Efficacy of barium-based fecal tagging for CT colonography: a comparison between the use of high and low density barium suspensions in a Korean population - a preliminary study.
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Optimizing computer-aided colonic polyp detection for CT colonography by evolving the Pareto fronta.
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A multiobjective genetic algorithm is designed to optimize a computer-aided detection (CAD) system for identifying colonic polyps. Colonic polyps appear as elliptical protrusions on the inner surface of the colon. Curvature-based features for colonic polyp detection have proved to be successful in several CT colonography (CTC) CAD systems. Our CTC CAD program uses a sequential classifier to form initial polyp detections on the colon surface. The classifier utilizes a set of thresholds on curvature-based features to cluster suspicious colon surface regions into polyp candidates. The thresholds were previously chosen experimentally by using feature histograms. The chosen thresholds were effective for detecting polyps sized 10 mm or larger in diameter. However, many medium-sized polyps, 6-9 mm in diameter, were missed in the initial detection procedure. In this paper, the task of finding optimal thresholds as a multiobjective optimization problem was formulated, and a genetic algorithm to solve it was utilized by evolving the Pareto front of the Pareto optimal set. The new CTC CAD system was tested on 792 patients. The sensitivities of the optimized system improved significantly, from 61.68% to 74.71% with an increase of 13.03% (95% CI [6.57%, 19.5%], p = 7.78 x 10(-5)) for the size category of 6-9 mm polyps, from 65.02% to 77.4% with an increase of 12.38% (95% CI [6.23%, 18.53%], p = 7.95 x 10(-5)) for polyps 6 mm or larger, and from 82.2% to 90.58% with an increase of 8.38% (95% CI [0.75%, 16%], p = 0.03) for polyps 8 mm or larger at comparable false positive rates. The sensitivities of the optimized system are nearly equivalent to those of expert radiologists. (+info)
CT colonography - towards applications for colorectal cancer screening.
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Three-dimensional (3D) imaging of the large intestine is globally called computed tomography colonography (CTC). CTC has been intensively investigated for application in colorectal cancer screening in Western countries and with the advent of multi-slice CT (MSCT), which provides effective high resolution in 3D CT images, the diagnostic use of CT for colorectal lesions has become a concept widely accepted throughout the world. Computer-aided detection (CAD) for colorectal polyps using digital CT image data and digital pre-processing are also advancing in the West. Compared with colonoscopy, which depends largely on the skill of the performer, CTC produces objective and reproducible diagnostic images and presents a high probability of standardizing examination protocols. Development of effective systems for screening colorectal lesions is expected, leveraging the excellent processing capability of MSCT to enhance 3D visualization and allow efficient detection. (+info)
A comparison of patient acceptance and preferences between CT colonography and conventional colonoscopy in colorectal cancer screening.
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Primary uncleansed 2D versus primary electronically cleansed 3D in limited bowel preparation CT-colonography. Is there a difference for novices and experienced readers?
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Patient satisfaction with colonoscopy: a literature review and pilot study.
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BACKGROUND: Current guidelines recommend that colonoscopic colorectal cancer screening be undertaken every 10 years after the age of 50 years. However, because the procedure does not meet criteria that promote screening uptake, patient satisfaction with colonoscopy may encourage repeat screening. OBJECTIVE: To systematically review the literature and conduct a pilot study of patient satisfaction with the colonoscopy experience. METHODS: All cohort studies from January 1997 to August 2008 in the MEDLINE database that measured either patient satisfaction with colonoscopy, patient willingness to return for colonoscopy under the same conditions or patient preference for colonoscopy compared with other large bowel procedures were identified. The search was supplemented by journal citation lists in the retrieved articles. RESULTS: Of the 29 studies identified, 15 met the inclusion criteria. Consistently, the vast majority of patients (approximately 95%) were very satisfied with their colonoscopy experience. Patient satisfaction was similar for screening and nonscreening colonoscopy. Patient willingness to return for the procedure ranged from 73% to 100%. Of the five studies that examined modality preference, three studies reported the majority of patients preferred colonography to colonoscopy and two studies reported the reverse. Our pilot study findings mirrored those of other studies that were conducted in the United States. The major limitation of the included studies was that patients who were most dissatisfied may have gone elsewhere to have their colonoscopy. CONCLUSIONS: Patients were very satisfied with colonoscopy. The majority were willing to return for repeat testing under the same conditions, and colonoscopy was not preferred over other modalities. However, studies were limited by methodological shortcomings. (+info)
Extracolonic findings of computed tomographic colonography in Koreans.
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AIM: To determine the frequency and characteristics of extracolonic lesions detected using computed tomographic (CT) colonography. METHODS: The significance of extracolonic lesions was classified as high, intermediate, or low. Medical records were reviewed to establish whether further investigations were carried out pertaining to the extracolonic lesions that were detected by CT colonography. RESULTS: A total of 920 cases from 7 university hospitals were included, and 692 extracolonic findings were found in 532 (57.8%) patients. Of 692 extracolonic findings, 60 lesions (8.7%) were highly significant, 250 (36.1%) were of intermediate significance, and 382 (55.2%) were of low significance. CT colonography revealed fewer extracolonic findings in subjects who were without symptoms (P < 0.001), younger (P < 0.001), or who underwent CT colonography with no contrast enhancement (P = 0.005). CT colonography with contrast enhancement showed higher cost-effectiveness in detecting highly significant extracolonic lesions in older subjects and in subjects with symptoms. CONCLUSION: Most of the extracolonic findings detected using CT colonography were of less significant lesions. The role of CT colonography would be optimized if this procedure was performed with contrast enhancement in symptomatic older subjects. (+info)