WordNet

put in opposition to show or emphasize differences; "The middle school teacher contrasted her best students work with that of her weakest student"
the opposition or dissimilarity of things that are compared; "in contrast to", "by contrast" (同)direct contrast
the act of distinguishing by comparing differences
the range of optical density and tone on a photographic negative or print (or the extent to which adjacent areas on a television screen differ in brightness)
the perceptual effect of the juxtaposition of very different colors
to show differences when compared; be different; "the students contrast considerably in their artistic abilities" (同)counterpoint
strikingly different; tending to contrast; "contrasting (or contrastive) colors" (同)contrastive

PrepTutorEJDIC

(違いを示すために)(二つのもの)'を'『対照させる』,対比する;(…と)…'を'対照させる《+『名』+『with』+『名』》 / (…と)『対照する』,対照的に引き立つ《+『with』+『名』》 / 〈U〉(…との)『対照』,対比《+『with』(『to』)+『名』》 / 〈C〉〈U〉(…間の)対照的な差,(特に色・明るさの)対照,コントラスト《+『between』+『名』+『and』+『名』》,(…との)著しい相違《+『to』+『名』》 / 〈C〉(…と)対照的な人(物)《+『to』+『名』》
mediumの複数形

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/05 21:52:32」(JST)

wiki en

A medical contrast medium (or contrast agent) is a substance used to enhance the contrast of structures or fluids within the body in medical imaging.^[1] It is commonly used to enhance the visibility of blood vessels and the gastrointestinal tract.

Types

Several types of contrast media are in use in medical imaging and they can roughly be classified based on the imaging modalities where they are used. Although other types exist, most common contrast agents work based on X-ray attenuation and magnetic resonance signal enhancement.

X-ray attenuation

Iodine and barium are the most common types of contrast medium for enhancing x-ray-based imaging methods. Various sorts of iodinated contrast media exist, with variations occurring between the osmolarity, viscosity and absolute iodine content of different media. Non-ionic dimers are favored for their low osmolarity and toxicity, but have a correspondingly higher price attached to their use.^[2]

MR signal enhancing

Gadolinium is used in magnetic resonance imaging as a MRI contrast agent.^[3] In the 3+ oxidation state the metal has 7 unpaired f electrons. This causes water around the contrast agent to relax quickly, enhancing the quality of the MRI scan.

Ultrasound scattering and frequency shift

Microbubble contrast agents are used to aid the sonographic examination, specifically echocardiograms, for the detection of a cardiac shunt. These bubbles are composed of agitated saline solution, most of which are too large to pass through the lung capillaries. Therefore, the only ones that reach the left side of the heart pass through an abnormal connection between the two sides of the heart, a so-called right-to-left shunt. In addition, pharmaceutically prepared microbubbles are composed of tiny amounts of nitrogen or perfluorocarbons strengthened and supported by a protein, lipid, or polymer shell. These are small enough to pass through the capillaries and are used to increase the contrast in the left ventricle, improving the visualization of its walls. The drop in density on the interface between the gas in the bubble and the surrounding liquid strongly scatters and reflects the ultrasound back to the probe. This process of backscattering gives the liquid with these bubbles a high signal, which can be seen in the resulting image.

Adverse effects

While modern contrast media are generally safe to use,^[2] medical conditions can be caused by the administration of various contrast media. Reactions can range from minor to severe, sometimes resulting in death^[4] with death being about 0.9 per 100,000 cases. To better understand the reactions and to efficiently manage patients at risk, it is useful to classify them.^[5] Risk factors for developing severe reactions include strong allergies, bronchial asthma, cardiac disease and beta-blocker use.^[6]^[7] While the previously suspected IL-2 medication is no risk for the acquisition of adverse events.^[8]

