WordNet

relating to or performed with the fingers; "digital examination"
displaying numbers rather than scale positions; "digital clock"; "digital readout"
of a circuit or device that represents magnitudes in digits; "digital computer"
the act of subtracting (removing a part from the whole); "he complained about the subtraction of money from their paychecks" (同)deduction
an arithmetic operation in which the difference between two numbers is calculated; "the subtraction of three from four leaves one"; "four minus three equals one" (同)minus
one of the elements that collectively form a system of numeration; "0 and 1 are digits" (同)figure
a finger or toe in human beings or corresponding body part in other vertebrates (同)dactyl
roentgenographic examination of blood vessels after injection of a radiopaque contrast medium; produces an angiogram

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指の / 数字の;計数型の / (タイプライターなどの)鍵(けん),キー
引き算;控除
(手足の)指 / アラビア数字(0から9までの一つ;0を除くこともある)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/12/30 21:02:10」(JST)

wiki en

Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a 'pre-contrast image' or the mask from later images, once the contrast medium has been introduced into a structure. Hence the term 'digital subtraction angiography'.

Procedure

DSA and Fluoroscopy

In traditional angiography, images are acquired by exposing an area of interest with time-controlled x-rays while injecting contrast medium into the blood vessels. The image obtained would also include all overlying structure besides the blood vessels in this area. This is useful for determining anatomical position and variations but unhelpful for visualizing blood vessels accurately.

In order to remove these distracting structures to see the vessels better, first a mask image is acquired. The mask image is simply an image of the same area before the contrast is administered. The radiological equipment used to capture this is usually an image intensifier, which will then keep producing images of the same area at a set rate (1 - 6 frames per second), taking all subsequent images away from the original 'mask' image. The radiologist controls how much contrast media is injected and for how long. Smaller structures require less contrast to fill the vessel than others. Images produced appear with a very pale grey background, which produces a high contrast to the blood vessels, which appear a very dark grey.

The images are all produced in real time by the computer, as the contrast is injected into the blood vessels.

Intravenous digital subtraction angiography

Intravenous digital subtraction angiography (IV-DSA) is a form of angiography which was first developed in the late 1970s.

IV-DSA uses a computer technique which compares an x-ray image of a region of the body before and after radiopaque iodine based dye has been injected intravenously into the body. Tissues and blood vessels on the first image are digitally subtracted from the second image, leaving a clear picture of the artery which can then be studied independently and in isolation from the rest of the body.

Some studies have indicated that IV-DSA is not suitable for patients with diabetes or renal insufficiency because the dye load is significantly higher than is used in arteriography. However, IV-DSA has been used successfully to study the vessels of the brain and heart and has helped detect carotid artery obstruction and to map patterns of cerebral blood flow. It also helps detect and diagnose lesions in the carotid arteries which is a potential cause of strokes.

IV-DSA has also been useful in assessing patients prior to surgery and after coronary artery bypass surgery and some transplant operations...

Applications

DSA is primarily used to image blood vessels. It is useful in the diagnosis and treatment of:

Arterial and venous occlusions, including carotid artery stenosis, pulmonary embolisms and acute limb ischaemia.
Arterial stenosis, which is particularly useful for potential renal donors in detecting renal artery stenosis. DSA is the gold standard investigation for renal artery stenosis.^[1]
Cerebral aneurysms and arterio-venous malformations (AVM).

The future

DSA is being used less and less routinely in imaging departments. It is being replaced by computed tomography angiography (CTA), which can produce 3D images through a test which is less invasive^[2] and stressful for the patient^{[citation needed]}. It is still considered the gold standard for arterial imaging ^[2]

Sources

Anagnostakos, Nicholas Peter; Tortora, Gerard J. (1990). Principles of Anatomy and Physiology. San Francisco: Harper & Row. ISBN 0-06-046694-4.
Eddy AC, Nance DR, Goldman MA, et al. (May 1990). "Rapid diagnosis of thoracic aortic transection using intravenous digital subtraction angiography". Am. J. Surg. 159 (5): 500–3. doi:10.1016/S0002-9610(05)81255-3. PMID 2334014.
Signs of a stroke
D'Alotto C, Pelz DM, Rankin RN (September 1985). "A comparison of angiography, intravenous digital subtraction angiography and duplex ultrasound in the diagnosis of carotid artery atherosclerosis". J Can Assoc Radiol 36 (3): 200–8. PMID 3900078.
Zwiebel WJ, Strother CM, Austin CW, Sackett JF (1 July 1985). "Comparison of ultrasound and IV-DSA for carotid evaluation". Stroke 16 (4): 633–43. doi:10.1161/01.STR.16.4.633. PMID 3895593.

