Fluorescein angiography

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Fluorescein angiography
Intervention
Fluorescein angiography.jpg
Retina during the effects of fluorescein angiography
ICD-9-CM95.12
MeSHD005451
 
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Fluorescein angiography
Intervention
Fluorescein angiography.jpg
Retina during the effects of fluorescein angiography
ICD-9-CM95.12
MeSHD005451

Intravenous Fluorescein angiography (IVFA) or Fluorescent Angiography (FAG) is a technique for examining the circulation of the retina and choroid using a fluorescent dye and a specialized camera. It involves injection of sodium fluorescein[1] into the systemic circulation, and then an angiogram is obtained by photographing the fluorescence emitted after illumination of the retina with blue light at a wavelength of 490 nanometers. The test uses the dye tracing method.

The fluorescein dye also reappears in the patient urine, causing the urine to appear darker, and sometimes orange.[2] It can also cause discolouration of the saliva.

Fluorescein angiography is one of several health care applications of this dye, all of which have a risk of severe adverse effects. See fluorescein safety in health care applications. Fluorescein angiography does not involve the use of ionizing radiation.[3]

Equipment[edit]

Technique[edit]

Normal circulatory filling[edit]

times are approximate

Fluorescein enters the ocular circulation from the internal carotid artery via the ophthalmic artery. The ophthalmic artery supplies the choroid via the short posterior ciliary arteries and the retina via the central retinal artery, however, the route to the choroid is typically less circuitous than the route to the retina. This accounts for the short delay between the "choroidal flush" and retinal filling.

Pathologic findings[edit]

Pathologic changes are recognized by the detection of either hyperfluorescence or hypofluroescence.

Causes of hyperfluorescence:

window/transmission (filling) defects
leaking defects (i.e. capillary leakage, aneurysm, neovascularization)
pooling defects
staining
abnormal vasculature

Causes of hypofluorescence:

blocking defect (i.e. blood)
filling defect (capillary nonperfusion/blockage)

Fluorescein angiography is used by physicians specializing in the treatment of eye diseases (ophthalmologists) to evaluate the vasculature of the retina, choroid, optic disc, and iris.[3] Among the common groups of ophthalmologic disease, fluorescein angiography can detect diabetic retinopathy (neovascularization), vein occlusions, retinal artery occlusions,[4] edema of the optic disc, and tumors. Additionally, the transit time (the period between injection of the dye and when it appears in the examined blood vessels) can provide an objective measurement of the rate of blood flow through the imaged blood vessels.[3]

Other types of fluorescent angiography[edit]

See also[edit]

References[edit]

  1. ^ Fluorescein Angiography at the US National Library of Medicine Medical Subject Headings (MeSH)
  2. ^ "Fluorescein angiography". U.S. National Library of Medicine. MedLine Plus. Retrieved 14 December 2012. 
  3. ^ a b c Kunimoto, Derek; Kunal Kanitkar; Mary Makar (2004). The Wills eye manual: office and emergency room diagnosis and treatment of eye disease. (4th ed.). Philadelphia, PA: Lippincott Williams & Wilkins. p. 365. ISBN 978-0781742078. 
  4. ^ Kumar, Vinay (2007). "Chapter 29: Eye, Retina and Vitreous, Retinal Vascular Disease". Robbins basic pathology (8th ed.). Philadelphia: Saunders/Elsevier. ISBN 978-1416029731. 

Additional references[edit]