| Summary: | Colonoscopy remains the gold standard for detection of dysplasia in the colon. Resection of dysplasia at colonoscopy has been shown to reduce the subsequent risk of colorectal cancer. With the recent advent of National Bowel Cancer Screening Programme the number of colonoscopies performed in the United Kingdom has increased significantly. In addition, the recent drive for quality improvement has resulted in increased number of dysplastic lesions detected, resected and sent for histopathology. This has led to substantial increases in the cost associated with the procedure. This thesis investigates how advanced technology can improve detection and characterisation of dysplasia at colonoscopy, potentially contributing to time and cost savings. The introduction reviews the literature on dysplasia detection at colonoscopy, both in terms of basic withdrawal technique and how advanced technology can help reduce miss rates. The significance of small colorectal polyps is reviewed and the accuracy of recent colonoscopic technologies in polyp characterization considered. Three studies examined detection of dysplasia: a small randomized control trial showed that magnetic endoscope imager did not improve caecal intubation or dysplasia detection rates in selected patients when used by experienced colonoscopists. Two studies, one of which was in patients with long standing colitis, did not demonstrate the benefit of narrow band imaging for detection of dysplasia. A cohort study revealed that in vivo characterization of dysplasia can be done accurately and is feasible in routine clinical practice although the inter-observer agreement is moderate at best as assessed by a retrospective study. A computer algorithm was devised to attempt to reduce the inter-observer variability and has shown promising results in a pilot study. A training module on the use of narrow band imaging in characterization was developed and validated leading to improved accuracy and reduced variability amongst the participants. Finally, a quality assurance study confirmed that the still photographs of polyps are adequate record of optical diagnosis.
|
|---|
