Preliminary study on the differentiation of vulnerable carotid plaques via analysis of calcium content and spectral curve slope by using gemstone spectral imaging

Figures

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  Figure 1. Gemstone spectral imaging of carotid plaque in a 64-year-old woman. (A) CTA source image presents a calcified plaque (indicated by pink dot). (B) Plaque energy spectrum shows a bow curve with negative slope and CT value >220 HU. (C) CTA source image presents a fibrous plaque (indicated by red cross). (D) Plaque energy spectrum displays a bow curve with negative slope and CT value between 30 and 150 HU. CTA, computed tomographic angiography; HU, hounsfield units.

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  Figure 2. Different locations of plaques in the carotid artery. The distribution of unstable plaque and stable plaque in different carotid segments were compared. The vertical axis indicates the proportion of the plaque distribution. CCA, common carotid artery; ECA, external carotid artery.

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  Figure 3. Serum levels of Hs-CRP and MCP-1 in the three groups, spectral curve slope and calcium content in the plaque groups. The serum levels of (A) Hs-CRP and (B) MCP-1 determined using immunoturbidimetry were compared among patients with stable plaques, unstable plaques and NC. (C) Calcium contents in plaque and (D) spectral curve slope of plaque are compared between patients with stable plaques and unstable plaques using gemstone spectral imaging. Horizontal lines indicate mean values with standard deviation or median values, while numerals on top are P-values. NC, normal controls; Hs-CRP, high-sensitivity C-reactive protein; MCP-1, monocyte chemotactic protein-1.

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  Figure 4. ROC curve analysis of spectral curve slope, calcium content in plaque and serum levels of Hs-CRP, MCP-1 in the plaque groups. Quantitative analysis for curve slope of plaque (green line), calcium content in plaque (orange line), serum MCP-1 level (blue line) and serum Hs-CRP level (red line) in plaque groups was performed using ROC curve analysis. The AUC for the calcium content in the plaque was 0.938 and the assumed cut-off for the calcium content for discriminating between stable and unstable plaque was 101.5 (g/l), with a sensitivity of 73.33% and a specificity of 100%. The AUC of the slope of the spectral curve was 0.942 and the assumed cut-off for the slope of the spectral curve for differentiating stable from unstable plaque was 3.835, with a sensitivity of 96.67% and a specificity of 77.27%. The AUC of serum Hs-CRP levels was 1 and the optimal Hs-CRP threshold cutoff was determined to be 7.14 mg/l, with associated sensitivity and specificity of 100 and 100%, respectively. The AUC of serum MCP-1 levels was 0.901 and the ideal MCP-1 threshold cutoff was determined to be 392.3 pg/ml, with associated sensitivity and specificity of 84 and 100%, respectively. ROC, receiver…