A medical expert, like a doctor, or experienced vascular technician is best able to help you find the information and care you need. This information does not constitute medical advice or diagnosis. A vein mapping, also called a venous insufficiency or venous reflux ultrasound, uses ultrasound imaging to create a map of your veins and arteries. This test can help diagnose chronic venous insufficiency, which is a condition that prevents veins from pumping blood back to the heart. A provider may order a vein mapping test before medical procedures or to check for health conditions that affect blood vessels. For example, a surgeon may use a vein mapping ultrasound to prepare for procedures like bypass graft surgery, or to diagnose Varicose Veins some of which may be hidden under the skin. A vein mapping ultrasound typically takes 30–90 minutes to complete. During the process, a technician applies a cooling gel to the skin and administers ultrasound waves. Patients may feel a cold sensation, but most report virtually no pain.