 都司影像专栏  颈动脉斑块相关信息 · 约30%缺血性卒中可归因于颈动脉疾病； · 由于血流动力学原因，颈动脉斑块主要发生在分叉部上下10mm以内。 
 1、动脉粥样硬化病理机制 血管内皮损伤→单核细胞进入血管内皮下间隙转化为巨噬细胞→巨噬细胞和平滑肌细胞摄入脂质形成泡沫细胞→聚集形成脂纹→胶原纤维、弹性纤维及蛋白聚糖形成纤维帽→演变成粥样斑块→纤维帽破裂→血栓形成。 AHA分类  2、易损斑块病理学特征   3、不同成像技术显示易损斑块的特征  4、颈动脉斑块高分辨MRI优势  5、颈动脉斑块高分辨MRI扫描条件  颈动脉斑块HR-MR影像判读 一 管腔 管腔狭窄程度及管壁厚度 斑块管腔面形态 常用参数指标： ✔ 脂质核心占比=脂质核心/管壁面积×100% ✔ 出血占比=出血/管壁面积×100% ✔ 钙化占比=钙化/管壁面积×100% ✔ 斑块体积比管腔狭窄程度更能提示动脉粥样硬化严重性 ✔ 管腔面积 Lumen area（LA） ✔ 管壁面积 Wall area（WA） ✔ 总血管面积 Total vessel Area TVA=LA+WA ✔ 标准化管壁指数 Normalized wall index NWI=WA/TVA 1、斑块管腔面形态 2、管腔狭窄程度及管壁厚度 二 管壁成分 纤维帽和富脂质坏死核心（LRNC） 斑块内出血（IPH） 新生血管与炎症 钙化 1、纤维帽和富脂质坏死核心 (LRNC) 富脂质坏死核心 (LRNC) · MR是检测LRNC的最佳成像方式； · 最大LRNC占比＞40%提示斑块破裂风险高； · 重点判读——增强前后T1WI黑血序列。 ✔ 3D-TOF稍低信号 ✔ T1WI等信号 ✔ T2WI/PDWI稍高信号 ✔ CE-TIWI几乎没有强化的低信号 纤维帽 (FC) · 是颈动脉斑块最重要的易损特征之一； · MRI 是观察纤维帽的首选成像方式； · 重点判读——CE-T1WI黑血序列。 纤维帽和LRNC 2、斑块内出血（IPH） · IPH 扩大坏死核心体积，加快斑块进展； · MRI 是唯一可以准确评估 IPH 的方法； ✦ MPRAGE/IR-TFE是显示IPH最常见的序列； ✦ 3D-SNAP、MATCH等新序列亦可较好显示IPH。 ✔ 3D-TOF高信号 ✔ T1WI较高信号 ✔ T2WI/PDWI等或高信号 ✔ CE-TIWI强化不明显 · IPH 发生在 LRNC 内——成像时信号与LRNC相叠加，在 T1WI 上均呈高信号； · MPRAGE —— IPH 呈明显高信号； · TOF —— IPH呈高信号， LRNC 呈稍低信号； · 出血时间决定T2WI信号强度。 左侧颈内动脉狭窄，伴斑块内出血 A. CE-MRA 示左侧颈内动脉光滑、无溃疡狭窄； B. 斜矢状位MPRAGE 图像广泛的斑块内出血，表现为高信号； C. IPH 在平扫T1WI上呈高信号，在CE-T1WI上（D）呈等信号； E. 在 TOF-MRA上，IPH 也呈高信号，但程度低于腔内血流信号。 LRNC无IPH LRNC伴新鲜IPH LRNC伴亚急性IPH 3、新生血管与炎症 · 斑块内新生微血管内皮发育不成熟，易破裂； · 血管新生的程度与炎症和IPH相关； · 巨噬细胞的存在与斑块破裂风险关系显著； · CE-MRI 强化，提示存在新生微血管/炎症。 4、钙化 · CT显示钙化更具有优势； · 钙化在斑块形成中起着复杂的作用； · 微钙化斑可增加斑块内压力，斑块内钙化区和非钙化区之间的相互作用甚至会增加斑块易损性； · 斑块中钙化比、绝对钙化体积与缺血性卒中风险的相关。 ✔ 3D-TOF低信号，显示最清楚 ✔ T1WI低信号 ✔ T2WI/PDWI低信号 ✔ CE-TIWI低信号 68岁女性颈动脉斑块钙化 （A）超声、（B）CTA、（C）MRI。 三 易损斑块特征MRI表现 MRI: Type Ⅰ Ⅰ型——内膜适应性增厚 MRI: Type Ⅱ Ⅱ型——充满脂质的巨噬细胞在该区域内聚集（脂肪条纹） MRI: Type Ⅲ Ⅲ型——斑块有少量细胞外脂质物质（黑色短箭头），动脉壁偏心性增厚 MRI: Type Ⅳ IV型——斑块内LRNC形成 ↗ LRNC 🔃 纤维帽 * 颈内动脉管腔 ○ 颈外动脉管腔 MRI: Type Ⅴ Ⅴ型——脂质核上的纤维增厚 （弯曲的箭头 ） 🔃 纤维帽 * 颈内动脉管腔 ○ 颈外动脉管腔 MRI: Type Ⅵ Ⅵ 型——斑块存在裂隙（黑色长箭头） 、血栓形成（星号）或斑块内出血（弯曲的白色箭头） MRI: Type Ⅶ VII 型病变——斑块中存在广泛的钙化 MRI: Type Ⅷ VIII型病变——纤维斑块，管腔严重狭窄 总结(Conclusion) 参考文献 🔻向下滑动查看 [1] Benjamin, EJ, Virani, SS, Callaway, CW, et al. 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CIRCULATION. 2003; 107 (19): 2453-8. doi: 10.1161/01.CIR.0000068315.98705.CC. [25] Saam, T, Hatsukami, TS, Takaya, N, et al. The vulnerable, or high-risk, atherosclerotic plaque: noninvasive MR imaging for characterization and assessment. RADIOLOGY. 2007; 244 (1): 64-77. doi: 10.1148/radiol.2441051769. [26] Saba, L, Saam, T, Jäger, HR, et al. Imaging biomarkers of vulnerable carotid plaques for stroke risk prediction and their potential clinical implications. LANCET NEUROL. 2019; 18 (6): 559-572. doi: 10.1016/S1474-4422(19)30035-3. 作者 陈思涵 武汉大学人民医院放射科 来源 都司影像公众号为武汉大学人民医院放射科官方平台，主要展示科室特色诊疗技术、精选专题讲座、经典临床病例、科研团队最新成果；兼具科室教研动态、会议信息发布功能。 -仅供与医疗卫生专业人士学术沟通使用- PP-GAD-CN-1313-1 扫码注册 |
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