These visible veins consequence from weakened valves that malfunction, enabling blood to move backward and pool in the veins. This congestion causes twisting and lengthening in the impacted veins, typically resulting in discomfort and agony. Transcranial Doppler ultrasound. Works by using sound waves to determine the velocity of blood stream https://www.sgvascularctr.com/understanding-venous-malformation-treatments-in-singapore/