computed tomographic colonography

• コンピュータ断層撮影コロノグラフィー

関

CT colonography、virtual colonoscopy

WordNet

1. X-ray machine in which a computer builds a detailed image of a particular plane through an object from multiple X-ray measurements

PrepTutorEJDIC

1. …'を'計算する,見積もる / 計算する,算定する

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/10/21 13:42:31」(JST)

wiki en

[Wiki en表示]

Virtual colonoscopy
Intervention
MeSH	D023881
MedlinePlus	007253

Virtual colonoscopy (VC, also called CT Colonography or CT Pneumocolon) is a medical imaging procedure which uses x-rays and computers to produce two- and three-dimensional images of the colon (large intestine) from the lowest part, the rectum, all the way to the lower end of the small intestine and display them on a screen. The procedure is used to diagnose colon and bowel disease, including polyps, diverticulosis and cancer. VC is performed via computed tomography (CT), sometimes called a CAT scan, or with magnetic resonance imaging (MRI). A virtual colonoscopy can provide 3D reconstructed endoluminal views of the bowel.

Procedure

This video shows a virtual colonoscopy of the rectosigmoid colon performed in a retrograde fashion. There is a 10-mm colonoscopically-proven polyp in the sigmoid colon seen at the top of the frame at the midpoint of the movie. The movie concludes at the tip of the rectal tube which was used to insufflate the colon.

While preparations for VC vary, the patient will usually be asked to take laxatives or other oral agents at home the day before the procedure to clear stool from the colon. A suppository is also used to cleanse the rectum of any remaining fecal matter. The patient may also given a solution designed to coat any residual faeces which may not have been cleared by the laxative. This is called 'faecal tagging'. This allows the user (usually a consultant radiologist), viewing the 3D images to effectively subtract the left over faeces, which may otherwise give false positive results.

VC takes place in the radiology department of a hospital or medical center. The examination takes about 10 minutes and does not require sedatives.

During the procedure:

• The patient is placed in a supine position on the examination table
• The patient may be given a dosage of Butylscopolamine intravenously to minimize muscle activity in the area.
• A thin tube is inserted into the rectum, so that air can be pumped through the tube in order to inflate the colon for better viewing.
• The table moves through the scanner to produce a series of two-dimensional cross-sections along the length of the colon. A computer program puts these images together to create a three-dimensional picture that can be viewed on the video screen.
• The patient is asked to hold his/her breath during the scan to avoid distortion on the images.
• The scan is then repeated with the patient lying in a prone position.

After the examination, the images produced by the scanner must be processed into a 3D image, +/- a fly through (a cine program which allows the user move through the bowel as if performing a normal colonoscopy). A radiologist evaluates the results to identify any abnormalities.

The patient may resume normal activity after the procedure, but if abnormalities are found and the patient needs conventional colonoscopy, it may be performed the same day.

Advantages

VC is more comfortable than conventional colonoscopy for some people because it does not use a colonoscope. As a result, no sedation is needed, and the patient can return to his/her usual activities or go home after the procedure without the aid of another person. The lack of sedation also lowers the risk of the procedure since some people may have adverse reactions to sedative medications used during conventional colonoscopy. VC provides clearer, more detailed images than a conventional x-ray using a barium enema, sometimes called a lower gastrointestinal (GI) series. Further, about 1 in 10 patients will not have a complete right colon (cecum) evaluation completed with conventional colonoscopy. It also takes less time than either a conventional colonoscopy or a lower GI series.

VC provides a secondary benefit of revealing diseases or abnormalities outside the colon.

Disadvantages

According to an article on niddk.nih.gov, the main disadvantage to VC is that a radiologist cannot take tissue samples (biopsy) or remove polyps during VC, so a conventional colonoscopy must be performed if abnormalities are found. Also, VC does not show as much detail as a conventional colonoscopy, so polyps smaller than between 2 and 10 millimeters in diameter may not show up on the images. Furthermore Virtual Colonoscopy performed with CT exposes the patient to ionizing radiation, however some research has demonstrated that ultra-low dose VC can be just as effective in demonstrating colon and bowel disease due to the great difference in x-ray absorption between air and the tissue comprising the inner wall of the colon.

Optical colonoscopy is taken as the "gold standard" for colorectal cancer screening by the vast majority of the medical and research communities. Some radiologists recommend VC as a preferred approach to colorectal screening. However, virtual colonoscopy is considered the gold standard by some professionals because it permits complete visualization of the entire colon, hence providing the opportunity to identify precancerous polyps and cancer, and then to do diagnostic biopsies or therapeutic removal of these lesions, as soon as possible.

External links

• RadiologyInfo - The radiology information resource for patients
• American College of Gastroenterology (ACG)
• International Foundation for Functional Gastrointestinal Disorders (IFFGD)
• Virtual colonoscopy information and articles from Viatronix

Source

• Adapted from public domain Virtual Colonoscopy. National Digestive Diseases Information Clearinghouse.

