関: computed tomographic colonography、CT colonography

WordNet

existing in essence or effect though not in actual fact; "a virtual dependence on charity"; "a virtual revolution"; "virtual reality"
being actually such in almost every respect; "a practical failure"; "the once elegant temple lay in virtual ruin" (同)practical
artistic quality (同)vertu
objet dart collectively (especially fine antiques)
love of or taste for fine objects of art (同)vertu, connoisseurship
visual examination of the colon (with a colonoscope) from the cecum to the rectum; requires sedation

PrepTutorEJDIC

(名目上・表面上はそうではないが)事実上の,実際上の
〈U〉(美術品などの)優秀性,よさ,値打ち / 《集合的に》《複数扱い》美術品,骨とう品 / {U}美術品(骨とう品)に対する造詣(知識) = vertu

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/03/11 14:11:38」(JST)

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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.^[1] 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).^[2] 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.^[3]

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.^[4] It also takes less time than either a conventional colonoscopy or a lower GI series.^[5]

VC provides a secondary benefit of revealing diseases or abnormalities outside the colon.^[6]

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.^[7] 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

^ Heiken, JP; Peterson CM, Menias CO (November 2005). "Virtual colonoscopy for colorectal cancer screening: current status: Wednesday 5 October 2005, 14:00–16:00". Cancer Imaging (International Cancer Imaging Society) 5 (Spec No A): S133–S139. doi:10.1102/1470-7330.2005.0108. PMC 1665314. PMID 16361129. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1665314/.
^ Bielen DJ, Bosmans HT, De Wever LL et al. (September 2005). "Clinical validation of high-resolution fast spin-echo MR colonography after colon distention with air". J Magn Reson Imaging 22 (3): 400–5. doi:10.1002/jmri.20397. PMID 16106357.
^ "Virtual Colonoscopy" - National Digestive Diseases Information Clearinghouse - NIH
^ Menardo G (December 2004). "Sensitivity of diagnostic examinations for colorectal polyps". Tech Coloproctol 8 Suppl 2: s273–5. doi:10.1007/s10151-004-0175-0. PMID 15666105.
^ Virtual Colonoscopy - Mayo Clinic. "Virtual colonoscopy is typically faster than traditional colonoscopy. A scan of your colon takes about 10 minutes. Expect the entire virtual colonoscopy procedure to take 20 to 30 minutes."
^ Yee J, Kumar NN, Godara S et al. (August 2005). "Extracolonic abnormalities discovered incidentally at CT colonography in a male population". Radiology 236 (2): 519–26. doi:10.1148/radiol.2362040166. PMID 16040909. http://radiology.rsnajnls.org/cgi/pmidlookup?view=long&pmid=16040909. Retrieved 2008-12-22.
^ Findings presented at the American College of Gastroenterology annual scientific meeting in Las Vegas, Nev. An abstract of the study was printed in the September 2006 issue of The American Journal of Gastroenterology.

UpToDate Contents

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1. CTコロノグラフィー 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. 成人における大腸内視鏡検査の概要 overview of colonoscopy in adults
5. スクリーニングのための全身CTスキャン full body ct scan for screening

English Journal

Comparison of the accuracy of CT colonography and colonoscopy in the diagnosis of colorectal cancer.

Martín-López JE1, Beltrán-Calvo C, Rodríguez-López R, Molina-López T.Author information 1Andalusian Health Technology Assessment (AETSA), Seville, Spain.AbstractAIM: The available evidence was reviewed to compare the effectiveness of CT colonography with that of colonoscopy for colorectal cancer (CRC) screening.
Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland.Colorectal Dis.2014 Mar;16(3):O82-9. doi: 10.1111/codi.12506.
AIM: The available evidence was reviewed to compare the effectiveness of CT colonography with that of colonoscopy for colorectal cancer (CRC) screening.METHOD: An electronic search was conducted using PubMed, EMBASE, the Cochrane Library and Centre for Reviews and Dissemination databases, from incep
PMID 24299052

CT colonography: does it satisfy the necessary criteria for a colorectal screening test?

