Thyroid Ultrasound

The thyroid is an endocrine organ that secretes hormones that regulate
metabolism and protein synthesis.
The gland is about 10 – 20 g and butterfly shaped with 2 lobes and isthmus, 30 % of the population also have a pyramidal lobe the extends superior to the isthmus.

Hormones

T3 triiodothyonine
reference range of T3: 75 -200 ng/dL
T4 Thyroxine
reference range for T4: 4.5 -11.5 ug/dL
TSH Thyroid stimulating hormone
reference range for TSH: 75 -200 ng/dL
Thyroid-binding globulin TBG
reference range for TBG:  1.1-2.1mg/dL

Ultrasound

Under ultrasound the thyroid is smooth, homogenous with mid level echoes. Colloid follicles are normally seen in the parenchyma and are considered normal, these are
small cysts with punctuate echoes within.
The thyroid is bordered posteriorly by the trachea, laterally by the carotid and juglular, and anteriorly by the strap and sternocelidomastoid muscles.

thyroid_normal_ultrasound_from_toshiba_pr

 

Indiciations

Goiter or palpable mass
Abnormal thyroid function tests
Family history of thyroid cancer

Conditions

Hashimoto’s thyroiditis (Chronic lymphocytic thyroiditis)
Hypothyroidism
Frequent in adolescent girls and women over 40
Gland is typically enlarged, grossly heterogenous and hyperemic (thyroid inferno). The thyroid can have numerous nodules.
Antibodies attack thyroglobulin and tsh receptors causing lymphocytic infiltration and follicular atrophy.

Grave’s disease (Thyrotoxicosis)
Hyperthyroidism
thyroid stimulating immunoblobulin binds to TSH receptors
findings are similar to hashimoto’s.

Clinical features and symptoms are exophthalmos (protruding eyes) insomnia, hand tremor, hyperactivity, hair loss, excessive sweating, shaking hands, itching, heat intolerance, weight loss despite increased appetite, diarrhea, frequent defecation, palpitations, muscle weakness, and skin warmth and moistness.

proptosis_and_lid_retraction_from_graves_disease

 

Thyroid Nodules and Cancer
1% of new cancer diagnoses in the US per year.
papillary carcinomas (80%)
follicular carcinomas (10%)
medullary thyroid carcinomas (5-10%)
anaplastic carcinomas (1-2%)
primary thyroid lymphomas and primary thyroid sarcomas (rare)

An estimated 5-10% of solitary thyroid nodules are malignant

ultrasound-evaluation-thyroid

 

                                   Source: 2015 American Thyroid Association Guidelines

 

Hyperparathyroidism and parathyroid masses
Hyperparathyroidism causes elevated parathyroid hormone (PTH) which increases serum calcium and may lead to calicifications and kidney stones
Caused by parathyroid adenoma in 80% of cases.

Henry

sources:
emedicine.com
Radiopaedia.org

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s