摘要:
Objective To evaluate the image quality of various dual-energy CT abdominal angiography, so as to determine the optimum dual-energy image fusion way. Methods A phantom was filled with various density iodine and 47 patients underwent dual-energy CT scanning, 9 kinds of mixed energy images were generated form 140 kV and 80 kV images with various methods for phantom and all patients. The CT value, noise and signal-to-noise rate (SNR) of iodine in phantom were compared among 140 kV, 9 kinds of mixed energy and 80 kV images, and the CT value, noise and SNR of celiac trunk, right renal arteries and right iliac arteries of 47 patients were also compared among 140 kV, 9 mixed energy and 80 kV images. The image quality score was ranked for mixed energy images with weight factor 0.3 and optimum mixed energy images. Results Based on phantom study, the noise on mixed energy images with weight factor 0.3 was minimum, and the SNR of iodine on mixed energy images with weight factor 0.5 was maximum. Among the 47 patients, the noise of celiac trunk, right renal arteries and right iliac arteries on mixed energy images with weight factor 0.3 were all minimum, the SNR of celiac trunk, right renal arteries and right iliac arteries on mixed energy images with weight factor 0.5 were all maximum. Image quality was rated as excellent, good and general for 17, 22 and 8 cases on mixed energy images with weight factor 0.3, and image quality was rated as excellent, good, and general for 28, 15 and 4 cases on mixed energy images with weight factor 0.5, respectively. There was significant difference in image quality score between mixed energy images with weight factor 0.3 and 0.5(Z=-3.64, P=0.00). Conchusion The mixed energy images with weight factor 0.5 can improve the image quality of dual-energy abdominal CTA.%目的:评估双能量腹部血管CT成像(CTA)的多种混合能量图像质量,以确定最佳能量融合方式.方法:对装满不同浓度碘水的模型及47例患者行双能量CT扫描,将140 kV和80 kV图像按照一定的能量比例融合生成9种混合能量图像.模型内碘水CT值、噪声及信噪比(SNR)在不同权重因子混合能量图像间进行比较,患者腹腔干、右肾动脉及右侧髂动脉的CT值、噪声和SNR亦在不同权重因子混合能量图像间进行比较.对权重因子为0.3和最佳的混合能量图像质量进行评分.结果:在模型研究中,权重因子为0.3的混合能量图像噪声最小,权重因子为0.5的混合能量图像碘水SNR值最大.47例患者中,腹腔干、右肾动脉及右侧髂动脉的权重因子为0.3的混合能量图像均噪声最小,且权重因子为0.5的混合能量图像SNR均最高.权重因子为0.3混合能量图像评分为优秀、良好、和一般的例数分别为17、22和8,权重因子为0.5的混合能量图像评分为优秀、良好和一般的例数分别为28、15和4,图像评分结果在2组间比较,差异有统计学意义(Z=-3.64,P=0.00).结论:权重因子为0.5的混合能量图像能够提高腹部动脉双能量CTA的图像质量,具有很好的应用价值.