Pickhardt PJ.Author information Department of Radiology, University of Wisconsin School of Medicine & Public Health, E3/311 Clinical Science Center, 600 Highland Ave., Madison, WI, USA.AbstractExisting and emerging colorectal screening tests can be assessed in terms of the key categories of diagnostic performance, procedural risks, patient acceptability, and cost-effectiveness. To push a new screening test to acceptance, it need not outperform existing strategies in all of these criteria. Rather, a relative advantage in one criterion combined with acceptable performance in the others may be considered adequate. For computed tomographic colonography (CTC), a strong case can be made that this test meets or exceeds optical colonoscopy, the current screening standard, in all of these categories. Published data, including our own experience with CTC screening, will be reviewed to support this claim. Reasons why CTC has not yet achieved its full potential as a valuable screening test for colorectal cancer prevention will also be considered.
Expert review of gastroenterology & hepatology.Expert Rev Gastroenterol Hepatol.2014 Mar;8(3):211-3. doi: 10.1586/17474124.2014.887436. Epub 2014 Feb 4.
Existing and emerging colorectal screening tests can be assessed in terms of the key categories of diagnostic performance, procedural risks, patient acceptability, and cost-effectiveness. To push a new screening test to acceptance, it need not outperform existing strategies in all of these criteria.
PMID 24490683

Computer-aided detection for computed tomographic colonography screening: a prospective comparison of a double-reading paradigm with first-reader computer-aided detection against second-reader computer-aided detection.

Iussich G1, Correale L, Senore C, Hassan C, Segnan N, Campanella D, Bert A, Galatola G, Laudi C, Regge D.Author information 1From the *Radiology Unit, Institute for Cancer Research and Treatment, Candiolo; †im3D S.p.A., Torino; ‡AOU S Giovanni Battista, Torino; §Gastroenterology and Endoscopy Unit, Nuovo Regina Margherita Hospital, Rome; and ∥Gastroenterology and Endoscopy Unit, Institute for Cancer Research and Treatment, Candiolo, Italy.AbstractOBJECTIVES: The objective of this study was to prospectively compare diagnostic performance and time efficiency of a double-reading paradigm in which a first-reader computer-aided detection (CAD) is followed by a fast 2-dimensional review (DR FR-CAD) with those of a double reading with second-reader CAD (SR CAD).
Investigative radiology.Invest Radiol.2014 Mar;49(3):173-82. doi: 10.1097/RLI.0000000000000009.
OBJECTIVES: The objective of this study was to prospectively compare diagnostic performance and time efficiency of a double-reading paradigm in which a first-reader computer-aided detection (CAD) is followed by a fast 2-dimensional review (DR FR-CAD) with those of a double reading with second-reader
PMID 24442160

Japanese Journal

腸管嚢腫様気腫症の診断における大腸3D-CTの有用性 : 当院の5例の検討から

加藤貴司,鎌田晶義,中川宗一,藤澤良樹,町田卓郎,碇修二,佐々木清貴,山田裕人,加賀谷英俊,中村英明,目黒高志,堀田彰一
日本消化器病學會雜誌 = The Japanese journal of gastro-enterology 109(4), 615-623, 2012-04-05
腸管嚢腫様気腫症（PCI）の5例に大腸3D-CTを施行した．VC像にて腸管内腔の隆起性病変が描出され，axial像やMPR像にて腸管壁内の気体を確認し得たためPCIの確定診断に結びついた．大腸内視鏡検査では指摘できなかった漿膜側の病変も評価し得た．また注腸類似画像にて正確な部位診断が可能であった．大腸3D-CTは存在診断，部位診断そして確定診断が可能であり，PCIに対する診断的有用性が高い．
NAID 10030560631

バーチャル大腸内視鏡のためのCT値勾配に着目した腸壁抽出手法(CT)

若松泰律,井村誠孝,池田聖,田畑慶人,石垣陸太,眞鍋佳嗣,千原國宏
電子情報通信学会技術研究報告. MI, 医用画像 109(407), 447-451, 2010-01-21
大腸検診の手段において,X線CT画像からなるボリュームデータから再構成したバーチャルな大腸を検査するバーチャル大腸内視鏡が注目されている.大腸内の腸液や糞便などの内容物はX線CT画像で障害陰影となるため,検査前に大腸内を空にする前処置が必要であるが,そのための内容物除去が患者に負担をかける.負担軽減の手段として,撮影前の造影剤投与により内容物を強調したX線CT画像のボリュームデータに対して画像処理 …
NAID 110007866470

CT colonography (virtual colonoscopy): the present and the future (医用画像)

Kim Se Hyung
電子情報通信学会技術研究報告. MI, 医用画像 109(407), 413-422, 2010-01-21
… CT colonography(CTC), also known as virtual colonoscopy, is a recent radiologic technique enabling the detection of tumoral lesions in the colon. …
NAID 110007866464