RF characteristics of wireless capsule endoscopy in human body

The wireless capsule endoscope,as a small electronic device,has conquered some limitations of traditional wired diagnosing tools,such as the uncomfortableness of the cables for the patient and the inability to examine the very convoluted small intestine section.However,this technique is still encountering a lot of practical challenges and is looking for feasible improvements.This work investigates the RF performance of the wireless capsule endoscope system by studying the electromagnetic(EM) wave propagation within the human body.A wireless capsule endoscopy transmission channel model is constructed to serve the purpose of investigating signal attenuations according to the relative position between the transmitter and the receiver.Within 300-500 MHz,the S_(21) results are regular and do not display any sudden changes,which allows a suitable expression to be derived for S_(21) in terms of frequency and offset.The results provide useful information for capsule localization.

The future of wireless capsule endoscopy

We outline probable and possible developments with wireless capsule endoscopy. It seems likely that capsule endoscopy will become increasingly effective in diagnostic gastrointestinal endoscopy. This will be attractive to patients especially for cancer or varices detection because capsule endoscopy is painless and is likely to have a higher take up rate compared to conventional colonoscopy and gastroscopy. Double imager capsules with increased frame rates have been used to image the esophagus for Barrett's and esophageal varices. The image quality is not bad but needs to be improved if it is to become a realistic substitute for flexible upper and lower gastrointestinal endoscopy. An increase in the frame rate, angle of view, depth of field, image numbers, duration of the procedure and improvements in illumination seem likely. Colonic, esophageal and gastric capsules will improve in quality, eroding the supremacy of flexible endoscopy, and become embedded into screening programs. Therapeutic capsules will emerge with brushing, cytology, fluid aspiration, biopsy and drug delivery capabilities. Electrocautery may also become possible. Diagnostic capsules will integrate physiological measurements with imaging and optical biopsy, and immunologic cancer recognition. Remote control movement will improve with the use of magnets and/or electrostimulation and perhaps electromechanical methods. External wireless commands will influence capsule diagnosis and therapy and will increasingly entail the use of real-time imaging. However, it should be noted that speculations about the future of technology in any detail are almost always wrong.

Wireless capsule endoscopy and proximal small bowel lesions in Crohn’s disease

AIM: To investigate the prevalence of proximal small bowel (SB) lesions detected by wireless capsule endoscopy (WCE) in Crohn's disease (CD). METHODS: WCE was performed in 64 patients: 32 with CD of the distal ileum, and 32 controls with iron-deficiency anemia (IDA) or diarrhea. WCE was performed using the Given SB-WCE, followed by small intestine contrast ultrasonography (SICUS). Findings compatible with CD by using WCE included erosions, aphthoid or deep ulcers, and strictures/stenosis. RESULTS: WCE detected proximal SB lesions in 16/32 (50%) patients (14 aphthoid ulcers, 2 deep ulcers, one stricture), which appeared not to be related to clinical parameters [epigastric pain, age, smoking, non-steroidalanti-inflammatory drugs (NSAIDs), IDA]. Among patients with proximal SB lesions, 6 (37%) were smokers, 3 (19%) NSAID users, 3 (19%) had epigastric pain and 4 (25%) had IDA. SICUS detected proximal SB lesions in 3/32 patients (19%) also showing lesions with WCE. No correlations were observed between proximal SB lesions assessed by WCE or by SICUS (χ2 = 1.5, P = 0.2). CONCLUSION: The use of WCE allows the detection of previously unknown upper SB lesions in a high proportion of patients with a previous diagnosis of CD involving the distal ileum.

Wireless capsule endoscopy

Wireless capsule endoscopy is a new technique that allows complete exploration of the small bowel without exlemal wires. Its role has been analyzed in many small bowel diseases such as obscure gastrointestinal bleeding, Crohn＇s disease and gastrointestinal polyposis syndromes with promising results. Studies on other pathologies （i.e. small bowel tumour, celiac disease） are under evaluation to define the role of this technique.

