TI-RADS is a now outdated risk stratification system for classifying thyroid lesions, originating from a study from 2009 3, and described in an American College of Radiology (ACR) white paper in 2015 1. Its use was originally advocated in a similar vein to the use of BI-RADS for breast lesions.
In 2017, a new white paper 2 was released by the ACR committee on thyroid imaging with a standardized scoring system, with guidance on fine needle aspiration (FNA) and follow-up. This resulted in the revised ACR TI-RADS system which superseded the original TI-RADS described herein.
Originally this classification system was proposed by Horvath et al. 3 in 2009, with a modified recommendation from Jin Kwak et al. in 2011 4.
Similar to BI-RADS category, the sonographic TI-RADS classification was as follows:
- TI-RADS 1: normal thyroid gland
- TI-RADS 2: benign lesions
- TI-RADS 3: probably benign lesions
- TI-RADS 4: suspicious lesions (subclassified as 4a, 4b, and later 4c 4 with increasing risk of malignancy)
- TI-RADS 5: probably malignant lesions (more than 80% risk of malignancy)
- TI-RADS 6: biopsy proven malignancy
TI-RADS 2 category
- avascular anechoic lesion with echogenic specks (colloid type I)
- vascular heteroechoic non-expansile, non-encapsulated nodules with peripheral halo (colloid type II)
- isoechoic or heteroechoic, non-encapsulated, expansile vascular nodules (colloid type III)
These conditions have 0% risk of malignancy.
TI-RADS 3 category
- hyperechoic, isoechoic or hypoechoic nodules, with partially formed capsule and peripheral vascularity, usually in setting of Hashimoto thyroiditis (Hashimoto pseudonodule)
Modified TIRADS classification 4 have simplified TIRADS 3 category as none of the suspicious malignant sonographic features described below. These lesions are mostly benign with <5% risk of malignancy 3.
TI-RADS 4 and 5 categories
These categories are based on five suspicious sonographic features of malignancy:
- solid component
- high stiffness of nodule on elastography if available
- markedly hypoechoic nodule
- microlobulations or irregular margins
- taller-than-wider shape
- TI-RADS 4a: one suspicious feature
- TI-RADS 4b: two suspicious features
- TI-RADS 4c: three/four suspicious features
- TI-RADS 5: all five suspicious features
TI-RADS 4a has 5-10% risk of malignancy, 4b and 4c may have 10-80% risk of malignancy. TI-RADS 5 category lesion have >80% risk of malignancy 3.
- ACR Thyroid Imaging Reporting and Data System (ACR TI-RADS)
- BI-RADS classification system
- 1. Grant EG, Tessler FN, Hoang JK et-al. Thyroid Ultrasound Reporting Lexicon: White Paper of the ACR Thyroid Imaging, Reporting and Data System (TIRADS) Committee. J Am Coll Radiol. 2015;12 (12): 1272-9. doi:10.1016/j.jacr.2015.07.011 - Pubmed citation
- 2. Tessler FN, Middleton WD, Grant EG, et al. ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee. J Am Coll Radiol. In press; 2017. doi.org:10.1016/j.jacr.2017.01.046
- 3. Horvath E, Majlis S, Rossi R et-al. An ultrasonogram reporting system for thyroid nodules stratifying cancer risk for clinical management. J. Clin. Endocrinol. Metab. 2009;94 (5): 1748-51. doi:10.1210/jc.2008-1724 - Pubmed citation
- 4. Kwak JY, Han KH, Yoon JH et-al. Thyroid imaging reporting and data system for US features of nodules: a step in establishing better stratification of cancer risk. Radiology. 2011;260 (3): 892-9. doi:10.1148/radiol.11110206 - Pubmed citation
- 5. Friedrich-Rust M, Meyer G, Dauth N et-al. Interobserver Agreement of Thyroid Imaging Reporting and Data System (TIRADS) and Strain Elastography for the Assessment of Thyroid Nodules. PLoS ONE. 24;8 (10): e77927. doi:10.1371/journal.pone.0077927 - Free text at pubmed - Pubmed citation
- 6. Russ G, Royer B, Bigorgne C et-al. Prospective evaluation of thyroid imaging reporting and data system on 4550 nodules with and without elastography. Eur. J. Endocrinol. 2013;168 (5): 649-55. doi:10.1530/EJE-12-0936 - Pubmed citation
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