Thyroid nodule — Ultrasound (ACR TI-RADS)

1.Location and number

Lobe (right/left/isthmus) and position. State the number of nodules and score the most suspicious, not simply the largest.

2.Size in three dimensions

Longitudinal × transverse × AP in cm. Compare with priors: significant growth is ≥20% in two dimensions (and ≥2 mm) or ≥50% volume.

Pitfall: Measuring only one dimension makes follow-up comparison impossible.

3.Composition

Cystic, spongiform (>50% microcystic), mixed cystic–solid, or solid.

4.Echogenicity

Relative to parenchyma: hyper-, iso-, or hypoechoic. Very hypoechoic = darker than the strap muscles.

5.Shape

Taller-than-wide is assessed on the axial plane and is a malignancy marker.

Pitfall: Only the axial plane counts; a 'tall' shape on the sagittal image does not.

6.Margin

Smooth, ill-defined, lobulated/irregular, or extra-thyroidal extension.

7.Echogenic foci

Punctate echogenic foci, macrocalcifications, peripheral (rim) calcification, or comet-tail artifacts.

8.Cervical lymph nodes

Abnormal features: microcalcifications, cystic change, hyperechogenicity, abnormal vascularity — name the levels involved.

Pitfall: A suspicious node changes management regardless of the nodule's TI-RADS level.