References

^ Sam, Amir H.; James T.H. Teo (2010). Rapid Medicine. Wiley-Blackwell. ISBN 1405183233.
^ ^a ^b R. Herzig, S. Burval, B. Krupka, I. Vlachova, K. Urbanek, J. Mares (2004). "Comparison of ultrasonography, CT angiography, and digital subtraction angiography in severe carotid stenoses". European Journal of Neurology: 774–5. Retrieved 26 June 2013.

External links

http://www.droid.cuhk.edu.hk/web/service/angio/dsa.htm

UpToDate Contents

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1. 腎同種移植片のC4d染色および抗体媒介性拒絶反応の治療 c4d staining in renal allografts and treatment of antibody mediated rejection
2. 中枢神経系の血管奇形 vascular malformations of the central nervous system
3. 腎移植におけるHLAとABOの感作および脱感作 hla and abo sensitization and desensitization in renal transplantation
4. 頚動脈狭窄の評価 evaluation of carotid artery stenosis
5. 中脳周囲非動脈瘤性くも膜下出血 perimesencephalic nonaneurysmal subarachnoid hemorrhage

English Journal

Comparison of 16-row multislice CT angiography with conventional angiography for detection and evaluation of intracranial aneurysms.

Donmez H, Serifov E, Kahriman G, Mavili E, Durak AC, Menku A.SourceUniversity of Erciyes, School of Medicine, Department of Radiology, Kayseri, Turkey.
European journal of radiology.Eur J Radiol.2011 Nov;80(2):455-61. Epub 2010 Aug 21.
PURPOSE: The aim of this study is to compare the diagnostic performance of 16-row computed tomographic angiography (MDCTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms in patients with nontraumatic subarachnoid hemorrhages (SAH).MATERIAL
PMID 20729022

FLOW 800-assisted surgery for arteriovenous malformation.

Jhawar SS, Kato Y, Oda J, Oguri D, Sano H, Hirose Y.SourceDepartment of Neurosurgery, Seth GS Medical College and King Edward Memorial Hospital, Parel, Mumbai, India.
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia.J Clin Neurosci.2011 Nov;18(11):1556-7. Epub 2011 Sep 14.
FLOW 800 is software for analytical colour visualisation and objective evaluation of fluorescence video obtained by microscope-integrated intraoperative indocyanine green fluorescence angiography. A 56-year-old male underwent surgical excision of a large complex arteriovenous malformation (AVM) of t
PMID 21920758

Japanese Journal

Image-guided Operating roomの現状と将来展望(<特集>21世紀のOperation Suite)

村山雄一,石橋敏寛,佐口隆之,荏原正幸,荒川秀樹,入江是明,長島弘康,磯島晃,大橋洋輝,加藤正高,高尾洋之,常喜達弘,池内聡,阿部俊昭
脳神経外科ジャーナル 20(4), 254-258, 2011-04-20
近年の脳血管内治療とクリッピング技術の進歩により,脳血管障害の治療成績は向上しつつある.しかしながら,複雑な脳動脈瘤など,血管内治療でも開頭手術でも単独では治療困難な疾患も存在し,最新のimaging technologyを併用した治療が望まれる.われわれは手術室内に血管撮影装置を設置し,脳血管内治療のみならずクリッピングなどの血管障害に対する外科的直達手術にも術中血管撮影を積極的に利用してきた. …
NAID 110008593910

Variant Deep Cerebral Venous Drainage in Idiopathic Subarachnoid Hemorrhage

KAWAMURA Yoichiro,NARUMI Osamu,CHIN Masaki,YAMAGATA Sen
Neurologia medico-chirurgica = 神経外科 51(2), 97-100, 2011-02-15
… In this study, deep venous drainage was compared between 13 patients with idiopathic SAH and 35 control patients with aneurysmal SAH diagnosed by digital subtraction angiography (DSA). …
NAID 10028104827

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★リンクテーブル★

国試過去問	「100G089」
リンク元	「デジタルサブトラクション血管造影」「DSA」「ディジタルサブトラクション血管造影術」「デジタルサブトラクション血管撮影」
拡張検索	「intravenous digital subtraction angiography」
関連記事	「digit」「subtraction」「digital」