Cardiovascular and Pulmonary Branches, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD.
Canon Medical Systems, Otawara, Japan.
Chest. 2019 Mar;155(3):528-533. doi: 10.1016/j.chest.2018.09.007. Epub 2018 Oct 3.
Given the rising utilization of medical imaging and the risks of radiation, there is increased interest in reducing radiation exposure. The objective of this study was to evaluate, as a proof of principle, CT scans performed at radiation doses equivalent to that of a posteroanterior and lateral chest radiograph series in the cystic lung disease lymphangioleiomyomatosis (LAM).
From November 2016 to May 2018, 105 consecutive subjects with LAM received chest CT scans at standard and ultra-low radiation doses. Standard and ultra-low-dose images, respectively, were reconstructed with routine iterative and newer model-based iterative reconstruction. LAM severity can be quantified as cyst score (percentage of lung occupied by cysts), an ideal benchmark for validating CT scans performed at a reduced dose compared with a standard dose. Cyst scores were quantified using semi-automated software and evaluated by linear correlation and Bland-Altman analysis.
Overall, ultra-low-dose CT scans represented a 96% dose reduction, with a median dose equivalent to 1 vs 22 posteroanterior and lateral chest radiograph series (0.14 mSv; 5th-95th percentile, 0.10-0.20 vs standard dose 3.4 mSv; 5th-95th percentile, 1.5-7.4; P < .0001). The mean difference in cyst scores between ultra-low- and standard-dose CT scans was 1.1% ± 2.0%, with a relative difference in cyst score of 11%. Linear correlation coefficient was excellent at 0.97 (P < .0001).
In LAM chest CT scan at substantial radiation reduction to doses equivalent to that of a posteroanterior and lateral chest radiograph series provides cyst score quantification similar to that of standard-dose CT scan.
ClinicalTrials.gov; Nos.: NCT00001465 and NCT00001532; URL: www.clinicaltrials.gov.
鉴于医学影像的应用日益增多以及辐射风险的增加，人们越来越关注降低辐射暴露。本研究的目的是评估 CT 扫描在囊性肺部疾病淋巴管平滑肌瘤病（LAM）中的应用，其放射剂量与后前位和侧位胸部 X 线摄影系列相当，以此作为原理验证。
从 2016 年 11 月至 2018 年 5 月，105 例连续的 LAM 患者接受了标准和超低辐射剂量的胸部 CT 扫描。分别使用常规迭代和新型基于模型的迭代重建方法对标准和超低剂量图像进行重建。LAM 严重程度可以通过囊肿评分（肺部被囊肿占据的百分比）来量化，这是评估与标准剂量相比降低剂量的 CT 扫描的理想基准。使用半自动软件对囊肿评分进行量化，并通过线性相关和 Bland-Altman 分析进行评估。
总体而言，超低剂量 CT 扫描的放射剂量降低了 96%，中位数剂量相当于 1 次后前位和侧位胸部 X 线摄影系列（0.14 mSv；第 5-95 百分位数为 0.10-0.20 与标准剂量 3.4 mSv；第 5-95 百分位数为 1.5-7.4；P < 0.0001）。超低剂量和标准剂量 CT 扫描之间的囊肿评分差异的平均值为 1.1%±2.0%，囊肿评分的相对差异为 11%。线性相关系数非常好，为 0.97（P < 0.0001）。
在 LAM 胸部 CT 扫描中，将放射剂量显著降低至与后前位和侧位胸部 X 线摄影系列相当的剂量，可提供与标准剂量 CT 扫描相似的囊肿评分定量。
ClinicalTrials.gov；编号：NCT00001465 和 NCT00001532；网址：www.clinicaltrials.gov。
