Contemporary Diagnosis of Carotid Fibromuscular Dysplasia: Role of Power Doppler and a Review of Other Diagnostic Modalities

Abstract

Fibromuscular dysplasia (FMD) is a nonatheromatous, noninflammatory arteriopathy with segmental involvement of medium-sized arteries in multiple vascular beds. It most commonly involves the renal and carotid arteries. The etiology is unknown, although various hormonal and mechanical factors have been suggested. The disease can occur at any age but is usually diagnosed in middle-aged individuals, predominantly women. FMD is much more common than previously thought, perhaps affecting as many as 4% of adult women. Clinical manifestations of the internal carotid artery involvement are transitory ischemic attacks or cerebral infarction, as well as nonspecific symptoms such as headache and vertigo. In cases of cerebrovascular events, endovascular or surgical treatment is recommended; therefore, detection of FMD is of considerable importance. The gold standard for diagnosing FMD is catheter angiography (with the classic "string of beads" pattern), but this invasive procedure is only used for patients in whom it is clinically pertinent to proceed with revascularization. The optimal noninvasive modality for diagnosis and quantification for FMD is not known and little information has been recently published about new diagnostic modalities. Although angiography, computed tomography angiography, and magnetic resonance angiography are excellent in confirming the morphologic diagnosis of FMD, they are less accurate in assessing the hemodynamic significance of the lesions. Ultrasonography is useful in assessing the degree of carotid artery stenosis. Use of power Doppler ultrasound improves the ability to detect the morphologic features of carotid FMD.