Abstract:

Objective   To study the effect of lipid and its residual risks on the components and stability of carotid plaque in the elderly. Methods   86 elderly patients with carotid artery of low echo or mixed echo plaques were screened by B type ultrasound. The patients received 3.0T magnetic resonance contrast enhancement scanning of carotid plaque in one week.We observed the cases of fibrous cap incompleteness, the lipid necrotic core size and the extent of vasa vasorum and inflammatory response.The relationships between the components and stability of plaques and triglyceride（TG）and high density lipoprotein cholesterin（HDL-C）levels in the target achieved group were also analyzed. Results   The proportion of fibrous cap incompleteness, plaque area, lipid necrotic core area and lipid necrotic core percentage in the target achieved group were smaller than those in the target unachieved group. Ktrans value was also lower in the target achieved group. The differences between the two groups had statistical significance(P＜0.05); But there were still six patients (16.2%) with vulnerable plaques in the target achieved group(the lipid necrotic core percentage>40%, Ktrans 0.097±0.013). The cases of high TG level were 6（2.18±1.62 vs 1.59±0.34）and the cases of low HDL-C level were 4(1.07±0.21 vs 1.31±0.42). The differences had statistical significance (P＜0.05). Conclusion   Ktrans of dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging may be a new indicator to measure the stability of plaques; High TG and/or low HDL-C is closely related to the stability of plaque. Even if the LDL-C level has reached the target, the lipid’s residual risk may exist. So the assessment of lipid and its residual risk is extremly important.

Key words: Lipid; Residual risk; 3.0T magnetic resonance (MR); Vulnerable plaque; Plaque component