疫苗相关淋巴结病变是新冠病毒病2019（COVID-19）疫苗接种后常见的结果，但在COVID-19加强针接种后的频率仍未知。在本研究中，我们比较了COVID-19加强针接种前后通过乳房磁共振成像观察腋窝淋巴结形态。本回顾性、单中心、获得IRB批准的研究包括在2021年10月至12月接受COVID-19加强针接种后进行乳房磁共振成像的患者。在加强针接种后的MRI上度量了同侧最大皮层厚度的腋窝淋巴结，并与最初COVID-19疫苗接种前进行比较，比较了皮层厚度≥0.2厘米增加和未增加的患者之间的情况。使用Wilcoxon秩和检验比较连续协变量，使用Fisher精确检验比较分类协变量。使用Benjamini-Hochberg程序进行多重比较调整。共有128名患者被纳入研究。其中24人（19％）显示出≥0.2厘米的淋巴结皮层厚度增加。接种加强针较近的患者更可能出现皮层增厚，中位数为9天（IQR 5, 20）vs. 36天（IQR 18, 59）（p <0.001）。年龄（p = 0.5）和疫苗类型（p = 0.7）与增厚无关。在随访中未发现同侧乳腺癌或恶性淋巴结病变。COVID-19加强针接种后乳房MRI上的腋窝淋巴结病变是一种常见现象，尤其是在接种后的前3周内。对于低度恶性病变风险的患者，可能可以省略额外的评估或随访。 版权所有©2023 The Association of University Radiologists。由Elsevier Inc.出版。

Vaccine-related lymphadenopathy is a frequent finding following initial coronavirus disease 2019 (COVID-19) vaccination, but the frequency after COVID-19 booster vaccination is still unknown. In this study we compare axillary lymph node morphology on breast MRI before and after COVID-19 booster vaccination.This retrospective, single-center, IRB-approved study included patients who underwent breast MRI between October 2021 and December 2021 after the COVID-19 booster vaccination. The axillary lymph node with the greatest cortical thickness ipsilateral to the side of vaccination was measured on MRI after booster vaccination and before initial COVID-19 vaccination. Comparisons were made between patients with and without increase in cortical thickness of ≥ 0.2 cm. Continuous covariates were compared using Wilcoxon rank-sum test and categorical covariates were compared using Fisher's exact test. Multiple comparison adjustment was made using the Benjamini-Hochberg procedure.All 128 patients were included. Twenty-four of 128 (19%) displayed an increase in lymph node cortical thickness of ≥ 0.2 cm. Patients who received the booster more recently were more likely to present cortical thickening, with a median of 9 days (IQR 5, 20) vs. 36 days (IQR 18, 59) (p < 0.001). Age (p = 0.5) and type of vaccine (p = 0.7) were not associated with thickening. No ipsilateral breast cancer or malignant lymphadenopathy were diagnosed on follow-up.Axillary lymphadenopathy on breast MRI following COVID-19 booster vaccination is a frequent finding, especially in the first 3 weeks after vaccination. Additional evaluation or follow-up may be omitted in patients with low concern for malignancy.Copyright © 2023 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.