 Okay, so here we are, thyroid imaging approach to common scenarios. And in this section, we are going to cover the anatomy of the thyroid gland. And after that, in the next section cover some essential knowledge about nodules and cancer, and then subsequently approach to common thyroid scenarios. So starting off with the anatomy, the thyroid gland is pretty basic. It's not as complicated as other sections in the head and neck with different subsites and sections and borders. The thyroid gland is a biloved organ centered in the lower neck. It extends up to the level of the thyroid cartilage here in the arrow. So you know that if it's extending above beyond that, possibly you've got a goiter. There's an isthmus connecting the two loaves and usually they're at the level of the trachea, as you can see here around the second and third rings of the trachea. Other important anatomy, well, it's the anatomy surrounding the thyroid that's essential for our staging of thyroid cancer. And thoroughly, we have the strap muscles, not important that you name them at all, but to know that they're overlying the thyroid and overlying that is the subcutaneous fat and then the skin. Then posteriorly, we've got a few important structures, particularly for thyroid staging, as you'll see later on. There's the trachea that the thyroid isthmus wraps around in the lobes hug, the esophagus, which is often after the left. And between the esophagus and the trachea, we've got the recurrent laryngeal nerve after it ascends down and loops around the aortic arch and the right subclavian artery. It ascends in this tracheosophageal groove, which means that there is a risk of vocal cord palsy after thyroid surgery due to injury to the recurrent laryngeal nerve. And then laterally, what have we got? We've got the vessels and we've got the vagus nerve and some of the synthetics. So here we've got the artery in the vein, artery in the vein lateral to the thyroid lobe. So with all these structures around the thyroid, you know that you're going to be looking at these structures for thyroid cancer staging. And then basic blood and nerve supply, probably not as essential to a radiologist, as you can't see most of these structures or you wouldn't normally be looking for them. But there is a rich blood supply to the thyroid from the superior and inferior thyroid artery. So here's the inferior thyroid artery coming off the cyrocephal trunk. It's drained not by two veins, but three veins superior, middle and inferior. And then there's this very rich lymphatic drainage system that we can't see on imaging. And it's one of the reasons why infections rarely occur in the thyroid gland. The automatic supply is by the vagus nerve, but that's not half as important as the recurrent laryngeal nerve to thyroid surgery, which leads me to let you know about this really important pitfall. This is the non-recurrent laryngeal nerve. As I mentioned before, normally on the right side, the recurrent laryngeal nerve loops around the subclavian artery and then ascends in the tracheosophial dual group. So in this location here, now in less than 1% of cases, there is a non-recurrent laryngeal nerve, which means the nerve that supplies the vocal cord comes straight off the vagus pretty much horizontally. And that poses this nerve to injury when there is this non-recurrent laryngeal nerve. How can we help as a radiologist since we can't see the nerve? Well, easy. If we see this aberrant subclavian artery, then we know that there is a 87% chance that this patient has a non-recurrent laryngeal nerve. So if you see this anomaly, make sure you mention in the impression if that patient is about to have thyroid surgery. Okay. Moving on to embryology, which is relevance for the occasional congenital abnormalities we see in related to the thyroid gland. The thyroid gland is derived from endoderm and it arises from the back of the tongue from the fremen's cecum, which is a junction between the anterior two thirds and the posterior two thirds of the tongue. From this location, it descends in the neck. And in green, I've outlined the course. So it courses down between the base of the tongue and the oral tongue. It actually loops behind the hyoid bone here, and then it descends down. And the track that it follows is the thyroglossal duct, and that involutes in the innate or life in utero. So here's an example of an intensely enhancing mass in the posterior two thirds of the tongue. What is that? That is a lingual thyroid and there is no thyroid. So this thyroid did not descend at all. And here are some examples of the thyroglossal cyst. So it's the tract that doesn't involute. In this first patient, that thyroglossal duct cyst is in the posterior third of the tongue. So that part was a remnant. In all of these cases, there's usually a thyroid in a typical location. In this next case, we see that this is the most common location. It's usually around the level of the hyoid and anterior in the neck, usually within one centimeter of midline. And then this final case is a really great example of how it loops behind the hyoid bone. So in this case, the cyst is actually posterior to the hyoid. And the surgery for this is a cyst trunk procedure. And in that procedure, they usually take a section of the hyoid for this very reason. So we don't leave any remnant thyroglossal duct behind. So that is the anatomy and the embryology. And next, we're going to move to our three scenarios, which are the incidental thyroid nodule, thyroid cancer, and gloidal. So I hope you stay tuned and stay with me. Thanks.