Model-Based Iterative Reconstruction Technique for Ultralow-Dose Chest CT Comparison of Pulmonary Nodule Detectability With the Adaptive Statistical Iterative Reconstruction Technique
Model-Based Iterative Reconstruction Technique for Ultralow-Dose Chest CT Comparison of Pulmonary Nodule Detectability With the Adaptive Statistical Iterative Reconstruction Technique
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DOI：
10.1097/rli.0b013e31827efc3a
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发表时间：
2013-04-01
影响因子：
6.7
通讯作者：
Ohtomo, Kuni
中科院分区：
文献类型：
--
作者：
Katsura, Masaki;Matsuda, Izuru;Ohtomo, Kuni
目的：本研究的目的是评估基于模型的迭代重建（MBIR）是否能够在保持诊断性能的同时降低自适应迭代重建（ASIR）的剂量。在这项机构审查委员会批准的符合健康保险携带和责任法案的研究中，59名患者（平均[SD]年龄，64.7 [13.4]岁）知情同意接受64排多排CT的参考、低剂量和超低剂量胸部计算机断层扫描（CT）。参考和低剂量CT涉及使用具有固定噪声指数（在0.625 mm处分别为31.5和70.44）的自动管电流调制，并使用50%的ASIC滤波反投影混合进行重建。超低剂量CT扫描采用固定的管电流时间积5 mA/s，重建采用MBIR。两名放射科医师分别对低剂量ASIR和超低剂量MBIR的2.5 mm和0.625 mm层厚轴向图像进行评价，记录每个结节候选者的模式，并为每个结节候选者分配一个置信度评分。由2名不同的放射科医师组成的共识小组建立了参考标准，他们在参考剂量ASIR上识别出84个直径为4 mm或更大的非钙化结节（毛玻璃样阴影，n = 18;部分实性，n = 11;实性，n = 55）。使用McNemar检验评估结节检测的灵敏度。采用Jackknife交替自由反应受试者工作特征（JAFROC）分析评估结果，包括置信度scores.Results：与低剂量CT相比，剂量长度乘积降低78.1%，与超低剂量CT。低剂量ASIR和超低剂量MBIR在总体结节检测灵敏度（P = 0.48-0.69）或JAFROC分析（P = 0.57）方面没有观察到显著差异。同样，毛玻璃样阴影、部分实性或实性结节检测的灵敏度（P = 0.08-0.65）或JAFROC分析（P = 0.21-0.90）也无显著差异。结论：基于模型的迭代重建能够将胸部CT的辐射剂量从低剂量水平降低近80%至超低剂量水平，而不影响结节检测能力。
Purpose: The purpose of this study was to evaluate whether model-based iterative reconstruction (MBIR) enables dose reduction over adaptive iterative reconstruction (ASIR) while maintaining diagnostic performance.Methods: In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study, 59 patients (mean [SD] age, 64.7 [13.4] years) gave informed consent to undergo reference-, low-, and ultralow-dose chest computed tomography (CT) with 64-row multidetector CT. The reference-and low-dose CT involved the use of automatic tube current modulation with fixed noise indices (31.5 and 70.44 at 0.625 mm, respectively) and were reconstructed with 50% ASIR-filtered back projection blending. The ultralow-dose CT was acquired with a fixed tube current-time product of 5 mA s and reconstructed with MBIR. Two radiologists evaluated 2.5- and 0.625-mm-slice-thick axial images from low-dose ASIR and ultralow-dose MBIR, recorded the pattern of each nodule candidate, and assigned each a confidence score. A reference standard was established by a consensus panel of 2 different radiologists, who identified 84 noncalcified nodules with diameters of 4 mm or greater on reference-dose ASIR (ground-glass opacity, n = 18; partly solid, n = 11; solid, n = 55). Sensitivity in nodule detection was assessed using the McNemar test. Jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was applied to assess the results including confidence scores.Results: Compared with the low-dose CT, a 78.1% decrease in dose-length product was seen with the ultralow-dose CT. No significant differences were observed between the low-dose ASIR and the ultralow-dose MBIR for overall nodule detection in sensitivity (P = 0.48-0.69) or the JAFROC analysis (P = 0.57). Likewise, no significant differences were seen for ground-glass opacity, partly solid, or solid nodule detection in sensitivity (P = 0.08-0.65) or the JAFROC analysis (P = 0.21-0.90).Conclusions: Model-based iterative reconstruction enables nearly an 80% reduction in radiation dose for chest CT from a low-dose level to an ultralow-dose level, without affecting nodule detectability.