Department of Radiology, University of Minnesota and Hennepin County Medical Centres, Minneapolis, MN, USA.
Br J Radiol. 2012 Jul;85(1015):e284-92. doi: 10.1259/bjr/33845823. Epub 2011 Sep 6.
Previous evidence supports a direct relationship between the calcium burden (volume) on post-contrast CT with the percent internal carotid artery (ICA) stenosis at the carotid bifurcation. We sought to further investigate this relationship by comparing non-enhanced CT (NECT) and digital subtraction angiography (DSA).
50 patients (aged 41-82 years) were retrospectively identified who had undergone cervical NECT and DSA. A 64-multidetector array CT (MDCT) scanner was utilised and the images reviewed using preset window widths/levels (30/300) optimised to calcium, with the volumes measured via three-dimensional reconstructive software. Stenosis measurements were performed on DSA and luminal diameter stenoses >40% were considered "significant". Volume thresholds of 0.01, 0.03, 0.06, 0.09 and 0.12 cm(3) were utilised and Pearson'S correlation coefficient (r) was calculated to correlate the calcium volume with percent stenosis.
Of 100 carotid bifurcations, 88 were available and of these 7 were significantly stenotic. The NECT calcium volume moderately correlated with percent stenosis on DSA r=0.53 (p<0.01). A moderate-strong correlation was found between the square root of calcium volume on NECT with percent stenosis on DSA (r=0.60, p<0.01). Via a receiver operating characteristic curve, 0.06 cm(3) was determined to be the best threshold (sensitivity 100%, specificity 90.1%, negative predictive value 100% and positive predictive value 46.7%) for detecting significant stenoses.
This preliminary investigation confirms a correlation between carotid bifurcation calcium volume and percent ICA stenosis and is promising for the optimal threshold for stenosis detection. Future studies could utilise calcium volumes to create a "score" that could predict high grade stenosis.
先前的证据支持在颈动脉分叉处对比增强 CT 上的钙负荷（体积）与颈内动脉（ICA）狭窄的百分比之间存在直接关系。我们通过比较非增强 CT（NECT）和数字减影血管造影（DSA）来进一步研究这种关系。
回顾性地确定了 50 名（年龄 41-82 岁）接受过颈椎 NECT 和 DSA 的患者。使用 64 排多排螺旋 CT（MDCT）扫描仪，并使用预设的窗口宽度/水平（30/300）对图像进行评估，该窗宽/水平针对钙进行了优化，通过三维重建软件测量体积。在 DSA 上进行狭窄测量，并且认为管腔直径狭窄>40%为“显著”狭窄。利用 0.01、0.03、0.06、0.09 和 0.12 cm(3)的体积阈值，计算 Pearson 相关系数（r）以将钙体积与狭窄百分比相关联。
在 100 个颈动脉分叉中，有 88 个分叉可用于评估，其中 7 个分叉有显著狭窄。NECT 钙体积与 DSA 上的狭窄百分比中度相关（r=0.53，p<0.01）。NECT 上钙体积的平方根与 DSA 上的狭窄百分比之间存在中度至强相关性（r=0.60，p<0.01）。通过接受者操作特征曲线，确定 0.06 cm(3)是检测显著狭窄的最佳阈值（敏感性 100%，特异性 90.1%，阴性预测值 100%和阳性预测值 46.7%）。
本初步研究证实了颈动脉分叉处钙体积与 ICA 狭窄百分比之间的相关性，并为狭窄检测的最佳阈值提供了希望。未来的研究可以利用钙体积来创建一个“评分”，该评分可以预测高度狭窄。
