Shiaw-oi Ho

International consensus recommendations for difficult biliary access

ERCP is the standard procedure for endoscopic biliary therapy. The endoscopic approach to the ampulla followed by selective deep biliary cannulation is the first step before further therapy. Difficult biliary access can occur during endoscope intubation or when attempting selective biliary cannulation in normal or surgically altered anatomy. Difficult cannulation increases the risk of post-ERCP adverse events, particularly post-ERCP pancreatitis (PEP) and perforation. In normal anatomy, about 11% of therapeutic ERCPs may be considered difficult biliary cannulation. Biliary access in patients with surgically altered anatomy, such as Billroth II or Roux-en-Y anastomosis, is considered difficult because special instruments and maneuvers are often needed. Various methods are used to overcome difficult biliary access, including advanced ERCP-based techniques using precut papillotomy or double guidewires (DGWs), specialized instruments like echoendoscopes or device-assisted enteroscopy, or percutaneous approach. These techniques and procedures are more complex and carry significant risks, requiring specific training. This consensus aims to develop an evidence-based framework for biliary endoscopists to tackle difficult biliary access.

Endoscopic Ablation Therapy for Biliopancreatic Malignancies

Biliopancreatic malignancies such as cholangiocarcinoma (CCA) has notoriously been diagnosed late. As such most therapy have been palliative in nature. Cholangioscopy allows for an earlier diagnosis to be made. Brachytherapy with the insertion of catheter with iridium-132 seeds, percutaneously or through endoscopic retrograde cholangiopancreatography (ERCP) was the earliest ablative techniques used. It has been shown to have a beneficial effect only in prolonging survival. Photodynamic therapy (PDT) has also been used for several years. stenting with PDT versus stenting alone for unresectable CCA showed a marked survival benefit with the addition of PDT. However the most exciting endoscopic ablative modality appears to be intraductal radiofrequency ablation using the Habib catheter and device. Several case series have shown the effectiveness of this technique in ablating tumors. This technique is evolving and coupled with early diagnosis of CCA through cholangioscopy will allow for a curative therapy. The crux to the effective treatment of early cancerous lesions in the bile or pancreatic duct is the early diagnosis of such lesions. Effective endoscopic ablative therapy is now available with the advent of radiofrequency ablation probes that can be passed through the duodenoscope via ERCP.

Basic principles and practice of gastric cancer screening using high-definition white-light gastroscopy: Eyes can only see what the brain knows.

Endoscopic diagnosis of gastrointestinal tumors consists of the following processes: (i) detection; (ii) differential diagnosis; and (iii) quantitative diagnosis (size and depth) of a lesion. Although detection is the first step to make a diagnosis of the tumor, the lesion can be overlooked if an endoscopist has no knowledge of what an early‐stage ‘superficial lesion’ looks like. In recent years, image‐enhanced endoscopy has become common, but white‐light endoscopy (WLI) is still the first step for detection and characterization of lesions in general clinical practice. Settings and practice of routine esophagogastroduodenoscopy (EGD) such as use of antispasmodics, number of endoscopic images taken, and observational procedure are customarily decided in each facility in each country and are not well standardized. Therefore, in the present article, we attempted to outline currently available evidence and actual Japanese practice on gastric cancer screening using WLI, and provide tips for detecting EGC during routine EGD which could become the basis of future research.

Preoperative drainage for malignant biliary strictures: is it time for self-expanding metallic stents?

Palliation of jaundice improves the general health of the patient and, therefore, surgical outcomes. Because of the complexity and location of strictures, especially proximally, drainage has been accompanied by increased morbidity due to sepsis. Another concern is the provocation of an inflammatory and fibrotic reaction around the area of stent placement. Preoperative biliary drainage with self-expanding metallic stent (SEMS) insertion can be achieved via a percutaneous method or through endoscopic retrograde cholangiopancreatography. A recently published multicenter randomized Dutch study has shown increased morbidity with preoperative biliary drainage. A Cochrane meta-analysis has also shown a significantly increased complication rate with preoperative drainage. However, few of these studies have used a SEMS, which allows better biliary drainage. No randomized controlled trials have compared preoperative deployment of SEMS versus conventional plastic stents. The outcomes of biliary drainage also depend on the location of the obstruction, namely the difficulty with proximal compared to distal strictures. Pathophysiologically, palliation of jaundice will benefit all patients awaiting surgery. However, preoperative drainage often results in increased morbidity because of procedure-related sepsis. The use of SEMS may change the outcome of preoperative biliary drainage dramatically.

