能谱纯化结合高级模拟迭代重建在成人胸部低剂量CT中的应用

目的探讨第3代双源CT能谱纯化结合高级模拟迭代重建(ADMIRE)技术在成人胸部低剂量CT检查中的应用价值。方法将100名成年体检者随机均分为A组和B组,采用Siemens Force双源CT扫描仪行胸部CT检查。对A组采用常规100kV扫描结合ADMIRE(强度3级)重建(获得A-ADMIRE图像),B组采用能谱纯化(Sn 100kV)扫描结合ADMIRE(强度1~5级)重建(分别获得B-ADMIRE1、B-ADMIRE2、B-ADMIRE3、B-ADMIRE4、B-ADMIRE5图像)。肺窗及纵隔窗图像ROI包括肺组织、胸主动脉、竖脊肌、背部皮下脂肪及背景空气。比较2组间辐射剂量指标的差异及2组不同ADMIRE图像间客观评价指标、主观图像质量评分的差异。结果 B组CT剂量指数(CTDIvol)、剂量长度乘积(DLP)及有效剂量(ED)均较A组明显下降(P均0.01)。2组不同ADMIRE图像间肺窗及纵隔窗各ROI图像噪声差异均有统计学意义(P均0.01),其中B-ADMIRE1图像噪声最高;肺组织、胸主动脉、竖脊肌信噪比(SNR)及肺组织-背部皮下脂肪、胸主动脉-竖脊肌、胸主动脉-背部皮下脂肪对比噪声比(CNR)差异均有统计学意义(P均0.01),其中AADMIRE图像SNR、CNR最高。B组中ADMIRE1~5图像噪声呈逐级递减趋势,SNR及CNR均呈逐级递增趋势(P均0.01)。2组不同ADMIRE图像间肺窗及纵隔窗图像质量评分差异均有统计学意义(P均0.01),其中AADMIRE图像质量评分最高。B组中B-ADMIRE3图像肺窗及纵隔窗图像质量评分最高,分别为(3.89±0.26)分和(3.00±0.15)分,均可满足诊断要求。结论成人胸部低剂量CT检查中,采用能谱纯化结合ADMIRE技术可在满足诊断要求的同时有效减低辐射剂量,且ADMIRE 3级强度重建图像质量最佳。

Application of spectral filtration and advanced modeled iterative reconstruction for adult chest low-dose CT scan

Objective To investigate the application value of spectral filtration and advanced modeled iterative reconstruction (ADMIRE) of adult chest low-dose CT using third-generation CT scanner.Methods One hundred adults of physical examination were randomly divided into group A and B (each n=50). Low-dose CT chest scanning was performed on all subjects using Siemens Force dual-source CT scanner. In group A,CT scans were done with normal 100 kV combining with ADMIRE (strength level 3) for getting A-ADMIRE images. In group B, CT scans were done with spectral filtration (Sn 100 kV) combining with ADMIRE (strength level 1-5) for getting B-ADMIRE1, B-ADMIRE2, B-ADMIRE3, B-ADMIRE4 and B-ADMIRE5 images. ROI in lung window and mediastinal window images included lung tissue, thoracic aorta, spine muscle, subcutaneous fat of the back and background air. The differences of radiation dose indexes between the two groups, and the objective and subjective image quality scores between the six ADMIRE images were compared.Results CT dose index volume (CTDI_vol), dose length product (DLP) and effective dose (ED) in group B were significantly lower than those in group A (all P<0.01). The differences of noise in lung window and mediastinal window between the six ADMIRE images were statistically significant (all P<0.01), and the noise in B-ADMIRE1 image was the highest. Statistically significant differences of signal-to-noise ratio (SNR) of lung tissue, thoracic aorta and spine muscles, as well as contrast-to-noise ratio (CNR) of lung tissue-back subcutaneous fat, thoracic aorta-spine muscle and thoracic aorta-back subcutaneous fat were found among six ADMIRE images (all P<0.01), and A-ADMIRE image had the highest SNR and CNR. The image noise showed a progressively decreasing trend for B-ADMIRE1-5 images (all P<0.01), while SNR and CNR showed a progressively increasing trend for B-ADMIRE1-5 images (all P<0.01). The differences of image quality scores of lung window and mediastinal window aomng the six ADMIRE images were statistically significant (all P<0.01), and the image quality score of A-ADMIRE image was the highest. In group B, the image quality scores of lung window and mediastinal window of B-ADMIRE3 image were the highest, that was (3.89±0.26) scores and (3.00±0.15) scores, respectively, which could meet the diagnostic requirement.Conclusion For chest low-dose CT scan in adult, spectral filtration scanning with ADMIRE technology can effectively reduce radiation dose and meet the diagnostic requirement. The image quality of ADMIRE 3 image is the best.