Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Division of Surgery, Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria.
PLoS One. 2020 Feb 5;15(2):e0228376. doi: 10.1371/journal.pone.0228376. eCollection 2020.
The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation.
This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared.
The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGycm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGycm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73).
Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.
本研究旨在探讨在肺移植患者中，采用 150kV 能谱过滤胸部成像方案（Sn150kVp）联合先进的模型迭代重建（ADMIRE）对辐射剂量和图像质量的影响。
本研究纳入了 102 例患者，他们均有可用于比较的非增强胸部 CT 检查，分别来自第二代双源 CT（DSCT）采用标准方案（100kVp，滤波反投影）和第三代 DSCT 采用 Sn150kVp 方案联合 ADMIRE。在 6 个标准化区域测量信噪比（SNR）。采用 5 分李克特量表评估主观图像质量。比较辐射指标。
两次采集的平均时间间隔为 1.1±0.7 年。与 100kVp 方案（6.2±1.8mGy；203.6±55.6mGycm；3.7±1.0mSv）相比，Sn150kVp 方案的平均容积 CT 剂量指数、剂量长度乘积和有效剂量显著降低（2.1±0.5mGy；72.6±16.9mGycm；1.3±0.3mSv）（p<0.001），剂量降低了 65%。所有研究均被认为具有诊断质量。与 Sn150kVp 方案相比，肺组织、气管内空气、椎体和体外线的 SNR 分别在 100kVp 方案中显著更高（12.5±2.7 vs.9.6±1.5；17.4±3.6 vs.11.8±1.8；0.7±0.3 vs.0.4±0.2；25.2±6.9 vs.14.9±3.3）（p<0.001）。Sn150kVp 方案中肌肉组织的 SNR 显著更高（3.2±0.9 vs.2.6±1.0）（p<0.001）。对于降主动脉的 SNR，Sn150kVp 方案的数值有升高趋势（2.8±0.6 vs. 2.7±0.9）（p=0.3）。总体 SNR 在 100kVp 方案中显著更高（5.0±4.0 vs.4.0±4.0）（p<0.001）。主观分析中，两种方案均获得中位数为 1（25%至 75%的百分位数：1-1）的 Likert 评分（25 分至 75 分：1-1；p = 0.122）。观察者间的一致性良好（组内相关系数=0.73）。
与使用滤波反投影的标准胸部 CT 方案相比，联合使用 150kV 能谱过滤胸部 CT 方案联合 ADMIRE 可显著降低辐射剂量，同时保持肺移植后随访的高度诊断图像质量。