Wireless capsule endoscopy in the investigation of patients with chronic renal failure and obscure gastrointestinal bleeding (preliminary data)

AIM： To investigate the role of wireless capsule endoscopy （WCE） in detection of small bowel （SB） pathology in patients with chronic renal failure （CRF） and obscure bleeding. METHODS： Consecutive CRF patients with obscure bleeding were prospectively studied. Patients with normal renal function and obscure bleeding, investigated during the same period with WCE, were used for the interpretation of results. RESULTS： Seventeen CRF patients （11 overt, 6 occult bleeding） and 51 patients （33 overt, 18 occult bleeding） with normal renal function were enrolled in this study. Positive SB findings were detected in 70.6% of CRF patients and in 41.2% of non-CRF patients （P〈0.05）. SB angiodysplasia was identified in 47% of CRF patients and in 17.6% of non-CRF patients. Univariate logistic regression revealed CRF as a significant predictive factor for angiodysplasia （P〈0.05）. Therapeutic measures were undertaken in 66% of the patients with the positive findings. CONCLUSION： According to our preliminary results, SB angiodysplasia was found in an increased prevalence among CRF patients with obscure bleeding. WCE is useful in diagnosis of gastrointestinal pathologies and in planning appropriate therapeutic intervention and, therefore, should be included in the work-up of this group of patients.

Comparison of the use of wireless capsule endoscopy with magnetic resonance enterography in children with inflammatory bowel disease

BACKGROUND Magnetic resonance enterography (MRE) and wireless capsule endoscopy (WCE) are equally accepted modalities for noninvasive screening of small bowel involvement (SBI) in children with Crohn’s disease (CD) and indeterminate colitis (IC) albeit there is a paucity of data comparing the two and thereby guiding the clinician in selecting the ideal diagnostic approach. Therefore, the goal of this study is to provide additional evidence for capsule endoscopy role in the evaluation of established Crohn’s disease exacerbation compared to MRE in relation to Pediatric Crohn's Disease Activity Index (PCDAI), and histological indices. AIM To prospectively compare the findings of MRE and WCE and their agreement with PCDAI or histology in children with CD or IC. METHODS Consecutive patients diagnosed with CD and IC were screened for inclusion. After informed consent, patient’s demographic and clinical data was abstracted. The current pediatric disease activity index (PCDAI) and endoscopic findings were included. Patients underwent MRE and WCE including preprocedural patency capsule within a maximum of 7 d of each other. Pathological presence of active small bowel disease in ileal and duodenal biopsies were collected if the endoscopy was performed within 2 mo of the WCE study. Patients who failed to pass the PC were excluded from the study. WCE was read by two different experienced gastroenterologists (Attard TM and Colombo JM) blinded to each other's findings and to the findings on MRE (Mardis NJ). Agreement between WCE reviewers, WCE and MRE findings and concordance between positive PCDAI and SBI based on MRE compared with WCE was computed. RESULTS Forty-five patients were included in the study, 18 withdrew and 27 (20 males and 20 CD), mean age (standard deviation) 13.46 (2.4) years, completed the study protocol. There were no instances of capsule retention. Concordance between gastroenterologist reviewers was excellent for the diagnosis of small intestinal CD with good correlation between the two Lewis scores (r=0.875, P<0.001). Concordance between WCE and MRE was poor (69%). In CD patients, when both MRE and WCE were compared using PCDAI>10 as the standard reference reflecting active small intestinal CD, the sensitivity of MRE and WCE were 100% and 83% respectively and the specificity of MRE and WCE were 57.14% and 78.6%, respectively. If the histology in ileum or/and duodenum was used as the reference for active small bowel involvement, WCE had a higher specificity as compared to MRE (83.3% vs 50%). In patients with Crohn’s disease, those with a positive PCDAI (>10) were more likely to have a positive WCE as compared to those with a negative PCDAI (83% vs 21%;P=0.018). CONCLUSION We suggest that MRE and WCE have a complementary role in the assessment of SBI in CD. WCE detected SBI with a much higher specificity while MRE had a higher sensitivity.

