detail of ffa and icg

1. FLUORESCEIN ANGIOGRAPHY AND
INDOCYANINE GREEN ANGIOGRAPHY
DR. NIRAV B. DADIA
FELLOW
NANDADEEP HOSPITAL

2. INTRODUCTION
 The word Angiography - Greek angeion,
"vessel" and graphien, "to write or record".
 Imaging of vessels, and the resulting pictures
are angiograms.
 In-vivo study of the retinal circulation

3. Basic principle
 luminescence- emission of light by
excitation of atoms or molecules to higher
energy levels
 fluorescence- luminescence that is
maintained by continuous excitation.

5.  The emitted energy is often less than the
absorbed energy, though of longer
wavelength (stoke’s law)
 Fluorescein absorbs blue light and emits
yellow green light
 Exciter filter (blue) and barrier filter (green)

7.  Properties of Flourescein Na

8. Chemical properties
Fluorescein sodium –
synthesized from the petroleum derivatives resorcinol and
phthalic anhydride
• Low molecular weight
• High solubility
• Rapid diffusion through body fluids but not large enough to
pass through tight junctions of retinal vessels, RPE and large
choroidal vessels.
•This is the basis for the diagnostic value of the test.

10. Optical properties
• It absorbs blue light, with peak absorption
and excitation occurring at wavelengths
between 465-490nm.
• Fluorescence occurs at the yellow-green
wavelengths of 520 to 530nm

12. Pharmacological properties
• 80% bound to serum proteins
• also bound to blood cells
• remaining i.e. Unbound dye is seen during
angiography

13. pharmacokinetics
• Metabolized by kidney, excreted from the body
within 24 to 36 hrs
• Small amounts are lost in bile.
• Skin - a yellowish tinge for a few hours
• Urine - yellow-orange color
• Dye is a biologically inert substance

14.  Requirement

16. Relevant anatomy
Outer blood
retinal barrier
Inner blood
retinal Barrier
Fluorescein cannot diffuse through tight
cellular junctions present at two sites within
the fundus

19.  Angiography is composed of the superimposition of
two separate circulations
 – Choroidal circulation
the fluorescein freely leaks out of the fenestrated
choroidal capillaries, and from there through Bruch's
membrane.
– Retinal circulation
the retinal blood vessel endothelial cells are joined
by tight junctions which prevent leakage of
fluorescein into the retina.

20. Phases of normal angiogram
• Arm to retina time: Normally 10-15 seconds
elapse between dye injection and arrival of
dye in the eye.
• Retinal ciculation time: Transit of dye
through the retinal circulation takes 15 to 20
seconds.

21. PHASES OF ANGIOGRAM
 1. PREARTERIAL [ CHOROIDAL FLUSH ] – 10 sec
 2. ARTERIAL – 12sec
 3. ARTERIO-VENOUS
- EARLYTRANSIT – 13 sec
- MIDTRANSIT – 16sec
- LATETRANSIT – 20 sec
3a. Peak phase – 25 sec
4. RECIRCULATION – 30sec
5. LATE FLURESCEINTRANSIT – after 10 min

22.  Choroidal phase
- initial patching filing of lobules, - followed by a
diffuse (flush) as dye leaks out of the
choroidocapillaris.

23.  visualisation of choroid depends on retinal
pigmentation - Cilioretinal vessels and
prelaminar optic disc capillaries fill during this
phase.

24. Arterial phase
• the central retinal artery fills about 1 second
later than choroidal filling

26. Venous phase
• Early venous phase: filling of the veins is from
tributaries joining their margins, resulting in a
tramline effect (lamellar flow)

27. Late phase
• after 10 to 15 minutes little dye remains within
the blood circulation.
• Dye which has left the blood to ocular
structures is particularly visible.
• it shows abnormal dye accumulations
indicative of leakage or staining.

29. DARK APPEARANCE OF FOVEA
The dark appearance of the fovea is caused by three
factors:
Absence of blood vessels in the FAZ.
Blockage of background choroidal fluorescence due
to the high density of xanthophyll at the fovea.
Blockage of background choroidal fluorescence by
the RPE cells at the fovea, which are larger and
contain more melanin and lipofuscin than else
where in the retina

31. SELECTION OF PATIENT
• Not recommended :
- History of allergy, severe urticaria or bronchial
asthma
- Patient with renal failure and poor general
condition.
• In pregnant women - it may be avoided.
• Safe: In diabetics, hypertensives and history of
previous cardiovascular disorders.

