Gastrointestinal miniprobe sonography: the current status

Utilizing a balloon sheath and miniprobe for diagnostic endoscopic ultrasound in eosinophilic esophagitis: a case series

BACKGROUND

Endoscopic ultrasound (EUS) is a unique example of POCUS, which allows the gastroenterologist to discuss subepithelial pathology immediately after an endoscopy. The challenges that are encountered to create an acoustic interface by adding free water during the endoscopy may be curtailing the full utilization of EUS during endoscopic procedures. Eosinophilic esophagitis (EoE) is a progressive inflammatory condition whose morbidity is related to esophageal wall remodeling. However, in clinical practice, in clinical guidelines, and in many trials, EoE outcomes are based on esophageal eosinophilia and symptoms. Hence, a method to identify and quantitate the thickening of the esophageal wall, could contribute to the management of this disease.

RESULTS

A modification of the approach employed to perform EUS during bronchoscopy was developed. An EUS miniprobe was positioned inside of a water filled balloon sheath. This technique permitted rapid and reproducible images acquisition of the total esophageal wall and its sublayers (mucosa, and submucosa + submucosa, which permitted derivation of the muscle layer). The presented series describes the results from  22 consecutive EoE patients. A full set of measurements from both the mid and distal esophagus were achieved in all EoE patients in an average time of less than 10 minutes.

CONCLUSIONS

This pilot study supports further investigations evaluating this economical, convenient, and safe technique to follow EoE patients. In addition, this approach could be potentially employed in all patients who are found to have subepithelial gastrointestinal pathology during routine endoscopic procedures.

Basic Principles and Role of Endoscopic Ultrasound in Diagnosis and Differentiation of Pancreatic Cancer from Other Pancreatic Lesions: A Comprehensive Review of Endoscopic Ultrasound for Pancreatic Cancer

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide. Pancreatic lesions consist of both neoplastic and non-neoplastic lesions and often pose a diagnostic and therapeutic challenge due to similar clinical and radiological features. In recent years, pancreatic lesions have been discovered more frequently as incidental findings due to the increased utilization and widespread availability of abdominal cross-sectional imaging. Therefore, it becomes imperative to establish an early and appropriate diagnosis with meticulous differentiation in an attempt to balance unnecessary treatment of benign pancreatic lesions and missing the opportunity for early intervention in malignant lesions. Endoscopic ultrasound (EUS) has become an important diagnostic modality for the identification and risk stratification of pancreatic lesions due to its ability to provide detailed imaging and acquisition of tissue samples for analysis with the help of fine-needle aspiration/biopsy. The recent development of EUS-based technology, including contrast-enhanced endoscopic ultrasound, real-time elastography-endoscopic ultrasound, miniature probe ultrasound, confocal laser endomicroscopy, and the application of artificial intelligence has significantly augmented the diagnostic accuracy of EUS as it enables better evaluation of the number, location, dimension, wall thickness, and contents of these lesions. This article provides a comprehensive overview of the role of the different types of EUS available for the diagnosis and differentiation of pancreatic cancer from other pancreatic lesions while discussing their key strengths and important limitations.

The Use of Endoscopic Ultrasonography in Inflammatory Bowel Disease: A Review of the Literature

The diagnosis of inflammatory bowel disease (IBD) can sometimes be challenging. By corroborating clinical, imaging and histological data, the two main entities of IBD, ulcerative colitis and Crohn's disease (CD), can be differentiated in most cases. However, there remains 10-20% of patients where the diagnosis cannot be accurately established, in which case the term "IBD unclassified" is used. The imaging techniques most used to evaluate patients with IBD include colonoscopy, ultrasonography and magnetic resonance imaging. Endoscopic ultrasonography is mainly recommended for the evaluation of perianal CD. Through this work, we aim to identify other uses of this method in the case of patients with IBD.

Clinical photoacoustic/ultrasound dual-modal imaging: Current status and future trends

Photoacoustic tomography (PAT) is an emerging biomedical imaging modality that combines optical and ultrasonic imaging, providing overlapping fields of view. This hybrid approach allows for a natural integration of PAT and ultrasound (US) imaging in a single platform. Due to the similarities in signal acquisition and processing, the combination of PAT and US imaging creates a new hybrid imaging for novel clinical applications. Over the recent years, particular attention is paid to the development of PAT/US dual-modal systems highlighting mutual benefits in clinical cases, with an aim of substantially improving the specificity and sensitivity for diagnosis of diseases. The demonstrated feasibility and accuracy in these efforts open an avenue of translating PAT/US imaging to practical clinical applications. In this review, the current PAT/US dual-modal imaging systems are discussed in detail, and their promising clinical applications are presented and compared systematically. Finally, this review describes the potential impacts of these combined systems in the coming future.

Miniprobe Endoscopic Sonography for Gastrointestinal Tract Assessment: A Case Series of 1451 Procedures

Conventional endoscopic sonography has allowed precise diagnostics without disturbances, and miniprobes can be easily introduced through the biopsy channel of the endoscope. Miniprobe endoscopic sonography has many benefits compared with conventional endoscopic sonography. Although there are well-known indications for miniprobe endoscopic sonography in endoscopic digestive tract assessment, there is still a need for this method to be widely spread among physicians and commonly used by most endoscopists. The aim of this series was to describe a multicenter retrospective experience with 1451 procedures using miniprobes, presenting examples and the applicability and usefulness of this technology in the daily activities of an endoscopy department.

