gauge needle. No complications were noted in the 25-gauge needle group, compared with pancreatitis in 2% of the 22-gauge needle group. This retrospective comparative study shows that EUS-FNA with a 25-gauge needle system is a safe and reliable method for tissue sampling in pancreatic masses. The system is more sensitive and has a slightly [corrected] higher NPV than the standard 22-gauge needle. Our study suggests that perhaps the smaller caliber FNA needle causes less trauma during EUS-FNA and hence less complications. Further studies including randomized trials are needed.

Quality EUS-FNA: The Potential for Malignant Cell Carry-Over and False-Positive Cytology During Luminal Tumor Staging

Background: Endoscopic Ultrasound (EUS) is considered the best modality for the locoregional staging of all gastrointestinal(GI) luminal cancers. No studies have investigated the possibility of false-positive lymph node FNA in patients with GI cancers or the potential for malignant cell carry-over and needle contamination. Endoscopes that traverse a luminal tumor (LT) may cause cancer cells to shed and contaminate the endoscope tip and the biopsy channel. This may result in false-positive cytology of an aspirate obtained from a sampled lymph node. Our primary aim was to determine if malignant cells carry-over and contaminate the (EUS) endoscope or FNA needle with passage of an endoechoscope through a LT. Methods: In this pilot study, we recruited 16 subjects who were referred for preoperative staging of gastrointestinal cancers; 13 patients with LT (esophageal cancers or gastric cancers) and 3 subjects for a control-arm with non-LT. All patients underwent a radial EUS for preoperative staging. A linear endoechoscope was then passed into their esophagus and stomach to perform either a sham FNA and when indicated a FNA for staging. Cytology samples were taken from the FNA needle, scope channel (brushings of and debris from the channel for cell block and histology), and the scope tip exterior. Direct tumor sampling was obtained for a control. Two blinded pathologists, with expertise in cytologic interpretations, read all slides. Results: Luminal cancers included 10 esophageal cancers, and 3 gastric cancers. Non-LT were pancreatic(2) or lung cancer(1). Of 13 luminal cancers, 7 (54%) had tumor cell carry-over detected by cytologic or histologic interpretation. Four(30%) had cell carry-over onto the cytology brush, 4 (30%) on the exterior scope, 4 (30%) from the cell block, and 2 (15%) from the FNA catheter tip. 29 percent of all patients with tumor cell carry-over had malignant cells found on the FNA needle. The 3 non-LT had no cell carry-over and all had negative controls. Conclusions: 1. Malignant cell contamination of endoechoscopes and FNA needles does occur when staging luminal cancers. 2. The FNA needle can be contaminated with tumor cells prior to obtaining non-peritumoral lymph node cytology, and has potential for false positive aspirates. 3. Endoscopist should be aware of the risks.

EUS-Guided Placement of Fiducial Markers Using a 22-Gauge Needle

Background: Image guided radiotherapy requires precise mapping of the therapeutic field such that maximal therapy can be applied to cancer tissue while minimizing toxicity to adjacent organs. In soft tissue tumors of the chest, abdomen and pelvis, implantation of radiographic markers (fiducials) is required to construct reference points. Endoscopic ultrasound is routinely employed as a safe and reliable means of staging and sampling many common gastrointestinal malignancies. Limited reports have described EUS-guided placement of fiducials with 19G FNA needles. However no data exists on the feasibility of fiducial placement with a 22G FNA needle. Aims: Describe the feasibility, success and safety of EUS guided fiducial placement with a 22 G FNA needle in GI malignancies and associated lymph nodes. Methods: Patients presenting for EUS evaluation of esophageal malignancies and subsequently found to have nodal positive disease were enrolled. EUS guided fiducial placement was utilized to demarcate the proximal and/or distal most extend of tumor burden. All underwent linear EUS by a single endosonographer. Visicoil gold cylindrical fiducials (0.35 mm X 10 mm) were inserted into tumor or nodal tissue using a standard 22G FNA needle. The cylindrical gold fiducial was manually inserted into the hollow channel of a 22G needle and kept in place with sterile bone wax such that when the tip of the needle was inserted into the target lesion, advancement of the stylet would results in the manual insertion of the fiducial under real time EUS visualization. The position of the fiducial was verified by EUS. Chart review was performed at two months for evaluation of complications. Demographic data including patient age, gender, and cancer stage were collected. Results: Four patients, median age 60 years, all with esophageal cancer (3 adenocarcinoma, 1 squamous) and nodal involvement had fiducials placed. A total of 1-2 fiducials were attempted for each patient. EUS guided fiducial placement was successful in 4/4 patients (100%). Locations of fiducial placed included celiac node (2) AP window node (2) gastrohepatic node (1) and esophagus (2). None of the patients had complications (perforation or infection) within two months of placement. 100% of fiducials attempted were appropriately placed in target site. In all patients (2) with available pretreatment CT scans, 100% of fiducials placed were easily identifiable. Conclusion: A standard 22G FNA needle is effective in directing fiducials into endoscopically accessible malignant nodes and esophageal cancer. This technique is feasible and safe and can be of benefit in mapping tumor extent for radiotherapy.