Wireless capsule endoscopy in detecting small-intestinal polyps in familial adenomatous polyposis

AIM:To detect the prevalence of small bowel polyps by wireless capsule endoscopy(WCE)in patients with familial adenomatous polyposis(FAP).METHODS:We examined prospectively 14 patients with FAP to assess the location,size and number of small-intestinal polyps.Patients'age,sex,years of observation after surgery,type of surgery,duodenal polyps and colorectal cancer at surgery were analyzed.RESULTS:During WCE,polyps were detected in 9/14(64.3%)patients.Duodenal adenomatous polyps were found in nine(64.3%)patients,and jejunal and ileal polyps in seven(50%)and eight(57.1%),respectively.The Spigelman stage of duodenal polyposis was associated with the presence of jejunal and ileal polyps.Identification of the ampulla of Vater was not achieved with WCE.Importantly,the findings of WCE had no immediate impact on the further clinical management of FAP patients.No procedure-related complications were observed in the patients.CONCLUSION:WCE is a promising noninvasive new method for the detection of small-intestinal polyps.Further investigation is required to determine which phenotype of FAP is needed for surveillance with WCE.

Role of wireless capsule endoscopy in inflammatory bowel disease

Capsule endoscopy(CE) offers state-of-the-art imaging of the small bowel.In Crohn's disease its clinical role is still uncertain.This report analyses the usefulness of CE in patients with suspected Cronh's disease,in patients with established Crohn's disease(when assessing severity,occult gastrointestinal bleeding and/or as a guide to therapy),in patients with inflammatory bowel disease unclassified(IBDU),and in individuals with ulcerative colitis.The first item in this group is the most important although there is no strong evidence to establish the position of CE in the diagnostic workup.In patients with established Crohn's disease,recently developed activity scores are promising tools for an accurate assessment of severity.As a guide to therapy,CE should be focused on patients with unexplained symptoms when other investigations are inconclusive.In postoperative Crohn's Disease,international consensus recommended considering CE only ifileocolonoscopy is contraindicated or unsuccessful.In the case of IBDU,studies have shown a significant proportion of patients reclassified with Crohn's disease.In this setting,CE could have a role determining small bowel involvement.The role of CE in ulcerative colitis is limited.Some authors advocate CE before colectomy for refractory cases in order to exclude Crohn's disease.In summary,CE offers a new horizon in inflammatory bowel disease,and a better knowledge of mucosal abnormalities that could offer a paradigm shift:changing from symptombased disease activity estimation to direct mucosal healing monitoring.Nevertheless,randomized controlled studies are still needed to provide stronger evidence in this setting.

Wireless capsule endoscopy: Perspectives beyond gastrointestinal bleeding

Wireless capsule endoscopy(CE) is a technology developed for the endoscopic exploration of the small bowel. The first capsule model was approved by the Food and Drug Administration in 2001, and its first and essential indication was occult gastrointestinal(GI) bleeding. Over subsequent years, this technology has been refined to provide superior resolution, increased battery life, and capabilities to view different parts of the GI tract. Indeed, cases for which CE proved useful have increased significantly over the last few years, with new indications for the small bowel and technical improvements that have expanded its use to other parts of the GI tract, including the esophagus and colon. The main challenges in the development of CE are new devices with the ability to provide therapy, air inflation for a better vision of the small bowel, biopsy sampling systems attached to the capsule and the possibility to guide and move the capsule with an external motion control. In this article we review the current and new indications of CE, and the evolving technological changes shaping this technology, which has a promising potential in the coming future of gastroenterology.

Detection of small bowel tumor in wireless capsule endoscopy images using an adaptive neuro-fuzzy inference system

Automatic diagnosis tool helps physicians to evaluate capsule endoscopic examinations faster and more accurate.The purpose of this study was to evaluate the validity and reliability of an automatic post-processing method for identifying and classifying wireless capsule endoscopic images, and investigate statistical measures to differentiate normal and abnormal images. The proposed technique consists of two main stages, namely, feature extraction and classification. Primarily, 32 features incorporating four statistical measures(contrast, correlation, homogeneity and energy) calculated from co-occurrence metrics were computed. Then, mutual information was used to select features with maximal dependence on the target class and with minimal redundancy between features. Finally, a trained classifier, adaptive neuro-fuzzy interface system was implemented to classify endoscopic images into tumor, healthy and unhealthy classes. Classification accuracy of 94.2% was obtained using the proposed pipeline. Such techniques are valuable for accurate detection characterization and interpretation of endoscopic images.

