Imaging Relevant to Endocrine Disease

Question 1

Pituitary gland location?

Answer 1

Found in the sella turcica and is closely related to the sphenoid sinus

It is inferior to the optic chiasm and hypothalamus and the carotid arteries are located laterally

Pituitary gland is connected to the brain via the pituitary stalk

Question 2

Label the MRI of the pituitary gland and the structures surrounding it?

Answer 2

Question 3

How does the posterior pituitary appear on MRI?

Answer 3

As a bright spot; if this is not present, it indicates posterior pituitary pathology

Question 4

Features of bleeding (e.g: pituitary apoplexy)?

Answer 4

Sudden onset headache + bright, uniform area on MRI scan

Question 5

Features of lymphocytic hypophysitis?

Answer 5

Hypopituitarism during pregnancy

+

Thickened pituitary stalk, loss of bright spot and enhancing pituitary gland

Question 6

Features of pituitary pareidolia?

Answer 6

Imagined perception of a pattern where it does not actually exist, in this case a “big bird” for a pituitary macroadenoma

Question 7

Location of the thyroid gland?

Answer 7

Deep to the strap muscles of the neck

Anterior to trachea and oesophagus

Medial to common carotid arteries and to internal jugular veins

Inferior relations include sternum, great vessels and the aortic arch

Question 8

Label the stuctures surrounding the thyroid gland?

Answer 8

Question 9

Label the inferior relations of the thyroid gland?

Answer 9

Question 10

Imaging modalities used to visualise the thyroid gland?

Answer 10

CT and USS

Radio-isotope studies

Question 11

Structures that are at risk during thyroid surgery?

Answer 11

Recurrent laryngeal nerves

Parathyroid glands

Question 12

Causes of a midline neck mass in adults?

Answer 12

Enlarged thyroid gland

Enlarged lymph nodes are common (usually obvious)

Others include thyroglossal cysts, cystic hygroma (these are rare outwith childhood)

Question 13

Aim of imaging the thyroid gland?

Answer 13

Differentiate between diffuse causes of goitre (e.g: Grave’s, thyroiditis) and focal causes (e.g: dominant nodule)

Question 14

Advantages of thyroid USS?

Answer 14

Safe (no ionising radiation) and it is well-tolerated

Can be combined with FNA

Question 15

When is thyroid USS used?

Answer 15

In euthyroid patients with goitre/palpable nodules

In hyperthyroid patients with focal masses/radio-isotope uptake

Question 16

What does thyroid scintigraphy involve?

Answer 16

Radio-isotope injected IV and patient is imaged after 20 minutes; image is assessed for pattern and quality of tracer uptake

Question 17

Features assoc. with Grave’s disease on thyroid scintigraphy?

Answer 17

Homogenously increased tracer uptake (>3% total tracer in gland)

Question 18

Features assoc. with thyroiditis on thyroid scintigraphy?

Answer 18

Homogenously reduced tracer uptake

Question 19

Features assoc. with multi-nodular goitre with dominant nodule on thyroid scintigraphy?

Answer 19

Focal uptake at right upper pole

Question 20

Features of well-differentiated thyroid cancer on imaging?

Answer 20

Heterogeneous microcalcification

Question 21

Location of adrenal glands?

Answer 21

Right adrenal - posterior to IVC

Left adrenal - lateral to aorta and left diaphragmatic crus

Question 22

Label the structures surrounding the adrenal glands?

Answer 22

Question 23

Different bone types on X-ray?

Answer 23

Cortical, trabecular

Medulla can also be seen

Question 24

Formation of the medulla and cortex of bone?

Answer 24

Osteoblasts replace the cartilage with osteoid, which mineralises to form bony trabeculae

Trabeculae are loosely packed in the medulla (cancellous bone) but condense towards the cortex (compact bone)

Question 25

What regions of cartilaginous bone ossify in which order?

Answer 25

Cartilaginous bones first ossify within the diaphysis; secondarily, they ossify within the epiphysis

Question 26

How is bone girth increased?

Answer 26

By cells derived from the periosteum, which lay down circumferential new bone on the periphery of existing cortex

Question 27

How is bone length increased?

Answer 27

Increased by cartilage proliferation at growth plates between the metaphysis and epiphysis; cartilage then ossifies

Question 28

Terms used to describe bone abnormality?

Answer 28

Diffuse (inv. many bones) Focal (single bone/single area, e.g: at the joint specifically)

Question 29

Types of focal bone abnormalities?

Answer 29

Traumatic Neoplastic: * Lytic (bone destruction) * Sclerotic (bone formation) Inflammatory Degenerative

Question 30

Types of diffuse bone abnormalities?

Answer 30

Bones too brittle: • Osteoporosis Bones too soft, i.e: appear deformed on X-ray: * Rickets and osteomalacia * Paget's disease

Question 31

Features of osteoporosis on imaging?

Answer 31

Reduction in trabecular density; typical fracture sites are: * Proximal femur * Sacrum and pubic rami * Thoracolumbar vertebral bodies * Distal radius Fractures in image

Question 32

Features of Rickets on imaging?

Answer 32

Widened growth plates Irregular, flared metaphyses

Question 33

Features of osteomalacia on imaging?

Answer 33

Poor cortico-medullary differentiation

Question 34

Features of Paget's disease on imaging?

Answer 34

Single/multiple bones affected Initial lytic phase causes: • Well-defined lucency Later sclerotic phase causes: **• Enlarged bone** **• Increased density** **• COARSE trabecular pattern**

Question 35

Features of lytic bone destruction on imaging?

Answer 35

Medullary lucency and loss of trabeculae Loss of inner cortex (endosteum) Complete loss of cortex and loss of both cortices

Question 36

Features of sclerotic bone lesion on imaging?

Answer 36

Subtle medullary density and loss of trabeculae Spreading zone of density, which includes cortex Featureless white bone Expansion beyond normal bone limits, with cortical destruction

Question 37

What is a bone scan?

Answer 37

Map of osteoblastic activity