Colour Doppler is a specialised ultrasound that shows blood flow through arteries and veins using colour mapping. It is used to detect blood clots, blockages, narrowing of vessels, varicose veins, and other vascular conditions.
Common types include lower limb Doppler (for DVT or varicose veins), carotid Doppler (for stroke risk), renal Doppler (kidney blood flow), and abdominal Doppler (portal vein assessment). The test is painless and does not use radiation.