Bleeding and Ulcer Detection Using Wireless Capsule Endoscopy Images

Wireless capsule endoscopes (WCEs) have been used widely to detect abnormalities inside regions of the small intestine that are not accessible when using traditional endoscopy techniques. However, an experienced clinician must spend an average of 2 hours to view and analyze the approximately 60,000 images produced during one examination. Therefore, developing a computeraided system for processing WCE images is crucial. This paper proposes a novel method used for detecting bleeding and ulcers in WCE images. This approach involves using color features to determine the status of the small intestine. The experimental results revealed that the proposed scheme is promising in detecting bleeding and ulcer regions.

Yield,etiologies and outcomes of capsule endoscopy in Thai patients with obscure gastrointestinal bleeding

AIM:To investigate the yield,etiologies and impact of capsule endoscopy(CE) in Thai patients with obscure gastrointestinal bleeding(OGIB).METHODS:The present study is a retrospective cohort study.All patients with OGIB who underwent CE in Siriraj Hospital,Bangkok,Thailand during 2005-2009 were included in the study.All the patients' medical records and results of the CE videos were reviewed.CE findings were classified as significant,suspicious/equivocal and negative.Sites of the lesions were located to duodenum,jejunum,jejunoileum,ileum and diffuse lesions by the localization device of the CE.Impact of CE on the patients' management was defined by any investigation or treatment given to the patients that was more than an iron supplement or blood transfusion.Patients' outcomes(rebleeding,persistent bleeding,anemia or requirement of blood transfusion) were collected from chart reviews and direct phone interviews with the patients.RESULTS:Overall,there were 103 patients with OGIB included in the study.Mean age of the patients was 64 ± 16 years(range 9-88 years) and 57 patients(55%) were male.Types of OGIB were overt in 80(78%) and occult in 23 patients(22%).The median time interval of CE after onset of OGIB was 10 d(range 1-180 d).The median time of follow-up was 19 mo(range 1-54 mo).Capsules reached caecum in 77 patients(74%) and capsule retention was found in 1 patient(1%).The diagnostic yield of CE revealed significant lesions in 37 patients(36%),suspicious/equivocal lesions in 15 patients(15%) and 51 patients(49%) had negative CE result.Among the significant lesions,the bleeding etiologies were small bowel ulcers in 44%,angiodysplasia in 27%,small bowel tumor in 13%,miscellaneous in 8% and active bleeding without identifiable causes in 8%.Patients with small bowel ulcers were significantly associated with the use of non-steroidal anti-inflammatory drugs(48%,P = 0.034),while patients with small bowel tumors were more commonly female(86%,P = 0.043) compared to the other etiologies.The rate of rebleeding,persistent bleeding or anemia in patients with positive,equivocal and negative CE results were 5%,0% and 18%,respectively(P = 0.078).All the 9 patients with rebleeding after negative CE were subsequently found to be from hematologic disorders(4),colonic diverticulosis(2),colonic Dieulafoy's(1),hemorrhoid(1) and hemosuccus pancreaticus(1).Results of CE had a positive impact on the patients' management in 35% of the patients whose results were positive,but none on the patients whose results were equivocal or negative CE(P < 0.001).CONCLUSION:In Thai OGIB patients,CE had low yield and small bowel ulcer was most common.Positive CE impacted managements and outcomes.Negative CE caused low rebleeding.

Small bowel capsule endoscopy and treat-to-target in Crohn’s disease: A systematic review

