Endocrine > Thyroid > Nodules

TIRADS Classification:

A scoring system derived from five categories:

If there are multiple nodules (four or more), only the four highest scoring nodules should be scored-

  • Cystic or completely cystic: 0 points
  • Spongiform: 0 points
  • Mixed cystic and solid: 1 point
  • Solid or almost completely solid (less than 5% cystic): 2 points
  • Anechoic: 0 points
  • Hyper- or isoechoic: 1 point
  • Hypoechoic: 2 points
  • Very hypoechoic (the nodule is less reflective than the anterior neck muscles on every image): 3 points
  • Wider than tall: 0 points
  • Taller than wide (on axial image- AP length is larger than transverse width): 3 points
  • Smooth: 0 points
  • Ill-defined: 0 points
  • Lobulated/irregular: 2 points
  • Extra-thyroidal extension: 3 points

Echogenic foci: (choose 1 or more)

  • None: 0 points
  • Large comet tail artifact (colloid crystal): 0 points
  • Macrocalcifications: 1 point
  • Peripheral/rim calcifications: 2 points
  • Punctate echogenic foci: 3 points


TR1 (cancer risk 0.3%): 0 points. Benign- no FNA required

TR2 (cancer risk 1.5%): 2 points. Not suspicious- no FNA required

TR3 (cancer risk 4.8% (2.1-5%)): 3 points. Mildly suspicious- = 1.5 cm followup at 1, 3, and 5 years; = 2.5 cm FNA

TR4 (cancer risk 9.1% (5.1-20%)): 4-6 points. Moderately suspicious- = 1 cm followup at 1, 2, 3, and 5 years; = 1.5 cm FNA

TR5 (cancer risk 35% (over 20%)): 7 points or more. Highly suspicious- = 0.5 cm followup annually for up to 5 years; = 1 cm FNA

The ACR recommends that FNAB should be limited to a maximum of two nodules [3]. If there are multiple nodules, the two with the highest ACR TIRADS grades should be sampled (rather than the two largest). Any suspicious lymph nodes should also be sampled [3].

Nodule growth us defined as a 20% increase in at least two dimensions and a minimal increase of 2 mm, or a 50% or greater increase in nodule volume [2].

Nodules that do not grow over the course of 5 years may be considered benign [2].

For TI-RADS, meta-analysis found a pooled estimated sensitivity of 89% and a pooled specificity of 70% [5]. Using a cutoff of TR4 produced a pooled sensitivity of 90% and a specificity of 65%, while a cutoff of TR5 had a pooled sensitivity of 61% and a specificity of 88% [5].

NOTE: A recent article has suggested that TI-RADS is inadequate for management of pediatric thyroid nodules because a high percentage of cancers (22%) would be missed at the initial encounter [4]. The article recommended changes to nodule management guidelines in pediatric patients with biopsy of all nodules larger than 4 cm (and consideration for surgical resection due to the potential for a higher rate of false-negative FNA results); adjustment of TR3 recommendations to perform FNA in nodules 1.5 cm or larger (and follow if 1-1.4 cm); adjustment of TR4 recommendations to perform FNA for nodules 1 cm or larger (and follow if 0.5- 0.9 cm); and to consider biopsy for suspicious TR5 nodules that measure 0.5-0.9 cm [4].


(1) AJR 2017; Middleton WD, et al. Mutliinstitutional analysis of thyroid nodule risk stratification using American College of Radiology thyroid imaging reporting and data system. 208: 1331-1341

(2) Radiology 2018; Tessler FN, et al. Thyroid imaging reporting and data system (TI_RADS): a users guide. 287: 29-36

(3) Radiographics 2019; Tappouni RR, et al. ACR TI-RADS: pitfalls, solutions, and future directions. 39: 2040-2052

(4) Radiology 2020; Richman DM, et al. Assessment of the American college of radiology thyroid imaging and reporting data system (TI-RADS) for pediatric thyroid nodules. 294: 415-420

(5) AJR 2021; Li W, et al. Diagnsotic performance of American College of Radiology TI_RADS: a systematic review and meta-analysis. 216: 38-47

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