Photoacoustic endomicroscopy based on a MEMS scanning mirror

In this Letter, we present a high-resolution photoacoustic endomicroscopy probe based on a microelectromechanical systems (MEMS) scanning mirror. The built-in optical assembly consists of a 0.7 mm graded-index (GRIN) lens for light focusing and a ϕ1  mm MEMS mirror to reflect and scan the beam. A miniaturized unfocused ultrasound transducer with a center frequency of 10 MHz is used for photoacoustic detection. Sharp blades, carbon fibers, and black tapes were utilized to evaluate the performance of the system. In vivo mouse ears and resected rectums were imaged to further demonstrate the feasibility of this probe for potential biological and clinical applications.

Intraductal Ultrasonography without Radiocontrast Cholangiogramin Patients with Extrahepatic Biliary Disease

BACKGROUND/AIMS

Intraductal ultrasonography (IDUS) has been performed as an adjunct to endoscopic retrograde cholangiography (ERC) during radiocontrast cholangiography (RC). Radiation exposure during RC poses a health risk to both patients and examiners. We evaluated the feasibility of IDUS without RC in various extrahepatic biliary diseases.

METHODS

IDUS was performed with the insertion of an IDUS probe from the papilla of Vater to the confluent portion of the common hepatic duct without fluoroscopy. The technical success rate and procedure-related complications were evaluated retrospectively.

RESULTS

Wire-guided IDUS without RC was performed in 105 patients. The mean age was 66.5 years, and 50 (47.6%) were male. The IDUS diagnoses included choledocholithiasis (73, 69.5%), benign biliary stricture (11, 10.5%), choledocholithiasis with biliary pancreatitis (9, 8.6%), bile duct cancer (5, 4.8%), pancreatic cancer (1, 0.9%), and others (6, 5.7%). After IDUS, 66 (62.8%) underwent stone removal, 19 (18.1%) underwent biliary drainage, and 7 (6.6%) underwent brush cytology and biopsy. No significant complications such as perforation or severe pancreatitis occurred.

CONCLUSIONS

IDUS without RC was a feasible and safe approach in patients with various extrahepatic biliary diseases. We anticipate a potentially important role of IDUS in various ERC procedures because it lacks the hazards of RC.

Role of endoscopic ultrasonography in the loco-regional staging of patients with rectal cancer

The prognosis of rectal cancer (RC) is strictly related to both T and N stage of the disease at the time of diagnosis. RC staging is crucial for choosing the best multimodal therapy: patients with high risk locally advanced RC (LARC) undergo surgery after neoadjuvant chemotherapy and radiotherapy (NAT); those with low risk LARC are operated on after a preoperative short-course radiation therapy; finally, surgery alone is recommended only for early RC. Several imaging methods are used for staging patients with RC: computerized tomography, magnetic resonance imaging, positron emission tomography, and endoscopic ultrasound (EUS). EUS is highly accurate for the loco-regional staging of RC, since it is capable to evaluate precisely the mural infiltration of the tumor (T), especially in early RC. On the other hand, EUS is less accurate in restaging RC after NAT and before surgery. Finally, EUS is indicated for follow-up of patients operated on for RC, where there is a need for the surveillance of the anastomosis. The aim of this review is to highlight the impact of EUS on the management of patients with RC, evaluating its role in both preoperative staging and follow-up of patients after surgery.

Catheter-based photoacoustic endoscope

We report a flexible shaft-based mechanical scanning photoacoustic endoscopy (PAE) system that can be potentially used for imaging the human gastrointestinal tract via the instrument channel of a clinical video endoscope. The development of such a catheter endoscope has been an important challenge to realize the technique's benefits in clinical settings. We successfully implemented a prototype PAE system that has a 3.2-mm diameter and 2.5-m long catheter section. As the instrument's flexible shaft and scanning tip are fully encapsulated in a plastic catheter, it easily fits within the 3.7-mm diameter instrument channel of a clinical video endoscope. Here, we demonstrate the intra-instrument channel workability and in vivo animal imaging capability of the PAE system.

Endoscopic papillectomy: Indications, techniques, and results

Endoscopic papillectomy (EP) is currently accepted as a viable alternative therapy to surgery in sporadic ampullary adenoma and has been reported to have high success and low recurrence rates. At present, the indications for EP are not yet fully established. The accepted criteria for EP include size (up to 5 cm), no evidence of intraductal growth, and no evidence of malignancy on endoscopic findings (ulceration, friability, and spontaneous bleeding). Endoscopic ultrasound (EUS) is the imaging modality of choice for local T staging in ampullary neoplasms. Data reported in the literature have revealed that linear EUS is superior to helical computed tomography in the preoperative assessment of tumor size, detection of regional nodal metastases and detection of major vascular invasion. Endoscopic ampullectomy is performed using a standard duodenoscope in a similar manner to snare polypectomy of a mucosal lesion. There is no standardization of the equipment or technique and broad EP methods are described. Endoscopic ampullectomy is considered a ‘‘high-risk’’ procedure due to complications. Complications of endoscopic papillectomy can be classified as early (pancreatitis, bleeding, perforation, and cholangitis) and late (papillary stenosis) complications. The appropriate use of stenting after ampullectomy may prevent post-procedural pancreatitis and papillary stenosis. Tumor recurrence of benign lesions occurs in up to 20% of patients and depends on tumor size, final histology, presence of intraductal tumor, coexisting familial adenomatous polyposis (FAP), and the expertise of the endoscopist. Recurrent lesions are usually benign and most can be retreated endoscopically.

