Supplementary Material for: Lipid Core Burden Index Assessed by Near-Infrared Spectroscopy of Symptomatic Carotid Plaques: Association with Magnetic Resonance T1-Weighted Imaging

<b><i>Introduction:</i></b> Vulnerable plaques are a strong predictor of cerebrovascular ischemic events, and high lipid core plaques (LCPs) are associated with an increased risk of embolic infarcts during carotid artery stenting (CAS). Recent developments in magnetic resonance (MR) plaque imaging have enabled noninvasive assessment of carotid plaque vulnerability, and the lipid component and intraplaque hemorrhage (IPH) are visible as high signal intensity areas on T1-weighted MR images. Recently, catheter-based near-infrared spectroscopy (NIRS) has been shown to accurately distinguish LCPs without IPH. This study aimed to determine whether the results of assessment of high LCPs by catheter-based NIRS correlate with the results of MR plaque imaging. <b><i>Methods:</i></b> We recruited 82 consecutive symptomatic carotid artery stenosis patients who were treated with CAS under NIRS and MR plaque assessment. Maximum lipid core burden index (max-LCBI) at minimal luminal areas (MLA), defined as max-LCBI_MLA, and max-LCBI for any 4-mm segment in a target lesion, defined as max-LCBI_AREA, were assessed by NIRS. Correlations were investigated between max-LCBI and MR T1-weighted plaque signal intensity ratio (T1W-SIR) and MR time-of-flight signal intensity ratio (TOF-SIR) in the same regions as assessed by NIRS. <b><i>Results:</i></b> Both T1W-SIR_MLA and T1W-SIR_AREA were significantly lower in the high LCP group (max-LCBI &gt;504, <i>p</i> &lt; 0.001 for both), while TOF-SIR_MLA and TOF-SIR_AREA were significantly higher in the high LCP group (<i>p</i> &lt; 0.001 and <i>p</i> = 0.004, respectively). A significant linear correlation was present between max-LCBI_MLA and both TIW-SIR_MLA and TOF-SIR_MLA (<i>r</i> = −0.610 and 0.452, respectively, <i>p</i> &lt; 0.0001 for both). Furthermore, logistic regression analysis revealed that T1W-SIR_MLA and TOF-SIR_MLA were significantly associated with a high LCP assessed by NIRS (OR, 44.19 and 0.43; 95% CI: 6.55–298.19 and 0.19–0.96; <i>p</i> &lt; 0.001 and = 0.039, respectively). <b><i>Conclusions:</i></b> A high LCP assessed by NIRS correlates with the signal intensity ratio of MR imaging in symptomatic patients with unstable carotid plaques.

<b><i>引言：</i></b> 易损斑块（vulnerable plaques）是脑血管缺血事件的强预测因子，而脂质核心负荷高的斑块（high lipid core plaques, LCPs）与颈动脉支架植入术（carotid artery stenting, CAS）过程中栓塞性梗死风险升高相关。近年来磁共振（magnetic resonance, MR）斑块成像技术的发展实现了颈动脉斑块易损性的无创评估，斑块内出血（intraplaque hemorrhage, IPH）与脂质成分在T1加权磁共振图像（T1-weighted MR images）上表现为高信号区域。近期研究证实，导管近红外光谱（catheter-based near-infrared spectroscopy, NIRS）可精准区分不伴IPH的LCPs。本研究旨在探究基于导管NIRS评估的高LCPs结果与MR斑块成像结果是否具有相关性。<b><i>方法：</i></b> 本研究纳入82例连续收治的症状性颈动脉狭窄患者，所有患者均在接受CAS治疗前完成NIRS与MR斑块评估。通过NIRS评估最小管腔面积（minimal luminal areas, MLA）处的最大脂质核心负荷指数（maximum lipid core burden index, max-LCBI），记为max-LCBI_MLA；同时评估靶病变中任意4mm节段的最大脂质核心负荷指数，记为max-LCBI_AREA。随后分析NIRS评估区域内的max-LCBI与MR斑块T1加权信号强度比（T1-weighted plaque signal intensity ratio, T1W-SIR）、MR时间飞跃法信号强度比（time-of-flight signal intensity ratio, TOF-SIR）之间的相关性。<b><i>结果：</i></b> 高LCP组（max-LCBI>504）的T1W-SIR_MLA与T1W-SIR_AREA均显著降低（两组均p<0.001），而TOF-SIR_MLA与TOF-SIR_AREA则显著升高（分别为p<0.001和p=0.004）。max-LCBI_MLA与T1W-SIR_MLA、TOF-SIR_MLA均存在显著线性相关性（相关系数r分别为-0.610和0.452，两组均p<0.0001）。此外，logistic回归分析显示，T1W-SIR_MLA与TOF-SIR_MLA与NIRS评估的高LCPs显著相关（优势比OR分别为44.19和0.43；95%置信区间CI分别为6.55~298.19和0.19~0.96；p分别为<0.001和0.039）。<b><i>结论：</i></b> 在伴不稳定颈动脉斑块的症状性患者中，NIRS评估的高LCPs与磁共振成像的信号强度比具有相关性。