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![Acknowledgment/References
• Dr Al Yaqdhan Al Ghafri presentation
• Dr Sawsan Nawilaty (AAO 2011)
• AAO BCSC 2015, Retina and vitreous
• Ophthalmology by Yanoff&Dukar
• Retina by Ryan
• Retinal Angiography and Optical Coherence
Tomography (Arevalo [Editor])
• Google!](https://image.slidesharecdn.com/ffaicg-170916141405/75/fundus-fluorescein-and-indocyanine-green-angiography-2-2048.jpg)
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fundus fluorescein and indocyanine green angiography
- 1. FFA/ICG Haitham Al Mahrouqi OmanMedical Speciality Board Sept 2017
- 2. Acknowledgment/References • Dr AlYaqdhan Al Ghafri presentation • Dr Sawsan Nawilaty (AAO 2011) • AAO BCSC 2015, Retina and vitreous • Ophthalmology by Yanoff&Dukar • Retina by Ryan • Retinal Angiography and Optical Coherence Tomography (Arevalo [Editor]) • Google!
- 3. Definition • Definition: Fluoresceinangiography (FA) is a diagnostic technique that uses intravenous fluorescein dye to allow the sequential visualization of the blood flow simultaneously through retinal, choroidal and iris tissue.
- 4. Concept • Fluorescent propertySodium fluorescein • Means: the ability of certain molecules to emit light of longer wavelength when stimulated by light of shorter wavelength.
- 6. Question? • What isthe excitation wavelength and the emitted wavelength in FFA? – Excited with blue light 490nm – Emit green light 530nm
- 7. Sodium Fluorescein • Awater-soluble dye of an orange-red crystalline hydrocarbon. • When injected intravenously, remains largely intravascular and circulates in the blood stream. • 80% of fluorescein molecules bind to serum proteins (albumin), the residue remaining unbound. Only the unbound molecules are available for fluorescence. • It undergoes both renal and hepatic metabolism and is excreted in the urine over 24–48 hours.
- 8. Sodium Fluorescein Absolute contraindication: •Fluorescein allergy Relative contraindications: • History of a severe reaction to any allergen is a strong relative contraindication. • Renal failure (lower the fluorescein dose if angiography is necessary) • Pregnancy: Although no reported birth defects. • Moderate-severe asthma • Significant cardiac disease.
- 9. Sodium Fluorescein • Discolouration ofskin and urine (invariable) Yanoff
- 10. The procedure 1. Bothpupils are dilated 2. The patient is seated at the camera and IV cannula is inserted in antecubital fossa. 3. Coloured funds photos, red-free photos +/- autofluorescence are taken. 4. Sodium fluorescein is injected 5 ml of 10% solution, or 2.5 ml of 25% solution (15mg/kg). 5. Images are taken in the following order: • Early rapid-sequence photographs (1 second intervals for 25–30 seconds). • Less rapid sequences between 5 and 10 min. • Late images at 10–20 minutes
- 11. What is theuse of red-free photos? • Better visualizing of the retinal vasculature and the vitreoretinal interface (e.g. ERM)
- 12. What is theuse of autofluorescence? • Autofluorescence describe the appearance of apparent hyperfluorescence in the absence of fluorescein. • It is an imaging modality of the RPE (lipofusin autoflouresce). • Described as: – Hyperautofluoresence – Hypoautofluorescence
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- 14. Examples • CSR •Optic disc drusen
- 15. What is pseudofluorescence? •Fake fluorescence • Filters problem
- 16. Anatomical consideration • Choroidalvasculature – 3 layers – Choriocappilaris are fenestrated. They are organised in lobules. Supply the outer 1/3 of retina. – RPE makes up the outer blood retinal barrier.
- 17. Anatomical consideration • Retinalvessels: – non-fenestrated (do not leak) – Inner blood retinal barrier is made up by the tight junctions of the capillary network with pericytes. – Supply the inner 1/3
- 18. Anatomical consideration • Thechoroid fills up first due to the shorter route (1 second before retinal arteries) • The retinal arteries fill up in 1 second (hence the early rapid- sequence photographs (1 second intervals for 25–30 seconds).
- 19. The procedure 1. Bothpupils are dilated 2. The patient is seated at the camera and IV cannula is inserted in antecubital fossa. 3. Coloured funds photos, red-free photos +/- autofluorescence are taken. 4. Sodium fluorescein is injected 5 ml of 10% solution, or 2.5 ml of 25% solution 5. Images are taken in the following order: • Early rapid-sequence photographs (1 second intervals for 25–30 seconds). • Less rapid sequences between 5 and 10 min. • Late images at 10–20 minutes
- 20. Choroidal phases Arm-Choroid time:8-15s Phases: • Early • Patchy choroidal filling • Choroidal flush • Recirculation phase
- 21. Choroidal journey Early • Dyein the large vessels before leaking into the choroidal stroma from the CC.
- 22. Choroidal journey Patchy choroidal filling •Accounted by the mosaic lobular pattern of the CC.
- 23. Choroidal journey Choroidal flush(20-25s) • Homogenous fluorescence of the choroid, due leaked fluorescein in the stroma from the CC.
