Carotid plaque characteristics on magnetic resonance plaque imaging following long-term cilostazol therapy

Cilostazol is an antiplatelet agent that can induce the regression of atherosclerosis. However, its long-term effects on plaque involution of the cervical carotid arteries remain unknown. Thus, we aimed to evaluate the effect of long-term cilostazol administration on carotid plaques using quantitative magnetic resonance (MR) plaque imaging.

Sixteen consecutive patients with carotid stenosis were examined using T1-weighted MR plaque imaging at baseline, 6 months, and 12 months after initiation of 200 mg per day of cilostazol. We calculated the contrast ratio of the carotid plaque against the sternocleidomastoid muscle and percent areas of the intraplaque fibrous tissue, lipid/necrosis, and hemorrhage components using automated software. We also measured the volume and echogenicity of the plaques using 3-dimensional ultrasonography.

The contrast ratio of the carotid plaque significantly decreased during the cilostazol administration (median 1.07, 1.04, and 1.00 at baseline, 6 months, and 12 months, respectively; P = .03). Furthermore, the area of the fibrous components significantly increased (73.9%, 80.3%, and 85.7%, respectively; P = .03) and that of the lipid/necrotic components significantly decreased (25.2%, 19.2%, and 14.3%, respectively; P = .04). There were no substantial changes in plaque volume or echogenicity on ultrasonography.

Signal alterations on MR plaque imaging indicated the increase of fibrous components and the decrease of lipid/necrotic components in the carotid plaque during the cilostazol therapy.