CLINICAL USE OF THE NEWLY DEVELOPED ELECTRONIC RADIAL ULTRASOUND ENDOSCOPE

Background: Endoscopic ultrasonography (EUS) is widely accepted as a diagnostic tool for bilio‐pancreatic and gastrointestinal tract diseases. Recently, an ultrasound endoscope with an electronic radial scan transducer has been developed. To evaluate the clinical usefulness of this system, its image quality, advantages and disadvantages were evaluated. Materials and methods: Ultrasound endoscope with electronic radial scan transducer and its monitor unit were used. The direction of the imaging plane was similar to that of the mechanical radial models. Color Doppler function and tissue harmonic imaging were feasible by this system. To evaluate this endoscope, we investigated the image quality and distance resolution by in‐vitro study using thin papers, and 50 patients were examined by this system. Results: Comparison with the mechanical radial endoscope GF‐UM2000 revealed that the image quality was almost equivalent. However, the ultrasound penetration of the electronic radial scanner was better and more satisfactory with less echoic reduction. In addition, the blood‐flow signal could be obtained by using the color Doppler function. In contrast, the diameter of the new endoscope was bigger than the advanced mechanical radial models, the monitor unit was bigger than that of the mechanical radial system, and the operation of this unit was complicated. Conclusion: A prototype of the ultrasound endoscope with electronic radial scan showed satisfactory results regarding the image quality, ultrasound penetration, and clinical diagnosis. The blood flow could be investigated by using the color Doppler function, which is useful to diagnose lesions and detect involvement of the blood vessels in cancers.     

CLINICAL USEFULNESS OF NEWLY DEVELOPED ELECTRONIC 360° RADIAL ENDOSCOPIC ULTRASONOGRAPHY

After the development of the mechanical radial scanning echoendoscope by Olympus Medical Systems (Tokyo, Japan), endoscopic ultrasonography (EUS) has become an indispensable examination in the clinical fields. Although mechanical radial EUS has no Doppler function because of its scanning method, Olympus Medical Systems developed a new electronic 360° radial EUS in 2003. Newly developed electronic radial EUS provides better penetration, fewer artifacts, color Doppler and power Doppler function, and tissue harmonic imaging. Its maneuverability is nearly the same as conventional mechanical radial EUS. With Doppler function it is easy to differentiate solid tumors such as pancreatic cancer, islet tumor etc., and to diagnose vascular invasion. Although there are some problems, electronic radial EUS has a promising future and it is believed that electronic radial EUS will become the standard model for the next generation of EUS equipment in imaging diagnosis.     

ELECTRONIC RADIAL ULTRASOUND ENDOSCOPE

Examination with a radial echoendoscope is an important part of endoscopic ultrasonography. Mechanical radial systems have been used since the initiation of endoscopic ultrasound (EUS) but a new generation of electronic array radial echoendoscopes offers some potential advantages. The lack of moving parts should improve the reliability and durability of the echoendoscope and with the electronic array, Doppler functions are possible. To date, however, no studies have conuincingly shown that the images are of superior quality or that diagnosis is improved with the electronic array systems versus the mechanical sector scanning echoendoscopes.     

Initial experience with an electronic radial array echoendoscope: randomized comparison with a mechanical sector scanning echoendoscope in humans

BACKGROUND: An electronic radial array echoendoscope has been developed that uses the same US processor as the linear array instruments made by the same company, thereby eliminating the need for two processors. The performance of this prototype instrument was compared with that of a mechanical radial echoendoscope in patients. METHODS: Fourteen patients underwent sequential examinations with both echoendoscopes in random order. Predefined criteria were used to evaluate the performance of each instrument. RESULTS: The quality of the electronic radial image was rated as "good" or "superior" to that of the mechanical radial echoendoscope in 12 patients. In 2 patients, imaging with the prototype was inferior because of positioning and/or operator inexperience. The forward-viewing optics of the prototype enhanced intubation and instrument advancement. Limitations included excessive stiffness of the tip of the instrument that resulted in occasional slippage from the duodenum. The prototype provided an adequate diagnosis in 12 patients and was superior to the mechanical radial endoscope in terms of diagnosis in 2 cases. CONCLUSION: The prototype electronic radial echoendoscope provides US images of similar quality and is equivalent in terms of clinical utility to the mechanical radial echoendoscope.     

