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PubMed2002

CT colonoscopy for obstructive sigmoid endometriosis: a new technique for an old problem.

Endometriosis of the sigmoid colon is a pathologic entity which is infrequently reported. A 29-year-old woman was admitted to the hospital because of abdominal pain, constipation, and menstrual rectal bleeding. Endometriosis was suspected, and CT (virtual) colonoscopy showed severe stenosis of the orthosigmoid canal due to a submucosal mass. Sigmoidoscopy using a pediatric endoscope was successful, and biopsies confirmed the original diagnosis. Non-invasive techniques such as endoscopic ultrasound and CT (virtual) colonoscopy now make it possible to diagnose sigmoid endometriosis. The latter technique, in particular, is feasible and well tolerated.

Journal Article↗

PubMed1976

Treatment of volvulus of the colon by colonoscopy.

The flexible colonoscope has notable advantages over rigid instruments and can be offered as an alternative and (probably) preferable method for non-surgical reduction of colonic volvulus. When operative intervention is called for because of repeated bouts of sigmoid volvulus, colonoscopy offers a means of preoperative deflation of the twisted loop, allowing time to prepare the bowel and correct systemic disturbances such as electrolyte imbalance. The first successful management of a case of recurrent sigmoid volvulus using fiberoptic flexible colonoscope is presented. It is suggested that the fiberoptic colonoscope may have similar application for instances of volvulus occurring more proximal than in the sigmoid colon. Sigmoid volvulus in children even though rare might also be amenable to correction by colonoscopy.

Aged↗

PubMedDate not supplied

Virtual colonoscopy: a new approach for colorectal cancer screening.

Virtual endoscopy is the processing of computerized tomography image data to create a virtual environment of the human body to allow diagnosis of disease processes. This new technique allows the observer the opportunity to interact with an image that is artificially generated by the computer. Virtual colonoscopy provides a method for processing data that can display computer images of the colon in a more anatomic life-like format to facilitate image interpretation and improve diagnostic accuracy. The clinical application of virtual endoscopic techniques is also being used with other procedures such as bronchoscopy, gastroscopy, cystoscopy, sinus imaging, virtual angioscopy, and cerebral ventriculography. Current screening recommendations for colorectal cancer are discussed in this article along with methods, advantages, challenges, and future opportunities for virtual colonoscopy.

Colonography, Computed Tomographic↗

PubMed2005

Virtual colonoscopy for colorectal cancer screening: current status.

Computed tomography colonography (CTC) (also known as 'virtual colonoscopy') is a noninvasive method of imaging the colon using helical CT. Although CTC has been shown to be useful for certain clinical indications, it has not yet been endorsed as a colorectal cancer screening test. The purpose of this article is to review the current status of CTC for colorectal cancer screening. CTC is an accurate method to detect colonic polyps and to select patients who would benefit from colonoscopy. The major advantages of CTC over conventional colonography include its relatively low risk and greater tolerance by patients. In this article, the CTC procedure and results of clinical trials are reviewed, as well as potential pitfalls related to CTC performance and interpretation. Finally, radiation dose, the discovery of incidental extracolonic findings with CTC, bowel preparation methods, and computer-aided diagnosis are addressed.

Colonic Neoplasms↗

PubMed2006

An improved electronic colon cleansing method for detection of colonic polyps by virtual colonoscopy.

Electronic colon cleansing (ECC) aims to segment the colon lumen from a patient abdominal image acquired using an oral contrast agent for colonic material tagging, so that a virtual colon model can be constructed. Virtual colonoscopy (VC) provides fly-through navigation within the colon model, looking for polyps on the inner surface in a manner analogous to that of fiber optic colonoscopy. We have built an ECC pipeline for a commercial VC navigation system. In this paper, we present an improved ECC method. It is based on a partial-volume (PV) image-segmentation framework, which is derived using the well-established statistical expectation-maximization algorithm. The presented ECC method was evaluated by both visual inspection and computer-aided detection of polyps (CADpolyp) within the cleansed colon lumens obtained using 20 patient datasets. Compared to our previous ECC pipeline, which does not sufficiently consider the PV effect, the method presented in this paper demonstrates improved polyp detection by both visual judgment and CADpolyp measure.

Algorithms↗

PubMed1976

Colonoscopy in the management of diseases of the colon and rectum.

