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Cancer
Published in Jahangir Moini, Matthew Adams, Anthony LoGalbo, Complications of Diabetes Mellitus, 2022
Jahangir Moini, Matthew Adams, Anthony LoGalbo
Colonoscopy is the diagnostic procedure of choice in patients with a clinical history suggestive of colon cancer. This procedure permits biopsy for pathologist confirmation of malignancy. Virtual colonoscopy uses CT to generate 2D and 3D images of the colon. This test may be good for people who cannot tolerate or are unwilling to have an endoscopic colonoscopy. A colonoscopy should be done every 10 years. However, if a patient has a family history, with a first-degree relative having had colon cancer before the age of 60, a colonoscopy should be done every 5 years starting at age 40 – or every 10 years. When a fecal occult blood test is positive, a colonoscopy is required. A colonoscopy is also required after a lesion is seen in an imaging study or during sigmoidoscopy. All lesions are completely removed and examined.
Colorectal cancer
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Svetlana Balyasnikova, Gina Brown
Computed tomography (CT) colonography (virtual colonoscopy) can detect large and medium sized polyps in addition to CRC (16). However, the costs and resources needed to run a virtual colonoscopy service has limited its incorporation as a first line test in national screening programmes. It is currently recommended that virtual colonoscopy is used in situations when conventional colonoscopy has failed or is contraindicated. It is also an optional method for screening (patient choice).
X-ray Vision: Diagnostic X-rays and CT Scans
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
The ability to perform spiral CT scans readily also enables “virtual endoscopy” applications such as virtual colonoscopy, in which computer-reconstructed views of the inside of the colon are generated from CT scans, and displayed as a three-dimensional image (Figure 5.34) or video. Early results from clinical studies have shown that virtual colonoscopy can be as accurate as traditional colonoscopy at finding polyps, growths that might indicate colon or rectal cancer. Although the spiral CT approach is noninvasive, less expensive, and appealing for patients who cannot or will not tolerate colonoscopy, it cannot remove or biopsy the tumors or polyps, unlike colonoscopic procedures, it exposures the patient to a radiation dose, and it still requires unpleasant procedures to clear the bowel of all stool.
Advances in tests for colorectal cancer screening and diagnosis
Published in Expert Review of Molecular Diagnostics, 2022
Sarah Cheuk Hei Chan, Jessie Qiaoyi Liang
Virtual colonoscopy (VC) is an imaging modality that uses computed tomography (CT) to generate two-dimensional and three-dimensional images of the colon for the detection of polyps and masses [125,126]. Its diagnostic performance is comparable to optical colonoscopy, the current gold standard for CRC detection. The sensitivities of VC in identifying adenomatous polyps of at least 10 mm, 8 mm, and 6 mm in diameter are 93.8%, 93.9%, and 88.7%, respectively, while the sensitivities of optical colonoscopy for these three categories are 87.5%, 91.5%, and 92.3%, respectively [127]. These findings are similar to that of another study, which reports a sensitivity of 70% for polyps with size between 6 and 9 mm and 85% for polyps larger than 9 mm [128].
Use of enteroscope without the overtube in incomplete colonoscopies
Published in Scandinavian Journal of Gastroenterology, 2020
Flaminia Purchiaroni, Silvia Conti, Giorgio Valerii, Guido Costamagna, Maria Elena Riccioni
The US Multi-society Task Force on CRC stated that caecal intubation rate should be above 90% for all colonoscopies and above 95% for screening colonoscopies [1]. Despite the progress in the endoscopy technology field and the improvement of training programmes for endoscopists, there still is a certain percentage of unsuccessful procedures, mostly related to either fixed and angulated colon or long and loopy colon. Incomplete procedures may lead to higher healthcare costs and possibly to increased morbidity and mortality because of missing lesions [22,23]. To overcome such issue, the use of scopes different from standard colonoscope has been suggested in literature, such as PCF [24,25], GIF [26,27], DBE and SBE [15–18,28] and PE [14]. However, there may be some disadvantages when using the aforementioned scopes to perform colonoscopy. Indeed, with respect to GIF, the main limitations are the relatively short scope length and the small suction channel, which can get easily occluded during aspiration of faecal residue. DBE and SBE are associated with higher costs and longer procedure time, because of the overtube-balloon equipment, and to patient’s X-ray exposure during fluoroscopic guidance. Moreover, they are usually available only in tertiary-care academic centres. PCF is useful in case of loopy and angulated colon because of its thinner diameter, but it is shorter than SBE and DBE and, therefore, it may not be helpful for the intubation of long colon. Other options for bowel study after an unsuccessful colonoscopy are computed tomographic virtual colonoscopy (CTVC) and capsule endoscopy (CE). However, both diagnostic techniques do not allow to perform operative endoscopy, such as polyps removal. Moreover, polyps smaller than 5 mm are not seen by CTVC, as they fall below its detection threshold [29].
Triumph against cancer: invading colorectal cancer with nanotechnology
Published in Expert Opinion on Drug Delivery, 2021
Preksha Vinchhi, Mayur M. Patel
CT colonography also termed as ‘virtual colonoscopy’, is a computerized x-ray imaging procedure that provides two-dimensional and three-dimensional images of the interior of the colon [33]. In patients having an obstructing or stenotic tumor, full colonoscopy cannot be performed, in such cases, CTCG serves as a potential substitute to colonoscopy [34]. The CT scanning procedure involves complete colon evacuation (bowel preparation), followed by its enlargement by insufflation with air or carbon dioxide for better viewing. Further after insufflation, the patient is scanned while lying in supine as well as prone position [31]. The discomfort to the patient undergoing CT colonography is comparable to colon endoscopy because of the requirement of colon evacuation and insufflation but on the other hand, it has an advantage of circumventing the requirement of sedation. The technique offers high detection sensitivity and specificity (82%) for polys >10 mm in size (large polyps) but has a low sensitivity (63%) for the detection of polyps with a 6–9 mm size range (small polyps) [35,36]. Moreover, the technique is not able to determine flat and serrated lesions. CTCG is a poor technique for the staging of CRC tumor whereas, MRI is highly recommended for determining the local stage of the tumor. Pre-operative MRI helps to design the surgery owing to high accuracy in identifying the invasion and spread of tumors. Major limitations of the CTCG diagnosis method comprises the exposure to radiation, less sensitivity to detect small polyps, the requirement of bowel preparation, and need of additional process for removal of polyps if detected. It is also associated with a high degree of extra-colonic lesions detection which further necessitates unnecessary monitoring, upturns patient’s anxiety and generates an additional cost [37]. MRI has a limitation in the detection of mesenteric, pelvic lateral and suprarenal CRC tumors.