References

UpToDate Contents

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• 1. コンピュータ断層撮影コロノグラフィの概要 overview of computed tomographic colonography
• 2. 大腸癌のスクリーニングのための検査：便検査、放射線検査および内視鏡検査 tests for screening for colorectal cancer stool tests radiologic imaging and endoscopy
• 3. 大腸癌のスクリーニング：平均的リスクの患者における戦略 screening for colorectal cancer strategies in patients at average risk
• 4. 大腸癌の臨床症状、診断、および病期分類 clinical presentation diagnosis and staging of colorectal cancer
• 5. 成人における大腸内視鏡検査の概要 overview of colonoscopy in adults

English Journal

• Endoluminal surface registration for CT colonography using haustral fold matching.

• Hampshire T, Roth HR, Helbren E, Plumb A, Boone D, Slabaugh G, Halligan S, Hawkes DJ.SourceCentre for Medical Image Computing, University College London, Gower Street, London WC1E 6BT, UK. Electronic address: thomas.hampshire.09@ucl.ac.uk.
• Medical image analysis.Med Image Anal.2013 Dec;17(8):946-58. doi: 10.1016/j.media.2013.04.006. Epub 2013 Apr 27.
• Computed Tomographic (CT) colonography is a technique used for the detection of bowel cancer or potentially precancerous polyps. The procedure is performed routinely with the patient both prone and supine to differentiate fixed colonic pathology from mobile faecal residue. Matching corresponding loc
• PMID 23845949

• Evaluating patients' preferences for type of bowel preparation prior to screening CT colonography: Convenience and comfort versus sensitivity and specificity.

• Ghanouni A, Halligan S, Taylor SA, Boone D, Plumb A, Wardle J, von Wagner C.SourceDepartment of Epidemiology and Public Health, University College London, London, UK.
• Clinical radiology.Clin Radiol.2013 Nov;68(11):1140-5. doi: 10.1016/j.crad.2013.06.018. Epub 2013 Aug 12.
• AIMS: To explore the relative value patients place on comfort and convenience versus test sensitivity and specificity in the context of computed tomographic colonography (CTC) screening.MATERIALS AND METHODS: Twenty semi-structured interviews were carried out with patients attending hospital for rad
• PMID 23948662

• Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms.

• Badiani S, Tomas-Hernandez S, Karandikar S, Roy-Choudhury S.SourceDepartment of General Surgery.
• Acta radiologica (Stockholm, Sweden : 1987).Acta Radiol.2013 Oct 1;54(8):851-62. doi: 10.1177/0284185113486371. Epub 2013 May 12.
• BACKGROUND: Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms.PURPOSE:
• PMID 23761550

Japanese Journal

• 大腸癌診断の変遷と検診の動向 (特集 大腸癌update : 基礎と臨床の研究動向) -- (大腸癌検診の動向)

• 日本臨床 74(11), 1889-1894, 2016-11
• NAID 40020984081

• 日本総合健診医学会　第44回大会・シンポジウム3　大腸がん検診のあり方：便潜血検査のピットフォールと新たなスクリーニング方法大腸がん検診における大腸CTの位置づけ

• 総合健診 43(3), 464-470, 2016
• NAID 130005161545

• 大腸CTの読影法「大腸展開像」vs.「仮想内視鏡像」:Pilot study

• 日本消化器がん検診学会雑誌 53(5), 600-606, 2015
• NAID 130005103516

Related Links

• CT colonography - RadiologyInfo

Current and accurate information for patients about Virtual Colonoscopy. Learn what you might experience, how to prepare for the exam, benefits, risks and more .

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★リンクテーブル★

リンク元	「CT colonography」「コンピュータ断層撮影コロノグラフィー」「virtual colonoscopy」
関連記事	「compute」「computed tomographic」「tomograph」「tomographic」

「CT colonography」

　　[★]

• コンピュータ断層撮影コロノグラフィー、CTコロノグラフィー

関

computed tomographic colonography、virtual colonoscopy

「コンピュータ断層撮影コロノグラフィー」

　　[★]

英

computed tomographic colonography、CT colonography

関

CTコロノグラフィー、仮想大腸内視鏡

「virtual colonoscopy」

　　[★]

仮想大腸内視鏡

関

computed tomographic colonography、CT colonography

「compute」

　　[★]

• v.

• 計算する、算出する、コンピュータ処理する、コンピュータ化する

関

calculate、calculation、computation、computerization、computerize

　

「computed tomographic」

　　[★]

• コンピュータ断層撮影の

関

computed tomography、computerized tomography、CT、CT scan

「tomograph」

　　[★]

• 断層撮影、断層撮影機

関

tomographic、tomography

　

「tomographic」

　　[★]

• 断層撮影の、断層撮影法の

関

tomograph、tomography