This report covers a 2.5-year experience with colonoscopy in the management of 208 patients (104 men and 98 women, average age 58 years). Colonic bleeding of unknown cause and abnormal barium-enema findings were the most common indications for colonoscopic examination. During this period, 110 colonoscopic polypectomies were performed. Among the few complications was one case of perforation of the sigmoid from transcolonoscopic removal of a small carcinoma; the perforation was incidentally discovered at the time of subsequent laparotomy. Bleeding occurred in 6 patients, but only one of them required surgical intervention to arrest the hemorrhage. Colonoscopy is a safe, effective and reliable diagnostic and therapeutic procedure. Its use can reduce expense for the patient and obviate a long painful postoperative period.

Adult↗

PubMed1978

Colonoscopy for unexplained rectal bleeding.

Two hundred and thirty-nine patients underwent colonoscopy for unexplained rectal bleeding. Local anorectal conditions were excluded by digital and proctosigmoidoscopic examinations and results of barium studies were negative for all patients. A cause for bleeding was found in 95 patients. Thirty-nine had adenomatous polyps, 24 had unrecognised inflammatory bowel disease, and most importantly 23 (10% of series) had carcinomas. Forty patients had diverticular disease, but nine of them were found to have an adenomatous polyp and four a carcinoma. Colonoscopy can contribute positively to the investigation and treatment of unexplained rectal bleeding and may prevent unnecessary laparotomy.

Colitis↗

PubMed1975

Colonoscopy in management of colonic strictures.

A total of 160 strictures were examined in 154 patients with the fibreoptic colonoscope. When it was possible to make a pre-examination diagnosis colonoscopy proved it wrong in 52% of cases. Unnecessary laparotomy was probably avoided in over half this series. All strictures of the large bowel should be examined colonoscopially whenever possible before considering surgery.

Colitis, Ulcerative↗

PubMed1979

Colonic adenomas--a colonoscopy survey.

A colonoscopy survey of 620 patients with 1049 colon adenomas showed a predominantly left-sided distribution (77%). Of these lesions 97% were amenable to endoscopic removal or ablation. Sixty per cent of patients presented with rectal bleeding as their major symptom. There was agreement between radiology and colonoscopy in only 62% of patients, as many of the studies were single contrast barium enemas, performed before referral. Forty-eight per cent of adenomas in our series were less than 1.0 cm in diameter. Of the larger adenomas (greater than 2.0 cm in diameter) 66% were situated in the sigmoid colon, and of those containing invasive carcinoma (4.8% of the total) an even higher percentage (94%) were in the sigmoid and low descending colon. With increasing polyp size, there was a greater predominance of villous elements and this was associated with a higher risk of malignant change than the more frequent and generally smaller tubular adenoma. Local colonoscopic excision alone is sufficient treatment for adenomas with malignant change unless they are poorly differentiated histologically and providing adequate resection is demonstrated. Twenty-eight patients treated in this way are alive without recurrence at periods from six to 62 months. Although 65% of patients had only one adenoma, and 90% three or less, there is a risk of developing other benign and malignant colon neoplasms and careful follow-up is required.

Adenoma↗

PubMed1977

Comparison of barium enema nad colonoscopy in the detection of small colonic polyps.

A total of 210 patients was examined by barium enema and colonoscopy. The authors found 219 polyps in 112 patients. Single-contrast barium enema missed 33 (45.2%) and double-contrast barium enema missed 17 (11.7%) polyps. Colonoscopy failed to detect 6 polyps (2.7%) and another 21 (10%) were not seen because the area could not be reached by the colonoscope. Malignancy was present in 5 small polyps. The authors conclude that the double-contrast barium enema offers a definite advantage in the right colon. In general, the two methods are complementary.

Barium Sulfate↗

PubMed2004

Extracolonic and incidental findings on CT colonography (virtual colonoscopy).

OBJECTIVE: The objective of our study was to prospectively determine the frequency and clinical importance of extracolonic findings on CT colonography in symptomatic patients. SUBJECTS AND METHODS. One hundred eleven symptomatic patients referred for colonoscopy underwent CT colonography before colonoscopy. Helical CT from the diaphragm to the symphysis was performed with the patient in the supine and prone positions after rectal air insufflation. Image interpretation was done on a digital workstation. Extracolonic findings were classified as minor, moderate, or major according to potential clinical importance. Patient records, with a follow-up time of about 3 years, were reviewed to determine final diagnoses. RESULTS: Twenty-six (23%) of the patients had CT findings of major importance such as lymphadenopathy (n = 7), aortic aneurysm (n = 6), suspected solid hepatic masses (n = 5), and suspected solid renal masses (n = 4). Fifty-eight patients (52%) had findings of moderate importance such as gallstones (n = 16), indeterminate renal masses (n = 9), adrenal masses with benign appearance (n = 8), and hiatal hernia (n = 7). Forty-six patients (41%) had no or only minor findings, such as renal cysts (n = 34), renal calcifications (n = 19), and hepatic cysts (n = 14). Review of patient records showed that CT colonography contributed to the detection of major, previously unknown extracolonic disorders in 14 (13%) of the 111 patients. CONCLUSION: Potentially important extracolonic findings were revealed in 23% of the patients, leading to additional diagnostic or therapeutic considerations. Some of these findings were clinically important, whereas others were previously known or led to unnecessary workup. This finding must be taken into account when CT colonography is considered for routine diagnostic workup or screening.

