What is indocyanine green (ICG)?

Indocyanine green (ICG) is a green cyanine dye. It is a water-soluble but relatively hydrophobic, anionic, tricarbocyanine molecule. Its molecular formula is C₄₃H₄₇N₂NaO₆S₂.

This amphiphilic fluorophore has a half-life of 150 to 180 seconds and a peak spectral absorption at about 800 nm. ICG is the only Near Infra-Red (NIR) contrast agent approved by the FDA for a limited number of indications in various surgical procedures.

Indocyanine green (ICG) is widely used in medicine to enhance visualization of blood vessels and other anatomic structures that may not be clearly visible in white light