A 2.5-mm diameter probe for photoacoustic and ultrasonic endoscopy

We have created a 2.5-mm outer diameter integrated photo-acoustic and ultrasonic mini-probe which can be inserted into a standard video endoscope's instrument channel. A small-diameter focused ultrasonic transducer made of PMN-PT provides adequate signal sensitivity, and enables miniaturization of the probe. Additionally, this new endoscopic probe utilizes the same scanning mirror and micromotor-based built-in actuator described in our previous reports; however, the length of the rigid distal section of the new probe has been further reduced to ~35 mm. This paper describes the technical details of the mini-probe and presents experimental results that both quantify the imaging performance and demonstrate its in vivo imaging capability, which suggests that it could work as a mini-probe for certain clinical applications.

Progress in the diagnosis of ileocecal lesions

The ileocecal area includes the ileocecal valve, terminal ileum, cecum, appendix, and top ascending colon. Since this area may be affected by pathologic conditions that are either common throughout the gastrointestinal system or exclusive to this area, a great variety of intestinal diseases may arise in this region, making the diagnosis of ileocecal lesions difficult. In clinic, the diagnosis of ileocecal lesions depends on the combination of disease history, clinical features, imaging and endoscopic findings. The development of advanced imaging and endoscopy technology has greatly increased the detection rate of ileocecal lesions. In this review, we discuss the use of imaging and endoscopic examinations for evaluation of ileocecal area to help ensure accurate diagnosis and appropriate treatment.

Usefulness of Intraductal Ultrasonography in the Diagnosis of Cholangiocarcinoma and IgG4-Related Sclerosing Cholangitis

The technique of intraductal ultrasonography (IDUS) of the bile duct with a thin-caliber probe and a ropeway system has provided excellent images of the bile duct and periductal structures and is an easy transpapillary approach. In addition, once the guide wire is inserted into the bile duct, IDUS and transpapillary biopsy after endoscopic retrograde cholangiopancreatography can be performed in a single session. Here, we review the usefulness of IDUS in the diagnosis of cholangiocarcinoma and IgG4-related sclerosing cholangitis.

Endoskopische Papillenresektion: Indikation und Grenzen

<b><i>Hintergrund: </i></b>Adenome der Papilla Vateri sind selten. Prävalenzen von 0,04–0,12% werden beschrieben. Eine maligne Transformation von benignen Adenomen zu Papillenkarzinomen ist möglich und folgt der Adenom-Karzinom-Sequenz. Die meisten Papillenadenome treten sporadisch auf, können jedoch z.B. bei Patienten mit familiärer adenomatöser Polyposis genetisch häufiger vorkommen. <b><i>Methode: </i></b>Es erfolgte eine aktuelle PubMed-Recherche zum Thema endoskopische Papillenresektion. <b><i>Ergebnisse/Schlussfolgerung: </i></b>Eine endoskopische Papillektomie kann bei Adenomen ohne duktale Infiltration durchgeführt werden, während es in Hinblick auf das papilläre Adenokarzinom noch keinen Konsens gibt. Jedoch konnten neuere Studien zeigen, dass Patienten mit hochgradiger intraepithelialer Neoplasie der Papilla Vateri keine lymphovaskuläre Invasion oder Lymphknotenmetastasen aufweisen, sodass eine endoskopische Papillektomie gerechtfertigt erscheint. Da papilläre Adenome in bis zu 30% der Fälle das Risiko für fokale karzinomatöse Areale beherbergen können, sollte jede Papillektomie «en bloc» durchgeführt werden.

Diagnosis and management of ampullary adenoma: The expanding role of endoscopy

Ampullary adenoma is a pre-cancerous lesion arising from the duodenal papilla that is often asymptomatic. It is important to distinguish whether the adenoma is sporadic or arises in the setting of familial adenomatous polyposis as this has important implications with respect to management and surveillance. Multiple modalities are available for staging of these lesions to help guide the most appropriate therapy. Those that are used most commonly include computed tomography, endoscopic ultrasound, and endoscopic retrograde cholangiopancreatography. In recent years, endoscopy has become the primary modality for therapeutic management of the majority of ampullary adenomas. Surgery remains the standard curative procedure for confirmed or suspected adenocarcinoma. This review will provide the framework for the diagnosis and management of ampullary adenomas from the perspective of the practicing gastroenterologist.

Real-time PCR-based analysis of the human bile microRNAome identifies miR-9 as a potential diagnostic biomarker for biliary tract cancer

Biliary tract cancer (BTC) is often difficult to diagnose definitively, even through histological examination. MicroRNAs (miRNAs) regulate a variety of physiological processes. In recent years, it has been suggested that profiles for circulating miRNAs, as well as those for tissue miRNAs, have the potential to be used as diagnostic biomarkers for cancer. The aim of this study was to confirm the existence of miRNAs in human bile and to assess their potential as clinical biomarkers for BTC. We sampled bile from patients who underwent biliary drainage for biliary diseases such as BTC and choledocholithiasis. PCR-based miRNA detection and miRNA cloning were performed to identify bile miRNAs. Using high-throughput real-time PCR-based miRNA microarrays, the expression profiles of 667 miRNAs were compared in patients with malignant disease (n = 9) and age-matched patients with the benign disease choledocholithiasis (n = 9). We subsequently characterized bile miRNAs in terms of stability and localization. Through cloning and using PCR methods, we confirmed that miRNAs exist in bile. Differential analysis of bile miRNAs demonstrated that 10 of the 667 miRNAs were significantly more highly expressed in the malignant group than in the benign group at P<0.0005. Setting the specificity threshold to 100% showed that some miRNAs (miR-9, miR-302c*, miR-199a-3p and miR-222*) had a sensitivity level of 88.9%, and receiver-operating characteristic analysis demonstrated that miR-9 and miR-145* could be useful diagnostic markers for BTC. Moreover, we verified the long-term stability of miRNAs in bile, a characteristic that makes them suitable for diagnostic use in clinical settings. We also confirmed that bile miRNAs are localized to the malignant/benign biliary epithelia. These findings suggest that bile miRNAs could be informative biomarkers for hepatobiliary disease and that some miRNAs, particularly miR-9, may be helpful in the diagnosis and clinical management of BTC.

