目的：评价能谱探测器CT在下肢动脉血管成像中的应用价值。方法：对48例拟诊为下肢动脉病变的患者进行Philips能谱探测器CT检查，所有图像重建为6组，包括120 kVp常规CT组及60 keV、65 keV、70 keV、75 keV、80 keV单能量能谱图像组。分别测定各组图像中髂总动脉、股浅动脉、腘动脉、胫前动脉的CT值、噪声、信噪比（SNR）、对比噪声比（CNR），并对图像质量进行评分。采用单因素方差分析比较６组图像的CT值、噪声、SNR、CNR的差异，组间两两比较采用LSD法，采用多组独立样本秩和检验（Kruskal Wallis H）比较图像质量的差异。结果：6组图像中，60 keV组主观评分最高（217分），与常规CT组及70 keV、75 keV、80 keV组评分两两比较差异均有统计学意义（P均＜0.01），与65 keV组评分比较差异不显著。60 keV、65 keV组CNR、SNR均显著高于常规CT组及70 keV、75 keV、80 keV组（P＜0.05），而60 keV组和65 keV组间进行比较差异无统计学意义（P＞0.05）。60 keV、65 keV组图像噪声均显著低于常规CT组（P＜0.05），而60 keV组和65 keV组间进行比较差异无统计学意义（P＞0.05）。60 keV组各目标血管的CT值显著高于65 keV组及其余各组（P＜0.05）。结论：能谱探测器CT 60 keV组单能量图像能显著提高下肢动脉血管成像质量，值得临床推广应用。
Abstract
Objective: To evaluate the application value of the dual-layer spectral detector CT(DLCT) in the CT angiography(CTA) of lower extremity. Methods: Forty-eight patients with suspected lower extremity arterial disease underwent CTA by DLCT. Virtual monoenergetic images(VMIs) were reconstructed at 60 keV to 80 keV with a 5 keV increment. Attenuation, noise, the corresponding contrast noise ratios(CNR）, and signal noise ratio(SNR) were assessed in iliac artery, femoral artery, popliteal artery and anterior tibial artery. Comparisons between VMIs and conventional images(CIs) were performed by one-way ANOVA test, and the differences of image quality were compared by Kruskal Wallis H. Results: In CI and VMI studies, 60 keV VMI showed highest subjective score(217 points). CNR and SNR at 60 keV and 65 keV were significantly higher than other VMIs and CIs(P＜0.05). Image noise at 60 keV and 65 keV were significantly lower than CIs(P<0.05). The attenuation of each target vessel at 60 keV were significantly higher than that at 65 keV and other level VMIs(P<0.05). Overall image quality was best at 60 keV. Conclusion: VMI level at 60 keV for lower extremity CTA can notably improve the overall image quality and may be using in clinical routine imaging protocols.
关键词
下肢 /
动脉 /
体层摄影术 /
螺旋计算机 /
血管造影术
Key words
Lower extremity /
Arteries /
Tomography, spiral computed /
Angiography
中图分类号：
Ｒ322.121
Ｒ814.42
Ｒ814.43
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