Fig. 1

Typical perfusion characteristics in an intrathyroidal parathyroid adenoma. 70 keV VMIs at (a, b) 25 s and (c, d) 55 s are shown of a surgically and pathologically proven intrathyroidal parathyroid adenoma (large arrow). The feeding vessel supplying the adenoma is also seen (small arrow) and is helpful for diagnosis, sometimes referred to as the polar artery. There is the typical rapid and robust enhancement on arterial phase images (a, b). On the more delayed images, there is contrast washout from the adenoma but increased attenuation of the thyroid gland and the adenoma cannot be clearly distinguished from the thyroid gland (c, d)