Background Interstitial lung abnormalities (ILAs) are incidental CT findings suggesting early interstitial lung disease. However ILA prevalence data are scarce in an unselected routine clinical setting. Purpose To evaluate the prevalence, underreporting rate, and potential clinical impact of ILAs recognizable on either abdominal CT scans or thoracoabdominal CT scans in a routine clinical setting of unselected patients. Materials and Methods Consecutive abdominal or thoracoabdominal CT scans from unselected inpatients and outpatients (age, ≥50 years; without any available prior chest CT and no clinical history of disease against the diagnosis of ILA) from a single-center tertiary hospital between January 2008 and December 2015 were retrospectively reviewed for the presence of ILAs and compared with the original clinical reports from the CT scans. Radiologic progression of ILA was evaluated by comparing consecutive CT points. Multivariable models adjusted for age, sex, race/ethnicity, oncologic disease, and cardiovascular disease were used to assess factors associated with odds of ILAs progression and all-cause and cause-specific mortality. Results Among 21 118 patients (median age, 72 years [IQR, 64-80 years]; 11 028 [52.2%] female patients), ILAs were observed in 362 (1.7%) patients, notably in 222 (1.0%) patients who had fibrotic features at CT. ILAs were recognized in 122 of 9415 (1.3%) and 240 of 11 703 (2.1%) of abdominal and thoracoabdominal CT scans, respectively. Of available original reports for 360 patients, 158 (43.9%) of all ILAs were not originally reported. Traction bronchiectasis index was the CT factor associated with higher odds of ILA progression (odds ratio, 3.47; 95% CI: 1.83, 6.58; P < .001). Fibrotic ILAs had a fourfold higher risk of respiratory-cause mortality (hazard ratio, 4.01; 95% CI: 2.02, 7.92; P < .001) compared with patients without ILAs. Conclusion The prevalence of ILAs was 1.7% in a large, unselected sample of patients who underwent either abdominal or thoracoabdominal CT for various clinical indications. Despite their prognostic significance, 43.9% of ILAs were unreported. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Hata in this issue.

中文翻译：

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21 118 例患者未经选择的腹部和胸腹 CT 扫描显示间质性肺异常。


背景间质性肺异常 （ILA） 是提示早期间质性肺病的偶然 CT 发现。然而，在未经选择的常规临床环境中，ILA 患病率数据很少。目的 在未经选择的患者的常规临床环境中，评估腹部 CT 扫描或胸部腹部 CT 扫描中可识别的 ILA 的患病率、漏报率和潜在临床影响。材料和方法 回顾性回顾性分析了 2008 年 1 月至 2015 年 12 月期间来自单中心三级医院的未经选择的住院患者和门诊患者 （年龄，≥50 岁;没有任何可用的先前胸部 CT 且无针对 ILA 诊断的疾病史）的连续腹部或胸腹部 CT 扫描，并与 CT 扫描的原始临床报告进行比较。通过比较连续的 CT 点来评估 ILA 的放射学进展。使用针对年龄、性别、种族/民族、肿瘤疾病和心血管疾病进行调整的多变量模型来评估与 ILA 进展几率以及全因和原因特异性死亡率相关的因素。结果 在 21 118 例患者 （中位年龄 72 岁 [IQR，64-80 岁];11 028 例 [52.2%] 女性患者中，362 例 （1.7%） 患者观察到 ILA，尤其是 222 例 （1.0%） CT 纤维化特征的患者。在腹部和胸腹 CT 扫描中，9415 例中有 122 例 （1.3%） 和 11 703 例 （2.1%） 分别在腹部和胸部腹部 CT 扫描中发现 ILA。在 360 名患者的可用原始报告中，158 名 （43.9%） 的所有 ILA 最初未报告。牵引性支气管扩张指数是与 ILA 进展的较高几率相关的 CT 因素 （比值比，3.47;95% CI：1.83,6.58;P < .001）. 纤维化 ILA 的呼吸原因死亡风险高出 4 倍（风险比，4.01;95% CI：2.02,7.92;P < .001） 与无 ILA 的患者相比。结论 在因各种临床适应症接受腹部或胸部腹部 CT 的大型未经选择的患者样本中，ILA 的患病率为 1.7%。尽管具有预后意义，但 43.9% 的 ILA 未被报道。© RSNA，2024 年本文提供补充材料。另请参阅本期 Hata 的社论。