From the Brigham and Women's Hospital, Boston MA.
J Comput Assist Tomogr. 2023;47(3):396-401. doi: 10.1097/RCT.0000000000001413. Epub 2023 Jan 14.
Pulmonary nodule growth is often measured by volume doubling time (VDT), which may guide management. Most malignant nodules have a VDT of 20 to 400 days, with longer VDTs typically observed in indolent nodules. We assessed the utility of VDT in differentiating pulmonary carcinoids and hamartomas.
A review was performed from January 2012 to October 2021 to identify patients with pathologic diagnoses and at least 2 chest computed tomography scans obtained 6 or more months apart. Visualization software was used to segment nodules and calculate diameter and volume. Volume doubling time was calculated for scans with 1-mm slices. For the remainder, estimated nodule volume doubling time (eVDT) was calculated using nodule diameter. Volume doubling times/eVDTs were placed into growth categories: less than 400 days; 400-600 days; and more than 600 days.
Sixty nodules were identified, 35 carcinoids and 25 hamartomas. Carcinoids were larger than hamartomas (median diameter, 13.5 vs 11.5 mm; P = 0.05). For carcinoid tumors, median VDT (n = 15) was 1485 days, and median eVDT (n = 32) was 1309 days; for hamartomas, median VDT (n = 8) was 2040 days and median eVDT (n = 25) was 2253 days. Carcinoid tumor eVDT was significantly shorter than hamartomas ( P = 0.03). By growth category, 1 of 25 hamartomas and 5 of 35 carcinoids had eVDT less than 400 days and 24 of 25 hamartomas and 27 of 35 carcinoids had eVDT more than 600 days. Of 4 carcinoid tumors with metastases, 2 had eVDT less than 400 days and 2 had eVDT more than 600 days.
Growth rate was not a reliable differentiator of pulmonary hamartomas and carcinoids. Slow growing carcinoids can metastasize. Radiologists should be cautious when discontinuing computed tomography follow-up based on growth rates alone.
肺结节的生长通常通过倍增时间（VDT）来测量，这可能有助于指导治疗。大多数恶性结节的 VDT 为 20 至 400 天，惰性结节的 VDT 通常较长。我们评估了 VDT 在鉴别肺类癌和错构瘤方面的作用。
对 2012 年 1 月至 2021 年 10 月期间进行的回顾性研究进行了评估，以确定至少有 2 次相隔 6 个月以上的胸部 CT 扫描且经病理诊断为患者。使用可视化软件对结节进行分割并计算直径和体积。对有 1 毫米切片的扫描进行 VDT 计算。对于其余扫描，使用结节直径计算估计的结节体积倍增时间（eVDT）。将体积倍增时间/eVDT 分为以下生长类别：小于 400 天；400-600 天；大于 600 天。
共发现 60 个结节，其中 35 个为类癌，25 个为错构瘤。类癌比错构瘤大（中位直径，13.5 与 11.5 毫米；P=0.05）。15 个类癌肿瘤的中位 VDT 为 1485 天，32 个类癌肿瘤的中位 eVDT 为 1309 天；8 个错构瘤的中位 VDT 为 2040 天，25 个错构瘤的中位 eVDT 为 2253 天。类癌肿瘤的 eVDT 明显短于错构瘤（P=0.03）。按生长类别，25 个错构瘤中有 1 个和 35 个类癌中有 5 个的 eVDT 小于 400 天，25 个错构瘤中有 24 个和 35 个类癌中有 27 个的 eVDT 大于 600 天。4 个有转移的类癌肿瘤中，有 2 个的 eVDT 小于 400 天，有 2 个的 eVDT 大于 600 天。
生长速度不是鉴别肺错构瘤和类癌的可靠指标。生长缓慢的类癌也可能发生转移。如果仅根据生长速度来停止 CT 随访，放射科医生应谨慎行事。
