FFA AND ICG

1. FOUNDUS FLUORESECEIN
ANGIOGRAPHY AND
INDOCYANINE ANGIOGRAPHY
MR.MOHAMED ALTHAF BASHA
MSC.OPTOMETRY FINAL YEAR

2. FLUORESCEIN ANGIOGRAPHY
• The study and diagnosis of retinal, macular and choroidal
pathologic lesions have been greatly revolutionized with
the advent of fundus fluorescein angiography (FFA).
• From an initial laboratory tool, it has now become a useful
diagnostic tool that has aided the diagnosis and monitoring
of the treatment of retinal vascular and macular diseases.
• Although the retina can be readily examined by direct and
indirect ophthalmoscopy and slit-lamp bio microscopy, the
fluorescein angiography provides a valuable addition to
these techniques.

3. PRINCIPLE OF FFA
• Luminescence
• Fluorescence
• Phosphorescence
• Two filters are used:
• COBALT BLUE EXCITATION FILTER
• YELLOW GREEN BARRIER FILTER

4. EXCITATION FILTER
•The dye absorbs light in the blue range of the visible spectrum with
absorption peaking at 465 to 490 nm. The blue flash excites the unbound
fluorescein within the blood vessels or the leaked out fluorescein.
• The blue filter shields out all other light and allows through only the blue
excitation light.
•Structures containing fluorescein within the eye emit green-yellow light.
• The blue light is reflected off of the fundus structures that do not have
fluorescein.

5. CONTRAINDICATIONS
ABSOLUTE
1) Known allergy to iodine containing compounds.
2) H/O adverse reaction to FFA in the past.
RELATIVE
1) Asthma
2) Hay fever
3) Renal failure
4) Hepatic failure
5) Cardiac disease – cardiac failure, Myocardial infarction
6) Previous mild reaction to dye.
7) Tonic-clonic seizures
6) Pregnancy ( especially 1st trimester)

6. COMPLICATIONS

7. EQUIPMENT

9. FFA PROVIDES THREE MAIN
INFORMATION:
• The flow characteristics in the blood vessels as
the dye reaches and circulates through the
retina and choroid.
• It records fine details of the pigment
epithelium and retinal circulation that may
not otherwise be visible
• Give a clear picture of the retinal vessels and
assessment of their functional integrity

10. FLUORESCEIN PATHWAY
• Arm-to-retina circulation time is 8-10 sec.
• Normally 10-15 seconds elapse between dye
injection and arrival of dye in the short ciliary
arteries.
• Choroidal circulation precedes retinal
circulation by 1 second.
• Transit of dye through the retinal circulation
takes approximately 15 to 20 seconds.

11. FLUORESCEIN PATHWAY

13. CSR-SMOKE STACK

14. PED

15. NVD,NVE

16. CUTICULAR DEUSENS

17. NON PERFUSION AREAS
VASUCLAR FILLING DEFECT

18. INDOCYANINE GREEN ANGIOGRAPHY
• Indocyanine green (ICG) angiography (ICGA) is fast
emerging as a popular and useful adjunct to the traditional
fundus fluorescein angiography (FFA) in the diagnosis of
macular, choroidal and outer retinal disorders.
• This technique was introduced in ophthalmology in 1973 by
Flower and Hochheimer.
• FDA approved the ophthalmic use of ICG dye in 1975.
• It remained largely unpopular owing mainly to technical
difficulties. With the advent of videoangiogram recordings
and the recognition of its potential in delineating occult
choroidal neovascular membranes, the clinical use of ICGA
has increased tremendously .

