Summary of meta-analyses of studies involving TIRADS classifications (EU-TIRADS,
ACR-TIRADS, and K-TIRADS) in evaluating the malignant potential of focal lesions of the
thyroid gland
Authors:   Department of Radiology II, Maria
            Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland, Dobruch-Sobczak Katarzyna , Adamczewski Zbigniew ,   Department of Nuclear
            Medicine, Medical University of Lodz, Lodz, Poland, Dedecjus Marek ,   Department of Oncological
            Endocrinology and Nuclear Medicine, Maria Skłodowska-Curie National Research Institute
            of Oncology, Warsaw, Poland, Lewiński Andrzej ,   Department of Endocrinology
            and Metabolic Diseases, Polish Mother’s Memorial Hospital – Research Institute, Lodz,
            Poland,   Department of Endocrinology
            and Metabolic Diseases, Medical University of Lodz, Lodz, Poland, Migda Bartosz ,   Ultrasound Diagnostics
            Laboratory, Department of Paediatric Radiology, Faculty of Medicine, Medical University
            of Warsaw, Warsaw, Poland, Ruchała Marek ,   Department of Endocrinology,
            Metabolism and Internal Diseases, Poznan University of Medical Sciences, Poznan,
            Poland, Skowrońska-Szcześniak Anna ,   Department of Internal
            Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland, Szczepanek-Parulska Ewelina ,   Department of Endocrinology,
            Metabolism and Internal Diseases, Poznan University of Medical Sciences, Poznan,
            Poland, Zajkowska Klaudia ,   Department of Oncological
            Endocrinology and Nuclear Medicine, Maria Skłodowska-Curie National Research Institute
            of Oncology, Warsaw, Poland, Żyłka Agnieszka ,   Department of Oncological
            Endocrinology and Nuclear Medicine, Maria Skłodowska-Curie National Research Institute
            of Oncology, Warsaw, Poland
Published: May 2022

Numerous scientific societies around the world have published their TIRADS
(Thyroid Imaging Reporting and Data System) classifications that evaluate the risk of
malignancy of focal thyroid lesions, presenting different ultrasound features for each
category and lesion size thresholds to determine eligibility for biopsy. The use of such
risk estimation systems in focal thyroid lesions facilitates the reporting of thyroid
ultrasound findings and improves the qualification of focal lesions for fine-needle
aspiration biopsy (FNAB). In this publication, the three most popular TIRADS
classifications, European – EU-TIRADS, Korean – K-TIRADS, and developed by the American
Society of Radiology – ACR-TIRADS, are presented and discussed based on a literature
review. The results of available head-to-head statistical analyses comparing the
classifications are also presented. The advantage of the EU-TIRADS and K-TIRADS systems
is that they include only the most important ultrasound features, so their application
is not time-consuming, and the scores are easy to incorporate into clinical practice.
ACR-TIRADS, unlike other scales, is based on a unique classification system and
represents the most comprehensive classification. Each of the five categories of
ultrasound features – morphology, echogenicity, shape, margins, microcalcifications –
are evaluated and assigned a score from 0 to 3, with a higher score being associated
with a higher risk of cancer. Based on the available data, the greatest benefit has been
demonstrated for the ACR-TIRADS classification, which also has implications for
minimising the number of unnecessary FNABs. However, limitations related to the
heterogeneity of the groups analysed in the study, including differences in the
populations studied, inclusion criteria, proportions of patients of either sexes, and
the number of malignant lesions analysed, should also be taken into account.