Development of a Prototype Trocar for Translumenal Therapeutic Interventions Using EUS

Introduction: For EUS-guided therapeutic interventions such as pancreatic pseudocyst drainages, current techniques rely on the use of a 19 gauge FNA needle to gain initial access across the GI lumen. However, advancement of catheter-based devices through the incision created by these needles is technically difficult thereby necessitating progressive dilation of the lumenal wall prior to undertaking endotherapy. The EUS 2008 Working Group recommended development of specific devices to facilitate easy endotherapy. An echoendoscope-compatible prototype 19 gauge trocar was designed to create a tissue puncture, significantly larger than its own profile, to facilitate easier passage of larger catheter-based devices for one-step endotherapy. Aim: This study compared a standard 19 gauge FNA needle to three versions of a prototype (“Extending Blade”) trocar based on: (1) the force required to puncture porcine GI lumenal tissue, and (2) the force required to subsequently pass large caliber catheters through the resulting puncture site. Methods: Ex-vivo porcine stomachs were used to compare puncture forces of a 19 gauge EUS-FNA needle with 1, 2 and 3-blade versions of the prototype trocar passed via the biopsy channel of an echoendoscope. Subsequently, the force required to pass a 2.2 mm dilating catheter and a 6mm balloon catheter through the punctures created by the FNA needle and prototype trocars were compared. Results: The force required for initial puncture of the tissue using all three prototype trocars was equal to that applied using a 19 gauge FNA needle. The force required to advance the 2.2 mm dilating catheter through the tissue punctured using the prototype trocars was 8 times (range, 6-11) less than the force required to advance them via the 19 gauge needle puncture site. Also, the force required to advance the 6mm balloon catheter through the tissue punctured by the prototype trocars was 9 times (range 7-11) less than the force required to advance them via the 19 gauge needle puncture site. Conclusion: Initial access created by the echoendoscope compatible prototype trocar obviates the need for progressive dilation of the GI lumenal wall and could potentially facilitate easier one-step translumenal endotherapy.

Endoscopic Ultrasonography (EUS) Strain Ratio (SR-EUS) vs. Contrast-Enhanced EUS (CE-EUS) for the Diagnosis of Focal Pancreatic Solid Lesions

Background: There are many difficulties in the differential diagnosis between pancreatic cancer and chronic pancreatitis despite recent progress. As a means of trying to overcome this in the endossonography field, the measurement of the tissue stiffness (elastography) by new image processors and the use of contrast agent to enhance the color Doppler pattern have been introduced. Aims: Our aim is to compare prospectively the ability of the SR-EUS and CE-EUS to differentiate between benign and malignant focal pancreatic lesions. Methods: Thirty-eight patients with a focal pancreatic lesion were included to date. EUS procedures were performed with linear-array echoendoscopes (FG36X or EG38UT, Pentax), an ultrasound platform (Hitachi 7500 or 8500) with an integrated elastography module. In order to obtain the SR-EUS, a circular area is adjusted to the focal lesion and a second one is adjusted to the surrounding tissue. The SR-EUS (focal lesion area strain % / surrounding tissue area strain %) is calculated. After elastography, SonoVue® 2.4 mL (Bracco) was injected intravenously at a rate of 1 ml/sec, following a flash of 10mL saline solution. The pattern of enhancement (hypo or hypervascular) was defined using power Doppler mode. EUS-FNA was performed by using a 22-gauge FNA needle (Echotip, Cook Endoscopy,). The final diagnosis was based on the histological assessment of the EUS-FNA samples and/or surgical specimens when available. A positive cytological diagnosis was taken as a final proof of malignancy. For negative cytological specimens, the diagnosis was confirmed by surgery or follow-up of at least six months. Results: The study population comprised 21 (55%) men, mean age 62±16 years, with 12 (32%) benign and 26 (68%) malignant pancreatic lesions. Univariate analysis determined that the variables associated with malignancy included lesion size, SR-EUS and CE-EUS (Table). Logistic regression analysis determined that hypovascular lesions at CE-EUS (odds ratio 6.2 [95% CI, 1.2-32.1], p=0.03) was the only variable independently predictive of malignant pancreatic lesion. Conclusion: In this small group, CE-EUS was superior to SR-EUS for the differentiation between benign and malignant focal pancreatic lesions.

EUS-Guided In Vivo Microdialysis of Pancreas: A Novel Technique of Potential Diagnostic and Therapeutic Application

Background: Microdialysis has been used as an in vivo research and clinical diagnostic tool in diverse organs to to measure dynamic temporal variations in the extracellular or interstitial concentration of non-protein-bound substance which is undetectable or unstable in the systemic circulation. Thus, we undertook a pre-clinical study to test the technical feasibility of in vivo pancreatic microdialysis with a specially developed microdialysis probe to be inserted into the pancreatic parenchyma through a EUS-guided FNA needle. Methods: Eight beagle dogs were used. Echoendoscope was inserted into the dog stomach under anesthesia. With the scanning plane displaying the pancreas, a 19-gauge needle was punctured into the pancreatic parenchyma. The microdialysis probe (membrane length, 3mm; whole length, 2m; outer diameter, 0.22mm, Fig.) was threaded through the lumen of the 19-gauge puncture needle and probe tip was protruded about 5mm that had been set in advance. The probe was constantly perfused with saline at a flow rate of 1.0 μl/min via the inlet tube and the dialysate in the outlet tube was allowed to drain into 1ml polypropylene vials before and after a single bouls intravenous infusion (20mg/kg) of 5-fluorouracil (5-FU). 5-FU concentration in microdialysates were measured serially every 10 minutes. Results. Microdialysis was unsuccessful in two dogs because the probe tips were broken while insertion into pancreatic parenchyma. In the other six dogs, the concentration of 5-FU in all samples after infusion of 5-FU could be measured as more than 100 folds of the cut-off value. The concentration of 5-FU in the microdialysate increased rapidly and peaked within 10 min (13.9 μg/ml). The peak was followed by a gradual decline. No local bleeding or abnormal fluid collections were observed around the pancreas. Conclusion. EUS-guided pancreatic microdialysis is feasible and has multiple potential clinical applications such as focal pharmocokinetics and detecting new biomarkers of pancreatic carcinomas.