Anatomic-manometric correlation of the upper esophageal sphincter: a concurrent US and manometry study

BACKGROUND

The pharyngoesophageal segment commonly referred to as the upper esophageal sphincter (UES) generates a high-pressure zone (HPZ) between the pharynx and the esophagus. However, the exact anatomical components of the UES-HPZ remain incompletely determined.

OBJECTIVE

To systematically define the US signature of various components of the pharyngoesophageal junction and to determine how these structures contribute to the development of the UES-HPZ.

DESIGN

Prospective, experimental study.

SETTING

Tertiary Academic Medical Center.

PATIENTS

This study involved 18 healthy volunteers.

INTERVENTION

We studied 5 participants by using a high-frequency US miniprobe (US-MP) and concurrent fluoroscopy and another 13 participants by using the US-MP and concurrent manometry.

MAIN OUTCOME MEASUREMENTS

Relative contribution of various muscles in the UES-HPZ.

RESULTS

Manometrically, the UES-HPZ had a median length of 4.0 cm (range 3.0-4.5 cm). A C-shaped muscle, believed to represent the cricopharyngeus muscle, was observed for a median length of 3.5 cm (range 2.0-4.0 cm). The oval configuration representing the esophageal contribution to the UES was seen in 10 of 13 participants (77%) at the distal HPZ (esophagus to UES transition zone). The flat configuration of the inferior constrictor muscle was noted in 7 of 13 participants (54%) at the proximal HPZ (UES to pharynx transition zone). There were 4 to 5 wall layers versus 3 layers in the distal and proximal HPZ, respectively. The mean (+/- SD) muscle thickness was relatively constant along the length of the UES-HPZ.

LIMITATIONS

Air artifacts in the UES-HPZ.

CONCLUSION

The configuration and layers of the UES-HPZ vary along its length. The upper esophagus is a significant contributor to the distal UES-HPZ.

Large endoscopic mucosal resection for colorectal tumors exceeding 4 cm

AIM: To evaluate the feasibility and the outcome of endoscopic mucosal resection (EMR) for large colorectal tumors exceeding 4 cm (LCRT) undergoing piecemeal resection.

METHODS: From January 2005 to April 2008, 146 digestive tumors larger than 2 cm were removed with the EMR technique in our department. Of these, 34 tumors were larger than 4 cm and piecemeal resection was carried out on 26 colorectal tumors. The mean age of the patients was 71 years. The mean follow-up duration was 12 mo.

RESULTS: LCRTs were located in the rectum, left colon, transverse colon and right colon in 58%, 15%, 4% and 23% of cases, respectively. All were sessile tumors larger than 4 cm with a mean size of 4.9 cm (4-10 cm). According to the Paris classification, 34% of the tumors were type Is, 58% type IIa, 4% type IIb and 4% type IIc. Pathological examination showed tubulous adenoma in 31%, tubulo-villous adenoma in 27%, villous adenoma in 42%, high-grade dysplasia in 38%, in situ carcinoma in 19% of the cases and mucosal carcinoma (m2) in 8% of the cases. The two cases (7.7%) of procedural bleeding that occurred were managed endoscopically and one small perforation was treated with clips. During follow-up, recurrence of the tumor occurred in three patients (12%), three of whom received endoscopic treatment.

CONCLUSION: EMR for tumors larger than 4 cm is a safe and effective procedure that could compete with endoscopic submucosal dissection, despite providing incomplete histological assessment.

Endoscopic ultrasonography can diagnose distal biliary strictures without a mass on computed tomography

AIM: To assess the diagnostic ability of endoscopic ultrasonography (EUS) for evaluating causes of distal biliary strictures shown on endoscopic retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography (MRCP), even without identifiable mass on computed tomography (CT).

METHODS: The diagnostic ability of EUS was retrospectively analyzed and compared with that of routine cytology (RC) and tumor markers in 34 patients with distal biliary strictures detected by ERCP or MRCP at Dokkyo Medical School Hospital from December 2005 to December 2008, without any adjacent mass or eccentric thickening of the bile duct on CT that could cause biliary strictures. Findings considered as benign strictures on EUS included preservation of the normal sonographic layers of the bile duct wall, irrespective of the presence of a mass lesion. Other strictures were considered malignant. Final diagnosis of underlying diseases was made by pathological examination in 18 cases after surgical removal of the samples, and by clinical follow-up for > 10 mo in 16 cases.

RESULTS: Seventeen patients (50%) were finally diagnosed with benign conditions, including 6 “normal” subjects, while 17 patients (50%) were diagnosed with malignant disease. In terms of diagnostic ability, EUS showed 94.1% sensitivity, 82.3% specificity, 84.2% positive predictive value, 93.3% negative predictive value (NPV) and 88.2% accuracy for identifying malignant and benign strictures. EUS was more sensitive than RC (94.1% vs 62.5%, P = 0.039). NPV was also better for EUS than for RC (93.3% vs 57.5%, P = 0.035). In addition, EUS provided significantly higher sensitivity than tumor markers using 100 U/mL as the cutoff level of carbohydrate antigen 19-9 (94.1% vs 53%, P = 0.017). On EUS, biliary stricture that was finally diagnosed as malignant showed as a hypoechoic, irregular mass, with obstruction of the biliary duct and invasion to surrounding tissues.

CONCLUSION: EUS can diagnose biliary strictures caused by malignant tumors that are undetectable on CT. Earlier detection by EUS would provide more therapeutic options for patients with early-stage pancreaticobiliary cancer.

