多个基于美国的甲状腺结节风险分层系统正在全球范围内使用。不幸的是，结节的恶性概率各不相同，术语和定义也不一致，导致混乱，并使比较研究结果和工艺修订变得困难。这些系统的一致应用进一步受到观察者之间在识别其所依据的超声检查特征方面的差异的阻碍。 2018 年，由 19 名甲状腺超声专业医师组成的国际多学科小组（称为国际甲状腺结节超声工作组）召开，目标是开发一个国际系统，暂称为国际甲状腺成像报告和数据系统，或 I- TIRADS，分两个阶段：（第一阶段）创建甲状腺结节美国描述符词典和图集；（第二阶段）开发估计甲状腺结节恶性风险的系统。本文介绍了第一阶段的方法和结果。本文的目的是展示迄今为止所取得的成就，并引起全球甲状腺界对这项工作的兴趣和支持。© RSNA，2023 另请参阅作者的文章Lee 等人和路透社在本期的社论。

Multiple US-based systems for risk stratification of thyroid nodules are in use worldwide. Unfortunately, the malignancy probability assigned to a nodule varies, and terms and definitions are not consistent, leading to confusion and making it challenging to compare study results and craft revisions. Consistent application of these systems is further hampered by interobserver variability in identifying the sonographic features on which they are founded. In 2018, an international multidisciplinary group of 19 physicians with expertise in thyroid sonography (termed the International Thyroid Nodule Ultrasound Working Group) was convened with the goal of developing an international system, tentatively called the International Thyroid Imaging Reporting and Data System, or I-TIRADS, in two phases: (phase I) creation of a lexicon and atlas of US descriptors of thyroid nodules and (phase II) development of a system that estimates the malignancy risk of a thyroid nodule. This article presents the methods and results of phase I. The purpose herein is to show what has been accomplished thus far, as well as generate interest in and support for this effort in the global thyroid community.© RSNA, 2023 See also the article by Lee et al and the editorial by Reuter in this issue.