Effect of reconstruction methods and x-ray tube current-time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study.
Effect of reconstruction methods and x-ray tube current-time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study.
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DOI：
10.1118/1.4941017
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发表时间：
2016-03
期刊：
影响因子：
3.8
通讯作者：
Hogg P
中科院分区：
文献类型：
--
作者：
Thompson JD;Chakraborty DP;Szczepura K;Tootell AK;Vamvakas I;Manning DJ;Hogg P
旨在评价在一定管电流-时间乘积（mAs）范围内使用自适应迭代剂量减少3D（AIDR 3D）和滤波反投影（FBP）重建的计算机断层扫描（CT）图像中拟人胸部体模中的结节检测。本研究中使用了两个体模：（i）一个拟人胸部体模装载有直径为5、8、10和12 mm的球形模拟结节，电子密度为+100、-630和-800 Hounsfield单位;这将生成用于观察者研究的CT图像;（ii）根据BEIR VII委员会的模型，使用全身剂量学验证体模来最终估计有效剂量和风险。在mAs范围（10、20、30和40）内扫描两个体模，而所有其他采集参数保持不变。用AIDR 3D和FBP重建图像。在观察者研究中，选择34例正常（无结节）和34例异常（含1-3个结节，平均1.35 ± 0.54）。11名观察员评价了所有mAs图像和自由反应范式下的重建方法。开发了一种用于数据分析的交叉模态折刀替代自由响应操作特征（JAFROC）分析方法，对本研究中影响结节检测的两个因素（mAs和图像重建（AIDR 3D或FBP））的数据进行平均。应用Bonferroni校正，并将声明显著性的阈值设定为0.025，以将I类错误的总体概率维持在α = 0.05。还测量了所有结节的对比噪声（CNR），并通过线性最小二乘分析进行评价。对于随机阅片者固定病例交叉模态JAFROC分析，当数据在mAs上取平均值时，AIDR 3D和FBP之间的结节检测无显著差异[F（1，10）= 0.08，p = 0.789]。然而，当对重建方法的数据进行平均时，在多对mAs设置之间观察到显著差异[F（3，30）= 15.96，p < 0.001]。有效剂量和有效风险的测量结果表明，预期的线性依赖mAs。在AIDR 3D重建的图像上，模拟结节的Noise CNR在统计学上更高（p < 0.001）。在使用FBP和AIDR 3D重建的图像之间，结节检测性能没有显著差异。发现mAs影响结节检测，但需要进一步的工作进行剂量优化。
To evaluate nodule detection in an anthropomorphic chest phantom in computed tomography (CT) images reconstructed with adaptive iterative dose reduction 3D (AIDR3D) and filtered back projection (FBP) over a range of tube current–time product (mAs). Two phantoms were used in this study: (i) an anthropomorphic chest phantom was loaded with spherical simulated nodules of 5, 8, 10, and 12 mm in diameter and +100, −630, and −800 Hounsfield units electron density; this would generate CT images for the observer study; (ii) a whole-body dosimetry verification phantom was used to ultimately estimate effective dose and risk according to the model of the BEIR VII committee. Both phantoms were scanned over a mAs range (10, 20, 30, and 40), while all other acquisition parameters remained constant. Images were reconstructed with both AIDR3D and FBP. For the observer study, 34 normal cases (no nodules) and 34 abnormal cases (containing 1–3 nodules, mean 1.35 ± 0.54) were chosen. Eleven observers evaluated images from all mAs and reconstruction methods under the free-response paradigm. A crossed-modality jackknife alternative free-response operating characteristic (JAFROC) analysis method was developed for data analysis, averaging data over the two factors influencing nodule detection in this study: mAs and image reconstruction (AIDR3D or FBP). A Bonferroni correction was applied and the threshold for declaring significance was set at 0.025 to maintain the overall probability of Type I error at α = 0.05. Contrast-to-noise (CNR) was also measured for all nodules and evaluated by a linear least squares analysis. For random-reader fixed-case crossed-modality JAFROC analysis, there was no significant difference in nodule detection between AIDR3D and FBP when data were averaged over mAs [F(1, 10) = 0.08, p = 0.789]. However, when data were averaged over reconstruction methods, a significant difference was seen between multiple pairs of mAs settings [F(3, 30) = 15.96, p < 0.001]. Measurements of effective dose and effective risk showed the expected linear dependence on mAs. Nodule CNR was statistically higher for simulated nodules on images reconstructed with AIDR3D (p < 0.001). No significant difference in nodule detection performance was demonstrated between images reconstructed with FBP and AIDR3D. mAs was found to influence nodule detection, though further work is required for dose optimization.