Narrow-band imaging and white-light endoscopy with optical magnification in the diagnosis of dysplasia in Barrett’s esophagus: results of the Asia-Pacific Barrett’s Consortium

Objective: The advent and utility of new endoscopic imaging modalities for predicting the histology of Barrett’s esophagus (BE) in real time with high accuracy appear promising and could potentially obviate the need to perform random biopsies where guidelines are poorly adhered to. We embarked on evaluating the performance characteristics of white-light endoscopy with magnification (WLE-z), narrow-band imaging with magnification (NBI-z) and a combination of both modalities. Design: This was a prospective online study with 28 endoscopists from 11 countries (Asia-Pacific region) participating as assessors. In total, 35 patients with BE were assessed using 150 slides from WLE-z and NBI-z randomly arranged using a simple classification with corresponding histology. The overall Accuracy (Acc), Sensitivity (Sn), Specificity (Sp), Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of WLE-z, NBI-z and a combination of both were calculated. Results: The overall Acc for WLE-z and NBI-z images was 87.1 % and 88.7 %, respectively. When images from the two modalities were placed side by side, the Acc increased to 90.3 %. The Sn, Sp, PPV, and NPV of WLE-z were 48 %, 92 %, 45 %, and 93 % while with NBI-z, these improved to 89 %, 89 %, 56 %, and 98 %, respectively. When both imaging modalities were viewed together, they improved further to 93 %, 90 %, 61 %, and 99 %. Conclusion: The high NPV (99 %) when both WLE-z and NBI-z were used simultaneously indicates that areas with regular appearance that are diagnosed with confidence can effectively be left alone and not biopsied when performed at a skilled resourced center. This approach could potentially lead to a paradigm shift of how patients with BE are assessed.

Development of an E-learning System for the Endoscopic Diagnosis of Early Gastric Cancer: An International Multicenter Randomized Controlled Trial

Background In many countries, gastric cancer is not diagnosed until an advanced stage. An Internet-based e-learning system to improve the ability of endoscopists to diagnose gastric cancer at an early stage was developed and was evaluated for its effectiveness. Methods The study was designed as a randomized controlled trial. After receiving a pre-test, participants were randomly allocated to either an e-learning or non-e-learning group. Only those in the e-learning group gained access to the e-learning system. Two months after the pre-test, both groups received a post-test. The primary endpoint was the difference between the two groups regarding the rate of improvement of their test results. Findings 515 endoscopists from 35 countries were assessed for eligibility, and 332 were enrolled in the study, with 166 allocated to each group. Of these, 151 participants in the e-learning group and 144 in the non-e-learning group were included in the analysis. The mean improvement rate (standard deviation) in the e-learning and non-e-learning groups was 1·24 (0·26) and 1·00 (0·16), respectively (P < 0·001). Interpretation This global study clearly demonstrated the efficacy of an e-learning system to expand knowledge and provide invaluable experience regarding the endoscopic detection of early gastric cancer (R000012039).

Genotype 3 is the predominant hepatitis C genotype in a multi-ethnic Asian population in Malaysia.