Adult↗

PubMed2000

Does flexible small-diameter colonoscope reduce insertion pain during colonoscopy?

AIM:It is well known that colonoscopy can be difficult due to abdominal pain induced during colonoscope insertion, if sedative agents are not given. Recently, an extra-flexible, small-diameter colonoscope (CF-SV, Olympus Inc.Japan) was developed in order to improve safety and comfort. The aim of this study was to access the usefulness of the CF-SV.METHODS:One hundred patients undergoing sigmoidoscopy were recruited and colonoscopy was performed by one experienced colonoscopist. First, a routine type colonoscope (CF-230I) was inserted into the colon without sedation. When the patient complained of abdominal pain (even if mild), the scope was not advanced further and was withdrawn after the anatomic location of its tip was determined fluoroscopically. Then, the CF-SV was inserted until it reached the cecun or the site where abdominal pain occurred. Previous abdominal surgery and abdominal disease were considered as unfavorable factors (UF) and the relationship between abdominal pain and UF, age and gender were investigated.Furthermore, the colonic insertion pressures in 36 patients with abdominal pain were measured with a force gauge.RESULTS:Thirty-four cases (34%) felt no pain with the CF-230I and successful pancolon-oscopies to the cecum were performed. Sixty-six cases (66%) complained of abdominal pain. The procedure was painless for 47% of men and 24% of women, respectively. The CF-230I scope failed to reach the sigmoid-descending colon junctions in 59 (89.4%) of the 66 patients complaining of abdominal pain. However, CF-SV reached proximal area in 94.9% of those who failed with CF-230I. The median pressure for pain-inducing was 700g/cm(2).CONCLUSION:Unsedated patients with UF were prone to complain of pain when the standard type CF-230I scope was used. The newly developed extra-flexible CF-SV is useful for the aged and for those with UF or being prone to suffer from abdominal pain. Sedative agents may be unnecessary if this new type of colonoscope is used.

Journal Article↗

PubMed2001

A review of technical advances in virtual colonoscopy.

Early detection of polyps has proven to lead to a decrease in incidence of colon cancer. In the past few years, virtual colonoscopy has been developed as a patient-friendly screen-ing technique. The procedure comprises the following steps. First, the patient's colon is cleansed and transanally inflated with air. Subsequently, a 3D image volume is acquired of the abdomen by CT or MRI. Finally, the bowel surface is extracted and visualized, after which the physician virtually navigates through the colon and examines the surface for abnormalities. This paper describes the progress in research for virtual colonoscopy.

Colonography, Computed Tomographic↗

PubMedDate not supplied

New automatic software for virtual colonoscopy: technical aspects.

PURPOSE: To evaluate a new virtual endoscopy software package capable of automatically plotting the path along which to perform endoscopic exploration. MATERIALS AND METHODS: We reviewed the examinations of 50 patients with colonic neoplasms studied by CT colonoscopy by using a single-detector CT scanner (Philips Tomoscan AVE1). The technical parameters used were: slice thickness 3 mm, pitch 1.4, reconstruction interval 2-2.5, 120 kV, 150-200 mA. The images were processed on a separate workstation (Philips Easy Vision 5.1) running an experimental virtual endoscopy software package capable of automatically drawing a line along which to move the virtual endoscope to explore the colon. Reconstruction of the endoscopic images along the path obtained was set at an interval of 15-20 mm between one endoscopic view and the next, to a total of 70 to 120 images. The endoscopic animated image sequence was then saved and evaluated by comparing the starting axial images and the three-dimensional images obtained. RESULTS: The programme plotted the endoscopic path correctly in a single pass in 40 of the 50 cases studied. The overall time spent by the radiologist on image-processing did not exceed 5 minutes. DISCUSSION: The need to reduce the time spent by audiologists on post-processing has led to a gradual improvement in image-processing hardware and software. In the context of virtual endoscopy, one of the main goals is to obtain the path for endoscopic exploration in as short a time as possible. The programme we evaluated successfully fulfils this requirement as, once the image-processing technical parameters have been defined, it plots a path along the entire colon and performs the reconstruction procedures automatically. The time spent by the operator on post-processing does not exceed 5 minutes. CONCLUSIONS: The new programme evaluated in this study facilitates the processing of endoscopic images, reduces radiologist time and may contribute to the widespread use of virtual colonoscopy.

