hello everyone this is dr sam and today we will study ultrasound appearances of thyroid the thyroid gland is located in the neck region it is divided into two lobes the right lobe and the left lobe and these two lobes are connected together through the isthmus and the thyroid has a hyperechoic appearance and over here is the trachea it is having shadows due to presence of air and anterior to the thyroid are the strap muscles these are the strap muscles and these anechoic regions are the common carotid arteries in cross section we start off with thyromegaly that is the enlargement of the thyroid gland when the AP diameter is more than two centimeters and the isthmus is more than four millimeters this is suggestive of thyromegaly and in the longitudinal view we can measure the length of the thyroid gland the normal value is around four centimeters and if it is more than four centimeters it can be a signal of thyromegaly the average weight of the thyroid gland is around 25 grams and another term that is commonly used for thyromegaly is goiter that is also the abnormal enlargement of thyroid gland which can be due to many reasons such as nodular hyperplasia or cancer or thyroiditis we will see all these cases now nodular hyperplasia can have many appearances this image shows internal cystic components and multiple septations here is another case of nodular hyperplasia having internal cystic components and spongy appearance they can also have thick walls or masses attached to the wall of the nodule these are called mural nodules here is an image showing hypervascularity on color doppler another feature of nodular hyperplasia a colloid nodule will have a cystic lesion that is filled with echogenic colloid crystals here you can see only one crystal in this image it is hyperechoic here is another image of colloid nodule having multiple colloid crystals that are hyperechoic and they can also have comet tail artifacts in this image you can see the comet tail artifacts more clearly usually these type of appearances are benign such cystic appearances or appearances with internal septations are usually benign a follicular adenoma is a hypoechoic mass here it is more hypoechoic as compared to the thyroid tissue and the halo is even more hypoechoic so like it is appearing more darker this type of appearance can be malignant here is a longitudinal view showing follicular adenoma a hypoechoic mass with a hypoechoic halo follicular carcinoma is the malignant form of this case this will have a hypoechoic halo a hyperechoic nodule and it can have some cystic areas now these type of appearances overlap with other appearances so we cannot confirm it on ultrasound a transverse view of follicular carcinoma also containing calcifications here you can see a thin hypoechoic halo and cystic areas papillary carcinoma is a more common form of malignancy in the thyroid it usually appears as hypoechoic lesions inside the thyroid and they may also have large calcifications but mostly they are hypoechoic lesions in this image you can see a hypoechoic structure with calcified walls with some posterior acoustic shadowing this can also be an appearance of papillary cancer here is another image of papillary carcinoma a hypoechoic lesion with calcified hyperechoic walls papillary cancer can also have a cystic form in which you will see cystic components and also has septations and solid components here is a transverse view showing cystic papillary cancer cystic mass with solid components anaplastic cancers are larger in size so you can differentiate them from other cancers due to their larger size they appear as hypoechoic and they can also deviate the common carotid artery and the internal jugular vein a lymphoma can involve the entire thyroid gland it can lead to enlargement of the thyroid and also giving it a heterogeneous appearance in this case you can see an enlarged thyroid gland with heterogeneous echo texture suggestive of a lymphoma metastasis to the thyroid can have variable appearances based on the type of primary cancer usually they are solid heterogeneous masses inside the thyroid now we move on to parenchymal diseases of the thyroid starting off with hashimoto's thyroiditis it can cause hypothyroidism in the patient there is enlargement of the thyroid and hypoechoic nodules that will be scattered throughout the parenchyma of the thyroid in this image you can also see hypoechoic nodules scattered throughout the thyroid proper diagnosis is made clinically and serologically along with ultrasound appearances because these appearances overlap with other diseases as well so we need proper clinical correlation on color doppler hashimoto's thyroiditis gives hypervascularity this type of appearance is called thyroid inferno graves disease is a common cause for hyperthyroidism in this the thyroid can appear enlarged and it can also appear homogeneous without any nodules in this image you can see heterogeneous areas in the thyroid but if we compare it to hashimoto's thyroiditis it is less heterogeneous so the echo texture is somewhat smoother in graves disease and also remember hashimoto's thyroiditis is hypothyroidism and graves disease is hyperthyroidism disease on doppler can also give hypervascularity that is thyroid inferno but it is more common in hashimoto's thyroiditis subacute thyroiditis which is also known as De Quervain's thyroiditis involves both lobes of the thyroid bilaterally we will see hyperechoic regions in both thyroid lobes here is another case of subacute thyroiditis showing hypoechoic areas bilaterally in the right and left lobes thank you so much for watching please subscribe and stay tuned for more imaging videos