Beaded or toous appearance of internal carotid aery Fibromuscular dysplasia Characterised by an idiopathic, non-inflammatory,non-atherosclerotic angiopathy of small and medium-sized aeries. More common in young women, typically diagnosed between the ages of 30 and 50 DSA is the gold standard. The characteristic findings alternating stenosis and dilatations, causing a String of beads appearance.