Thyroid Ultrasound > Technique


Sonography Technique

To visualize the thyroid gland optimally, the patient is placed in the supine position with a pillow underneath the shoulders to extend the neck slightly, allowing the head to rest on the examination table. The normal thyroid gland is uniformly echogenic relative to the overlying strap muscles of the neck.

 

A thyroid nodule is defined as a region of parenchyma sonographically distinct from the remainder of the thyroid and located within the confines of the echogenic thyroid capsule. When a nodule is detected, its size should be measured in three dimensions and the location within the thyroid gland (upper pole, mid-gland, lower pole) should be noted by the sonographer. 

Several sonographic features are helpful for differential diagnosis, including nodule echogenicity, morphology, cystic change, presence of echogenic foci with comet-tail artifact representing colloid, presence and type of calcifications, and flow pattern (peripheral or central). 

*A high-frequency (1015 MHz) linear transducer is used. The highest frequency is used while still allowing adequate sonographic penetration.

 



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