Fibromuscular dysplasia, or FMD, is a vascular condition that causes abnormal cell growth in the walls of medium-sized arteries, most commonly the renal arteries and internal carotid arteries. The classic form produces a string-of-beads appearance on angiography due to alternating areas of stenosis and dilation. On Doppler ultrasound, fibromuscular dysplasia may show elevated velocities in the affected artery segments, turbulent flow, and sometimes the characteristic beaded irregularity of the vessel wall. FMD predominantly affects young to middle-aged women and can cause hypertension when it involves the renal arteries or stroke and dissection when it affects the carotid arteries.
Sonography Term