BACKGROUND Genotypes of hepatitis C virus (HCV) are distributed differently across the world. There is a paucity of such data in a multi-ethnic Asian population like Malaysia. The objectives of this study were to determine the distribution of HCV genotypes between major ethnic groups and to ascertain their association with basic demographic variables like age and gender. METHODS This was a cross-sectional prospective study conducted from September 2007 to September 2013. Consecutive patients who were detected to have anti-HCV antibodies in the University of Malaya Medical Centre were included and tested for the presence of HCV RNA using Roche Cobas Amplicor Analyzer and HCV genotype using Roche single Linear Array HCV Genotyping strip. RESULTS Five hundred and ninety-six subjects were found to have positive anti-HCV antibodies during this period of time. However, only 396 (66.4%) were HCV RNA positive and included in the final analysis. Our results showed that HCV genotype 3 was the predominant genotype with overall frequency of 61.9% followed by genotypes 1 (35.9%), 2 (1.8%) and 6 (0.5%). There was a slightly higher prevalence of HCV genotype 3 among the Malays when compared to the Chinese (P=0.043). No other statistical significant differences were observed in the distribution of HCV genotypes among the major ethnic groups. There was also no association between the predominant genotypes and basic demographic variables. CONCLUSIONS In a multi-ethnic Asian society in Malaysia, genotype 3 is the predominant genotype among all the major ethnic groups with genotype 1 as the second commonest genotype. Both genotypes 2 and 6 are uncommon. Neither genotype 4 nor 5 was detected. There is no identification of HCV genotype according to ethnic origin, age and gender.

A multicenter randomized comparison between high-definition white light endoscopy and narrow band imaging for detection of gastric lesions.

Objective Narrow band imaging (NBI) is generally considered to be useful for lesion characterization, but not enhanced detection of gastric lesions, because of the dark endoscopic view. We tested whether the new generation of NBI (190-NBI or 290-NBI), which is twice as bright as the previous version, would improve detection of premalignant gastric lesions compared with high-definition white light endoscopy (HD-WLE). Patients and methods This was a multicenter prospective randomized study involving five tertiary institutions in the Asia-Pacific region. A total of 579 patients aged older than 50 years who underwent diagnostic upper gastrointestinal endoscopy were randomized to either HD-WLE or NBI. The outcome measurements were detection of intestinal metaplasia (IM), focal gastric lesions, and gastric cancers. Results Focal gastric lesions were detected in 83/286 (29%) and 119/293 patients (40.6%) by HD-WLE and by NBI, respectively (P=0.003). IM was detected in 22/286 patients (7.7%) by HD-WLE and in 52/293 patients (17.7%) by NBI (P<0.001). Gastric cancer were found in 7/286 (2.4%) and 3/293 patients (1%) in HD-WLE and NBI groups, respectively (P=0.189). Conclusion NBI increased the detection rate of IM compared with HD-WLE.

Differences in routine esophagogastroduodenoscopy between Japanese and international facilities: a questionnaire survey

The mortality rate of gastric cancer (GC) is close to the incidence rate worldwide. However, in Korea and Japan, the mortality rate of GC is less than half of the incidence rate. We hypothesized that good‐quality routine esophagogastroduodenoscopy (EGD) contributes to a high detection rate for early GC (EGC) and improves mortality in these countries.

Image Enhancement Using Geometric Mean Filter and Gamma Correction for WCE Images

The application of image enhancement technology to Wireless capsule Endoscopy (WCE) could extremely boost its diagnostic yield. WCE based detection inside gastrointestinal tract has been carried out over a great extent for the seek of the presence of any kind of etiology. However, the quality of acquired images during endoscopy degraded due to factors such as environmental darkness and noise. Hence, decrease in quality also resulted into poor sensitivity and specificity of ulcer and diagnosis. In this paper, a method based on color image enhancement through geometric mean filter and gamma correction is proposed. The developed method used geometric mean filtering to reduce Gaussian noise present in WCE images and achieved better quality images in contrast to arithmetic mean filtering, which has blurring effect after filtration. Moreover, Gamma correction has been applied to enhance small details, texture and contrast of the images. The results shown improved images quality in terms of SNR (Signal to Noise Ratio) and PSNR (Peak Signal to Noise Ratio) which is beneficial for automatic detection of diseases and aids clinicians to better visualize images and ease the diagnosis.