Note to first time users: this calculator aids in the use of the reporting system designed by the American College of Radiology for the ultrasound assessment of thyroid nodules. Other, to a varying degree different reporting systems such as the EU-TIRADS and K-TIRADS have also been published. Please consult institutional and national guidelines to decide which system should you use. In any case it is recommended to indicate the exact reporting system (e.g. “ACR TI-RADS 4”) on the report instead of an ambiguous terminology (“TIRADS 4”).
This calculator is based upon the American College of Radiology (ACR) TI-RADS™ classification, however it is neither supported, nor endorsed by the aforementioned organization.
Notes:
The system uses the following scoring:
- TR1: 0 points
- benign
- TR2: 2 points
- not suspicious
- TR3: 3 points
- mildly suspicious
- TR4: 4-6 points
- moderately suspicious
- TR5: ≥7 points
- highly suspicious
- Spongiform nodules (>50% small cystic spaces) are inherently benign according to this reporting system, and thus no further points are added from other categories (this is reflected by the design of this calculator).
- For mixed cystic and solid lesions points should be assigned based on the appearance of the solid part of the nodule.
- Some specific, benign nodule appearances, e.g. the uniformly hyperechoic white knight nodule, or the giraffe hide pattern made of hyperechoic areas separated by band-like hypoechoic regions (both occur in the setting of Hashimoto thyreoditis) are not formally incorporated into ACR TI-RADS.
- Distinguishing anechoic (0 points) vs. very hypoechoic (3 points) lesions is crucial. Anechoic lesions represent fluid-filled cysts whilst very hypoechoic lesions are high risk lesions with echogenicity lower than that of the strap muscles.
- In all other cases echogenicity should be compared to the adjacent thyroid tissue.
- Another important point is the taller-than-wide shape, which is generally defined as and anteroposterior/transverse diameter (AP/T) ratio >1
- In this system there is no grade for normal thyroid glands unlike in other reporting systems (e.g. EU-TIRADS).
For further informations and official educational materials make sure to visit the official ACR TI-RADS™ website.
The Radiopaedia.org page on the ACR TI-RADS™ also provides a good, brief summary on the topic.
Last updated: 2021-08-17