32. 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
 8) Pregnancy ( especially 1st trimester

33. preparation
• make sure the patient is well dilated
• Log the patient information
• Injectable fluorescein dye comes in 5%(10cc) ,
10% (5cc), and 20% (2cc or 3cc) solutions.
• 20% solution is preferred because this larger
bolus produces better photographic contrast and
detail in the initial phases of the angiogram

34. analysis
– Sequential analysis
- frame by frame. useful in analysing vascular
disorders of the retinal and choroidal.
– Anatomic analysis
- observes each of the major layers of the posterior
pole of the eye - the choroidal, RPE and
neurosensory retina.
– Morphologic analysis
- considers overall patterns. (hyperfluorescent) or
lighter (hypofluorescent)

35. reporting
• Start with any striking abnormality and describe
this in detail:
- phase of angiogram
– Hypo/hyperfluorescent components
– Intensity of fluorescence and changes with time
– Area of fluorescence and changes with time

36. Common abnormalities
•Timing
-arm to eye time and retinal circulation may
be prolonged if the cardiac output is low or
the carotid perfusion is reduced.
• Abnormal dye distribution:
hypofluorescence/
hyperfluorescence

39. Hypofluorescence
Transmission defect
-blood,
-pigment,
-hard exudates
-abnormal material (eg, the yellow flecks in
patient with Stargardt's disease etc)

41.  pre-retinal opaque structures superficial to
the retinal circulation will mask both the
retina and choroidal circulation eg. -
Preretinal hemorrhage, -myelinated nerve
fibres

42.  prechoroidal opaque structures deep to the
retinal circulation but superficial to the
choroidal circulation will mask only the
choroidal circulation for example:

43. blood
 - retinal haemorrhages
 - subretinal blood from choroidal new vessels

44. Filling defect due to abnormal
circulation
• arterial non-perfusion is seen in occlusion of
the central retinal artery and its branches
• capillary non-perfusion is an important sign of
retinal ischaemia.

49. Leakage of dye
 • occurs when there is breakdown of the
tight junction of the RPE or the retinal
endothelium.

54. Autofluorescence
• Presence of hyperfluorescence in the fundus
seen in pre-injection photographs.
• optic disc drusen is the classic example.
• Others:
astrocytic hamartoma
large deposits of lipofuscin
and exudates

56. FFA patterns of some common
diseases

58. ARMD
• FA is not indicated in each and every case and
in every visit
• Indications
- possibility of finding CNVM
metamorphopsia
recent decrease in vision
central or paracentral scotoma
- undergone laser treatment

60. Wet ARMD
• FA helps in determining the extent and the
type of neo-vascularization.
• Classified into classic and occult variety into
extrafoveal
juxtafoveal
subfoveal

65. BRAO
• Artery occlusion
• Purtschners retinopathy-
blocked fluoroscence partly due to ischaemia
and intracellular edema
-opacified edematous retina

71. CHOROIDITIS

72. Oral FA
Indication:
Psychologically or technically unsuitable for i/v
injection especially children, obese pts.
Dose:
1 gm Na fluorescein (5ml of 20% dye)
(mixed in 200 ml of orange juice – Body weight
40kg.
1.5 gm in pts with a body wt 60 kg
while 2.0 gm is given to pts over 60 kg

73.  Post-administration photographs taken after
15, 30, 45 and 60 minutes.
 Reserved - lesions resulting in late dye
leakage and pooling like CSR, disciform disc
degeneration etc.
 Not recommended when early circulation
dynamics are to be studied

74. Adverse events
severity Adverse events percentage
 Mild Nausia, vomiting, 1-10
extravasation
 moderate Urticaria, 1-6
pyrexia,
local tissue necrosis,
nerve palsy
 severe Bronchospasm, 0.05
anaphylaxis,
shock
death 1/222,000

75. EMERGENCY in FA Case
• Allergic reaction: Local / Generalised
Manifest: redness, itching, oedema & urticaria.
• Stop dye injection.
• Monitor Pulse , BP & Resp.
• Inj. Avil 2ml IV
• Inj Efcorlin 100mg IV
• Normal Saline – wash the local site

76. Fluorescein Angioscopy
• Indirect Ophthalmoscope along with its blue
filter attachment, is used for viewing of the
fundus periphery.
• Pathology including Eales disease,
sarcoidosis, retrolental fibroplasia and
peripheral vasculitides, both in active
inflammatory stage and later stage, are
effectively visualised by F-scopy

77. Limitations of FFA
1) Does not permit study of choroidal circulation details due to
a) melanin in RPE
b) b) low mol wt of fluorescein
how to overcome ---- ICG
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

79. 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 .