A NEWLY DEVELOPED ELECTRONIC 360° RADIAL SCANNING ECHOENDOSCOPE

Background: Development of an electronic radial scanning echoendoscope has been anticipated, because radial scanning images readily demonstrate features of anatomy while electronic scanning provides information about blood flow. Here we present images obtained with a newly developed 360° radial scanning electronic echoendoscope and consider its utility. Methods: Using an electronic radial scanning echoendoscope, developed in 2003, the XGF‐UE240‐AL5, B‐mode images were obtained at 5, 6, 7.5, and 10 MHz, while tissue harmonic images at 3.75 and 5 MHz; color Doppler and power Doppler functions also were used. Images obtained by the new echoendoscope were compared with those obtained by a conventional echoendoscope. We performed contrast‐enhanced endoscopic ultrasonography (EUS) with a galactose‐based contrast agent in patients with pancreatobiliary diseases. Results: Images at all frequencies and with the Doppler mode were excellent, being more clear than images obtained with a mechanical radial echoendoscope. Gastric wall structure, cystic areas, and tumor contours were visualized more clearly at 3.5 and 5 MHz by tissue harmonic imaging than by mechanical radial scanning echoendoscope, or by ordinary imaging with the electronic radial scanning echoendoscope. Contrast‐enhanced EUS should be helpful in hemodynamic analysis of gastrointestinal tumors. Conclusions: The electronic radial echoendoscope provides improved images and is highly useful for detailed diagnosis of digestive diseases.     

A New Method for Measurement of Gastric and Colonic Lesions with an Electronic Endoscope and Image Processor

In order to measure the sizes of gastric and colonic lesions endoscopically, we established a system composed of an electronic endoscope, image processor, and personal computer. The long and short diameter of the lesion were calculated by a program which corrected the curvature radius of the lens of the endoscope and variables. 1) To evaluate its accuracy, we measured a 10 mm scale spherical model at different distances from the lens of the endoscope. The mean value was 9.7 mm, ranging from 9.0 to 10.9 mm. The rate of error was –0.38±4.4 % (mean±SE). 2) Using this system, we measured the sizes of 34 gastric and colonic lesions in 34 patients (3 with gastric cancers, 20 with gastric polyps, and 11 with colonic polyps), and compared them with the real sizes of the resected or polypectomized specimens. The rate of error was–1.1±1.3% (mean±SE). The results showed that our system was useful to evaluate the accurate sizes of gastric and colonic lesions endoscopically.     

Comparison of image quality between electronic and mechanical radial scanning echoendoscopes in pancreatic diseases

BACKGROUND AND AIM: It is common knowledge that endoscopic ultrasonography (EUS) can accurately diagnose pancreatic diseases. Echoendoscopes for EUS are roughly classified into two categories, the mechanical radial scanning echoendoscope (MR-ES) and the electronic linear array echoendoscope, both of which have their merits and demerits. In 2000, a newly designed echoendoscope, the electronic radial scanning echoendoscope (ER-ES), appeared. The aim of the present study was to compare B-mode image quality between the ER-ES and the MR-ES in pancreatic diseases. METHODS: Patients with pancreatic diseases (30 cystic diseases and 22 solid diseases) underwent EUS with both ER-ES and MR-ES. The B-mode images obtained using both echoendoscopes were graded using a scoring system and statistically analyzed. The assessed point for cystic lesions was the existence of mechanical-noise-like ring-like artifacts derived using multiple reflections ('ring-down'), grating robe and so on, and that for solid lesions was the scale of penetration. The authors compared maneuverability, endurance and endoscopic images between the two types of echoendoscopes. RESULTS: The ER-ES had a significantly higher score than the MR-ES (P < 0.05) in the analysis of both cystic and solid diseases. There was no apparent difference as to maneuverability, endurance and endoscopic images. CONCLUSION: Ultrasound images acquired by ER-ES appear better compared with those acquired by MR-ES.     

