在计算机断层扫描中，不同血管大小下非离子型碘代二聚体和单体之间的定量和定性图像质量之间的平衡：一项体模研究。
Balancing act between quantitative and qualitative image quality between nonionic iodinated dimer and monomer at various vessel sizes during computed tomography: a phantom study.
机构信息
Diagnostic Radiology Department, American University of Beirut Medical Center, Beirut, American University of Beirut Medical Center, Beirut, Lebanon. P O Box: 11-0236 Riad El-Solh, Beirut, 1107 2020, Lebanon.
出版信息
Biomed Phys Eng Express. 2020 Mar 4;6(3):035001. doi: 10.1088/2057-1976/ab78dc.
PURPOSE
Investigate the impact of nonionic dimer and monomer on iodine quantification in different vessel sizes when employing a vascular specific phantom and varying iodinated contrast media (ICM) concentrations during computed tomography (CT).
MATERIALS AND METHODS
We created a vascular specific phantom (30 cm) to simulate human blood vessel diameters (25 cylinders of different diameters: 10 × 9mm, 10 × 12mm and 5 × 21mm). The phantom was filled with two ICM separately: Group: Iohexol(monomer)350 mg ml and B: Iodixanol(Dimer)320 mg ml. Cylinders of same size were filled with increasing ICM concentration(10%-100%) while large cylinders were filled in quartiles(25%-100%). Phantom was scanned with different tube potential (80-140kVp), current (50-400mAs), reconstruction method [filtered back projection (FBP), hybrid-based iterative reconstruction (HBIR) and model-based iterative reconstruction (MBIR)] for each ICM. Chi-square was employed to compare mean opacification, contrast/noise ratio (CNR) and noise. Qualitative analysis was assessed by Visual grading characteristic (VGC) and Cohens-kappa analyses.
RESULTS
At 80 and140kVp significant difference in opacification between Group A (2054 ± 1040HU and 1696 ± 1027HU) and B (2169 ± 1105HU and 1568 ± 1034HU) was demonstrated (p < 0.001). However, at 100 and 120kVp no difference was noted (p > 0.05). When comparing image noise, it was higher in Group A compared to B (p < 0.05). CNR was higher in Group B (119.99 ± 126.10HU) than A (107.09 ± 102.56HU) (p < 0.0001). VGC: Group A outperformed B in image opacification in all vessel sizes and ICM concentrations except at medium vessels with concentration group 2(0.4-0.6 mg ml). Cohens'-kappa: agreement in opacification between each ICM group and iodine concentration 1(0-0.3 mg ml): κ = 0.253 and 0.014 respectively, concentration 2(0.4-0.6 mg ml):κ = -0.017 and -0.005 respectively and concentration 3(0.7-1 mg ml):κ = 0.031 and 0.115 respectively.
CONCLUSION
Nonionic dimer (Iodixanol) surpasses monomer (Iohexol) in quantitative image quality assessment by having lower image noise and higher CNR during CT.
目的
研究在使用血管专用体模和不同浓度的碘对比剂（ICM）进行计算机断层扫描（CT）时，不同血管大小对非离子二聚体和单体碘定量的影响。
材料和方法
我们创建了一个血管专用体模（30 厘米），以模拟人体血管直径（25 个不同直径的圆柱体：10×9mm、10×12mm 和 5×21mm）。体模分别用两种 ICM 填充：A 组：碘海醇（单体）350mg/ml 和 B 组：碘克沙醇（二聚体）320mg/ml。相同大小的圆柱体用递增的 ICM 浓度（10%-100%）填充，而大圆柱体用四分之一填充（25%-100%）。体模用不同的管电压（80-140kVp）、电流（50-400mAs）、重建方法[滤波反投影（FBP）、基于混合的迭代重建（HBIR）和基于模型的迭代重建（MBIR）]进行扫描。采用卡方检验比较平均对比度、对比噪声比（CNR）和噪声。定性分析采用视觉分级特征（VGC）和 Cohen-kappa 分析。
结果
在 80 和 140kVp 时，A 组（2054±1040HU 和 1696±1027HU）和 B 组（2169±1105HU 和 1568±1034HU）之间的造影剂浓度有显著差异（p<0.001）。然而，在 100 和 120kVp 时，没有发现差异（p>0.05）。比较图像噪声时，A 组高于 B 组（p<0.05）。CNR 在 B 组（119.99±126.10HU）高于 A 组（107.09±102.56HU）（p<0.0001）。VGC：A 组在所有血管大小和 ICM 浓度下的图像造影效果均优于 B 组，除了在中等血管中浓度组 2（0.4-0.6mg/ml）时。Cohen's-kappa：每个 ICM 组与碘浓度 1（0-0.3mg/ml）之间的造影剂浓度的一致性：κ=0.253 和 0.014，浓度 2（0.4-0.6mg/ml）：κ=-0.017 和 -0.005，浓度 3（0.7-1mg/ml）：κ=0.031 和 0.115。
结论
在 CT 中，非离子二聚体（碘克沙醇）的图像噪声较低，CNR 较高，因此在定量图像质量评估方面优于单体（碘海醇）。
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