Intraductal ultrasonography (IDUS) for the diagnosis of biliopancreatic diseases

Intraductal ultrasonography (IDUS) is an imaging modality having unique characteristics and suitable for imaging of a narrow ductal cavity, its wall and the neighbouring structures. As IDUS uses high-frequency ultrasound (12-30MHz), its image quality is very high within approximately 2-cm range of radius. The bile duct and the pancreatic duct, therefore, are good targets for the assessment by IDUS. Biliopancreatic IDUS is mainly performed through the papilla of Vater in the same session as endoscopic retrograde cholangiopancreatography (ERCP). Biliary IDUS is possible through the percutaneous transhepatic route as well. Not many comparative studies on biliopancreatic IDUS have been published. Gallbladder IDUS as well as most pancreatic IDUS are still at the level of clinical research. Constant delineation of Oddi's sphincter with the improvement of instruments will expand the use of IDUS for the assessment of the papilla of Vater lesions.

Photoacoustic endoscopy

We have developed photoacoustic endoscopy with a miniaturized imaging probe. A light-guiding optical fiber, an ultrasonic sensor, and a mechanical scanning unit are integrated to enable circumferential sector scanning, which produces B-scan images. Biological tissues, including the gastrointestinal tract of a rat, have been imaged ex vivo or in situ.

Endoscopic approaches to Barrett's oesophagus with high-grade dysplasia/early mucosal cancer

This chapter will review the endoscopic approaches to the management of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer. Factors to consider when evaluating patients for endoscopic management are detailed. Ablation and resection methods for eradication of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer are reviewed. Strategies for combining therapies to achieve safe and effective eradication are discussed. Recommendations for complete eradication of all Barrett's mucosa and follow-up considerations are put forward.

Values of endoscopic ultrasonography for diagnosis and treatment of duodenal protruding lesions

OBJECTIVE

The diagnoses of patients with duodenal protruding lesions are difficult when using conventional examinations such as computed tomography (CT) and conventional endoscope etc. Thus, we investigated the clinical value of endoscopic ultrasonography (EUS) with miniature ultrasonic probes on the diagnosis and treatment of duodenal protruding lesions.

METHODS

Patients with duodenal protruding lesions who were indicated for EUS were examined by EUS with 12 approximately 15 MHz miniature ultrasonic probes and double-cavity electronic endoscope. According to diagnosis of EUS, those patients were indicated for biopsy and treatment received biopsy, endoscopic resection or surgical excision. The postoperative histological results were compared with the preoperative diagnosis of EUS. Those patients without endoscopic resection or surgical excision were periodically followed up with EUS.

RESULTS

A total of 169 patients with duodenal protruding lesions were examined by EUS, of which 40 were diagnosed with cysts, 36 with inflammatory protruding or polyp, 25 with Brunner's gland adenoma, 19 with ectopic pancreas, 17 with gastrointestinal stromal tumor, 12 with extrinsic compression, 12 with minor papilla, 6 with lipoma, 1 with adenocarcinoma and 1 with lymphoma. After EUS examinations, 75 patients received biopsy, endoscopic resection or surgical excision respectively. The postoperative histological results of 70 patients were completely consistent with the preoperative diagnosis of EUS, with 93.33% diagnostic accuracy. The results of follow-up with EUS indicated that duodenal cyst, Brunner's gland adenoma, ectopic pancreas, gastrointestinal stromal tumor and lipoma remained unchanged within 1 approximately 3 years. No related complications occurred among all patients that received EUS examinations.

CONCLUSION

EUS is an effective and reliable diagnostic method for duodenal protruding lesions.

Prospective evaluation of advanced molecular markers and imaging techniques in patients with indeterminate bile duct strictures

BACKGROUND AND AIMS

Standard techniques for evaluating bile duct strictures have poor sensitivity for detection of malignancy. Newer imaging modalities, such as intraductal ultrasound (IDUS), and advanced cytologic techniques, such as digital image analysis (DIA) and fluorescence in situ hybridization (FISH), identify chromosomal abnormalities, and may improve sensitivity while maintaining high specificity. Our aim was to prospectively evaluate the accuracy of these techniques in patients with indeterminate biliary strictures.

METHODS

Cholangiography, routine cytology (RC), intraductal biopsy, DIA, FISH, and IDUS were performed in 86 patients with indeterminate biliary strictures. Patients were stratified based on the presence or absence of primary sclerosing cholangitis (PSC).

RESULTS

RC provided low sensitivity (7-33%) but high specificity (95-100%) for PSC and non-PSC patients. The composite DIA/FISH results (when considering trisomy-7 [Tri-7] as a marker of benign disease) yielded a 100% specificity and increased sensitivity one- to fivefold in PSC patients versus RC, and two- to fivefold in patients without PSC, depending on how suspicious cytology results were interpreted. For the most difficult-to-manage patients with negative cytology and histology who were later proven to have malignancy (N = 21), DIA, FISH, composite DIA/FISH, and IDUS were able to predict malignant diagnoses in 14%, 62%, 67%, and 86%, respectively.

CONCLUSIONS

DIA, FISH, and IDUS enhance the accuracy of standard techniques in evaluation of indeterminate bile duct strictures, allowing diagnosis of malignancy in a substantial number of patients with false-negative cytology and histology. These findings support the routine use of these newer diagnostic modalities in patients with indeterminate biliary strictures.

Imaging in local staging of gastric cancer: a systematic review

PURPOSE

Endoscopic ultrasound (EUS) has been established as the diagnostic modality of choice in local (T) staging of gastric cancer. Multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI) are promising alternatives. The aim of this study was to systematically review the literature regarding the performance of each of these imaging modalities.