19. PRINCIPLES OF ICG
• ICG fluorescence is only 1/25th that of fluorescein. So modern
digital ICGA uses high-sensitivity videoangiographic image capture
by means of an appropriately adapted camera.
• Both the excitation (805 nm) and emission (835 nm) filters are set
at infrared wavelengths.
• Alternatively, scanning laser ophthalmoscopy (SLO) systems
provide high contrast images, with less scattering of light and fast
image acquisition rates facilitating high quality ICG video.
• The technique is similar to that of FA, but with an increased
emphasis on the acquisition of later images (up to about 45
minutes) than with FA. A dose of 25–50 mg in 1–2 ml water for
injection is used

21. ADVERSE EFFECTS
• Nausea, vomiting are uncommon.
• Anaphylaxis, approximately equal incidence to
FA.
• Serious reactions are exceptionally rare.
• ICG contains iodide and so should not be given
to patients allergic to iodine or possibly
shellfish.
• Iodine-free preparations such as infracyanine
green are available.

22. CONTRAINDICATIONS
• ICGA is relatively contraindicated in liver
disease (excretion is hepatic)
• In patients with a history of a severe reaction
to any allergen.
• moderate or severe asthma
• significant cardiac disease.
• Its safety in pregnancy has not been
established

23. PHASES OF ICGA
• Early – up to 60 seconds post-
injection
• Early mid-phase – 1–3 minutes
• Late mid-phase –3–15 minutes
• Late phase – 15–45 minute

24. INDICATIONS OF ICGA
• Polypoidal choroidal vasculopathy (PCV): ICGA is far superior to FA
for the imaging of PCV.
• Exudative age-related macular degeneration (AMD): Conventional
FA remains the primary method of assessment, but ICGA can be a
useful adjunct, particularly if PCV is suspected.
• Chronic central serous chorioretinopathy often difficult to
interpret areas of leakage on FA. ICGA shows choroidal leakage and
the presence of dilated choroidal vessels.
• Posterior uveitis. ICGA can provide useful information beyond that
available from FA in relation to diagnosis and the extent of disease
involvement.

25. ADVANTAGES OF ICGA OVER FFA
• FA is an excellent method of studying the retinal
circulation, it is of limited use in delineating the
choroidal vasculature, due to masking by the RPE.
• In contrast, the near-infrared light utilized in
indocyanine green angiography (ICGA) penetrates
ocular pigments such as melanin and xanthophyll, as
well as exudate and thin layers of subretinal blood,
making this technique eminently suitable.
• ICG fluorescence can be imaged even in the presence
of considerable blood, due to the phenomenon of
forward scatter

26. • The peak absorption of ICG coincides with the
emission spectrum of diode laser, which allows
the selective ablation of chorioretinal lesions
using ICG dye-enhanced laser photocoagulation
wherein a target tissue containing ICG is exposed
to the diode laser beam.
• Photophobic patients tolerate ICGA better than
FFA.
• ICGA accurately measures the size of an occult
choroidal neovascular membrane(CNVM).

27. LIMITATIONS OF ICGA
• The choriocapillaris cannot be imaged separately with ICGA
since their average cross-sectional diameter (21 μm) is much
smaller than that of their feeding and draining vessels, and
hence the fluorescence of the former cannot be differentiated
from that arising from the latter.
• The phenomenon of Mie scatter also masks the unfilled
retinal vessels that cannot be visualized well in low speed
angiography systems.
• Bright areas do not necessarily signify dye leakage due to the
phenomenon of additive fluorescence
• Although superior to FFA in the imaging of occult CNVM, ICGA
may underestimate the size of the CNVM.

29. RECENT ADVANCES IN INDOCYANINE
GREEN ANGIOGRAPHY
• Wide-angle angiography: This is carried out by performing ICGA with the
aid of wide angle contact lenses, such as Volk SuperQuad and a traditional
Topcon fundus camera. This allows real-time imaging of a wide field of the
choroidal circulation up to 160 degrees of field of view.
• Overlay technique: This technique allows lesion on one image to be
traced on to another color or red-free image.
• Digital stereo imaging: Elevated lesions such as PEDs can be better imaged
in this way.
• ICG as a photo sensitizer: It is considered to be a cheaper alternative to
vertoporfin in photodynamic therapy of neovascularAMD& other
disorders .
• Digital subtraction ICGA: It uses digital subtraction of sequentially
acquired ICG images along with pseudo color imaging. It shows occult
CNVM in greater detail and within a shorter time than conventional ICGA.

30. THANK YOU