<prompt> A 68-year-old woman presented with unstable angina and underwent cardiac catheterization by radial access. There was difficulty advancing the guidewire; a brachial angiogram revealed the following. What is the diagnosis?Takayasus arteritisArteriovenous malformationBrachial artery stenosisFibromuscular dysplasia  <response>: Answer D. Fibromuscular dysplasiaThe correct answer is fibromuscular dysplasia. This right brachial angiography has a classic string of beads pattern consistent with fibromuscular dysplasia, a noninflammatory, nonatherosclerotic disorder of the blood vessels. Fibromuscular dysplasia is most commonly seen in the carotid and renal arteries but has been observed in nearly every arterial bed. 