METHODS

A systematic search for relevant studies was performed in the PubMed/MEDLINE and EMBASE databases. Two reviewers independently assessed the methodological quality of each study. Local staging performance of included studies was calculated.

RESULTS

Twenty-two EUS studies, five MDCT studies, one combined EUS and MDCT study, and three MRI studies met the inclusion criteria. The studies were of moderate methodological quality. Diagnostic accuracy of overall T staging for EUS, MDCT, and MRI varied between 65% to 92.1%, 77.1% to 88.9%, and 71.4% to 82.6%, respectively. Sensitivity for assessing serosal involvement for EUS, MDCT, and MRI varied between 77.8% to 100%, 82.8% to 100%, and 89.5% to 93.1%, respectively. Specificity for assessing serosal involvement for EUS, MDCT, and MRI varied between 67.9% to 100%, 80% to 96.8%, and 91.4% to 100%, respectively.

CONCLUSION

EUS, MDCT, and MRI achieve similar results in terms of diagnostic accuracy in T staging and in assessing serosal involvement. Most experience has been gained with EUS. Few MDCT studies and even fewer MRI studies are available. Thus, EUS remains the first-choice imaging modality in preoperative T staging of gastric cancer.

[The role of endosonography (EUS) in preoperative staging of patients with stomach cancer]

BACKGROUND

To evaluate the diagnostic accuracy of endosonography (EUS) in preoperative staging of stomach cancer.

METHODS

Sixty-two patients with gastric carcinoma were investigated by endosonography. 49 underwent surgery. EUS reports were compared with operative and histology findings. Tumours were staged according to the 2000. TNM classification.

RESULTS

EUS had a diagnostic accuracy of 89.8% for the T category, 83.7% for the N category.

CONCLUSION

EUS is an excellent clinical procedure for the staging of local-regional spread of gastric cancer and useful complement to the other gastrointestinal examinations for evaluation of these tumours.

Role of endoscopic ultrasonography in the staging and follow-up of esophageal cancer

PURPOSE

To evaluate the role of endoscopic ultrasonography (EUS) in the initial staging and follow-up of esophageal cancer on the basis of a review of the published literature.

METHODS

Articles published from 1985 to 2005 were searched and reviewed using the following keywords: "esophageal cancer staging," "endoscopic ultrasound," and "endoscopic ultrasonography."

RESULTS

For initial anatomic staging, EUS results have consistently shown more than 80% accuracy compared with surgical pathology for depth of tumor invasion (T). Accuracy increased with higher stage, and was >90% for T3 cancer. EUS results have shown accuracy in the range of 75% for initial staging of regional lymph nodes (N). EUS has been invariably more accurate than computed tomography for T and N staging. EUS is limited for staging distant metastases (M), and therefore EUS is usually performed after a body imaging modality such as computed tomography or positron emission tomography. Pathologic staging can be achieved at EUS using fine-needle aspiration (FNA) to obtain cytology from suspect Ns. FNA has had greatest efficacy in confirming celiac axis lymph node metastases with more than 90% accuracy. EUS is inaccurate for staging after radiation and chemotherapy because of inability to distinguish inflammation and fibrosis from residual cancer, but a more than 50% decrease in tumor cross-sectional area or diameter has been found to correlate with treatment response.

CONCLUSION

EUS has a central role in the initial anatomic staging of esophageal cancer because of its high accuracy in determining the extent of locoregional disease. EUS is inaccurate for staging after radiation therapy and chemotherapy, but can be useful in assessing treatment response.

Endoscopic retrograde cholangiopancreatography, intraductal ultrasonography, and magnetic resonance cholangiopancreatography in bile duct strictures: a prospective comparison of imaging diagnostics with histopathological correlation

OBJECTIVES

A variety of imaging techniques are available to diagnose bile duct strictures; the most effective imaging technique, however, has not been established yet. In the present study, we compared the impact of endoscopic retrograde cholangiopancreatography (ERCP), intraductal ultrasonography (IDUS), and magnetic resonance cholangiopancreatography (MRCP) with regard to diagnosing bile duct strictures.

METHODS

We prospectively examined 33 patients with jaundice due to bile duct strictures by ERCP plus IDUS and MRCP. The objectives were to assess diagnostic quality of imaging, complete presentation of the bile duct, and differentiation of malignant from benign lesions. Surgical and histopathological correlations, which were used as the gold standard, were available in all cases since all included patients underwent laparotomy.

RESULTS

Diagnostic image quality for ERCP was 88% and 76% for MRCP (p > 0.05). Comparing ERCP and MRCP, complete presentation of the biliary tract was achieved in 94% and 82%, respectively (p > 0.05). ERCP and MRCP allowed correct differentiation of malignant from benign lesions in 76% and 58% (p= 0.057), respectively. By supplementing ERCP with IDUS, the accuracy of correct differentiation of malignant from benign lesions increased significantly to 88% (p= 0.0047).

CONCLUSIONS

Comparing ERCP with MRCP, we found adequate presentation of bile duct strictures in high imaging quality for both techniques. ERCP supplemented by IDUS gives more reliable and precise information about differentiation of malignant and benign lesions than MRCP alone without additional imaging sequences.

Miniature ultrasonic probes for diagnosis and treatment of digestive tract diseases

AIM: To investigate the clinical value of miniature ultrasonic probes (MUPs) for the diagnosis and treatment of digestive tract diseases.

