Chen Lihong, Pan Ning, Hu Bin, Li Yaofeng, Dong Shushan, Zhou Yinan, Guo Jianxin, Yang Jian, Luo Yongbai, Jian Zhijie
Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Bayer Healthcare Company Limited, Xi'an, China.
Quant Imaging Med Surg. 2024 Oct 1;14(10):7671-7683. doi: 10.21037/qims-24-786. Epub 2024 Sep 24.
The effectiveness of coronary computed tomography (CT) angiography in assessing stent restenosis is hindered by heavy metal artifacts. This study aimed to evaluate the image quality of monoenergetic reconstructions and iodine density map for coronary stent imaging using an 8-cm dual-layer detector spectral CT.
In this study, 8 stents with a diameter <3 mm (group A) and 10 with a diameter ≥3 mm (group B) were placed in plastic tubes filled with iodinated contrast media and scanned. The internal diameter of the prepared stents was then measured by intravascular ultrasound. The reconstructed images included iodine density maps, conventional images, and different energy levels. The visualization of the stent lumen and stent structure was subjectively assessed using a 4-point Likert scale. The objective evaluation was performed using the in-stent lumen signal-to-noise ratio (SNRis), non-stent lumen SNR (SNRns), internal diameter difference (IDD), and blooming artifact index (BAI). The Friedman test and analysis of variance were used for multiple comparisons.
For lumen visualization, the optimal monoenergetic images received the highest score for both group A (2.56±0.51) and group B (3.1±0.55). Multiple comparisons showed that there were significant differences between the optimal monoenergetic images and iodine density maps. However, for stent structure, iodine density maps received the highest score for group A (3.0±0.52) and group B (3.8±0.41). For quantitative assessment, the optimal monoenergetic images had the highest SNRis and SNRns, while the iodine density maps had the lowest SNRis and SNRns. For IDD and BAI, the iodine density maps yielded the smallest value.
The monoenergetic images on the second-generation dual-layer detector CT provide better visualization of the lumen and higher SNR. However, iodine density maps are superior for evaluating stent structure and IDD and BAI compared to monoenergetic and conventional reconstructions.
冠状动脉计算机断层扫描（CT）血管造影在评估支架再狭窄方面的有效性受到重金属伪影的阻碍。本研究旨在使用8厘米双层探测器光谱CT评估单能重建和碘密度图在冠状动脉支架成像中的图像质量。
在本研究中，将8个直径<3毫米的支架（A组）和10个直径≥3毫米的支架（B组）放置在充满碘化造影剂的塑料管中并进行扫描。然后通过血管内超声测量制备好的支架的内径。重建图像包括碘密度图、传统图像和不同能量水平的图像。使用4点李克特量表对支架管腔和支架结构的可视化进行主观评估。客观评估使用支架内管腔信噪比（SNRis）、非支架管腔信噪比（SNRns）、内径差异（IDD）和伪影放大指数（BAI）进行。采用Friedman检验和方差分析进行多重比较。
对于管腔可视化，最佳单能图像在A组（2.56±0.51）和B组（3.1±0.55）中均获得最高分。多重比较显示，最佳单能图像与碘密度图之间存在显著差异。然而，对于支架结构，碘密度图在A组（3.0±0.52）和B组（3.8±0.41）中得分最高。对于定量评估，最佳单能图像具有最高的SNRis和SNRns，而碘密度图具有最低的SNRis和SNRns。对于IDD和BAI，碘密度图的值最小。
第二代双层探测器CT上的单能图像能更好地显示管腔并具有更高的信噪比。然而，与单能和传统重建相比，碘密度图在评估支架结构、IDD和BAI方面更具优势。
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