THYROID ULTRASOUND IMAGING


WHY IS THIS PROCEDURE USED?

  • to determine if a lump in the neck is arising from the thyroid or an adjacent structure

  • to analyze the appearance of thyroid nodules and determine if they are the more common benign nodule or if the nodule has features that require a biopsy. If biopsy is required, ultrasound-guided fine needle aspirationcan help improve accuracy of the biopsy.

  • to look for additional nodules in patients with one or more nodules felt on physical exam

  • to see if a thyroid nodule has substantially grown over time

INTRATHYROIDAL MASSES

CYSTS

Resemble those in other parts of the body, except that their walls may be irregular and that they may contain internal echoes from haemorrhage. They are predominantly benign when within the thyroid.

ADENOMAS

The most common of thyroid masses. Typically appear as:

  • a halo of echopenic tissue surrounding a more echogenic mass with echoes that are more dense than the remainder of the gland.

  • a solid homogenous mass with very few internal echoes that can easily be confused with a cyst

  • a densely echogenic lesion.

Ulike carcinomas, adenomas are also invariably benign.

CARCINOMAS

  • an echophrenic mass with an irregular border

  • tiny foci of calcification

  • a single nodular lesion

  • development of nodes in neighbouring structures.

The presence of microcalfications within a mass is a strong predictor for malignancy.

GOITERS

Diffuse, asymmetric expansion of the thyroid with a coarse acoustic texture, usually with multiple nodules.

HASHIMOTO'S THYROIDITIS

Inflammatory condition with a diffuse, mild enlargement of the thyroid with multiple echophrenic nodules. Fibrous interfaces between the nodules are evident. Increased blood flow is often seen.

HEMORRHAGE

Sudden onset of pain with development of a mass associated with intrathyrodial clot, similar in appearance to other clots in the body.

SUBACUTE THYRODITIS

Painful condition exhibiting diffuse, mild enlargement of thyroid with an echophrenic texture but no focal nodules. May be a prelude to Hashimoto's thyroiditis.

EXTRATHYROIDAL MASSES

THYROGLASSAL DUCT CYST

Embryological remnant with an appearance of a cyst, but containing either simple or complex fluid, found in the mid-line high in the neck above the thyroid.

NODES

Enlarged lymph nodes in the neck. With homogenous texture, but less echogenic than normal thyroid texture. Usually benign.

ABSCESS

May develop in the neck with typical ultrasonic features as in the rest of the body, associated with pain fever and focal swelling.

CARCINOMA INVASION

Carcinoma, from the tongue for example, can invade the neck.

Sources:

Clinical sonography, Roger C. Sanders, Tom C. Winter

#ultrasound #imaging

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