Nagano Keiko, Yamagami Hiroshi, Tsukamoto Yoshitane, Nagatsuka Kazuyuki, Yasaka Masahiro, Nagata Izumi, Hori Masatsugu, Kitagawa Kazuo, Naritomi Hiroaki
Stroke Division, Department of Internal Medicine, National Cardiovascular Center, Osaka, Japan.
Cerebrovasc Dis. 2008;26(6):578-83. doi: 10.1159/000165110. Epub 2008 Oct 23.
Echogenicity of carotid plaque well reflects the risk of ischemic stroke and may be predictive of the histologic content of the plaque. However, objective evaluation of plaque echogenicity has been hampered by a lack of established quantitative measures. This study examined the relation between echogenicity assessed by integrated backscatter (IBS) analysis and (1) symptomatic history and (2) histologic features of carotid plaques.
We used acoustic densitometry to quantify by IBS analysis the echogenicity of 31 carotid plaques of 26 patients undergoing carotid endarterectomy or stenting. IBS was subsequently compared with histologic findings of the respective tissue in 10 patients who underwent endarterectomy. The IBS value was calibrated with 2 reference structures (vessel lumen and adventitia) as the IBS index.
The IBS index of symptomatic plaques was lower than that of asymptomatic plaques (23.1 +/- 12.5 vs. 36.5 +/- 18.2, p < 0.05). The IBS index in fatty/necrotic atheromatous sites (n = 20, 16.6 +/- 10.7) was lower than that in fibrous (n = 26, 42.4 +/- 13.6, p < 0.01) or calcified (n = 11, 87.7 +/- 17.4, p < 0.01) sites and the same as that in intraplaque hemorrhagic sites (n = 50, 23.6 +/- 16.9).
Carotid plaque echogenicity, as quantitatively assessed by IBS analysis, correlates well with the presence or absence of prior symptoms and histologic contents of the plaques. IBS analysis may aid in the assessment of carotid plaque-related risk of stroke.
颈动脉斑块的回声性很好地反映了缺血性卒中的风险，并且可能预测斑块的组织学成分。然而，由于缺乏既定的定量测量方法，对斑块回声性的客观评估受到了阻碍。本研究探讨了通过背向散射积分（IBS）分析评估的回声性与（1）症状史和（2）颈动脉斑块组织学特征之间的关系。
我们使用声学密度测定法，通过IBS分析对26例行颈动脉内膜切除术或支架置入术患者的31个颈动脉斑块的回声性进行定量。随后，将10例行内膜切除术患者的IBS与相应组织的组织学结果进行比较。IBS值以2个参考结构（血管腔和外膜）进行校准，作为IBS指数。
有症状斑块的IBS指数低于无症状斑块（23.1±12.5对36.5±18.2，p<0.05）。脂肪/坏死性粥样斑块部位（n=20，16.6±10.7）的IBS指数低于纤维斑块部位（n=26，42.4±13.6，p<0.01）或钙化斑块部位（n=11，87.7±17.4，p<0.01），与斑块内出血部位（n=50，23.6±16.9）相同。
通过IBS分析定量评估的颈动脉斑块回声性与既往症状的有无及斑块的组织学成分密切相关。IBS分析可能有助于评估与颈动脉斑块相关的卒中风险。