METHODS: Endoscopic ultrasonography (EUS) was performed for patients with its indications with 7.5-20 MHz MUPs and double-cavity electronic endoscope. According to the diagnosis of MUPs, patients who had indications of treatment received endoscopic resection or surgical excision. Postoperative histological results were compared with the preoperative diagnosis of MUPs. A few patients without endoscopic resection or surgical excision were periodically followed up with MUPs.

RESULTS: A total of 537 patients were examined by MUPs, of them, 256 were diagnosed with gastrointestinal submucosal lesions, 146 with pseudo-submucosal lesions, 50 with digestive tract cancers, 17 with peptic ulcer, 11 with cholecystolithiasis, 8 with chronic pancreatitis, and 2 with achalasia and 47 were diagnosed as normal. After MUPs examinations, 220 patients received endoscopic resection or surgical excision, and the postoperative histological results of 211 patients were completely consistent with the preoperative diagnosis of MUPs. The diagnostic accuracy of MUPs was 95.9%. The result of follow-up with MUPs indicated that gastrointestinal leiomyoma, lipoma, phlebangioma and cyst were unchanged within 1-2 years. The patients who received endoscopic resection or centesis did not have any complications.

CONCLUSION: MUPs are of value in diagnosing gastrointestinal submucosal lesions, staging of digestive tract cancers and biliary-pancreatic diseases. They play a very important role in making therapeutic plans.

Biliary endoscopy

The literature this year contained a number of articles reviewing the different methods of biliary drainage for malignant obstruction, highlighting approaches to unilateral drainage, and stressing the risks of incomplete drainage after contrast injection. A number of articles addressed issues surrounding the differentiation of benign and malignant biliary strictures.

Impact of miniprobe ultrasonography on planning of minimally invasive surgery for gastric and colonic tumors

BACKGROUND

The use of minimally invasive procedures for the management of gastrointestinal cancer is increasing. The aim of this study was to investigate the role of high-frequency miniprobe endoscopic ultrasound (EUS) for therapeutic decisions making in patients with gastric or colonic tumors.

METHODS

A total of 137 patients underwent EUS with a 12.5-MHz miniprobe for preoperative staging of tumors of the stomach ( n = 49) or colon ( n = 88). After resection, the surgical path was reviewed to analyze the role of preoperative staging with miniprobes.

RESULTS

Miniprobe EUS enabled accurate assessment of the infiltration depth of gastric and colonic tumors. The overall accuracy rates were 88% and 87%, respectively. The lymph node status was predicted correctly in 82% of the patients (sensitivity, 61%, specificity, 94%). Based on the results of miniprobe EUS, patients with gastric cancer were accurately selected to undergo endoscopic mucosal resection, laparoscopic resection, or open surgery in 100%, 91%, and 86% of the cases, respectively. In patients with colonic tumors, the treatment decision analysis showed that the stratification was correct in 90% of the patients.

CONCLUSIONS

Miniprobe EUS is a reliable method for validating treatment decisions for patients undergoing minimally invasive procedures for gastric and colonic tumors. This method is particularly valuable in the management of colon cancer, because endoscopic and laparoscopic resections can be offered to selected patients as an alternative to open surgery.

[Diagnosis of biliary tract carcinoma]

There are several diagnostic tools available in the diagnosis of bile duct cancer. Tumors of the middle and distal part of the extrahepatic bile duct are accessible to endosonography. Endoscopic retrograde cholangiopancreatography (ERC) and percutaneous transhepatic cholangiography (PTC) are the most invasive procedures for diagnosis of bile duct cancer. However, they offer the opportunity to obtain material for cytological or histological investigation. Moreover, bile flow can be assured by inserting endoprostheses during the procedure. Cholangioscopy and/or intraductal ultrasonography can be performed during ERC. They confer to the diagnosis of a malignant bile duct tumor and are the most accurate methods to diagnose the extent of longitudinal spread. Magnetic resonance imaging-cholangiography is an efficient diagnostic procedure which should be used first, if the bile duct tumor is located in the hilar region.

ENDOSCOPIC ULTRASOUND INSTRUMENTATION, APPLICATIONS IN HUMANS, AND POTENTIAL VETERINARY APPLICATIONS

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.

Innovative methods of biliary tract diagnosis: intraductal ultrasound and tissue acquisition

Tissue can be acquired from the bile and pancreatic duct with either brush cytology or biopsy forceps, often without the need for sphincterotomy. Although the diagnosis of malignancy with these sampling techniques is often specific, the sensitivity is limited, and a wide range of diagnostic accuracies has been reported. A combination of biopsy and brush cytology along with some newer techniques in the development stage may increase the sensitivity. Intraductal ultrasound is a newer technique offers the endoscopist the ability to image the bile and pancreatic duct wall, adjacent organs, and vascular structures with a high degree of detail. This visualization can be accomplished during the course of an ERCP or percutaneously under fluoroscopic guidance. Indications for the procedure include detection of choledocholithiasis, differentiation of benign and malignant ductal strictures, pancreaticobiliary tumor staging, and detection of various pancreatic tumors. Continued research into the design of the probes, which could improve durability and extend the depth of penetration, may promote more widespread use of this novel technology.

Endoscopically inserted endoluminal receiver coil for high-resolution magnetic resonance imaging of the pancreas: Initial results in an animal model

BACKGROUND

This study assessed the feasibility of high-resolution magnetic resonance imaging of the pancreas by means of an endoscopically inserted endoluminal magnetic resonance receiver coil.

METHOD

A 0.032-inch diameter internal magnetic resonance imaging receiver coil was endoscopically inserted into the pancreatic duct in 4 pigs through the accessory channel of a standard duodenoscope to obtain high-resolution magnetic resonance images by using T1- and T2-weighted sequences.

