Nanjing Medical University, Nanjing, Jiangsu Province, PR China; Department of Radiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China; School of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China; Institute of Medical Imaging and Digital Medicine, Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China.
Department of Radiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China; School of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China; Institute of Medical Imaging and Digital Medicine, Xuzhou Medical University, Xuzhou, Jiangsu Province, PR China.
Eur J Radiol. 2022 Aug;153:110364. doi: 10.1016/j.ejrad.2022.110364. Epub 2022 May 20.
In this study, we aimed to evaluate the associations between pericarotid fat density (PFD) and various risk characteristics of carotid plaque.
We retrospectively evaluated consecutive patients who were subjected to both high-resolution MRI and carotid artery CT angiography CTA at our institution between January 2016 and April 2021. The section of the carotid artery with the most severe lumen stenosis was selected from each patient for analysis. Two separated regions of interest (ROI) (each with an area of 2.5 mm and located at least 1 mm from the outer margin of the carotid artery wall) were defined in the perivascular fat tissue. The mean value of PFD (mean HU) was measured on the plaque side and the same axial non-plaque side. Then, the bilateral difference (D-value HU) was calculated (plaque side mean HU minus non-plaque side mean HU). According to carotid plaque risk characteristics (American Heart Association VI type [AHA VI], intraplaque hemorrhage [IPH], thinning and/or rupture of the fibrous cap [TRFC], lipid-rich necrotic core [LRNC], and calcification [CA]), the associations between PFD and five different risk characteristic subgroups were analyzed. The Student's t-test, Mann-Whitney U test, and Chi-square test were used to compare differences between different risk subgroups. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive efficacy of PFD for carotid plaque risk characteristics. P < 0.05 was considered statistically significant.
A total of 71 eligible patients (mean age 61.25 ± 10.35 years, 57 male) were examined in this study. For the plaque side and the non-plaque side, the mean PFD values were -36.25 ± 20.65 HU and -66.87 ± 15.00 HU, respectively. In the non-AHA VI and AHA VI subgroups, the values for the mean HU of the plaque side were -49.50 ± 20.53 and -33.55 ± 19.78, respectively (P = 0.014). The D-value HU was higher for the AHA VI group compared to the non-AHA VI group (33.61 ± 16.72 vs. 15.91 ± 14.52, respectively; P = 0.001). Compared to the non-IPH subgroup, the IPH subgroup had a higher mean HU value for the plaque side (-47.68 ± 18.26 vs. -29.63 ± 19.16, respectively; P < 0.001) and a higher D-value HU (17.80 ± 13.27 vs. 38.03 ± 15.46, respectively; P < 0.001). Compared to the low risk non-TRFC subgroup, the TRFC subgroup had a higher D-value HU (24.51 ± 16.16 vs. 33.55 ± 17.65, respectively; P = 0.042). The D-value of PFD was found to be a significant predictor of both AHA VI classification (AUC: 0.79; SE: 64.41%; SP: 83.33%; P = 0.0001) and IPH (AUC: 0.83; SE: 88.89%; SP: 65.38%; P < 0.0001).
Our study found that PFD was significantly associated with high risk AHA VI plaque characterization, IPH, and TRFC. Therefore, PFD has the potential to be used as an indirect clinical marker of plaque instability.
本研究旨在评估颈动脉斑块周围脂肪密度（PFD）与颈动脉斑块各种风险特征之间的关系。
我们回顾性评估了 2016 年 1 月至 2021 年 4 月期间在我院接受高分辨率 MRI 和颈动脉 CT 血管造影（CTA）的连续患者。从每位患者的颈动脉最严重狭窄部位中选择一个节段进行分析。在血管周围脂肪组织中分别定义两个分离的感兴趣区域（ROI）（每个 ROI 的面积为 2.5mm，距离颈动脉壁外边缘至少 1mm）。在斑块侧和相同的轴向非斑块侧测量 PFD 的平均值（mean HU）。然后计算双侧差值（D 值 HU）（斑块侧平均值 HU 减去非斑块侧平均值 HU）。根据颈动脉斑块风险特征（美国心脏协会 VI 型[AHA VI]、斑块内出血[IPH]、纤维帽变薄和/或破裂[TRFC]、富含脂质的坏死核心[LRNC]和钙化[CA]），分析 PFD 与五个不同风险特征亚组之间的相关性。使用学生 t 检验、Mann-Whitney U 检验和卡方检验比较不同风险亚组之间的差异。采用接收者操作特征（ROC）曲线分析评估 PFD 对颈动脉斑块风险特征的预测效能。P＜0.05 为统计学显著差异。
本研究共纳入 71 例符合条件的患者（平均年龄 61.25±10.35 岁，男性 57 例）。对于斑块侧和非斑块侧，PFD 的平均 HU 值分别为-36.25±20.65HU 和-66.87±15.00HU。在非 AHA VI 组和 AHA VI 组中，斑块侧平均 HU 值分别为-49.50±20.53HU 和-33.55±19.78HU（P=0.014）。AHA VI 组的 D 值 HU 高于非 AHA VI 组（33.61±16.72 对 15.91±14.52，分别；P=0.001）。与非 IPH 亚组相比，IPH 亚组的斑块侧平均 HU 值更高（-47.68±18.26 对-29.63±19.16，分别；P＜0.001），D 值 HU 更高（17.80±13.27 对 38.03±15.46，分别；P＜0.001）。与低风险非 TRFC 亚组相比，TRFC 亚组的 D 值 HU 更高（24.51±16.16 对 33.55±17.65，分别；P=0.042）。PFD 的 D 值被发现是 AHA VI 分类的一个显著预测因素（AUC：0.79；SE：64.41%；SP：83.33%；P=0.0001）和 IPH（AUC：0.83；SE：88.89%；SP：65.38%；P＜0.0001）。
本研究发现 PFD 与高危 AHA VI 斑块特征、IPH 和 TRFC 显著相关。因此，PFD 有潜力成为斑块不稳定的间接临床标志物。
