Thyroid ultrasound

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2. Objectives
To review thyroid anatomy
To describe U/S technique for
thyroid
To discus the U/S findings in
thyroid abnormality.
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3. Normal thyroid anatomy
 The normal thyroid has two lobes and the isthmus,
bridging the lobes, ahead the trachea. Size and shape are
variable, according to age It has a medium to high level
echogenicity.
 The relationships with the surrounding structures are as
follows:
Ahead, the strap muscles and sterno-cleido-mastoid
muscle.
Behind, the trachea and longus colli muscles.
on both sides, the common carotid artery and jugular vein
The esophagus, behind the left thyroid lobe
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5. Thyroid Anatomy
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6. Congenital anomalies
Congenital agenesis or hypoplasia of
the thyroid gland may include the
whole gland or just one of the lobes.
Ectopic thyroid: is a migration of the
thyroid gland to the lower neck from its
origin at the base of the tongue.
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7. Thyroid U/S Indications
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Neck swelling
Abnormal thyroid lab. Test
Follow-up
Screening

8. Recommended U/S protocol
 The patient is examined in supine position, the
neck hyperextended, with a high frequency linear
transducer (7-15 MHz).
 Transverse scans of the whole gland at the upper,
mid, lower poles and the isthmus.
 Side-by-side images of each lobe is scanned to
compare echogenicity and size of both lobes.
 Each lobe length, width and AP diameters are
measured.
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9. Recommended U/S protocol
 Longitudinal scans through each lobe on
sternocleidomastoid muscle, on medial mid and
lateral planes. The length of the lobes is measured.
 Identify focal lesions, measure the main lesion and
identify the dominant one (according to size).
 Document the presence of dilated lymph nodes or
thrombosed jugular vein.
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10. Normal thyroid size in adults
Length = 4-6 cm
Anteroposterior : 2-3 cm
Width = 1.5-2 cm
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11. Technique
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13. Transverse view
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14. Thyroid Abnormality
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15. Diffuse disease
 Multinodular goiter (MNG) (U/S features)
Iso-or hyper- echoic nodules with cystic degeneration
Well-defined halo surrounding nodules-due to
compressed adjacent tissue.
Colloid component of cystic elements-"ring down"
sign.
Heterogenous background echotexture of the thyroid
Calcified-nodules.
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17. Thyroiditis
Acute phase
Focal nodular thyroiditis-
small hypo echoic nodules
with ill defined margins-
are seem. representing
lymphocytic infiltration.
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19. Thyroiditis
Chronic phase:
 Hashimoto's thyroiditis is the most common of
the chronic thyroiditis, and the most common cause
of hypothyroidism. It is an autoimmune condition.
Features:
1-Enlarged, slightly lobular outline, the thyroid is
diffusely hypoechoic with fine echogenic septae.
2.Small atrophic gland with heterogeneous
echogenicity.
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Hashimoto's
thyroiditis

21. Graves disease
 The typical biochemical thyrotoxic profile is
matched by a diffuse enlargement of the
thyroid gland with rounding of the normal
angular outline.
 The gland is diffusely hypoechoic and color
flow imaging reveals marked hyper
vascularity.
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24. Thyroid Nodules – Characterization
Characteristics of a Cyst
• Echo free center
• Smooth back wall
• Acoustic enhancement
Cyst
Solid
Complex
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25. Characteristics of a Solid Nodule
• Many echo reflections
• Back wall unclear
• No acoustic enhancement
Characteristics of a Complex Nodule
• Cyst + Solid Features Combined
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26. Characteristics of a Cyst
•
Echo free center
•
Smooth back wall
•
Acoustic enhancement
Longitudinal Right
Lobe
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27. Characteristics of a Solid Nodule
• Many echo reflections
• Back wall indistinct
• No acoustic enhancement
Longitudinal Right Lobe
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28. Characteristics of a Complex Nodule
Cyst + Solid Features Combined
Longitudinal Right Lobe 28

29. Hypoechoic
Isoechoic
Hyperechoic
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Solid nodules

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Hyper vascular
nodule

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