Imaging in Endocrinology Flashcards
(37 cards)
What can be used to image the pituitary gland?
MRI = midline structure, anterior and posterior parts
Where is the pituitary gland found?
In the sella turcica, connected to brain via pituitary sinus and is closely related to the sphenoid sinus
What are some anatomical relationships of the pituitary gland?
Inferior to optic chiasm, carotid arteries laterally, inferior to hypothalamus
Where may pathology occur that causes vision loss?
Eye, optic nerve, chiasm, optic tract, brain
Where does peripheral vision information strike?
Medial retina and crosses optic chiasm
What do lesions of the optic chiasm cause?
Bilateral peripheral vision loss
What can be used to image the thyroid gland?
Well visualised on CT and US, also imaged using Nuc Med
What is the anatomy of the thyroid gland?
Right and left lobes joined by isthmus, located deep to strap muscles of the neck
What are the anatomical relationships of the thyroid gland?
Anterior to trachea and oesophagus, medial to common carotid arteries and internal jugular vein
Inferiorly = sternum, great vessels, aortic arch
What structures can be damaged in surgery of the thyroid gland?
Recurrent laryngeal nerves and parathyroid glands
What are the differential diagnoses for midline neck masses?
Enlarged thyroid, enlarged lymph nodes
Thyroglossal cysts and cystic hygromas are rare outside childhood
What is the aim of imaging midline neck masses?
To differentiate between diffuse and focal causes = achieved with combination of radioisotope studies and US
What are the benefits of thyroid ultrasounds?
Safe, no ionising radiation, well-tolerated, can be combined with fine needle aspiration
What patients get thyroid ultrasounds?
Euthyroid patients with goitre or palpable nodules
Hyperthyroid patients with focal masses or radioisotope uptake
What are some features of thyroid scintigraphy?
I-123 or Tc 99m, Tc 99m used locally (injected IV, image after 20mins), images assessed for pattern and quantity of tracer uptake
What result of a thyroid scintigraphy indicates Grave’s disease?
Homogenously increased tracer uptake, >3% total tracer in gland
How does thyroiditis present on a thyroid scintigraphy?
Homogenously reduced tracer uptake
What does a multinodular goitre with a dominant nodule cause in a thyroid scintigraphy?
Focal uptake of the right upper pole
What are some features of the adrenal glands?
Two lines = medial and lateral
Right adrenal lies posterior to IVC
Left adrenal lies lateral to aorta and left of diaphragmatic crus
What is a phaeochromocytoma?
Uncommon tumour of adrenal gland, said to follow 10% rule = 10% extra-adrenal, 10% bilateral, 10% found in children, 10% familial, 10% not linked to hypertension
What kind of ossification do long bones undergo?
Endochondral ossification = starts as cartilage, osteoblasts replace cartilage with osteoid, which mineralises to form bony trabeculae
How are trabeculae arranged in long bones?
Loosely packed in the medulla but condense towards the cortex
Where do cartilaginous bones ossify?
Firstly within the diaphysis then secondly within the epiphysis (intramembranous ossification)
How is bone girth increased?
Cells derived from the periosteum lay down circumferential new bone on the periphery of the existing cortex
