View clinical trials related to Polyps.
Filter by:The hypothesis of this study is that prophylactic coagulation therapy with coagulation forceps to visible vessels within the mucosal defect for colonic Endoscopic Mucosal Resection (EMR) will reduce the rate of delayed bleeding when compared with current established standard EMR technique.
The investigators seek to compare the accuracy of the existing colonoscope model to determine the magnitude of the improvement the investigators can expect in polyp discrimination as neoplastic or non-neoplastic.
We hypothesize that high definition narrow band imaging (NBI) colonoscopy compared to high definition white light colonoscopy will detect an increased number of nonpolypoid (flat and depressed) colorectal neoplasm.
Polyps found during screening colonoscopy have to be removed or at least biopsied. Attempts to save costs include endoscopic assessment of polyps with regards to differential diagnoses between adenomas (which have to be removed) and hyperplastic polyps (could be left in place or removed and not examined histologically). Such a concept would only be feasible if endoscopy can make the differential diagnosis with high accuracy. Such high accuracy rates - between 80% and 95% - have been reported from reference centers with specific scientific interest. The investigators want to test whether these results a) can be reproduced in the private practice setting performing large-volume screening colonoscopies and b) whether latest generation endoscopes provide benefit in terms of better accuracy.
The investigators hypothesize that high definition colonoscopy with close focus narrow band imaging features has a high diagnostic accuracy for colorectal polyp histology, and can replace formal pathologic assessment in cases of high diagnostic confidence.
Nasal polyp is a significant health problem with a prevalence of 4%. It is increased in patients with asthma (7-15%), Cystic fibrosis (39-56%) or aspirin intolerance (36-96%).The quality of life (QOL) is worse than in patients suffering from hypertension, migraine, angina pectoris and head & neck cancer as per a previous study by Videler WJM et al.QOL is in comparison to chronic obstructive pulmonary disease.The reason why it develops in some and not in others remains unknown despite the disease being present for centuries.A definite relationship exists in patients with 'Sampter triad': Asthma, non steroidal anti-inflammatory drug sensitivity and nasal polyps. But not all patients with NSAID sensitivity have nasal polyps and vice verse. Etiology is largely unknown despite the disease being present for centuries. Although the factors like wood stove exposure, smoking, allergic rhinitis, rhino sinusitis have been strongly implicated in literature from various studies, most data available is on ethmoidal polyps.The present study is an attempt to study the association of important risk factors with both antrochoanal(AC) and ethmoidal nasal polyps(EP).One study found that a significantly smaller proportion of the population with polyps were smokers compared to the unselected population (15% v/s 35%). But this is not confirmed by other studies. Seven percent of asthma patients have nasal polyps and in non atopic asthma and late onset asthma, polyps are diagnosed more frequently (10-15%).Eosinophil numbers are significantly higher in nasal polyp tissue and further increased in patients with co-morbid asthma and aspirin sensitivity. Nasal colonization in increased amounts was found by Staphylococcus aureus and presence of specific Immunoglobulin E directed against S.aureus enterotoxins was found. Rates of colonization and IgE presence in nasal polyp tissue were increased in subjects with nasal polyp associated with co-morbid asthma and aspirin sensitivity. Nasal polyps are frequently found to run in families, suggesting a hereditary or with shared environmental factor. In the study by Rugina et al., more than half of 224 nasal polyp patients (52%) had a positive family history while the study by Greisener et.al, reported 14% of family history strongly suggesting hereditary factors in the pathogenesis of nasal polyps. Some studies have found environmental factors like smoking and those using wood stove as a primary source of heating with the development of nasal polyps. The studies are contrasting. There is presently a need of understanding the differences in the pathogenesis of antrochoanal polyp and ethmoidal nasal polyp clearly.There are hardly any concrete research performed on them to note the differences in the etiology and their pathogenesis. Hence the study is undertaken to extensively study the etiologies responsible for them and to note the differences.
Recent studies have shown that narrow-band imaging (NBI) is a powerful diagnostic tool for the differentiation between neoplastic and non-neoplastic colorectal polyps. The aim of the present study is to develop and evaluate a computer-based method for automated classification of small colorectal polyps on the basis of vascularization features.In a prospective study 207 polyps with a size of 10mm or smaller should be detected by a zoom NBI colonoscopy. These polyps were imaged and subsequently removed for histological analysis. the polyp images were analyzed by a computer algorithm. The proposed computer-based method consists of several steps: preprocessing, vessel segmentation, feature extraction and classification. The results of the automatic classification (sensitivity, specificity, negative predictive value, positive predictive value and accuracy)were compared to those of human observers, who were blinded to the histological gold standard.
