This study aims to assess whether iScan, an intra-endoscopic imaging technique is an accurate and reliable tool in detecting and characterising Helicobacter pylori (H pylori) and comparing this to standard endoscopic imaging with white light endoscopy (WLE), narrow band imaging (NBI) and histology.

The ultimate goal of endoscopy will be the 'optical biopsy' i.e. forgoing the need to take histological samples to make a diagnosis in order to reduce complication rates, cost and time. There are a number of imaging techniques which promise to improve our diagnostic rates for pathology, but there have been few comparative studies.

This is randomized controlled parallel trial in a 1:1 ratio with examination of the upper gastrointestinal tract with WLE followed by either NBI or iscan.

(Note: Prior to commencement of the study, technical issues and operational changes in our organisation forced the removal of the Pentax 'i-scan' endoscopes. Recruitment to this arm was anticipated, but was ultimately not possible.)

Patients attending the department for routine examinations for dyspepsia and abdominal pain will be randomised into 2 study arms (1WLE and NBI, and the other - WLE and iscan).

The investigator carrying out the procedure will be blinded to the indication for the procedure until a full examination with both white light endoscopy and either NBI or iscan has been used as this could lead to bias. They will determine if H pylori is present, and if so the severity of infection with WLE and again with either NBI or iscan depending on their study arm. Histopathological confirmation of H pylori and an assessment to the degree of infection will be assessed with samples taken using the updated Sydney system (5 gastric samples from different parts of the stomach).

The endoscopists reviewing the images will be blinded to all patient information and indications throughout the study period. Questionnaires will then be given to the endoscopists to determine what endoscopic features led them to their diagnosis.

Inclusion Criteria:

• All patients attending for a routine diagnostic endoscopic procedure at St Mary's Hospital NHS Trust for dyspepsia and abdominal pain

Exclusion Criteria:

• Patients attending for a therapeutic endoscopic procedure e.g. variceal banding, stent insertion, balloon dilatation.
• Patients with a known diagnosis e.g. upper gastrointestinal cancer
• Patients previously treated with HP eradication therapy
• Patients who had taken PPI, H2 receptor antagonists and antibiotics within 4 weeks
• Patients with acute gastrointestinal bleeding
• Patients who'd had previous gastric surgery
• Patients with chronic liver disease
• Patients with abnormal coagulation or any other contra-indication to use of standard biopsy in routine diagnostic endoscopic procedures
• Patients who are unable or unwilling to give informed consent
• Patients under the age of 18 years

1 year

Patients developing adverse events were to be identified either at the time of endoscopy, or on review of patient records at the time of study reporting.