Indocyanine Green Injection for Angiography | Uses & Side Effects

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What is Indocyanine Green Injection?

Indocyanine green injection comprises the API Indocyanine Green which is used in tests to measure cardiac output, liver function, and liver blood flow. It is also used to make certain parts of the eye easier to see during medical procedures such as angiography. ICG is used to obtain angiographic images of the choroid

The Indocyanine Green Angiography procedure is similar to fluorescein angiography, but ICG angiography uses indocyanine green dye that fluoresces with infrared (invisible) light. Infrared penetrates the layers of the retina and has the ability to reveal blood flow in deeper layers when taken with an infrared-sensitive camera. Other major uses of Indocyanine Green Injection include Capsulorhexis (used to colour the capsular bag during cataract surgery), Tissue and Organ circulation Diagnosis (ICG is used as a marker) and Navigation for tumours in Sentinel Lymph node Biopsy.

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Angiography with Indocyanine green Injection

Indocyanine green angiography or better known as ICGA is a diagnostic procedure that uses ICG pigment to study blood flow in the choroid (the layer of blood vessels beneath the retina). Indocyanine green dye is injected into the veins of the arm/hand. ICG has the ability to bind 98% to plasma proteins (80% to globulin, 20% to alpha lipoproteins and albumin), resulting in less leakage (dye leakage from blood vessels) compared to fluorescein as a marker.

Pictures are taken to record the blood flow as the dye flows through the blood vessels of the eye. Choroidal blood vessels are hidden under a layer of pigmented cells. The infrared light emitted by the ICG dye can be imaged through a tinted layer using a special filter. The most common use of indocyanine green angiography is the detection of choroidal neovascularization, a common component of age-related macular degeneration. 

Indocyanine Green Angiography vs Fluorescein Angiography

Indocyanine Green Angiography(ICGA) Fluorescein Angiography(FA)
Indocyanine green dye is used for the procedure. Sodium Fluorescein dye is used for the procedure.
ICG dye has high protein binding capacity (about 98%) and thus can image the choroidal vasculature better than fluorescein angiography. Sodium Fluorescein dye has less protein binding capacity.
Fluorescence efficiency of ICG molecule is less (only 4% of that of sodium fluorescein). Fluorescence efficiency of sodium fluorescein is more.
To detect ICG fluorescence, charge coupled device (CCD) cameras with a digital acquisition process are necessary. In FA, Cameras with photographic films are used.
USES:- detection of Choroidal neovascularization, Capsulorhexis, Tissue and organ circulation diagnosis, Navigation for tumours in Sentinel Lymph node Biopsy, etc. USES:- Macular edema, Diabetic Retinopathy, Macular degeneration, Ocular melanoma, etc.

Macsen Labs is also a leading manufacturer and supplier of Fluorescein Sodium API.


Read more about what is fluorescein sodium.

Dosage and Administration

Indocyanine Green for Injection USP is a sterile, lyophilized green powder containing 25 mg of Indocyanine Green with no more than 5% sodium iodide. When performing a dye dilution curve, a known amount of dye is infused as a single bolus as quickly as possible into a selected site of the vasculature via a cardiac catheter. A recording device (oximeter or densitometer) is attached to the needle or catheter to collect a mixture of dye and blood from the arterial sampling site throughout the body. 

Under sterile conditions, indocyanine green powder for injection should be reconstituted with sterile water for injection provided with it and the solution used six hours after preparation. 

If there is a precipitate, discard the solution. The usual doses of indocyanine green for injection on the dilution curves are:

Adults – 5.0 mg

Children – 2.5 mg

Infants – 1.25 mg

These doses of dye are usually infused in 1 mL volume. An average of 5 dilution curves is recommended for cardiac catheterization. The total dose of infused dye should be kept below 2 mg/kg.

The syringe can be flushed with sterile water for injection, but residual dye should be flushed from the cardiac catheter into the circulatory system using isotonic saline to avoid hemolysis. 

Saline should be used in all other parts of the catheterization procedure, except to flush the syringe.

How to use Indocyanine green Injection

Under Sterile conditions, reconstitute one 25mg vial of Indocyanine Green for Injection USP using one 10 ml sterile Water for Injection, USP vial located in the injection set. Shake the ICG vial gently to dissolve. After reconstitution, a 25 mg vial of ICG contains 2.5 mg of dye per ml of solution, so a 1.0 ml injection contains a 2.5 mg dose of ICG. The patient should be weighed and the dosage for one administration should be calculated on the basis of 0.1 mg/kg (0.04ml/kg) – 0.3 mg/kg (0.12ml/kg) of body weight. Multiple administrations can be performed up to 2mg/kg (0.8ml/kg) per patient.

Indocyanine Green for Injection, USP must be used within 6 hours after reconstitution. If a precipitate is present, discard the solution. ICG should be administrated immediately before IR imaging. This drug should only be given by a doctor or under the supervision of a doctor. 

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Side effects of ICG injection

In addition to the required effects, the drug can have some unwanted effects. Not all of these side effects occur, but you may need to see a doctor if they do. Get in touch with your doctor if you have any of the following side effects

  • Cough
  • Difficulty while swallowing
  • Puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • Redness of the skin
  • Tightness in the chest
  • Unusual tiredness or weakness
  • Dizziness
  • Fast heartbeat
  • Hives or welts, itching, skin rash


Q. What is indocyanine green angiography used for?

Indocyanine Green Angiography (ICGA) is a diagnostic process that involves the use of ICG dye to monitor blood flow in the CHOROID – the layer of blood vessels beneath the retina.

Q. How long does indocyanine green work?

ICG can persist in the vessels for up to 20 to 30 minutes due to plasma protein binding (intranasally). When the eye is inspected, the blood lingers in tissues with a higher blood flow, like the choroid and the blood vessels of the retina, for a long period. 

Q. What is Indocyanine green injection used for?

Indocyanine green injection is used in tests to measure cardiac output, liver function, and liver blood flow. It is also used to make certain parts of the eye easier to see during medical procedures such as angiography.

Q. How do you inject Indocyanine Green?

Indocyanine green is administered as a rapid IV bolus.

Q. How does Indocyanine Green injection works?

ICG is used to measure liver blood flow by using Fick Principle. For more details refer here.

Resources on Indocyanine Green

Indocyanine Green | Chemical Properties, Uses and Side Effects

Indocyanine Green | Uses in Medical Imaging & Surgery


The information provided here is based on general knowledge, articles, research publications etc and we do not claim the authenticity of any of the information provided above. We do not claim or suggest/advise any medical, therapeutic, health or nutritional benefits of Indocyanine green. We do not supply or promote our Indocyanine green product for the applications which are covered by valid patents and which are not approved by the FDA.

Macsen Labs is a manufacturer and supplier of several grades of Indocyanine Green such as:-

Indocyanine Green USP-43

Buy Indocyanine Green Dye From Macsen Labs