Fundus fluorescein angiography of retina

imaging for retinal pathology

1. FUNDUS FLUORESCEIN ANGIOGRAPHY PRESENTER: Dr NIKITA JAISWAL 2 nd RESIDENT

2. F : FUNDUS – corresponds to retina F: FLUORESCEIN – corresponds to dye used A: ANGIOGRAPHY – study of the blood vessels

3. BACKGROUND PHASES INDICATIONS CONTRADICTIONS INTRODUCTION

4. FFA : This is based on the principle of studying the vasculature of retina with the help of injecting dye and then studying the contrast report after photographing it. The dye used is the fluorescein solution. Introduction:-

5. Fundus angiography---fluorescence-- luminiscence When light energy is absorbed into a luminescent material, free electrons are elevated into higher energy states. This energy is then re-emitted by spontaneous decay of the electrons into their lower energy states. When this decay occurs in the visible spectrum, it is called luminescence. BACKGROUND: Fluorescence is luminescence that is maintained only by continuous excitation

6. INTRODUCTION : An orange-red crystalline hydrocarbon,has a low molecular weight & readily diffuses through most of the body fluids and through the choriocapillaris . AVALABILITY : 500 mg fluorescein are available in vials of 10 mL of 5% fluorescein or 5 mL of 10% fluorescein. Also 3 mL of 25% fluorescein solution (750 mg) ELIMINATION : T his is eliminated through liver & kidneys FLUORESCEIN SOLUTION

7. Fundus camera and auxiliary equipment Matched fluorescein filters (barrier and exciter) 23-gauge scalp vein needle 5 mL syringe 5 mL of l0% fluorescein solution 2 -inch needle to draw the dye Armrest for fluorescein injection Tourniquet Alcohol swabs Bandage Standard emergency equipment Things we require :-

8. E xposed to light to a particular wavelength---fluorescent su bs tance absorbs energy & electrons are raised to a higher energy—now this substance emits light of longer wavelength. When excited by blue light(465-490nm) It emits yellow green light (520—530nm). ACTION:

9. Pupils: dilated Film: white& black on which retnal & choroidal vasculature is recorded. Camera:electronic flash of a xenon light source. Excitor filter: permits transfer of only blue light into the eye Barrier filter: it filters & eliminates the unwanted blue light Photography:

10. Fundamentals PRINCIPLES

11. Anatomy & physiology of eye. The retinal circulation The choroidal circulation The blood retinal barrier Passage of the dye. FUNDAMENTALS :

12. Retinal circulation: Choroidal circulation: Blood vessels– from CRA— The main vessels are found in the nerve fibre layer. Fine capillaries are found in inner nuclear layer & outer plexiform layer. There are no capillaries in about 400-500 microns in diameter around the fovea. Endothelial cells in these capilaries have tight junctions which prevent its passage . 30% of eyes there is a cilioretinal artery. Highly vascular tissue. Chorocapillaries consists of large ,thin walled capillaries with fenestrations which allow the passage which allows some plasma proteins. choroid is supplied by segmentally supplied by both the large & small capillaries.

13. Outer blood barrier Retina—RPE---choroid. Hexagonal cells are arranged in a monolayer – zona occludentes which do not allow the diffusion of smaller molecules Transport of water & waste occurs in the other direction. Blood retinal barrier :-

14. The endothelial cells lines the capillaries of the retina & thus forms the inner retinal blood barrier All fluid & metabolic transport takes place by active process through the endothelial cells. Inner blood barrier

15. Dye passes through the choroidal circulation first & then through the retinal circulation. It does not crosses through the bruch’s membrane Passage of the dye:

16. Time it appears:-10-15 secs after injection. Factors influences it-speed of injection tight clothing around the arm cardiovascular status. Sequential photography: Dye appearance in choroidal then followed by retina after 1-2 secs only. Normal angiogram:-

17. Choroidal phase(pre-arterial phase) Arterial phase Arteriovenous phase(capillary) Early venous phse Mid-venous phase Late fluorescence Phases:

18. Choroidal phase:- Occurs after 9-15 secs after injection Patchy lobular due to leakage of free fluorecein from fenestration choriocapillaries .

19. Arterial phase: Starts about a second after the choroidal fluorescence . Retinal arteriolar filling is seen.

20. Arteriovenous phase: Shows complete filling of arteries & capillaries with early laminar flow in the veins. Laminar flow Seen Leaving an axial hypofluorescnt

21. Early venous phase: Shows progress to complete filling

22. Mid-venous phase: Reduced arterial fluorescence.

23. Late (recirculation): Shows recirculation , dilution & elimination of the dye. Fluorescein disappears from retinal vasculature after 10 minutes.

24. NORMAL ANGIOGRAM:-

25. Hyperfluorescence : I s abnormally excessive fluorescence Hypofluorescence : Reduction or absence of fluorescence.

26. Autofluorescence : It occurs in absence of fluorescein. ex: exposed optic nerve drusen which is inherently fluorescent.

27. Pseudofluorecence /Fake fluorescence I t is due to reflected light from the eye passing through the camera filters. Scar tissue Foreign body Myelinated nerve fibre

28. LEAKAGE: This is a misuse word & it implies permeability of “BRB” which can be focal & diffuse.

29. Pooling: Dye collection in anatomical spaces leads to characteristics pattern. Ex: cystoid macular oedema central serous retinopathy

30. Staining: often confused with the leakage. It means that the stain is taken up by the tissues even after the stain has left the ocular circulation.

31. Transmission/window defect:-reduction of pigmentation without any breach in the physiological barrier between the neuroretina & the choroidal vasculature

32. Rpe atrophy allows choroidal fluorescence through with choroidal flush . Does not change size or shape with time. Fades with choroidal fluorescence.

33. Angoid streaks:-

34. BLOCKAGE /MASKING: OPTICALLY OPAQUE STRUCTURE IN THE PATH OF LIGHT BETWEEN FUNDUS & CAMERA. HYPOFLUORESCENCE:

35. M anagements Complications

36. Extravasation and local-tissue necrosis 13 Inadvertent arterial injection Nausea 11–13 Vomiting Vasovagal reaction (circulatory shock, myocardial infarction) 12 Allergic reaction, anaphylaxis (hives and itching, respiratory problems, laryngeal edema , bronchospasm) Nerve palsy Neurologic problems (tonic- clonic seizures) Thrombophlebitis Pyrexia Death Complications:

37. Extravasation: for this local ice pack should be given at the area of extravasation. If the extravasation occurs earlier it’s the physician who decides whether to continue the procedure or not. Prevention: to use a scalp vein needle which is flexible & not the large needle which is directly attached to the syringe. NAUSEA: I t starts within 20-30 seconds & last for 2-3 minutes & then disappears slowly. VOMITING:It starts within 40-50 seconds post injection. HIVES & ITCHING: It starts after 2-15 mins of injection. Management:

38. No contraindication to cardiac disease, pace makers,cardiac arrhythmias. No teratogenicity ( but avoided in 1 st trimester of pregnancy). Contraindications:

39. An oxygen cylinder A sphygmomanometer A stethoscope An airway support system. Ready to go instruments:

40. Thank you Have a great day