Colorectal cancer is the second most common cause of cancer death in the US. Colonoscopy is considered the best test colorectal cancer screening. It allows resection of adenomatous polyps (a known cancer precursor) and thus, interrupt the adenoma-carcinoma sequence. Despite the potential benefit of screening colonoscopy recent studies have reported cases of colorectal cancers in a short interval after prior screening or surveillance colonoscopies. One possible cause of such interval cancers may be incomplete resection of adenomatous polyps and hence ongoing growth and cancer development in such lesions. Complete resection may be particularly important for polyps of at least 5mm in size as up 10% of such polyps higher risk lesions as villous adenoma, tubulovillous adenoma, high grade dysplasia, or early carcinoma. Although adenoma resection of sessile and flat adenomatous polyps between 5 and 20mm is believed to be well standardized data on complete resection of adenomatous tissue are sparse. This may be related to the assumption that using a snare with electro-cautery will successfully remove the polyp and cauterize remaining marginal adenomatous tissue and hence completely remove and or destroy the lesion. The investigators are interested in examining how often sessile adenomatous polyps between 5 and 20mm are completely removed using standard polypectomy snare. The investigation was also directed at a comparison between complete resection of polyps between 5 and 9mm and 10 and 20mm.
Chromoendoscopy (that involves spraying of dyes over the colonic mucosa) combined with magnification has been utilized for polyp histology identification. Pit patterns on the surface of polyps described by Kudo et al have been shown to have a high diagnostic accuracy in differentiating the polyp types (18, 19). NBI, that is also referred to as "electronic chromoendoscopy" is another technique that has been evaluated for polyp histology identification by highlighting the superficial mucosal and vascular architecture (15, 20, 21). pCLE is another novel addition to the technologies aiming to accomplish in vivo histologic diagnosis with a high degree of accuracy. The pCLE system has three major components (Mauna Kea Technologies, Paris, France). The first is the confocal miniprobe made of approximately thirty thousand optical fibers bundled together and terminated by a distal microsystem. The images obtained have a lateral resolution of 1µm, an axial resolution of 10 µm and a maximum field of view of 240 µm. The depth of observation is from 55 to 65 µm. The miniprobe tip diameter is 2.5 mm and can be passed through the accessory channel of any standard endoscope. The second is the laser scanning unit (excitation wavelength - 488 nm) that combines the functions of laser light illumination and rapid laser scanning, enabling a frame rate up to 12 images per second and signal detection. The third is the control and acquisition software for real time image reconstruction, immediate sequences display and post-procedure analysis and editing tools. Once an area of interest (e.g. a polyp) is identified, 5 ml of 10% fluorescein sodium is injected intravenously; the confocal probe is passed through the accessory channel of the endoscope and placed against the lesion to obtain several high-quality images and video sequences. In a study by Buchner et al from the Mayo Clinic, Jacksonville, (22) this system was used to evaluate confocal images of 37 polyps from 25 patients in a blinded fashion without the knowledge of their histologic diagnosis or endoscopic appearance. The investigators developed the following criteria that were suggestive of neoplastic polyps: villiform pattern, nuclear characteristics - oval/irregular nuclear shape and increased number of nuclei. These features had a sensitivity of 82.6%, specificity of 92.9% and accuracy of 86.5% for the characterization of neoplastic polyps. Similarly, Meining et al (23) have also evaluated criteria for differentiating neoplastic from benign lesions in the colon with encouraging results. The investigators hypothesize that pCLE will have a high rate for accurate characterization of polyp histology real time during colonoscopy
This simple technique of attaching a transparent cap to the tip of the colonoscope has been evaluated in Japan for improving the detection of polyps and cecal intubation but has not been formally evaluated in the US and other western countries. In one study (19), the polyp detection rate was higher with the transparent cap compared to no cap (49% vs. 39%, p=0.04). Also, the cecal intubation time was shorter with the cap (11.5 min vs 14 min, p=0.008). In a recently published study, a variation of the cap called the transparent retractable extension device was used (21). Overall, the number of adenomas detected were significantly higher with the device compared to without it (205 vs. 150, p=0.04). In an earlier study by Tada et al (22), use of a transparent cap improved the detection rate of lesions per patient (0.86 vs. 0.58) but did not increase the cecal intubation time. Finally, Lee et al (20) used cap assisted colonoscopy in patients with difficult colonoscopy procedure (defined as failure to pass through sigmoid colon after 20 minutes or failure to reach cecum). Using the cap, cecal intubation was achieved in 94% of patients and this proved to be an effective rescue method for failed or difficult colonoscopy. The major appeal of this technique is that it is inexpensive, very practical, and easy to use. Furthermore it is safe and there are no reported complications from this. If found to be effective in increasing the polyp yield it has the potential to being incorporated by busy gastroenterologists in their day to day clinical practice. These features and the preliminary data from Japan merit the evaluation of this promising technique in the US.