Thyroiditis is a group of conditions involving inflammation of the thyroid gland. The most common form is Hashimoto thyroiditis (chronic lymphocytic thyroiditis), an autoimmune condition that is the leading cause of hypothyroidism. Other types include subacute (de Quervain) thyroiditis, postpartum thyroiditis, and acute suppurative thyroiditis. On ultrasound, Hashimoto thyroiditis typically causes the thyroid to appear diffusely heterogeneous and hypoechoic (darker than normal), with a coarsened echotexture and often increased vascularity on color Doppler. The gland may be enlarged initially but can become atrophic (small) over time. Subacute thyroiditis may show focal hypoechoic areas corresponding to regions of inflammation and pain. Recognizing the sonographic pattern of thyroiditis helps clinicians correlate imaging findings with thyroid function tests and clinical symptoms.
Sonography Term