Nε-(carboxymethyl) lysine Concentration in Debris from Carotid Artery Stenting Correlates Independently with Signal Intensity on T1-Weighted Black-Blood Magnetic Resonance Images

Background and Purpose: Because magnetic resonance imaging (MRI) focuses on the morphological characteristics of carotid artery plaques, its diagnostic value with respect to plaque vulnerability is limited. We examined the correlation between Ne-(carboxymethyl) lysine (CML), a main chemical structure of advanced glycation end-products, and the vulnerability of plaques visualized on MRI scans. Materials and Methods: We enrolled 43 patients who had undergone carotid artery stenting (CAS) for carotid artery stenosis; all underwent MRI studies, including blackblood MRI and diffusion-weighted imaging (DWI). The signal intensity ratio (SIR) of plaques to adjacent sternocleidomastoid muscle (P/M) on T1-and T2-weighted images (T1WI, T2WI) was calculated. Protein samples were extracted from debris trapped by a filter device. The concentrations of CML and myeloperoxidase (MPO) were measured by solid-phase enzyme-linked immunosorbent assay. Results: The patients were classified into 2 groups based on their SIR-P/M on T1WI and T2WI scans. We observed a higher incidence of post-CAS DWI lesions in patients with a higher than a lower SIR-P/M on T1WI; the CML and MPO concentrations in their CAS debris were also higher. No such differences were seen in patients with a higher or lower SIR-P/M on T2WI scans. The concentration of CML in CAS debris correlated independently with the SIR-P/M on T1WI of the carotid plaques, and was related to the concentration of MPO in CAS debris. Conclusions: Our findings suggest CML as a candidate molecular imaging probe for the identification of vulnerable plaques.