目的探讨CT平扫检测短暂性脑 缺血发作(TIA)患者颈内动脉虹吸部钙化 与MSCTA显示颈动脉分叉处狭窄的关系。 方法 对84例同时行CT平扫及MSCTA检查 的TIA患者影像资料进行回顾性分析，根 据MSCTA图将颈动脉分叉处狭窄分为无狭 窄、轻度狭窄(0-49%)、中度狭窄(50- 69%)、重度狭窄(70-99%)、闭塞(100%) 五种；根据平扫CT图将颈内动脉虹吸部 钙化分为0-4级，0级为无钙化，1级为点 状钙化，2级为(弧形钙化占管壁的范围) ＜90°，3级90-270°，4级＞270°，0-1 级为低级别钙化，2-4级为高级别钙化， 分析虹吸部钙化、钙化形态与颈动脉分 叉处狭窄的关系。结果 84例患者中，左 侧、右侧及混合组狭窄发生率为43%、43% 及58%；颈动脉虹吸部有钙化且钙化范围 越大高度提示颈动脉分叉处狭窄，诊断具 有较高的敏感性(73%)和特异性(71%)；虹 吸部没有钙化的颈动脉较少发生中度或重 度的狭窄，即狭窄程度超过50%(诊断特异 度100%)；虹吸部钙化无法有效预测颈动 脉中度和重度狭窄，诊断敏感性为5.8%。 结论 虹吸部钙化及钙化范围可以作为TIA 患者预测颈动脉分叉处狭窄的两项指标。

Objective To evaluate the relation between carotid siphon calcification with the presence of TIA on non-enhanced CT images and carotid artery bifurcation stenosis(CABS) on MSCTA images. Methods This IRB-waived retrospective study included 84 consecutive patients suspected of TIA who underwent non-enhanced CT and MSCTA of the head and neck. CABS was rated on CTA as not present or present with non-significant (0-40%), moderate (50-69%), significant (70-99%) and occlusion (100%). And carotid siphon calcification was classified into 5 grades on non-enhanced CT images including grade 0 (no calcification), grade 1 (small spotty foci of calcification), grade 2 (a single calcification occupying <90°), grade 3 (90-270°), grade 4 (>270°). Furthermore, grade 0-1 were defined as low grade calcification, and grade 2-4 were defined as high grade calcification. Presence, shape of carotid siphon calcification were analyzed the relationship with CABS. Results The presence of CABS were as follows: left side, 43%; right side, 43%; bilateral sides, 58%. The presence of carotid siphon calcification and bigger extent of calcification resulted in odds ratios for having CABS, with a high sensibility (73%) and specificity (71%). Absence of calcification in carotid artery siphon has a high negative predictive value for CABS in patients (specificity of diagnosis=100%). However, siphon calcification is not a reliable indicator of moderate and significant carotid artery stenosis (sensibility of diagnosis=5.8%). Conclusion Presence and extent of calcification in carotid artery siphon can be indicators of CABS in the patients with TIA.