低剂量CT联合全模型迭代重建对肺磨玻璃结节的诊断价值研究

目的探讨低剂量CT联合全迭代重建算法对肺磨玻璃结节的诊断能力。方法回顾性分析经病理证实的肺磨玻璃结节患者100例,在行低剂量扫描(40 mAs,120 KeV)后分别进行混合迭代算法iDose4重建和全模型迭代算法(Iterative model reconstruction,IMR)重建,分别在右肺上、中、下叶外侧带、支气管分叉层面升主动脉内、膈肌层面降主动脉内测量噪声值,并取平均值。对比分析iDose4和IMR图像噪声值、肺磨玻璃结节各个征象的显示效能。结果IMR图像5个感兴趣区域的平均噪声值均低于iDose4图像,P值均<0.05,差异有统计学意义;在iDose4图像上纯磨玻璃结节显示39枚,IMR图像显示68枚,P值<0.05,差异有统计学意义。在iDose4图像上瘤-肺界面清晰显示74枚,IMR图像显示119枚,P值=0.001。在iDose4图像上肿瘤微血管Ⅱ型显示27例,IMR图像显示54例,P值>0.01,差异有统计学意义。结论低剂量联合IMR算法较iDose4算法具有更低的噪声。IMR算法对于纯磨玻璃结节的检出、瘤-肺界面及肿瘤微血管征Ⅱ型的显示优于iDose4算法。低剂量联合全迭代重建在肺磨玻璃结节诊断中具有较高的应用价值。

Application of low dose CT combined with iterative modelreconstruction in pulmonary nodules

Objective To study the diagnostic ability of low-dose CT combined with full iterative reconstruction algorithm for pulmonary ground glass nodules.Methods We retrospectively analysed 100 patients with ground-glass nodules of lung.After low-dose scanning(40 mAs,120 Kev),iDose4 algorithm reconstruction and iterative model reconstruction reconstruction were performed respectively.Noise values were measured and compared in the lateral zone of the upper,middle and lower lobes of the right lung,in the ascending aorta at the level of branching bronchus and in the descending aorta at the diaphragmatic level.We calculated the average noise value of 5 areas,analyzed and compared the image noise value of iDose4,IMR,and the display efficiency of various signs of pulmonary ground glass nodules.Results The average noise value of five regions of interest in IMR image was lower than iDose4 image P<0.05,the difference was statistically significant;In iDose4 image,39 pure ground glass nodules were displayed,68 IMR images showed,P=0.048,the difference was statistically significant.In iDose4 image,74 lesions were clearly displayed on tumor lung interface,119 lesions were displayed on IMR image(P=0.001),the difference was statistically significant.In iDose4 image,27 cases showed tumor microvascular sign typeⅡ,54 cases showed IMR image(P=0.023),the difference was statistically significant.Conclusion The low dose combined IMR algorithm has lower noise than iDose4 algorithm.IMR algorithm is better than iDose4 algorithm in the detection of pure ground glass nodules,tumor lung interface and tumor microvascular sign typeⅡ.Low dose combined with full iterative reconstruction has application value in the detection of pulmonary nodules.