[Development of nonstenotic extracranial carotid plaques--a prospective study of its course with the Duplex system].

The natural history of a prospectively investigated group of patients with small non-stenotic extracranial carotid lesions (less than 30% lumen narrowing) was studied during 18 months. Using a specially designed high resolution (10 MHz) ultrasound Duplex system, 43 lesions were followed in 31 patients. Whereas the majority of the carotid atheromas remained unchanged (51%) or deteriorated (30%), spontaneous regression could be observed in 19%. Regression was limited to volume reduction of "soft plaques" and healing of "ulcerative" lesions, while "fibrous" and "hard plaques" remained unchanged or deteriorated. None of the patients developed cerebrovascular events during follow-up.