A duplex ultrasound is often a non-invasive way of detecting and quantifying the narrowing and blockage in the blood vessels. It can be performed by a skilled sonographer which is confirmed by a Radiologist. It's a pain-free process carried out over a sofa and typically takes one-two hrs. Ultrasound scanning: https://sgvasculargrp.com/medical-condition/peripheral-arterial-disease/icon-peripheral-arterial-disease-pad-2-3/