Hypothyroidism is a condition in which the thyroid gland produces insufficient amounts of thyroid hormones, slowing the body’s metabolism. The most common cause in developed countries is Hashimoto thyroiditis, an autoimmune condition in which the immune system attacks the thyroid gland. On ultrasound, the thyroid in Hashimoto thyroiditis typically appears diffusely hypoechoic, heterogeneous, and often with a characteristic micronodular pattern or fibrous septations dividing the gland into pseudonodules. Decreased blood flow may also be seen on Doppler in later stages. Ultrasound is useful for evaluating the thyroid’s size and appearance, identifying any coexisting nodules that may need biopsy to rule out malignancy, and monitoring the gland over time.
Sonography Term