Transcript Thyroid Diseases

Thyroid disease
By
Dr Fahad
Anatomy of the Thyroid Gland
Location: ant neck at C5-T1, overlays 2nd
– 4th tracheal rings
 Average width: 12-15 mm (each lobe)
 Average height: 50-60 mm long


Method of Imaging Investigation
Ultrasound
N/M
MRI/ CT
TC THYROID SCAN
NORMAL UPTAKE
THYROID ULTRASOUND
NORMAL
0.99 X 1.07 CM
1.25 X 1.14 CM
3.75 X 1.16 CM
3.18 X 1.03 CM
THYROID COMPUTED TOMOGRAPHY
NORMAL
0.99 X 1.07 CM
3.75 X 1.16 CM
Thyroid Diseases
 Thyrotoxicosis
 Hypothyroidism
 Thyroid
nodules
Thyrotoxicosis VS
Hyperthyroidism
Thyrotoxicosis: a group of symptoms and
signs due to elevated thyroid hormones in
the body of any cause.
 Hyperthyroidism: a group of symptoms
and signs due to increased production of
thyroid hormones by hyper functioning
thyroid gland.

Causes of Thyrotoxicosis
Hyperthyroidism
1- Diffuse toxic goiter (Graves’ disease)
2- Single toxic nodule
3- Toxic multi-nodular goiter
 Early phase sub-acute thyroiditis
 Exogenous thyroid hormone intake

Thyroid scan and uptake
Radioactive Iodine (RAI) is used for
thyroid scan and uptake.
 RAI is given orally.
 Image and uptake are obtained after 24
hours
 Follicular cell traps Iodine and organifys it
to be incorporated with thyroid
hormone.

Imaging findings
Symmetric or asymmetric lobes.
 Homogeneous or inhomogeneous uptake
 Nodules; cold or hot

24-hour RAI uptake
Measure photons in the given RAI by a
special probe (uptake probe) just before
taking RAI.
 After 24 hours, measure photons in the
neck (thyroid gland).
 Calculate % of photons concentrated in
thyroid gland.
 Normal range of 24 RAI uptake is 10%30%

Increase uptake
Hyperthyroidism
 Iodine starvation
 Thyroiditis
 Hypoalbominemia
 lithium

decrease uptake
Hypothyroidism
 Thyroid hormon therapy, PTU ,Lugol’s
solution
 Medication(contrast , multivitamins )
 Thyroiditis

Diffuse Toxic goiter (Graves’ Disease)
Diffuse enlargement of thyroid gland.
 Homogeneous uptake.
 No significant focal abnormalities
(nodules).
 24-hour RAI uptake is elevated, usually >
35% (mean of 40%).

Graves’ Disease
Single Toxic Nodule
Single hot nodule (independent of TSH or
autonomous).
 Rest of thyroid gland is poorly visualized
due to low TSH level (TSH dependant).
 24-hour RAI uptake is slightly elevated,
usually around 20%.

Multi-nodular Goiter
• Cut surface of one
lobe of thyroid gland
showing ill defined
nodules.
• Focus of cystic
degeneration seen
(blue arrow).
• Some hemorrhage
(red arrow) and some
scarring.
Multi-nodular Goiter
Multi-nodular Goiter
6.75 X 3.16 CM
7.34 X 4.21 CM
THYROID COMPUTED TOMOGRAPHY
NORMAL
0.99 X 1.07 CM
3.75 X 1.16 CM
NODULES
Toxic Nodule
Hot Nodule
US images of thyroid nodule of varying parenchymal composition (solid to cystic).
papillary carcinoma
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US features of thyroid nodules
there is some overlap between the US
appearance of benign nodules and that of
malignant nodules
 certain US features are helpful in differentiating
between the two. These features include

1.
2.
3.
4.
5.

micro-calcifications
local invasion
lymph node metastases
a nodule that is taller than it is wide
markedly reduced echogenicity.
Other features, such as the absence of a halo, illdefined irregular margins, solid composition, and
vascularity, are less specific but may be useful.
US Features Associated with
Thyroid Cancer
Recommendations for Thyroid Nodules
1 cm or Larger in Maximum Diameter
Society of Radiologists in Ultrasound
Consensus Conference Statement
Punctate echogenicities in thyroid nodules.
papillary carcinoma
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US images of thyroid nodules of varying parenchymal composition (solid to cystic).
papillary carcinoma
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US images of thyroid nodules of varying parenchymal composition (solid to cystic).
proved to be benign at cytologic examination
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US images of thyroid nodules of varying parenchymal composition (solid to cystic).
proved to be benign at cytologic examination
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US images of thyroid nodules of varying parenchymal composition (solid to cystic).
proved to be benign at cytologic examination
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
Role of color Doppler US. (a) Transverse gray-scale image of predominantly solid thyroid
nodule (calipers).
papillary carcinoma
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
Role of color Doppler US. (a) Transverse gray-scale image of predominantly solid thyroid
nodule (calipers).
papillary carcinoma
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
Transverse US images of mostly cystic thyroid nodule with a mural component containing
flow.
The lesion was benign at cytologic examination
Frates M C et al. Radiology 2005;237:794-800
©2005 by Radiological Society of North America
US-guided FNA Technique

The needle may be introduced parallel or
perpendicular to the transducer, and the
needle tip should be carefully monitored
during the procedure.
US-guided FNA Technique
Parallel positioning of the fine-gauge needle for thyroid nodule biopsy.
Kim M J et al. Radiographics 2008;28:1869-1886
Thank you