BACKGROUND Crohn’s disease(CD)can affect the entire gastrointestinal tract.Proximal small bowel(SB)lesions are associated with a significant risk of stricturing disease and multiple abdominal surgeries.The assessment of SB in patients with CD is therefore necessary because it may have a significant impact on prognosis with potential therapeutic implications.Because of the weak correlation that exists between symptoms and endoscopic disease activity,the“treat-to-target”paradigm has been developed,and the associated treatment goal is to achieve and maintain deep remission,encompassing both clinical and endoscopic remission.Small bowel capsule endoscopy(SBCE)allows to visualize the mucosal surface of the entire SB.At that time,there is no recommendation regarding the use of SBCE during follow-up.AIM To investigate the impact of SBCE in a treat-to-target strategy in patients with CD.METHODS An electronic literature search was conducted in PubMed and Cochrane library using the following search terms:“capsule endoscopy”,in combination with“Crohn’s disease”and“treat-to-target”or synonyms.Two authors independently reviewed titles and abstracts identified by the search strategy after duplicates were removed.Following the initial screening of abstracts,all articles containing information about SBCE in the context of treat-to-target strategy in patients with CD were included.Full-text articles were retrieved,reference lists were screened manually to identify additional studies.RESULTS Forty-seven articles were included in this review.Two indexes are currently used to quantify disease activity using SBCE,and there is good correlation between them.SBCE was shown to be useful for disease reclassification in patients who are suspected of having or who are diagnosed with CD,with a significant incremental diagnostic yield compared to other diagnostic modalities.Nine studies also demonstrated that the mucosal healing can be evaluated by SBCE to monitor the effect of medical treatment in patients with CD.This review also demonstrated that SBCE can detect post-operative recurrence to a similar extent as ileocolonoscopy,and proximal SB lesions that are beyond the reach of the colonoscope in over half of the patients.CONCLUSION SBCE could be incorporated in the treat-to-target algorithm for patients with CD.Randomized controlled trials are required to confirm its usefulness and reliability in this indication.

Meckel's diverticulum diagnosis by video capsule endoscopy: A case report and review of literature

BACKGROUND Meckel’s diverticulum （MD） occurs predominantly in chil-dren and adolescents. It is rarely diagnosed in adults. Preoperative diagnosis is diffcult due to low sensitivity of the radiological imaging studies. The role of video capsule endoscopy （VCE） in the diagnosis of MD is unknown, and the endoscopic patterns are not defned. We will describe four of our cases of MD evaluated with VCE and make a review of the literature focusing on the endoscopic characteristics.CASE SUMMARYWe present four cases of MD confirmed by surgery. They were all adult males with ages going from 18 to 50 years, referred to our service from 2004 to 2018, due to obscure gastrointestinal bleeding （OGIB）. TheyGarcía-Compeán D et al . Merckel’s diverticulum diagnosis by VCEhad a history of 1 mo to 10 years of overt and occult bleeding episodes. Laboratory blood test showed an iron-deficiency anemia from 4 to 9 g/dL of hemoglo-bin that required multiple hospitalizations and blood transfusions in all cases. Repeated upper digestive endoscopies and colonoscopies were negative. Small bowel was examined with VCE, which revealed double lumen images in all cases, one with polyps and three with circumferential ulcers in the diverticulum. However, based on VCE findings, preoperative diagnosis of MD was suggested only in two patients. Capsule was retain-ed in one patient, which was recovered with surgery. The anatomopathological report revealed ulcerated ectopic gastric mucosa in all cases.CONCLUSIONVCE is useful for the diagnosis of MD. However, endo-scopic characteristics must be recognized in order to establish preoperative diagnosis.

QI-BRiCE: Quality Index for Bleeding Regions in Capsule Endoscopy Videos

With the advent in services such as telemedicine and telesurgery,provision of continuous quality monitoring for these services has become a challenge for the network operators.Quality standards for provision of such services are application specic as medical imagery is quite different than general purpose images and videos.This paper presents a novel full reference objective video quality metric that focuses on estimating the quality of wireless capsule endoscopy(WCE)videos containing bleeding regions.Bleeding regions in gastrointestinal tract have been focused in this research,as bleeding is one of the major reasons behind several diseases within the tract.The method jointly estimates the diagnostic as well as perceptual quality of WCE videos,and accurately predicts the quality,which is in high correlation with the subjective differential mean opinion scores(DMOS).The proposed combines motion quality estimates,bleeding regions’quality estimates based on support vector machine(SVM)and perceptual quality estimates using the pristine and impaired WCE videos.Our method Quality Index for Bleeding Regions in Capsule Endoscopy(QI-BRiCE)videos is one of its kind and the results show high correlation in terms of Pearson’s linear correlation coefcient(PLCC)and Spearman’s rank order correlation coefcient(SROCC).An F-test is also provided in the results section to prove the statistical signicance of our proposed method.

Understanding deep learning in capsule endoscopy: Can artificial intelligence enhance clinical practice?

