Background Data on the diagnostic accuracy of ultralow-dose (ULD) CT protocols for periodic surveillance in recipients of lung transplant are lacking. Purpose To assess the potential for radiation dose reduction using ULD photon-counting CT (PCT) to detect lung abnormalities in recipients of lung transplant during repeat CT follow-up. Materials and Methods Consecutive adult recipients of lung transplant undergoing same-day standard-of-care low-dose (LD) and ULD PCT from March 2023 to May 2023 were prospectively included. The ULD protocols were performed with two target effective doses comprising 20% (hereafter, ULD1) and 10% (hereafter, ULD2) of the standard LD protocol. The 1-mm reconstructions were reviewed by three readers. Subjective image quality, the visibility of certain anatomic structures (using a five-point Likert scale), and the presence of lung abnormalities were independently assessed. The χ2 or t tests were used to evaluate differences between the ULD1 and ULD2 protocols. Results A total of 82 participants (median age, 64 years [IQR, 54-69 years]; 47 male) were included (41 participants for each ULD protocol). The mean effective doses per protocol were 1.41 mSv ± 0.44 (SD) for LD, 0.26 mSv ± 0.08 for ULD1, and 0.17 mSv ± 0.04 for ULD2. According to three readers, the subjective image quality of the ULD images was deemed diagnostic (Likert score ≥3) in 39-40 (ULD1) and 40-41 (ULD2) participants, and anatomic structures could be adequately visualized (Likert score ≥3) in 33-41 (ULD1) and 34-41 (ULD2) participants. The detection accuracy for individual lung anomalies exceeded 70% for both ULD protocols, except for readers 1 and 3 detecting proximal bronchiectasis and reader 3 detecting bronchial wall thickening and air trapping. No evidence of a statistically significant difference in noise (P = .96), signal-to-noise ratio (P = .77), or reader accuracy (all P ≥ .05) was noted between the ULD protocols. Conclusion ULD PCT was feasible for detecting lung abnormalities following lung transplant, with a tenfold radiation dose reduction. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ciet in this issue.

中文翻译：

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超低剂量光子计数 CT 检测肺移植后肺变化的准确性。


背景 用于肺移植受者定期监测的超低剂量 (ULD) CT 方案的诊断准确性数据缺乏。目的 评估使用 ULD 光子计数 CT (PCT) 减少辐射剂量的潜力，以在重复 CT 随访期间检测肺移植受者的肺部异常。材料和方法 前瞻性地纳入了 2023 年 3 月至 2023 年 5 月连续接受当天标准护理低剂量 (LD) 和 ULD PCT 的肺移植成年受者。 ULD 方案采用两个目标有效剂量，包括标准 LD 方案的 20%（以下简称 ULD1）和 10%（以下简称 ULD2）。三位读者对 1 毫米重建进行了审查。独立评估主观图像质量、某些解剖结构的可见度（使用五点李克特量表）以及肺部异常的存在。 χ2 或 t 检验用于评估 ULD1 和 ULD2 方案之间的差异。结果 总共纳入 82 名参与者（中位年龄 64 岁 [IQR，54-69 岁]；47 名男性）（每个 ULD 方案 41 名参与者）。每个方案的平均有效剂量为 LD 1.41 mSv ± 0.44 (SD)、ULD1 0.26 mSv ± 0.08 和 ULD2 0.17 mSv ± 0.04。根据三位读者的说法，ULD 图像的主观图像质量在 39-40 (ULD1) 和 40-41 (ULD2) 参与者中被认为具有诊断意义（Likert 评分≥3），并且解剖结构可以充分可视化（Likert 评分≥3） ）在 33-41 (ULD1) 和 34-41 (ULD2) 参与者中。两种 ULD 协议对个体肺部异常的检测准确度都超过了 70%，除了读取器 1 和 3 检测近端支气管扩张以及读取器 3 检测支气管壁增厚和空气滞留之外。 没有证据表明 ULD 协议之间的噪声 (P = .96)、信噪比 (P = .77) 或读取器准确度（所有 P ≥ .05）存在统计显着差异。结论 ULD PCT 用于检测肺移植后的肺部异常是可行的，辐射剂量可减少十倍。 © RSNA，2024 本文提供补充材料。另请参阅本期 Ciet 的社论。