A new filtering algorithm for medical magnetic resonance and computer tomography images. (1/2057)

Inner views of tubular structures based on computer tomography (CT) and magnetic resonance (MR) data sets may be created by virtual endoscopy. After a preliminary segmentation procedure for selecting the organ to be represented, the virtual endoscopy is a new postprocessing technique using surface or volume rendering of the data sets. In the case of surface rendering, the segmentation is based on a grey level thresholding technique. To avoid artifacts owing to the noise created in the imaging process, and to restore spurious resolution degradations, a robust Wiener filter was applied. This filter working in Fourier space approximates the noise spectrum by a simple function that is proportional to the square root of the signal amplitude. Thus, only points with tiny amplitudes consisting mostly of noise are suppressed. Further artifacts are avoided by the correct selection of the threshold range. Afterwards, the lumen and the inner walls of the tubular structures are well represented and allow one to distinguish between harmless fluctuations and medically significant structures.  (+info)

Consent obtained by the junior house officer--is it informed? (2/2057)

Of 30 junior house officers questioned, 21 had obtained patients' consent for colonoscopy. Of these 21, about one-third did not routinely discuss with patients the risks of perforation and haemorrhage. Ideally, consent should be obtained by a person capable of performing the procedure. If it is to be obtained by junior house officers, they need to know exactly what must be disclosed about each procedure. This could easily be done as part of the induction package.  (+info)

Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation. (3/2057)

BACKGROUND AND AIMS: Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy. METHODS: Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination. Light of 337, 405, or 436 nm wavelength was used as excitation. Stepwise multivariate linear regression analysis was performed. RESULTS: With 337 nm excitation, 100% sensitivity and 96% specificity was obtained between normal mucosa and adenomas. Seventy seven per cent of the hyperplastic polyps were classified as non-neoplastic. When exciting with 405 and 436 nm, the possibility of distinguishing different types of tissue was considerably better in the ALA patients than in the non-ALA patients. CONCLUSIONS: The in vivo point measurements imply that a good discrimination between normal tissue and adenomatous polyps can be obtained using the LIF technique. Excitation at 337 nm and at 405 nm or 436 nm using ALA gives good results. LIF also shows potential for distinguishing adenomatous from hyperplastic polyps. The number of detection wavelengths could be reduced if chosen properly.  (+info)

Transmesenteric hernia after laparoscopic-assisted sigmoid colectomy. (4/2057)

BACKGROUND AND OBJECTIVES: Laparoscopic-assisted surgery has been applied for a variety of colonic surgery. The objective of this paper is to demonstrate a possible and avoidable complication of laparoscopic colonic surgery. CASE PRESENTATION: A 47-year-old woman underwent gasless laparoscopic-assisted sigmoid colectomy. On the 20th postoperative day, she developed bowel obstruction. Decompression with a long tube failed to resolve the bowel obstruction. Open laparotomy was performed. Abdominal exploration revealed a loop of the small bowel incarcerated in the mesenteric defect caused by the previous operation. Adhesiolysis was performed, and the postoperative course was uneventful. DISCUSSION: Despite technical difficulty, complete closure of the mesentery after bowel resection is strongly recommended for prevention of transmesenteric incarcerated hernia after laparoscopic surgery.  (+info)

Randomised trial of two pharmacological methods of bowel preparation for day case colonoscopy. (5/2057)

AIMS: To undertake a prospective, single blind, randomised trial comparing the efficacy and tolerance of two outpatient colonoscopy bowel preparation regimens. METHODS: Patients aged between 18 months and 16 years being admitted for day case colonoscopy were allocated randomly to receive either Picolax (an oral, sugar free powder containing sodium picosulphate 10 mg/sachet with magnesium citrate) and clear fluids or bisacodyl tablets with an unrestricted diet and a phosphate enema just before colonoscopy. Patient compliance, bowel frequency, and associated symptoms were recorded, and the adequacy of the bowel preparation was assessed in a blinded manner. RESULTS: 63 of 66 patients completed the trial. Mean age, mean weight, extent of colonoscopy, and distribution of underlying pathology were similar in both groups. Bowel preparation was good or excellent in all of the patients in the Picolax group (n = 32) compared with 22 patients in the bisacodyl/phosphate enema group (n = 31). The latter group experienced more abdominal discomfort during bowel preparation but three of the Picolax group vomited and the lack of solid food distressed some children. CONCLUSIONS: All bowel preparation methods have limitations and unpleasant side effects but the use of Picolax and clear fluids proved superior to bisacodyl tablets and a phosphate enema in children undergoing day case colonoscopy.  (+info)

Colonic ulceration caused by administration of loxoprofen sodium. (6/2057)

A 54-year-old female with chronic headache was admitted to our hospital because of hematochezia. She had routinely taken loxoprofen sodium because of severe headache. Emergent colonoscopic examination revealed ulceration of the cecum. After administration of loxoprofen sodium was discontinued and administration of sulfasalazine was initiated, her intestinal bleeding subsided. Two months after discontinuation of loxoprofen sodium, the colonoscopic examination revealed scar formation at the site of cecal ulceration. In this case, it was conceivable that the administration of loxoprofen sodium might have induced colonic ulceration.  (+info)

Colorectal cancer: risk factors and recommendations for early detection. (7/2057)

Spurred by mounting evidence that the detection and treatment of early-stage colorectal cancers and adenomatous polyps can reduce mortality, Medicare and some other payors recently authorized reimbursement for colorectal cancer screening in persons at average risk for this malignancy. A collaborative group of experts convened by the U.S. Agency for Health Care Policy and Research has recommended screening for average-risk persons over the age of 50 years using one of the following techniques: fecal occult blood testing each year, flexible sigmoidoscopy every five years, fecal occult blood testing every year combined with flexible sigmoidoscopy every five years, double-contrast barium enema every five to 10 years or colonoscopy every 10 years. Screening of persons with risk factors should begin at an earlier age, depending on the family history of colorectal cancer or polyps. These recommendations augment the colorectal cancer screening guidelines of the American Academy of Family physicians. Recent advances in genetic research have made it possible to identify persons at high risk for colorectal cancer because of an inherited predisposition to develop this malignancy. These patients require aggressive screening, usually by lower endoscopy performed at an early age. In some patients, genetic testing can guide screening and may be cost-effective.  (+info)

Issues of consent in colonoscopy: if a patient says 'stop' should we continue? (8/2057)

Colonoscopy is generally performed under intravenous sedation, which may alter a patient's responses and perception. What should be done if, during the procedure, a patient withdraws the consent previously given? The views of gastroenterologists and patients were ascertained by mailing questionnaires to 100 members of the British Society of Gastroenterology and to 100 patients who had undergone colonoscopy with intravenous sedation. Only 1 of 59 eligible consultants who replied said they would stop the procedure after a single request, but a further 51 would stop if repeatedly asked to do so. Of the remaining 7 who would complete the procedure, 1 nevertheless believed that a sedated patient is capable of making a rational decision. Of the 51 patients who returned a usable questionnaire, 25 thought that the procedure should be stopped immediately following a request, while 26 felt that the doctor should continue. The divergent and sometimes inconsistent views found in this study highlighted the need for further clarification of the issue of informed consent for procedures conducted with the patient under sedation.  (+info)

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