Magnifying Observation of Ectopic Gastric Mucosa of the Cervical Esophagus

We attempted to investigate the fine mucosal patterns of inlet patches using a transparent-tip-hood-fitted magnifying electronic endoscope (Olympus, GIF-200Z). The prevalence of inlet patch was 10.1%, 26 out of 257 patients undergoing screening endoscopic examination using a GIF-200Z. This rate was higher than that of previous reports in Japan, higher in the young group than in the aged group, and higher in males than in females. The mean inlet patch size, measured by the new method using a transparent hood, was 5.2 mm. Large inlet patches, above 8.1 mm, were found more frequently in males than in females. The number of inlet patches in one patient was one in 19 patients and two in seven. The inlet patches were oval and had a smooth margin in 23 (69.7%) cases, and irregular in 10 (30.3%). The oval patches with smooth margins were significantly larger than those with an irregular form. The fine mucosal pattern of inlet patches was mixed with B, BC and C type. Inlet patches with acid production were suggested to be fewer in number than expected, and patients with an inlet patch appear to have minimal, if any, complaints. A transparent-tip-hood-fitted magnifying electronic endoscope was thought to facilitate accurate diagnosis of the inlet patch.     

Development of magnifying video endoscopes with high resolution

Background: The diagnostic capability of a video‐endoscope has been remarkably enhanced by using a high pixel count charge‐coupled device (CCD) and is getting closer to that of the stereomicroscope as its image quality is improved. From this standpoint, the authors have been developing high‐resolution magnifying video‐endoscopes. Methods: There are two methods available to increase the resolution of a video‐endoscope: (i) use a CCD with large pixel number and (ii) optically magnify the image impinging on the CCD. Since the video‐endoscope using a 410 Kilo (K) pixel count CCD was introduced in 1993, the authors have been developing a video‐endoscope using a large pixel count number CCD in pursuit of obtaining better image quality and resolution. Also, the technological innovations in CCD manufacturing have allowed CCDs to become much smaller in size with higher pixel numbers. As the CCD size decreases, the distal part of a video‐endoscope can be made thinner. With respect to optical magnification, two methods are available, the fixed close‐focusing system and variable focus. Results: With combined use of the variable focus magnification and the electronic magnification, a magnification more than × 100 can be achieved on a 14″ television monitor with higher resolution power and wider depth of field. Conclusions: The images captured by the latest magnifying video‐endoscope prove that the image quality of video‐endoscopy is improving and is approaching the diagnostic capability of the stereomicroscope.     

An Attempt to Analyze Color Wavelengths with an Electronic Endoscope

We attempted to measure the dominant wavelengths of gastric mucosal lesions and to extract and present color differences of the lesions in image form, by converting spectroscopic visual signals (composed of red, green and blue components) obtained from an electronic endoscope into digital color files. The dominant wavelength, as measured from signals input without gamma correction, was significantly shorter in gastric mucosa affected by atrophic gastritis and type lie early gastric cancer than in normal mucosa. This analysis revealed a significant difference in dominant wavelengths between the endoscopically normal mucosa of the stomach and that found to have been affected by early gastric carcinoma and atrophic gastritis. Color difference extraction allowed us to make a morphological characterization of the surface of type lie early gastric cancer, although this was possible in only one case. The results of this study suggest the diagnostic value of digital representation of the mucosal surface features provided by endoscopy. It is suggested that, in the future, analog endoscopic diagnosis will be replaced by digital endoscopic diagnosis and computerized endoscopic diagnosis.     

CONTRAST‐ENHANCED ENDOSCOPIC ULTRASONOGRAPHY IN THE DIAGNOSIS OF PANCREATO‐BILIARY DISEASES

In diagnostic imaging, techniques represented by computed tomography (CT) and magnetic resonance imaging (MRI), diagnosis by evaluation of plain images in combination with contrast‐enhanced images is considered important. Recently, the ultrasound contrast media that can be administered from peripheral veins have been developed, and their utility is reported not only for the circulatory organ area but also the digestive organ area, mainly for liver diseases. As for the pancreato‐biliary diseases, there often are the cases that visualization of the diseases itself is not easy by transabdominal ultrasonography, so, the evaluation of contrast‐enhanced ultrasonography remains difficult. In contrast, endoscopic ultrasonography (EUS) is thought to be one of the most valuable modality for those diseases. The mainstream of an operation method of EUS was mechanical radial type, but in late years, endoscopic ultrasonography of an electronic linear method and an electronic radial method have been developed. Because an electronic scan method was adopted, we get possible to apply technology of color Doppler flow imaging and power Doppler flow imaging and harmonic imaging methods to EUS. We would like to outline the usefulness of contrast‐enhanced color/power Doppler EUS and contrast‐enhanced harmonic EUS, moreover, tissue harmonic imaging and three dimensional imaging, on the basis of our experiences.     