A common misconception that even exists among healthcare professionals is that an allergy to contrast media is related to an allergy to seafood (usually shellfish) because both share iodine in their construction, implicating iodine as a source.^[9]^[10] Numerous studies have shown that although iodine is common in contrast media, iodine is not the cause of allergic reactions to contrast media and instead the more likely culprit are the inert ingredients and the patient's past history of having other strong allergic reactions.^[11] One important distinction is that allergic effects are by definition immunoglobulin E related histamine storms and studies have shown that contrast media cause no such reaction in vivo ^[12] thereby refuting the possibility that contrast media or the iodine in it is likely to be an allergen. Although it may seem contradictory, the few rare cases of contrast medium mediated IgE are exceedingly rare compared to all adverse reactions and when they happen, are often because the patient already has multiple risk factors that suggest the patient has other allergy related problems.^[6]

Historically, contrast media was sometimes highly dangerous but these dangers were not well-understood during the development of the early types of contrast media, such as Thorotrast.

References

^ "contrast agent" at Dorland's Medical Dictionary
^ ^a ^b Thomson, K; Varma, D (2010). "Safe use of radiographic contrast media". Australian Prescriber, 33:19-22. Available at http://www.australianprescriber.com/magazine/33/1/19/22/
^ "MR Contrast Agents". 2014.
^ Caro, J. Jaime; Evelinda Trindade; Maurice McGregor (1991). "The Risks of Death and of Severe Nonfatal Reactions with High- vs Low Osmolarity Contrast Media: A Meta-analysis". American Journal of Roentgenology (American Roentgen Ray Society) 156 (4): 825–832. doi:10.2214/ajr.156.4.1825900. PMID 1825900.
^ Böhm I, Heverhagen JT, Klose KJ. Classification of acute and deleayed contrast media-induced reactions: proposal of a three-step system. Contrast Media & Molecular Imaging 2012;7(6) 537-41 url=http://onlinelibrary.wiley.com/doi/10.1002/cmmi.1475/pdf
^ ^a ^b Brockow, K. et al. (11 Jan 2005). "Management of hypersensitivity reactions to iodinated contrast media". Allergy (European Journal of Allergy & Clinical Immunology) 60 (2): 150–158. doi:10.1111/j.1398-9995.2005.00745.x. PMID 15647034.
^ Boehm I. Contrast media and patients at risk: asthma. Acta Radiologica 2009; 50(3) 348
^ Boehm I. Is interleukin-2 (still) a risk factor for adverse reactions in concert with radiographic contrast medium injection? Acta Radiol 2009; 50(7) 752-3
^ Coakley, Fergus; David M. Panicek (October 1997). "Iodine Allergy: An Oyster Without a Pearl?". American Journal of Roentology (AJR) 169 (4): 951–952.
^ http://www.wdxcyber.com/ngen22.htm
^ Boehm, Ingrid (August 2008). "Seafood Allergy and Radiocontrast Media: Are Physicians Propagating a Myth?". The American Journal of Medicine (Elsevier) 121 (8): e19. doi:10.1016/j.amjmed.2008.03.035. PMID 18691465.
^ Carr, Denis H.; Archi C. Walker (1984). "Contrast Media Reactions: experimental evidence against the allergy theory". British Journal of Radiology (British Institute of Radiology) 57 (678): 469–473. doi:10.1259/0007-1285-57-678-46. PMID 6722447.

UpToDate Contents

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1. 造影剤誘発性腎症の予防 prevention of contrast induced nephropathy
2. 造影剤に対する即時型過敏反応：臨床症状、診断、および治療 immediate hypersensitivity reactions to radiocontrast media clinical manifestations diagnosis and treatment
3. 造影剤誘発性腎症の病因、臨床的特徴、および診断 pathogenesis clinical features and diagnosis of contrast induced nephropathy
4. 造影剤に対する即時型過敏反応：再発反応の予防 immediate hypersensitivity reactions to radiocontrast media prevention of recurrent reactions
5. 核磁気共鳴画像法の原理 principles of magnetic resonance imaging

English Journal

Homogeneous functional Ni-P/ceramic nanocomposite coatings via stable dispersions in electroless nickel electrolytes.