Wireless capsule endoscopy(WCE)enables physicians to examine the gastrointestinal tract by transmitting images wirelessly from a disposable capsule to a data recorder.Although WCE is the least invasive endoscopy technique for diagnosing gastrointestinal disorders,interpreting a WCE study requires significant time effort and training.Analysis of images by artificial intelligence,through advances such as machine or deep learning,has been increasingly applied to medical imaging.There has been substantial interest in using deep learning to detect various gastrointestinal disorders based on WCE images.This article discusses basic knowledge of deep learning,applications of deep learning in WCE,and the implementation of deep learning model in a clinical setting.We anticipate continued research investigating the use of deep learning in interpreting WCE studies to generate predictive algorithms and aid in the diagnosis of gastrointestinal disorders.

基于无线胶囊内窥镜图像的胃肠道病变智能检测方法综述

无线胶囊内窥镜(WCE)以其无痛和非入侵的特点,为胃肠道疾病检查提供了新颖方式,在临床上得到了广泛应用。然而,WCE每次检测均产生数以万计图像,但其中病变图像可能仅占少数。传统的WCE图像筛查主要依赖医生的临床经验,其过程耗时费力且存在漏检和误检风险。因此,开发WCE胃肠道病变图像的智能检测方法,用于辅助临床诊断,提高医生诊断效率和准确率,已成为当前的研究热点。综述了WCE胃肠道病变图像智能检测的最新研究进展;介绍了WCE病变图像智能检测的基本原理和评价指标;从传统机器学习和深度学习方法的角度出发,回顾了WCE胃肠道病变图像自动分类和预测的研究,总结了不同方法的优势与不足;探讨了WCE病变智能检测未来发展所面临的挑战及可能的拓展方向。

融合颜色特征和背景先验的WCE出血图像显著性检测

目的利用显著性检测方法,通过构建一个适用于胶囊内窥镜(WCE)图像出血检测的模型,进行出血病变的识别。方法利用WCE出血图像的特性来获取图像的彩色尺度不变三值模式(CSILTP)和背景先验知识以得到最终的出血显著图。结果数据结果以医院提供的数据集作为实验对象,利用临床医师提供的人工标记(GT)图像对实验结果进行客观评价,检测结果与GT图像基本一致。本文算法得到的曲线下面积(AUC)以及平均绝对误差值(MAE)整体上优于MR、BCon以及SUB等主流算法。结论融合颜色特征和背景先验的WCE出血图像的显著性检测方法能够更好地检测到图像的背景区域,并有效识别图像中的出血病变。

基于特征融合的WCE图像检索

无线胶囊内镜(WCE)是一种新型的、具有极大市场价值的肠道疾病检测技术。该技术产生的图像数据量极大,为医生开展疾病诊断带来了困难。WCE图像快速检索技术是WCE后端智能图像分析软件的基本功能之一。本文针对WCE图像中相似图像的快速检索问题开展研究。通过对大量WCE图像本身特征的分析,提出了一种融合颜色特征与纹理特征的图像检索算法。首先分别提取图像的色调饱和度二维相关直方图以及图像的局部二值模式(LBP)纹理特征,然后采用高斯归一化的方法对不同的特征进行融合,最后采用融合特征为待检索图像建立索引,实现了输入目标WCE图像的快速准确查找。实验结果表明本文所提方法计算复杂度低和检索结果良好。

Bleeding Detection from Wireless Capsule Endoscopy Images Using Improved Euler Distance in CIELab

Bleeding in the digestive tract is one of the most common gastrointestinal (GI) tract diseases,as well as the complication of some fatal diseases. Wireless capsule endoscopy (WCE),which is widely applied in the clinical field,allows physicians to noninvasively examine the entire GI tract. However,it is very laborious and timeconsuming to detect the huge amount of WCE images,and limits its wider application. It is urgent and necessary to develop the automatic and intelligent computer aided bleeding detection technique. This paper improves the Euler distance with the covariance matrix of image to measure the colour similarity in CIELab colorimetric system,and proposes a novel method of bleeding detection in WCE images. The experiments demonstrate that the bleeding region in WCE images can be correctly recognized and marked out,and the sensitivity of this method is 92%,the specificity is 95%.