Confocal Laser Endomicroscopy Findings in Patients With Proctosigmoiditis Before and After Initiation of Treatment

Confocal laser endomicroscopy findings in patients with proctosigmoiditis before and after initiation of treatment

Background Inflammatory bowel disease (IBD) includes Crohn's disease and ulcerative colitis. Crohn's disease often strikes the terminal ileum, but may occur from the mouth to the anus. It is characterized by segmental spreading with transmural inflammation and occasional presence of granulomas in the tissue samples. Ulcerative colitis is only found in the colon and involves in practice always the rectum. The inflammation is limited to the mucosa and submucosa, and the diffusion is continuous.

The development of endoscopy has made these procedures a central part of the diagnostic and therapeutic management of patients with gastrointestinal diseases, including IBD. The entire gastrointestinal tract is now available for inspection and therapy. A limitation of these studies is that the histology, which is often essential for the diagnosis and treatment of the patient, cannot always be precisely evaluated by a conventional examination. The proper handling of detected lesions require in addition to the endoscopic evaluation, a histological evaluation of the tissue involved, making tissue samples necessary in order to obtain a definitive diagnosis and thus optimal handling. Therefore, during the endoscopic procedure tissue samples from the intestinal mucosa must be taken, which rarely involves a greater risk to the patient, but causes a delay, due to preparation time for the histological analysis and in some cases even due to re-examination if histopathology is negative. In the treatment of IBD the endoscopic assessment of the severity and extension is absolutely essential for the choice of treatment. The "Gold standard" for the optimal treatment is called "deep" remission, defined by clinical and endoscopic remission as assessed by conventional endoscopy.

Within recent years a new approach was introduced, wherein the microscopic structures of the intestinal mucous can be evaluated continuously in vivo during the endoscopic procedure. The technique is called confocal laser endomicroscopy (CLE). CLE functions by means of a laser device, which is inserted or build into an endoscope, and used as an illuminator of the lining of a small area and at a precise depth. The tissue is first added with fluorescence by intravenous administration. The reflection of the mucosa is captured in a focused area and magnified by which a two-dimensional image of mucosal microscopic structures is formed. This provides us with an "optical biopsy", which can be compared with a similar microscopic image.

This provides us with a potential opportunity for immediate diagnosing and targeted therapy during the same procedure. The optical biopsy is stored digitally in such a way that it can also be evaluated postprocedure. During CLE multiple frames are generated per second, which is stored continuously, thereby forming a movie sequence, so that the microscopic assessment of the tissue becomes dynamic i.e. the flow in the small vessels may be observed.