OBJECTIVES Normal pulmonary artery (PA) diameter remains blurred and the definitions of PA aneurysm are heterogenous. We aimed to assess PA diameters, identify a threshold for normal diameters, define PA aneurysms, possible predictors of PA size and evaluate the correlation with mid-ascending aortic diameters. METHODS Between April 2018 and August 2019, 497 consecutive patients who underwent whole-body computed tomographic angiography were reviewed. Clinical and imaging data were collected from our institutional database. Precise three-dimensional centreline measurements were taken. Linear regression analysis was performed to detect parameters associated with PA diameter. A two-stage model was created to identify potential predictors and the resulting statistically significant interactions were tested. Data were grouped and PA, standard deviation, and upper normal limits were calculated. RESULTS Among 497 patients with an average age of 51.4 (20.2) (74.6% males), the mean PA diameter measured 32.0 (4.6) mm [female: 31.2 (4.7) mm vs male: 32.2 (4.5) mm; P = 0.032]. The mean PA length, left PA and right PA diameters were similar between male and female patients. We found a significant correlation (r = 0.352; P < 0.001) between the PAs and mid-ascending aortic diameters. Body surface area (P = 0.032, β = 4.52 [0.40; 8.64] 95% CI) was the only significant influencing variable for PA diameter. CONCLUSIONS The normal mean PA diameter in a reference cohort is 32.0 (4.6) mm. Body surface area is the only influencing variable of PA diameter. The normal diameters measured and corresponding upper limits of normal revealed that a PA aneurysm should not be considered below a threshold of 45 mm.

中文翻译：

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肺动脉直径：平均值和正常范围——计算机断层扫描血管造影评估

目的 正常肺动脉 (PA) 直径仍然模糊，并且 PA 动脉瘤的定义是异质的。我们旨在评估 PA 直径，确定正常直径的阈值，定义 PA 动脉瘤，PA 大小的可能预测因子，并评估与升主动脉中部直径的相关性。方法 2018 年 4 月至 2019 年 8 月，回顾了 497 例连续接受全身 CT 血管造影的患者。从我们的机构数据库中收集临床和影像学数据。进行了精确的三维中心线测量。进行线性回归分析以检测与 PA 直径相关的参数。创建了一个两阶段模型来识别潜在的预测因子，并测试了由此产生的具有统计学意义的相互作用。对数据进行分组，PA、标准差、并计算正常上限。结果 在平均年龄为 51.4 (20.2) (74.6% 男性) 的 497 名患者中，平均 PA 直径测量为 32.0 (4.6) mm [女性：31.2 (4.7) mm vs 男性：32.2 (4.5) mm；P = 0.032]。男性和女性患者的平均 PA 长度、左 PA 和右 PA 直径相似。我们发现 PA 与升主动脉中部直径之间存在显着相关性（r = 0.352；P < 0.001）。体表面积 (P = 0.032, β = 4.52 [0.40; 8.64] 95% CI) 是唯一显着影响 PA 直径的变量。结论 参考队列中的正常平均 PA 直径为 32.0 (4.6) mm。体表面积是PA直径的唯一影响变量。测量的正常直径和相应的正常上限表明，不应将 PA 动脉瘤视为低于 45 mm 的阈值。