- 24. Choroidal journey Recirculation phases Lessintense fluorescence Clearance from the large choroidal vessels makes them silhouette darkly Clearance from the CC, back to “patchy choroidal filling”!
- 25. Retinal journey Arm-retina time≈ 13s Phases • Pre-arterial • Arterial (1s) • Arteriovenous (8-12s) – Capillaries phase – Laminar flow (early venous phase) • Venous phase (12s) • Recirculation – Early (30s-5mins) – Late (10-20mins)
- 26. Retinal journey Pre-arterial Cilioretinal arterypresent in 30% of population comes from the posterior ciliary artery. - Which choroidal phase is this? Patchy choroidal filling
- 27. Retinal journey Arterial • Fillsup in 1s
- 28. Retinal journey Early arteriovenous(Retinal capillaries phase) • Complete arterial filling, no dye in veins, 1-3 sec.
- 29. Retinal journey Late arteriovenous(Laminar flow). • Dye appears in retinal venules entering along venous walls
- 30. Retinal journey Venous phase(12s) • When veins are evenly filled. Homogeneous hyperfluorescent background with dye equally distributed in retinal arterioles, capillaries, venules and choroid. • Best to visualize the foveal avascular zone (FAZ).
- 31. FAZ • FAZ correspondsto the foveola (350-500um) • Dark because: – Avascular – Densely packed and tall RPE – Xanothophyls • Ischaemic macula if FAZ > 1000um
- 32. Retinal journey Early recirculation phase(30s-5mins) • Veins brighter than arteries • Best phase for detecting staining.
- 33. Retinal journey Late recirculationphase (10-20mins) • Fading fluorescence.
- 34. Optic disc • Stainswith FFA due to staining of the lamina cribrosa and from the posterior ciliary arteries.
- 35. Abnormal FFA • Hyperfluorescence –Leaking – Window defect – Pooling – Staining • Hyporfluorescence – Blockage – Vascular filling defect/capillary dropout.
- 36. Abnormal FFA Hyperfluorescence: Leaking Extravasationof dye due to incompetent blood retinal barriers. • Pattern: early continuous increase in fluorescence In intensity and/or size • Margins: fuzzy • Level: intravitreal, intraretinal, subretinal
- 37. Abnormal FFA Hyperfluorescence: Leaking Example:Leaking microaneurysm
- 38. Abnormal FFA Hyperfluorescence: Leaking Example:Leaking CNVM
- 39. Abnormal FFA Hyperfluorescence: Windowdefect Increased transmission of the normal choroidalfluorescence (Atrophic RPE /reduced RPE pigment) • Pattern: parallels choroidal fluorescence • Size: no change • Margins: distinct • Level: subretinal (RPE)
- 40. Abnormal FFA Hyperfluorescence: Pooling Pattern: •Steady increase in the hyperfluorescence intensity • Stable size • Distinct margins PED
- 41. Abnormal FFA • Hyperfluorescence:Staining Leakage into tissue Pattern: steady increase in intensity • Size: stable • Margins: distinct • Level: retinal or subretinal Staining drusen
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- 43. Abnormal FFA • Hyporfluorescence:Vascular filling defect/capillary dropout. Capillary dropout in BRVO
- 44. RPE is ascreen Dampens transmission of choroidal fluorescence (melanin acts as a curtain). • How can we then image the choroid better?
- 45. Indocyanine green angiography •First used in cardiology to measure cardiac output in 1957 • Large molecular weight compound • 98% bound to plasma globulins. • Metabolised in the liver.
- 46. Indocyanine green angiography •Does not leak through the fenestrations of the CC. Therefore perfect for imaging the choroidal vasculature. • Its maximal peak of absorption is at 790 to 805nm and has a peak emission of 835 nm. • The infra-red light can cross through the RPE. • Poor efficacy in fluorescence – only 4%, thus poor resolution.
- 47. Indocyanine green angiography •Contraindication - Contraindicated in iodine allergy - Patients with liver disease - Patients taking metformin (precipitates lactic acidosis) - Pregnancy • Adverse events (less than fluorescein): - Used with caution in patients with shellfish allergy. - Nausea and vomiting - Anaphylaxis - Death
- 48. Procedure • Similar toFFA. • Fundus camera must be equipped with infra-red light. • Inject 25mg in 5 mls • Can be done sequentially with FFA • Image acquisition: 10 images in the first 30s and then every 15s for the first 5mins and then delayed at 10mins, 20mins and 40mins.
- 49. Image acquisition • Camera:Fundus camera can be used with filters however, newer technologies which block reflections give better resolution. Visupac, Ziess
- 50. Indications • AMD • Choroidalpolypoidal vasculopathy • Retinal Angiomatous Proliferation • Choroidal tumours • Chorioretinal Inflammatory Diseases
- 51. Indocyanine green angiography •Phases: – Early : 0-3mins – Mid (3-15mins): Fading away – Late (15-40mins): Staining of the extrachoroidal tissue • Interpretation: Same as FFA – Hypocyanescence: Blockage and filling defects – Hypercyanescence: Leakage, staining, pooling and window defects
- 52. Indocyanine green angiography(Early phase)
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Editor's Notes
- #32 The umbo (the very centre) The foveola (0.35mm) which is also the FAZ The fovea is 1.5mm (1 disc diameter) Para and then perifoveolar