Endoscopic lithotripsy with peroral direct cholangioscopy using a conventional endoscope

Recently,peroral direct cholangioscopy(PDCS) using an ultra-slim endoscope has come into the spotlight.However,the working channel is too small to use various devices for lithotripsy.We report a case of endoscopic lithotripsy with PDCS using a conventional endoscope as a cholangioscope.Computed tomography scan on an 80-year-old female who was admitted with acute cholangitis showed two large stones in the bile duct.Endoscopic retrograde cholangiopancreatography was attempted first.However,mechanical lithotripsy failed because the stone was too large for the basket catheter.Finally,electric hydraulic lithotripsy with PDCS using a conventional endoscope was performed allowed the stones to be cleared completely.In conclusion,PDCS using a conventional endoscope can be an alternative solution for endoscopic lithotripsy for patients with large stones in the dilated bile duct.     

Overview of upcoming advances in colonoscopy

Although colonoscopy is a very commonly carried out procedure, it is not without its problems, including a risk of perforation and significant patient discomfort, especially associated with looping formation. Furthermore, looping formation may prevent a complete colonoscopy from being carried out in certain patients. The conventional colonoscope has not changed very much since its original introduction. We review promising technologies that are being promoted as a way to address the problems with current colonoscopy. There are some methods to prevent looping formation, including overtube, variable stiffness, computer-guided scopes, Aer-O-Scope, magnetic endoscopic imaging and the capsule endoscope. In recent years, with the progress of microelectromechanical and microelectronic technologies, many biomedical and robotic researchers are developing autonomous endoscopes with miniaturization of size and integration functionality that represent state of the art of the micro-robotic endoscope. The initial results by using aforementioned methods seem promising; however, there are some conflicting reports of clinical trials with the overtube colonoscope, the computer-guided scope and the variable stiffness colonoscope. There are also some limitations in the use of the Aer-o-scope and the capsule endoscope. The autonomous endoscope is based on a self-propelling property that is able to avoid looping completely. This novel technology could potentially become the next generation endoscope; however, there are still critical techniques to be approached in order to develop the effective and efficient novel endoscope.     

Distal arteriovenous fistula formation after percutaneous coronary intervention: An old complication of a new access site

Dorsal or distal transradial artery access has recently gained popularity due to several perceived benefits that include favorable ergonomics, the potential for rapid hemostasis and lower rates of vascular complications. Still, no vascular access site is free of complications and reports of hematoma and pseudoaneurysm formation related to distal radial artery access have been reported in the literature. We present a case of a 71-year-old male who developed an arteriovenous fistula (AVF) involving the distal left radial artery following repeated access of the artery. This rare complication is likely avoidable with a comprehensive understanding of the surrounding anatomy and proper procedural technique, including the routine use of ultrasound for access.     

内镜止血联用大剂量洛赛克治疗溃疡病大出血

目的：探讨内镜止血联用大剂量洛赛克治疗消化性溃疡大出血的临床价值。方法：对３２例溃疡病大出血患者进行内镜治疗,然后将内镜止血成功的２１例继续抑酸治疗,１０例用大剂量洛赛克,１１例用常规剂量西米替丁。结果：内镜即刻止血成功２１例,失败１例。     

ENDOSCOPIC NECROSECTOMY UNDER DIRECT VISION AFTER ENDOSCOPIC ULTRASOUND‐GUIDED CYSTGASTROSTOMY FOR ORGANIZED PANCREATIC NECROSIS

A 56‐year‐old man was referred for an enlarging pancreatic pseudocyst that developed after severe acute pancreatitis with gallstones. Abdominal ultrasound showed a huge cystic lesion with a large amount of solid high echoic components. Arterial phase contrast‐enhanced computed tomography scan revealed arteries across the cystic cavity. Stents were placed after endoscopic ultrasound‐guided cystgastrostomy; however, the stents were obstructed by necrotic debris, and secondary infection of the pseudocyst occurred. Therefore, the cystgastrostomy was dilated by a dilation balloon, and a forward‐viewing endoscope was inserted into the cystic cavity. Many vessels and a large amount of necrotic debris existed in the cavity. Under direct vision, all necrotic debris was safely removed using a retrieval net and forceps. One year after this procedure, there was no recurrence. Our case indicates that peripancreatic fat necrosis can cause exposure of vessels across/along the cystic cavity, and blind necrosectomy should be avoided.     

