Villanueva-Meyer Javier E, Naeger David M, Courtier Jesse L, Hope Michael D, Lambert Jack W, MacKenzie John D, Phelps Andrew S
Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, M-391, San Francisco, CA, 94143, USA.
Thoracic Radiology Section, University of California San Francisco, San Francisco, CA, USA.
Emerg Radiol. 2017 Aug;24(4):369-376. doi: 10.1007/s10140-017-1487-5. Epub 2017 Mar 14.
Computed tomography (CT) use in emergency departments represents a significant contribution to pediatric patients' exposure to ionizing radiation. Here, we evaluate whether ultralow-dose chest CT can be diagnostically adequate for other diagnoses and whether model-based iterative reconstruction (MBIR) can improve diagnostic adequacy compared to adaptive statistical iterative reconstruction (ASIR) at ultralow doses.
Twenty children underwent chest CTs: 10 standard-dose reconstructed with ASIR and 10 ultralow-dose reconstructed with ASIR and MBIR. Four radiologists assessed images for their adequacy to exclude five hypothetical diagnoses: foreign body, fracture, lung metastasis, pulmonary infection, and interstitial lung disease. Additionally, pairwise comparison for subjective image quality was used to compare ultralow-dose chest CT with ASIR and MBIR. Radiation dose and objective image noise measures were obtained.
For exclusion of an airway foreign body, the adequacy of ultralow-dose CT was comparable to standard-dose (p = 0.6). For the remaining diagnoses, ultralow-dose CT was inferior to standard-dose (p = 0.03-<0.001). MBIR partially recovered the adequacy of ultralow-dose CT to exclude pulmonary infection (p = 0.017), but was suboptimal for the other diagnoses. Image noise was significantly lower with MBIR compared to ASIR in ultralow-dose CT (p < 0.001), although subjective preference showed only a slight advantage of MBIR (58 versus 42%).
Ultralow-dose chest CT may be adequate for airway assessment, but suboptimal for the evaluation parenchymal lung disease. Although MBIR improves objective and subjective image quality, it does not completely restore the diagnostic adequacy of ultralow-dose CT when compared to standard-dose CT.
计算机断层扫描（CT）在急诊科的应用对儿科患者接受电离辐射有重大影响。在此，我们评估超低剂量胸部CT在其他诊断方面是否具有足够的诊断价值，以及与自适应统计迭代重建（ASIR）相比，基于模型的迭代重建（MBIR）在超低剂量下能否提高诊断准确性。
20名儿童接受胸部CT检查：10名采用ASIR进行标准剂量重建，10名采用ASIR和MBIR进行超低剂量重建。四名放射科医生评估图像以确定其排除五种假设诊断的充分性：异物、骨折、肺转移、肺部感染和间质性肺疾病。此外，使用主观图像质量的成对比较来比较超低剂量胸部CT与ASIR和MBIR。获取辐射剂量和客观图像噪声测量值。
对于排除气道异物，超低剂量CT的充分性与标准剂量相当（p = 0.6）。对于其余诊断，超低剂量CT不如标准剂量（p = 0.03 - <0.001）。MBIR部分恢复了超低剂量CT排除肺部感染的充分性（p = 0.017），但对其他诊断效果欠佳。在超低剂量CT中，与ASIR相比，MBIR的图像噪声显著更低（p < 0.001），尽管主观偏好仅显示MBIR有轻微优势（58%对42%）。
超低剂量胸部CT可能足以用于气道评估，但对实质性肺部疾病的评估欠佳。尽管MBIR提高了客观和主观图像质量，但与标准剂量CT相比，它并未完全恢复超低剂量CT的诊断充分性。
