Date post: | 23-Aug-2014 |
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FUNDUS FLUORESCEIN ANGIOGRAPHY
NISHITA AFRINB.OPTOM
3rd batchICO,CU
INTRODUCTION
Fluorescein angiography refers to photographing
fluorescein dye in the retinal vasculature following intravenous injection of fluorescein solution
FLUORESCENCE
C20H12O5
Refers to fluorescein sodium (C20H10Na2O5)
A brown or ornge red crystalline substance, alkaline in nature
First synthesized in 1871 in Germany by Von Bayer
CONTINUE…
Absorbs blue light (490nm ) and emits yellow-green light (530nm)
Metabolized by liver and exerted by kidney
HAZARDS OF FLUORESCEIN DYE Reletively safe drug Temporary tan skin coloration Urine discoloration Transient nausea and vomiting More severe : hives ,asthmatic
symptoms and laryngeal edema
CONTINUE…
Syncope , anaphylactic reaction to fluorescein
Myocardial infraction
Respiratory and Cardiac arrest
INDOCYANINE GREEN
Cyanine dye Binds to plasma protein, confined to
vascular system Molecular wt. 775 dalton Half life – 150- 180 dalton Remove from circulation by the liver
to bile juice
Absorbs 600 nm -900 nm and emits 750 nm to 950 nm
General Principles of ICG Angiography1. Binding
• 98% bound to proteins
2. Fluorescence• Much less than fluorescein
• Less leakage from choriocapillaris
• Excitation peak 800 nm
• Emission at 835 nm
3. Filters• Infrared barrier and excitation
4. Safer than fluorescein
Side effects of ICG…
Risk in pregnancy Sore throats and hot flashes Anaphylactic shock Hypotension Trachycardia Dyspnea and Urticaria
CLINICAL USE OF FLUORESCENCE DYE
Clinical use
Research Care -treatment protocol for retinal diseases - to understand retinal and choroidal leisons . E.g. Age related macular
degeneration, diabetic retinopathy ,retinal detachment…
Anatomic Considerations
FFA
General principles of FAFluorescein• 85% bound to serum proteins• 15% unbound ‘free’ fluorescein
• Impermeable to fluorescein
Outer blood-retinal barrier (zonula occludens)• Impermeable to fluorescein
Choriocapillaris• Permeable only to ‘free’ fluorescein
Inner blood-retinal barrier (retinal capillaries)
OPTICAL PRINCIPLE
Filters1.Blue excitation filter
2.Yellow-green filter
PROCEDURE…
Pupils should well dialed Patient seat infront of the camera Red free photographs taken Dye injected in the forearm or anticubital
vein Photographs with fluorescein - 1 sec interval between 5 and 25 secs - late photographs after 10-15 mins
Retractable needle with catheter system
Mild hematoma
Insertion of needle containing
Syringe with NaF
Angiographic phases:
Five angiographic phases:• Pre arterial (choroidal 9-15 seconds)• Arterial• Arteriovenous(capillary)• Venous• Recirculation
Circulation of NaF Dye injected from peripheral vein
venous circulation
heart
arterial system INTERNAL CAROTID ARTERY
Ophthalmic artery Short posterior ciliary artery) Central retinal artery (choroidal circulation.) ( retinal circulation)
N.B. The choroidal filling is 1 second prior to the retinal filling.
1-Choroidal flush 2-Arterial phase
3-Arteriovenous phase
4-Venous phase
Mid Phase Late Phase
Interpretation of FA
Red-free fundus photos
Normal appearance Autofluorescence
Abnormal angiographic findingsHypofluorescence: Filling defect Blocking defect
Hyperfluorescence : window defect Leakage Pooling Staining
HyperfluorescenceAnomalous vessels
Choroid
Retina
Optic nerve head
Subretinal neovasculari-zationTumor vesselsChorioretinal anastomosisVascular tortuositiesDilation and shuntsAnastomosisNeovascularizationAneurysmsTeleangiectasiaTumor vesselsHamatoma
NeovascularizationTortuosityDilationHamatomaTumor vessels
Hyper-fluorescenceLeakage
In a preformedspace (pooling)
Into tissue(staining)
Retinal
Subretinal
Retina
Subretinal
Cystoid edema
Detachment ofthe pigmentepithelium
Detachment ofthe sensoryretina
noncystoidedema
e.g.dursen
Fluorescencewithout theadministration of fluorescein
Autofluorescence
Pseudofluorescence
Drusen of the optic nerve head
Hamatoma
Scleral exudate
Myelinate nerve Fibers, optic nerve drusen
Scar tissue
Foreign body
Causes of dark appearance of fovea
Avascularity
• Increased density of xanthophyll
• Large RPE cells with more melanin
Blockage of background choroidal fluorescence by:
Causes of hyperfluorescence RPE ‘ window’ defect
RPE atrophy (bull’s eye maculopathy
Pooling of dye
Under RPE (pigment epithelial detachment)
Under sensory retina (central serous retinopathy)
Causes of hyperfluorescence
Leakage of dye Prolonged dye retention ( staining )
Into sensory retina (cystoid macular oedema)
From new vessels (choroidal neovascularization
Associated with drusen
Vascular occlusion
Capillary non-perfusion(venous occlusion)
Loss of vascular tissue
Choroideremia or high myopia
Causes of hypofluorescence
Red-free fundus photos
Normal appearance Autofluorescence
Autofluorescence
Macular hole
CHOROIDAL NAEVUS
DIABETIC MACULOPATHY TREATED WITH LASER
BACKGROUND DIABETIC RETINOPATHY
CENTRAL SEROUS RETINOPATHY
PROLIFERATIVE DIABETIC RETINOPATHY (early venous phase)
Stargardt's Disease
DIABETIC AND HYPERTENSIVE RETINOPATHY
Limitations of FFA
1) Does not permit study of choroidal circulation details due to a) melanin in RPE b) low mol wt of fluorescein
2) More adverse reaction
3) Inability to obtain angiogram in patient with excess hemoglobin or serum protein.e.g.
polycythemia weldenstrom macroglobulenaemia
binding of fluorescein with excess Hb or protein
Lack of freely circulating molecule
THANKS TO ALL