80. 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.

82. INDOCYANINE GREEN
The indocyanine green (ICG) is a tricarbocyanine dye that comes packaged as a
sterile lyophilized powder and is supplied with an aqueous solvent.
Molecular weight :774.97
It contains less than 5% sodium iodide (in order to increase its solubility).
It has a pH of 5.5 to 6.5 in the dissolved state, has limited stability, and hence
must be used within 10 hours after reconstitution.
98% of the injected dye is bound to plasma proteins, with 80% being bound
to globulins, especially alpha- 1 lipoproteins.

83. CLEARANCE
The dye is secreted unchanged by the liver into
the bile.
There is no renal excretion of the dye
It does not cross the placenta.
The dye also has a high affinity for vascular
endothelium, and hence persists in the large
choroidal veins, long after injection.

84. 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.

85. 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

87. 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

89. HYPERFLOURESCENE
A window defect similar to those seen with FA.
Leakage from retinal or choroidal vessels the optic nerve head or the RPE
gives rise to tissue staining or to pooling.
Abnormal retinal or choroidal vessels with an anomalous morphology
exhibiting greater fluorescence than normal

90. HYPOFLOURECENCE
 Blockage (masking) of fluorescence.
A particular phenomenon to note is that in contrast to its
FA appearance, a pigment epithelial detachment
appears predominantly hypofluorescent on ICGA.
Pigment and blood are self-evident causes, but fibrosis,
infiltrate, exudate and serous fluid also block
fluorescence
Filling defect due to obstruction or loss of choroidal or
retinal circulation.

91. INDICATIONS OF ICGA
 Polypoidal choroidal vasculopathy (PCV)
 Exudative age-related macular degeneration (AMD)
 Chronic central serous chorioretinopathy.
 Posterior uveitis.
 Choroidal tumors may be imaged effectively
 Breaks in Bruch membrane
 If FA is contraindicated.

92. 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.
ICGA can be used even when the ocular media are too hazy for FFA.This is
due to the phenomenon of Rayleigh scatter.
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 Mie or forward scatter.

93. 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).

94. 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
Although superior
to FFA in the
imaging of occult
CNVM, ICGA may
underestimate the
size of the CNVM.
Bright areas do not
necessarily signify
dye leakage due to
the phenomenon
of additive
fluorescence
The phenomenon
of Mie scatter also
masks the unfilled
retinal vessels that
cannot be
visualized well in
low speed
angiography
systems.
ICGA is poorer
than FFA in the
imaging of classic
CNVM since the
early hyper
fluorescence of the
CNVM is
overwhelmed by
the intense
background
choroidal filling

95. 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 asVolk SuperQuad and a
traditionalTopcon 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
neovascular AMD& 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.

96. SUMMARY

97. Fundus fluorescein angiography ICG angiography
For retinal circulation For choroidal circulation
Dye used – sodium fluorescein Dye used – indocyanin green
80% plasma protein bound 98% plasma protein bound
low MW high MW
Light of visible spectrum used Infrared spectrum of light used
Blue green filters used Infrared filters used
More side effects Less side effects

98. FFA
•Valuable in DR
– Neovascularisation
– CNP areas
- Maculopathy
• CNVM activity
• CSR
•Venous occlusion
• Patient education

99. FUTURE APPLICATIONS OF INDOCYANINE
GREEN ANGIOGRAPHY
In the future, ICGA is expected to play a more important
and wider role especially in the management of macular
disorders.
Identifying subclinical neovascular lesions in the other eye
of patients with AMD.There are several reports that
mention that 10% of such eyes with no clinical or
fluorescein angiographic evidence of an exudative process
harbor plaques of neovascularization evident on ICGA.
ICG-guided feeder vessel photocoagulation: SLO high-
speed ICGA can adequately image the feeding vessels of
the CNVM which are 0.5 to 3 mm in length and are believed
to lie in the Sattler’s layer of the choroid

100.  THANK YOU