RESULTS

The pig anatomy precluded the usual transoral approach; however, transgastric access allowed endoscopic transpapillary insertion of a receiver coil into the pancreatic duct in all animals without the need for sphincterotomy. The small swine pancreas could then be visualized by magnetic resonance imaging with a 0.3 x 0.3-mm in-plane resolution.

CONCLUSION

High-resolution pancreas magnetic resonance imaging is feasible by using an endoscopically inserted endoluminal receiver coil. The smaller stomach and larger pancreatic duct diameter in humans will facilitate clinical application of the imaging procedure.

Evaluation of indeterminate bile duct strictures by intraductal US

BACKGROUND

Cholangiography and tissue sampling (brush cytology, biopsy) are the standard nonsurgical techniques for determining whether a bile duct stricture is benign or malignant. The aim of this study was to determine whether intraductal US is of assistance in distinguishing benign from malignant biliary strictures.

METHODS

A retrospective review was undertaken of 30 patients with indeterminate bile duct strictures who underwent ERCP and tissue sampling from September 1999 to November 2000. A 20 MHz over-the-guidewire intraductal US catheter probe was used during ERCP for further examination of the strictures. Final diagnoses of malignant strictures (18 patients) were confirmed histopathologically; confirmation of benign stricture (12 patients) was based on negative tissue sampling plus extended clinical follow-up.

RESULTS

Based on retrospective blinded review, the diagnosis by ERCP was correct in 67% of patients, by tissue sampling in 68%, by combined ERCP/tissue sampling in 67%, and by intraductal US in 90% (p = 0.04 vs. ERCP/tissue sampling) of cases. No complication of intraductal US or ERCP was recorded.

CONCLUSIONS

Intraductal US is safe and can improve on the ability at ERCP to distinguish benign from malignant biliary strictures.

Food allergy and intolerance: response to intestinal provocation monitored by endosonography

OBJECTIVE

Objective assessment of adverse reactions to food is a long-felt want. We report our preliminary experience with a new endosonographic allergen provocation test.

METHODS

Twenty patients were examined, seven patients having food allergy and 13 having food intolerance. The duodenal mucosa was challenged with allergen extracts via a nasoduodenal tube. The responses were recorded using a miniprobe for endosonography through the tube. Thereafter, intestinal lavage was performed by giving 2 l PEG solution containing micro Ci (51)CrEDTA. The gut lavage fluid and urine for 5 h were collected.

RESULTS

Increased mucosal thickness in response to provocation was recorded in 11 patients, but not more often or pronounced in the allergic than in the intolerance group. Interestingly, increased mucosal thickness associated with a new echogenic layer was seen in two patients and a sustained duodenal contraction, lasting 15-20 min associated with pain, in another two. Intestinal permeability and inflammatory mediators were not significantly different in the two groups.

CONCLUSION

In patients with self-reported adverse reactions to food abnormal responses to duodenal provocation may be recognised by endosonography. However, neither endosonography nor intestinal permeability or faecal calprotectin responses were able to distinguish between food allergy and intolerance. Sustained duodenal contractions in response to food might be a cause of abdominal pain.

Subepithelial masses of the gastrointestinal tract evaluated by endoscopic ultrasonography

OBJECTIVES

To diagnose and characterize subepithelial lesions of the gastrointestinal (GI) tract using endoscopic ultrasonography (EUS) and search for markers of malignancy in stromal cell tumors.

METHODS

Fifty-four patients with suspected subepithelial lesions at endoscopy were examined using miniature ultrasound probes, integrated ultrasound endoscopes, or both. Surgical treatment was considered if a solid lesion had a maximum diameter of at least 3 cm, mixed echogenicity, or an ill-defined or irregular border.

RESULTS

EUS disclosed 37 solid lesions and ten fluid-filled structures. In seven patients, including two with protrusion from a normal spleen, no pathology could be demonstrated. Thirteen patients were operated and 41 were observed clinically with (n = 9) or without EUS (n = 32) for a median follow-up period of 36 months. Twenty-three patients had an intramural stromal cell tumor. None of these were malignant, but increased mitotic activity was found in two medium-sized resected tumors with mixed echogenicity and bleeding lesions of the endoluminal surface.

CONCLUSION

EUS can detect and characterize subepithelial masses in the GI tract. Pathologic lesions of the overlying mucosa may indicate malignant development in stromal cell tumors, but valid markers of malignant potential are still lacking.

Intraductal ultrasound in the biliary tract

Although endoscopic ultrasonography (EUS) represents a major advance in endoscopic imaging, endosonography using dedicated echoendoscopes has some serious drawbacks, including the diameter of the echoendoscope (12 to 13 mm), the lack of intraluminal examination of the pancreatobiliary duct system due to the size of the instrument, unsatisfactory image quality and resolution for small lesions, and the need for a second examination separate from the previous routine endoscopy. Recently developed ultrasonographic miniprobes (diameter, about 2 mm; frequency, 12 to 20 MHz) can be passed through the working channel of standard endoscopes to provide high-frequency ultrasound images. These miniprobes may overcome some of the noted drawbacks and add to the safety and convenience of patients. Moreover, in various diseases of the gastrointestinal tract and the pancreatobiliary ductal system, the diagnostic accuracy of miniprobe ultrasonography has been proven to be superior to that of EUS. Miniprobe ultrasonography is a promising tool that adds new capabilities to the armamentarium of gastroenterologic diagnostic assessment.

Role of endoscopy in the staging of esophageal and gastric cancer

Progress in instrumentation and clinical research continues to expand the potential utility of endoscopic ultrasound (EUS) in the treatment of esophageal and gastric cancer. This review focuses on the role of EUS in the staging and treatment planning of patients with esophageal and gastric cancer.