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

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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

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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