Thyroid & Neck Sonography

Thyroid Embryology

First endocrine gland to develop

Thyroid Anatomical Variants

Thyroglossal duct cyst

Congenital Hypothyroidism

Pyramidal Lobe

Absent Isthmus

Absent Lobe

Ectopic Thyroid

Thyroid Physiology

Maintains metabolism

Thyroid Hormones

T3

T4

Calcitonin

Normal Thyroid Sonographic Appearance

Homogeneous

Medium to High level gray

Surrounding muscles usually more hypoechoic

*Length: 4-6 cm

*AP of Isthmus: 0.4-0.6 cm

Hyperthyroidism/Thyrotoxicosis

High thyroid hormones

Grave's Disease

Enlarged thyroid (goiter)

Bulging eyes

Thick, red skin on skins/tops of feet

Hypothyroidism

Low thyroid hormones

Hashimoto's Disease/Thyroiditis

Fatigue

Weight gain

Slowed heart rate

Sensitive to cold

Puffiness of face

Dry skin

Thyroiditis

inflammation of thyroid gland

Post-Partum Thyroiditis

Most common thyroid dysfunction after delivery, abortion or miscarriage

TI-RADS Categories

Composition (solid/cystic)

Echogenicity

Shape (is it taller than wide)

Margin (smooth/ill-defined)

Echogenic Foci

Thyroid Nodule

Any thyroid mass

Benign or Malignant

Solid, Cystic, or Complex

Palpable or Not Palpable

Thyroid Cysts

Simple, complex, or hemorrhagic

*Posterior Enhancement

Thyroid Adenoma

Benign mass that results in hyperthyroidism

Goiter

Enlarged thyroid

Can be endemic or sporadic

Papillary Thyroid Carcinoma

Most common thyroid malignancy

Least aggressive type

Follicular Thyroid Carcinoma

2nd most common type of thyroid carcinoma

Slow-growing

Metastases to bone, lung, liver

Medullary Thyroid Carcinoma

Neuroendocrine tumor

Can be sporadic or familial

Anaplastic Thyroid Carcinoma

Rare

Fast-growing

Hurthle Cell Thyroid Carcinoma

Similar appearance to benign adenoma

Parathyroid Embryology

3rd pharyngeal pouch produces 2 inferior parathyroid glands

4th pharyngeal pouch produces 2 superior parathyroid glands

Parathyroid Anatomy

Composed of adipose tissue, chief cells, and oxyphil cells

Connected to inferior thyroid arteries & thyroid vein plexus

Parathyroid Physiology

Regulation of calcium and phosphorus levels

Parathyroid Anatomical Variants

Less than 4 parathyroid glands

Ectopic glands

Accessory/supernumerary gland

Normal Parathyroid Gland Sonographic Appearance

Usually don't see normal - Isoechoic to thyroid

Oval/Almond shaped

Primary Hyperparathyroidism

Extremely elevated levels of PTH and calcium levels

Caused by presence of an adenoma

Parathyroid Adenoma

Solitary, benign mass

Primary Parathyroid Hyperplasia

Enlargement of all 4 parathyroid glands

Associated with Multiple Endocrine Neoplasia (MEN) syndromes

Parathyroid Carcinoma

Associated with primary hyperparathyroidism; highly elevated calcium levels

Thyroglossal Duct Cyst

Remnant of thyroglossal duct

More common in children

Branchial Cleft Cyst

Remnant of embryologic development

Cystic Hygroma

Congenital lymphatic malformation

Webbed neck

Associated with chromosomal anomalies

Characteristics of Normal Cervical Lymph Nodes

Maintains morphology

Fatty hilum intact

Hyperemic

Mobile

Will decrease in size once cause of inflammation is resolved

Characteristics of Malignant Cervical Lymph Nodes

Changes in morphology

Fatty hilum lost

Hyperemic

Hard, Fixed

Will not decrease in size

Cervical Lymphadenopathy

Malignant cervical lymph nodes