Disinfection of gastrointestinal endoscopes and accessories

Abstract A worldwide concern has emerged with regard to endoscope disinfection and many gastrointestinal endoscopy associations have developed guidelines for proper disinfection of endoscopes and endoscopic accessories. A working party was convened to formulate guidelines for the Asia–Pacific region, pertaining to any setting in which gastrointestinal endoscopy is performed. Endoscope reprocessing that meets the established standard of practice helps to ensure a microbial-free endoscope for all patients, reduces the risk of disease transmission and helps to prolong the life of the endoscope. The recommendations included mechanical cleaning as the first and most important step followed by immersion in 2% glutaraldehyde for a minimum period of 10 min. Automated disinfectors have been recommended for busy endoscopy centres to ensure better compliance. Reuse of endoscopic accessories meant for 'single use' remains a controversial issue. Strict quality assurance programmes are a must to preclude lack of compliance with these guidelines.     

A study on the new measurement of gastric lesions with an electronic endoscope

We carried out measurement of gastric lesions in the inner surface of the stomach with a measuring system, which is composed of a stereo endoscope and a personal computer. Basically, the length on a flat board from 10 mm to 50 mm was measured by varying the distance between the lens and the board and the angles of the endoscope at first. The error of the measurement was less than 8.5%. Secondly, ten physicians of our clinic attempted the measurement of the pasted discs on the inner wall of a stomach model with the endoscope. The average measurement error and the average time required for endoscopy became more better using the newly developed system than a measuring rod. Clinically, we measured the length of stomach lesion and of normal mucosa in six patients and compared the values obtained with those of resected fresh specimens. The length of stomach lesions could be measured more accurately than that of normal mucosa of stomach. From our observations, it can be said that this system is as available as the basic examination procedures in use at present and worth using in clinical procedure for it's high reliability.     

磁控胶囊内镜在37例上消化道疾病患者诊断中的临床应用

目的 探讨磁控胶囊内镜在上消化道疾病诊断中的临床应用.方法 对37例有上消化道症状的患者随机进行食管胃十二指肠镜检查和磁控胶囊内镜检查.通过体外巡航胶囊内镜控制系统对磁控胶囊内镜进行控制,完成磁控胶囊内镜对食管、贲门、胃底、胃体、胃窦和十二指肠球部的观察,并与食管胃十二指肠镜检查结果进行比较,观察磁控胶囊内镜对上消化道病变的检出率、阳性预测值、阴性预测值、敏感性以及特异性.结果 食管胃十二指肠镜检查发现病变34例,磁控胶囊内镜发现病变32例,两者检查一致率为86.5％.磁控胶囊内镜检查对上消化道病变检查的敏感性为91％,特异性为67％,阳性预测值为97％,阴性预测值为40％.结论 磁控胶囊内镜对发现上消化道病变有较高的敏感性和阳性预测值,并且检查过程无创、可控,可用于上消化道疾病的诊断.     

Radial endobronchial ultrasound for the diagnosis of peripheral pulmonary lesions: A systematic review and meta‐analysis

Tissue diagnosis of peripheral pulmonary lesions (PPLs) can be challenging. In the past, flexible bronchoscopy was commonly performed for this purpose but its diagnostic yield is suboptimal. This has led to the development of new bronchoscopic modalities such as radial endobronchial ultrasound (R‐EBUS), electromagnetic navigation bronchoscopy (ENB) and virtual bronchoscopy (VB). We performed this meta‐analysis using data from previously published R‐EBUS studies, to determine its diagnostic yield and other performance characteristics. Ovid MEDLINE and PubMed databases were searched for R‐EBUS studies in September 2016. Diagnostic yield was calculated by dividing the number of successful diagnoses by the total number of lesions. Meta‐analysis was performed using MedCalc (Version 16.8). Inverse variance weighting was used to aggregate diagnostic yield proportions across studies. Publication bias was assessed using funnel plot and Duval and Tweedie's test. 57 studies with a total of 7872 lesions were included in the meta‐analysis. These were published between October 2002 and August 2016. Overall weighted diagnostic yield for R‐EBUS was 70.6% (95% CI: 68–73.1%). The diagnostic yield was significantly higher for lesions >2 cm in size, malignant in nature and those associated with a bronchus sign on computerized tomography (CT) scan. Diagnostic yield was also higher when R‐EBUS probe was within the lesion as opposed to being adjacent to it. Overall complication rate was 2.8%. This is the largest meta‐analysis performed to date, assessing the performance of R‐EBUS for diagnosing PPLs. R‐EBUS has a high diagnostic yield (70.6%) with a very low complication rate.