de Hazan Y, Knies F, Burnat D, Graule T, Yamada-Pittini Y, Aneziris C, Kraak M.SourceLaboratory for High Performance Ceramics, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, CH-8600 Dubendorf, Switzerland.
Journal of colloid and interface science.J Colloid Interface Sci.2012 Jan 1;365(1):163-71. Epub 2011 Sep 21.
Stable nanoparticle dispersions in concentrated electrolytes are prerequisite for a variety of advanced nanocomposites prepared by deposition techniques. In this work we investigate the synthesis of electroless Ni-P/functional ceramic coatings from concentrated electrolytes containing functional nan
PMID 21993547

Japanese Journal

Serial Scans in Healthy Volunteers Following Intravenous Administration of Gadoteridol: Time Course of Contrast Enhancement in Various Cranial Fluid Spaces

NAGANAWA Shinji,SUZUKI Kojiro,YAMAZAKI Masahiro,SAKURAI Yasuo
Magnetic Resonance in Medical Sciences, 2014
… Purpose: Heavily T2-weighted, 3-dimensional, fluid-attenuated inversion recovery (hT2W-3D-FLAIR) imaging has been reported to detect low concentrations of gadolinium-based contrast media (GBCM) in the anterior eye segment (AES), subarachnoid space (SAS), and labyrinthine perilymph as well as in the cerebrospinal fluid (CSF) of the internal auditory canal (IAC) 4 hours after intravenous administration of a single dose (IV-SD-GBCM) in patients with inner ear disorders. …
NAID 130003392991

The Growth of Steroidobacter agariperforans sp. nov., a Novel Agar-Degrading Bacterium Isolated from Soil, is Enhanced by the Diffusible Metabolites Produced by Bacteria Belonging to Rhizobiales

Sakai Masao,Hosoda Akifumi,Ogura Kenjiro,Ikenaga Makoto
Microbes and Environments, 2014
… The strain grew on media containing culture supernatants in a temperature range of 15–37°C and between pH 4.5 and 9.0, with optimal growth occurring at 30°C and pH 6.0–8.0. … In contrast, strain FST was motile, did not grow on the agar plate, and its dominant cellular fatty acids were C15:0 and C17:1ω8c. …
NAID 130003390916

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★リンクテーブル★

リンク元	「造影剤」「radiocontrast」「contrast agent」「contrast medium」「contrast material」
関連記事	「media」「med」「contrasting」

「造影剤」

　　[★]

英: contrast media, contrast medium, contrast agent
関: ヨード造影剤

種類

ヨード造影剤

禁忌

ヨード造影剤の禁忌　参考(1)

絶対禁忌

ヨード造影剤に対する過敏症の既往
重症の甲状腺疾患

相対禁忌

全身状態不良
気管支喘息
重症心疾患、重症肝疾患、腎不全、急性膵炎、マクログロブリン血症、多発性骨髄腫、テタニー、褐色細胞腫

バリウムの禁忌 RNT.33

腸管穿孔、縫合不全(疑い)

副作用 RNT.33

ヨード製剤

アナフィラキシーショック、喉頭浮腫
嘔気・嘔吐、皮疹(蕁麻疹、発赤)、腎機能低下

バリウム製剤

便秘

要注意 RNT.33

ヨード製剤

高度の人気脳障害、高度の肝機能障害、多発骨髄腫(腎不全誘発)、褐色細胞腫(発作性高血圧誘発)

バリウム製剤

誤嚥の可能性

誤嚥により、呼吸困難、肺炎、肺肉芽腫の形成等を引き起こすおそれがあるので、誤嚥を起こすおそれのある患者（高齢者、嚥下困難、喘息患者等）に経口投与する際には注意すること。誤嚥した場合には、観察を十分に行い、急速に進行する呼吸困難、低酸素血症、胸部Ｘ線による両側性びまん性肺浸潤陰影が認められた場合には、呼吸管理、循環管理等の適切な処置を行うこと。(参考3)
老人など誤嚥の可能性がある患者は、肺に入った場合除去できないので使用しない。(参考4)

→食道気管支瘻の場合は使えないことになる