Tempkin C16 pg424-443 Thyroid and Parathyroid Scanning

Where can we locate the parathyroid glands

4 glands lie between th eposterior aspect of the thyroid gland and the longus colli muscle; Deep to the cricoid cartilage, midway between the adam's apple and the suprasternal notch

What is the frequency and transducer used for a thyroid and parathyroid gland scan

7.5 - 10 MHz high res, real-time linear

Lingual thyroids account for 90% of ectopic thyroids

90%

What is the patient prep for thyroid and parathyroid scan?

NONE

T/F: For diagnostic puposes the thyroid's right and left lobes and the isthmus are examined separately

TRUE

T/F: The parathyroid glands are symmetric in position

TRUE

T/F: The thyroid gland has bilateral lobes that lie on each side of the trachea and are bordered laterally by the CCA and th IVJ

TRUE

How does the thyroid gland look sonographically?

homogeneous and moderatelt echogenic; similar in appearance to the normal liver and testes parenchyma and hyperechoic compared to adjacent muscualture

Neck muscles appear distinctively ___ compared to the thyroid gland

hypoechoic

what do the minor neurovascular bundle consist of

inferior thyroid artery and recurrent laryngeal nerve

What does the isthmus of the thyroid gland do

it unites the lobes

Where is the thyroid gland located

lower, anterior portion of the neck, anterior to the trachea and inferior to the larynx; lies between the anterior strap muscles and the posterior colli muscle and minor neurovascular bundle

The parathyroid glands are endocrine glands that secretethe hormone ___ which acts as the antagonist for calcitonin and controls he calcium level in the blood stream

parathormone (PTH)

What are the normal variants of the thyroid gland

pyramidal thyroid, dilated follicles, ectopic thyroid

What are the normal variants of the parathyroid gland

ectopic parathyroid glands (15-20%), variant parathyroid gland shapes (elongated 11%; bi-lobed 5%; multi-lobed 1%)

The thyroid gland is and ____ gland that is responsible for secreting the hormones __, __ and __ that assist in regulating the metabolic rate and the metabolism of lipids, proteins, and carbohydrates and in the absorption of calcium from the blood for storage in the bones.

endocrine; thyroxine (T4), triiodothyronine (T3)and calcitonin

How does the parathyroid gland look sonographically?

flat, hypoechoic structure lying between the thyroid gland anteriorly and longus colli muscle posteriorly; occasionally visualized with newer high frequency transducers esp in children

The 2 superior parathyroid glands are situated slightly more ____ than the 2 inferior parathyroid glands

medial

What is a dialted follicle

normal variant of thyroid; intersperesed throughout the thyroid, they appear as 1-3mm cystic areas

What is a pyramidal lobe

normal variant of thyroid; triangualr-shaped, superior extension of the isthmus; variable in size; extends to the left side (often); present in 15-30% of thyroid glands

Explain the anatomy of the parathyroid gland

oval or bean shaped; 5-7 mm long, 1-2 mm thick, and 3-4 mm wide; blood supply and drainage by separate small branches of the inferior and superior thyroid arteries and veins and the middle thyroid veins

what are the anterior strap muscles

sternocleidomastoid, sternothyroid, and sternohyoid muscles

Explain the anatomy of the thyroid gland

superficial, butterfly-shaped gland; highly vascular (paired superior and inferior arteries and veins and middle thyroid veins); weighs approx 25-35 g; normal adult 4-6 cm long, 1.3-1.8 cm anteroposteriorly & 3 cm at its greatest width, isthmus is 2-6 mm; in newborns and children 2-3 cm long, 0.2-1.2 cm anteroposteriorly, & 1.5 cm at its greatest width; tall, thin people have elongated lateral lobes up to 8 cm long; short, obese 5 cm or less; larger in women and becomes enlarged during pregnancy

What is the patient position for a thyroid and parathyroid gland scan

supine with the neck mildly hyperextended and the head turned slightly away from the side of interest