Hardware and software advances in capsule endoscopy

Capsule endoscopy was introduced in 2000 and has since become the investigative modality of choice for mucosal diseases of the small bowel. This innovative device, which comprises of imaging components encased within a pill-sized capsule, allows for non-invasive examination of the small bowel. The aim of this thesis is to evaluate advances in capsule endoscopy which have the potential to extend and improve the practice of this tool. The first section of this thesis examines the impact of fatigue on the accuracy of small bowel capsule endoscopy interpretation. Capsule studies involve the presentation of many thousands of repetitive images, which are time-consuming to interpret. There is some evidence for the impact of fatigue in the detection of adenomas during colonoscopy. In comparison capsule interpretation is passive, has little visual variability, and may, therefore, have a greater potential to induce fatigue. Here we hope to establish if this does indeed occur and if so, whether it affects the quality of subsequent readings. The second section investigates a potential solution to the numerous images presented. Omni-Mode is a novel rapid reading algorithm which proposes to remove similar images in order to reduce the images presented. By limiting the images to only those displaying unique information, accurate diagnosis could be made in a fraction of the time. This software was evaluated in a multi-centre European trial, where the diagnostic accuracy and reading times achieved with Omni-Mode were compared to conventional reading. The final section of this thesis explores the use of capsule endoscopy outside of the small bowel by means of a modification to the capsule hardware. The addition of magnetic material within the capsule allows in-vivo manoeuvrability under the control of an external magnet. Here we explore the use of a Magnetically Assisted Capsule Endoscope as an alternative to conventional endoscopy, providing a non-invasive method for examination of the upper gastrointestinal tract. In this study, we have focussed on the detection of oesophageal pathology, which has the potential to be missed during the rapid oesophageal transit of a standard capsule endoscope

Optimising the performance and interpretation of small bowel capsule endoscopy

Small bowel capsule endoscopy has become a commonly used tool in the investigation of gastrointestinal symptoms and is now widely available in clinical practice. In contrast to conventional endoscopy, there is a lack of clear consensus on when competency is achieved or the way in which capsule endoscopy should be performed in order to maintain quality and clinical accuracy. Here we explore the evidence on the key factors that influence the quality of small bowel capsule endoscopy services

Diagnosis of Barrett’s esophagus and Esophageal Varices using a Magnetically Assisted Capsule Endoscopy system

Background and AimsMagnetically assisted capsule endoscopy (MACE) potentially offers a comfortable, patient friendly, and community-based alternative to gastroscopy (EGD). This pilot study aims to explore whether this approach can be used to accurately diagnose Barrett’s esophagus and esophageal varices.MethodsThe MiroCam Navi capsule system was used to examine the upper GI tract in patients due to undergo a clinically indicated EGD. A total of 50 participants were enrolled, of which 34 had known pathology, 17 Barrett’s esophagus (BE), 17 esophageal varices (EV), with 16 controls. Patients underwent the MACE procedure, with the operator blinded to the indication and any previous endoscopic diagnoses. The subsequent EGD was performed by an endoscopist blinded to the MACE findings. Diagnostic yield, comfort and patient preference between the 2 modalities were compared.ResultsParticipants had a mean age of 61 years old, a M:F ratio of 2.1:1, a mean body mass index (BMI) of 29.5, with an average chest measurement of 105.3 cm. Forty-seven patients undertook both procedures; 3 patients were unable to swallow the capsule. With the use of the magnet, it was possible to hold the capsule within the esophagus for a mean duration of 190 seconds and up to a maximum of 634 seconds. A correct real-time MACE diagnosis was made in 11 of 15 patients with EV (sensitivity 73.3% [95% CI, 44.9% - 92.2%] and specificity 100% [95% CI, 89.1% - 100%]) and 15 of 16 patients with BE (sensitivity 93.8% [95% CI, 69.8% - 99.8%] and a specificity of 100% [95% CI, 88.8% - 100%]). MACE was considered more comfortable than conventional endoscopy (p [less than] 0.0001) with a mean score of 9.2 with MACE compared with 6.7 with EGD, when assessed on a 10-point scale. No MACE or EGD -elated adverse events occurred.ConclusionThis pilot study demonstrates that MACE is both safe and well tolerated by patients. Accuracy for the diagnosis of BE was high and may therefore have a role in screening for this condition

Narrow band imaging and serology in the assessment of premalignant gastric pathology

