By Dr Riaz MohammadRadiology of Thyroid and

parathyroid

Thyroid and parathyroidNormal Anatomy.Radiological test. Disease

Thyroid and parathyroidNormal Anatomy

Embryology: Thyroid gland is derived from a tubular structure at the base of tongue called

foramen cecum

AnatomyThyroid gland has two elongated lateral

lobes.United in the middle by a median isthmusIt is 4-6 cm in L, 1.3-18cm thick. Isthmus is

6mm thickSome time a pyramidal lobe is present which

extend upward from the isthmus.Thyroid is supplied by superior and inferior

thyroid arteries. It is extremely vascular

Thyroid AnatomyPosterior aspect Anterior and posterior

aspect

Thyroid produce T3, T4, and calcitonin.Parathyroid are two pairs(4 in number)

located on the back of thyroid. The superior pair is located near the middle of thyroid and the inferior pair at the lower pole on both side.

Parathyroid are the size of a grain of rice(3-5mm). It produce parathyroid hormone.

Normal ultrasound anatomy Transverse image Color Doppler image

Longitudinal image of LT lobe

Isthmus

Imaging modalities used for evaluation of thyroid and parathyroid.

UltrasoundRadionuclide studiesCT scanBiopsy Ultrasound/ CT guided

Ultrasound technique

High frequency sound wave are usedPatient is supine with hyperextended neckBoth right ,left lobes and isthmus are examinedColor Doppler is used to see vascularityTransverse and longitudinal images are takenUltrasound shows anatomical detail of thyroid

and adjacent blood vessels and structures.Normal parathyroid can not be seen with U/S,

however parathyroid adenoma and cervical nodes involved in thyroid cancer can be sampled

Radioisotopes studyA radionuclide is injected or given orally.Radioisotope taken up by

thyroid/parathyroidPatient is put under the gamma camera to

see the uptakeSeries of images are taken in different

projectionsRadionuclide studies show function.

Anatomical details are poor.

Gama camera

Normal Normal

CT images of thyroidCT shows clear anatomy of thyroid gland. Test is done without and with contrast

Diseases of thyroidFunctional disorders. 1. Hyperthyroidism 2. HypothyroidismInflammations. 1.Hashimoto 2. Sub acute etc.Nodular disorders. 1. simple goiter 2. Multinodular goiterTumors. 1. Adenoma1) Carcinoma-Follicular, papillary,

Medullary, anaplastic, hurthle cells and secondary

Hyperthyroidism and gravis disease

Hyper functioning thyroid glandGravis disease occur in young women. Thyroid gland is hyper functioning and hypervascular

InflammationsHashimoto thyroiditis is an autoimmune inflammation. The gland may be hyper functioning or hypo functioningIn the these images the gland is diffusely enlarge and inhomogeneousIn the image below there is abscess formation in the gland

TumorsAdenoma is benign tumor. It is hypo echoic well-definedCarcinoma. Hypo echoic, irregular and infiltrate in to the surrounding tissues.On radionuclide imaging carcinoma is usually cold nodule(no uptake)

Ultrasound guided biopsy

Parathyroid Adenoma: is a benign lesion . It is well defined and hypo echoic. It is usually associated with hyperparathyroidism

Parathyroid carcinoma. Aggressive lesion irregular hypo echoic. Diagnosis is confirm by biopsy

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