From the Guidelines
The Thyroid Imaging, Reporting and Data System (TI-RADS) categorization is a system used to guide the decision to biopsy thyroid nodules based on their sonographic features and size.
Key Points
- The TI-RADS system is used to characterize thyroid nodules for the risk of malignancy, with certain sonographic features being more prevalent in malignancies 1.
- The combination of these features and the nodule size guide the decision to biopsy under the ACR TI-RADS and other risk stratification criteria 1.
- The system is designed to aid in the management of thyroid nodules detected on ultrasound, reducing the need for unnecessary biopsies and surgeries.
- The ACR TI-RADS system is part of the American College of Radiology's efforts to address issues of thyroid nodule biopsy and unnecessary surgery, as the majority of small thyroid cancers are indolent 1.
TI-RADS Categorization
The TI-RADS system categorizes thyroid nodules into different risk categories based on their sonographic features, including:
- Composition (cystic, solid, or mixed)
- Echogenicity (hypoechoic, isoechoic, or hyperechoic)
- Shape (wider-than-tall or taller-than-wide)
- Margin (smooth, irregular, or lobulated)
- Echogenic foci (presence or absence of microcalcifications, macrocalcifications, or rim calcifications) The system assigns a score based on these features, which corresponds to a specific risk category, ranging from TR1 (benign) to TR5 (highly suspicious). The TI-RADS system is a valuable tool for radiologists and clinicians to evaluate thyroid nodules and make informed decisions about biopsy and treatment.
From the Research
Thyroid Imaging, Reporting and Data System (TI-RADS) Categorization
The Thyroid Imaging, Reporting and Data System (TI-RADS) is a classification system used to standardize thyroid ultrasound reports and predict the probability of malignancy in thyroid nodules. The system uses a scoring system (TR1-TR5) based on multiple ultrasound characteristics and nodule size 2. The TI-RADS categorization is as follows:
- TR1: Benign nodules
- TR2: Benign nodules
- TR3: Nodules with a low risk of malignancy
- TR4: Nodules with a moderate risk of malignancy, further divided into:
- TR4a: One suspicious feature
- TR4b: Two suspicious features
- TR4c: Three or four suspicious features
- TR5: Nodules with a high risk of malignancy, typically with five suspicious features 3, 4
TI-RADS Features
The TI-RADS features used to categorize thyroid nodules include:
- Composition (solid, cystic, or mixed)
- Echogenicity (hypoechoic, isoechoic, or hyperechoic)
- Nodule border or margin (smooth, irregular, or microlobulated)
- Shape (wider-than-tall or taller-than-wide)
- Presence of calcifications (microcalcifications or macrocalcifications)
- Nodule dimensions (size and volume) 2, 5
Clinical Application
The TI-RADS categorization is used to guide clinical management decisions, including the need for fine-needle aspiration (FNA) biopsy. Nodules with a higher TI-RADS score are more likely to be malignant and may require biopsy, while those with a lower score may be monitored or dismissed as benign 6, 4. The use of TI-RADS has been shown to reduce unnecessary biopsies and improve the diagnosis of thyroid cancer 6, 5.