Background: Patient outcomes in gastric adenocarcinoma are poor due to late diagnosis. Detecting and treating at the premalignant stage has the potential to improve this. Helicobacter pylori is also a strong risk factor for this disease.Aims: Primary aims were to assess the diagnostic accuracy of magnified narrow band imaging (NBI-Z) endoscopy and serology in detecting normal mucosa, H. pylori gastritis and gastric atrophy. Secondary aims were to compare the diagnostic accuracies of two classification systems using both NBI-Z and white light endoscopy with magnification (WLE-Z) and evaluate the inter-observer agreement.Methods: Patients were prospectively recruited. Images of gastric mucosa were stored with histology and serum for IgG H. pylori and Pepsinogen (PG) I/II ELISAs. Blinded expert endoscopists agreed on mucosal pattern. Mucosal images and serological markers were compared with histology. Kappa statistics determined inter-observer variability for randomly allocated images among four experts and four non-experts.Results: 116 patients were prospectively recruited. Diagnostic accuracy of NBI-Z for determining normal gastric mucosa was 0.87(95%CI 0.82–0.92), H. pylori gastritis 0.65(95%CI 0.55–0.75) and gastric atrophy 0.88(95%CI 0.81–0.94). NBI-Z was superior to serology at detecting gastric atrophy: NBI-Z gastric atrophy 0.88(95%CI 0.81-0.94) vs PGI/II ratio

MWCNTs of different physicochemical properties cause similar inflammatory responses, but differences in transcriptional and histological markers of fibrosis in mouse lungs

Multi-walled carbon nanotubes (MWCNTs) are extensively produced and used in composite materials and electronic applications, thus increasing risk of worker and consumer exposure. MWCNTs are an inhomogeneous group of nanomaterials that come in various lengths, shapes and with different metal contaminations, which makes hazard evaluation difficult. However, several studies suggest that length plays an important role in the toxicity induced by MWCNTs. How the length influences toxicity at the molecular level is yet to be characterized. Female C57BL/6 mice were exposed by single intratracheal instillation to 18, 54 or 162 µg/mouse of a short MWCNT (NRCWE-026, 847±102 nm in length) or long MWCNT (NM-401, 4048±366 nm in length). The two MWCNTs were extensively characterized. Lung tissues were harvested 24 h, 3 d and 28 d after exposure. We employed DNA microarrays, bronchoalveolar lavage fluid analysis, comet assay and dichlorodihydrofluorescein assay in order to profile the pulmonary responses. Bioinformatics tools were then applied to compare and contrast the expression profiles and to build a length dependent property-response matrix for gene-by-gene comparison. The toxicogenomic analysis of the global mRNA changes after exposure to the short, entangled NRCWE-026 or the longer, stiffer NM-401 showed high degree of similarities. The toxicity of both MWCNTs was driven by strong inflammatory and acute phase responses, which peaked at day 3 and was observed both in bronchoalveolar lavage cell influx and in gene expression profiles. The inflammatory response was sustained at post-exposure day 28. Also, at the sub-chronic level, we identified a sub-set of 14 fibrosis related genes that were uniquely differentially regulated after exposure to NM-401. Acellular ROS production occurred almost exclusively with NRCWE-026, however the longer NM-401 induced in vivo DNA strand breaks and differential regulation of genes involved in free radical scavenging more readily than NRCWE-026. Our results indicate that the global mRNA response after exposure to MWCNTs is length independent at the acute time points, but that fibrosis may be length dependent sub-chronic end point.JRC.H.6-Digital Earth and Reference Dat

Hardware and software advances in capsule endoscopy

Capsule endoscopy was introduced in 2000 and has since become the investigative modality of choice for mucosal diseases of the small bowel. This innovative device, which comprises of imaging components encased within a pill-sized capsule, allows for non-invasive examination of the small bowel. The aim of this thesis is to evaluate advances in capsule endoscopy which have the potential to extend and improve the practice of this tool. The first section of this thesis examines the impact of fatigue on the accuracy of small bowel capsule endoscopy interpretation. Capsule studies involve the presentation of many thousands of repetitive images, which are time-consuming to interpret. There is some evidence for the impact of fatigue in the detection of adenomas during colonoscopy. In comparison capsule interpretation is passive, has little visual variability, and may, therefore, have a greater potential to induce fatigue. Here we hope to establish if this does indeed occur and if so, whether it affects the quality of subsequent readings. The second section investigates a potential solution to the numerous images presented. Omni-Mode is a novel rapid reading algorithm which proposes to remove similar images in order to reduce the images presented. By limiting the images to only those displaying unique information, accurate diagnosis could be made in a fraction of the time. This software was evaluated in a multi-centre European trial, where the diagnostic accuracy and reading times achieved with Omni-Mode were compared to conventional reading. The final section of this thesis explores the use of capsule endoscopy outside of the small bowel by means of a modification to the capsule hardware. The addition of magnetic material within the capsule allows in-vivo manoeuvrability under the control of an external magnet. Here we explore the use of a Magnetically Assisted Capsule Endoscope as an alternative to conventional endoscopy, providing a non-invasive method for examination of the upper gastrointestinal tract. In this study, we have focussed on the detection of oesophageal pathology, which has the potential to be missed during the rapid oesophageal transit of a standard capsule endoscope