Colonic Neoplasms↗

PubMed2002

Considering virtual colonoscopy.

Virtual colonoscopy continues to show promise as a colorectal cancer screening test and is technically evolving rapidly. It has particular advantages with regard to acceptability by both radiologists and patients. Important steps to achieve implementation include clear delineation of all of the technical components necessary to produce consistent high performance and development of clear-cut recommendations for interpretation and management of polyps of various sizes and the range of extracolonic findings identified. Development of an effective methodology to perform the test without bowel preparation or demonstration of cost-effectiveness for identification and treatment of one or more significant extracolonic diseases would be major breakthroughs, provided they are still accompanied by effective detection of significant colon neoplasms. Issues regarding general effectiveness and cost-effectiveness must be resolved before virtual colonoscopy is endorsed for widespread colorectal cancer screening or utilized for that purpose.

Colonic Polyps↗

PubMed1976

Does bacteremia follow colonoscopy?

In order to determine the risk of bacteremia from colonoscopy, we cultured blood specimens from 40 patients the day before laxative and enema preparation; right after such preparation; and 15 min, 1 hr, and 4 hr after colonscopy. Bacteremia was not induced by either the vigorous preparation or the colonscopy which, in 27 patients, included polypectomy, biopsy, and/or fulgurations. On the basis of our data, we conclude that the risk of bacteremia following colonoscopy is small, and we doubt the need of antibiotic prophylaxis for those with susceptible hearts.

Colon↗

PubMed1976

The diagnosis of colitis by colonoscopy with biopsy and X-ray examination. A blind comparative study.

The examinations were performed in 40 outpatients, of whom 21 were women. From the rectal and colonic mucosa 185 biopsies were obtained. The X-ray examination was performed within one week from the colonoscopy, using a conventional barium enema. A complete agreement between the colonoscopic diagnosis and that of the directed biopsy was found in 33 cases (80 per cent), and minor disagreements in 3 cases. A complete agreement between the colonoscopic and X-ray diagnoses was obtained in 22 patients (55 per cent), and minor disagreements in 16 cases, most of whom showed "unspecific" non-ulcerative colitis. In 3 cases with ulcerative colitis a normal colon was found by X-ray. A higher percentage of cases showed decreased haustration by X-ray examination than by colonoscopy, whereas a fairly equal percentage of ulceration was detected by the two methods. Erosions, mucus covering, oedema, vascular injection, and bleedings were not detected by X-ray examination.

Adult↗

PubMed2003

Computed tomography colonography (virtual colonoscopy): update on technique, applications, and future developments.

Computed topography colonography (CTC) was first described in 1994 as a rapid, non-invasive imaging method to investigate the colon and rectum. Since the advent of CTC, it has been regarded as a potential alternative technique to conventional colonoscopy for detection of colorectal polyps and cancers. Patients undergo standard bowel preparation 24 to 48 hours before the procedure, using either a standard barium enema preparation or balanced polyethylene glycol (PEG) solution. This rapid examination, without the use of sedation or intervention, is well-tolerated by patients. The potential for limited bowel preparation can reduce discomfort associated with traditional purging techniques significantly, and result in an improved perception of the screening study. CTC is performed using a single or multislice CT scanner, with acquisition of volumetric data from the entire colon. Multislice technology enables fast scanning with high resolution. To minimize the radiation dose, efforts have been made to adapt the tube current to the minimum accepted dose while not diminishing study performance. Acquired CT data are transferred onto a dedicated workstation equipped with navigator software, which permits the radiologist to obtain multiplanar reformations as well as construct an endoluminal model of the air-distended colon. Currently, the most widely accepted application for CTC is following incomplete colonoscopy. Other indications that await further clinical validation include colorectal screening. The collective experience of published studies shows CTC to be an accurate tool for detection of clinically significant colorectal polyps. Specificity and sensitivity of CTC are excellent for polyps larger than 10 mm.

Colectomy↗