Metabolic Bone Disease – Radiology

Question 1

What are the two main radiographic signs?

Answer 1

Osteopenia Osteosclerosis

Question 2

What is the lucency of the following scans proportional to: a. X rays b. Densitmetry c. CT scans d. MRI scans e. Radionucline bone scans

Answer 2

a. X rays Density b. Densitometry Density and attenuation c. CT scans Density and attenuation d. MRI scans Chemical and water content e. Radionuclide bone scans Bone turnover

Question 3

What is the main difference between osteoporosis and osteomalacia?

Answer 3

Osteoporosis – decreased bone mass Osteomalacia – decreased bone mineralisation

Question 4

Describe the microstructure in osteoporosis.

Answer 4

Normal Though there is an overall decreased quantity of bone

Question 5

What are the features of osteomalacia?

Answer 5

Too little mineral – osteopenic and soft bone bends and deforms Too much osteoid – Looser’s zones If calcium remains low –> secondary hyperparathyroidism

Question 6

What are Looser’s zones? Where are they found?

Answer 6

Narrow lucency, perpendicular to the bone cortex Found in the pubic rami, proximal femur, scapular and lower ribs

Question 7

What is a distinctive feature of osteomalacia that can be seen in an X-ray of the vertebrae?

Answer 7

Codfish vertebrae – biconcave loss of height

Question 8

What radiographic feature is common to both osteomalacia andosteoporosis?

Answer 8

Osteopenia

Question 9

What is the key difference between osteomalacia and rickets?

Answer 9

Rickets occurs before the growth plates have fused As the metaphysis grows most rapidly, it shows the most obvious changes

Question 10

What are the radiographic features of rickets that are linked to the metaphysis?

Answer 10

Indistinct frayed metaphyseal margin Widened growth plate (no calcification taking place) Bowing of weight bearing bones

Question 11

What is Rickety Rosary?

Answer 11

Enlargement of the anterior ribs

Question 12

Describe how PTH, calcium and phosphate change in: a. Primary HPT b. Secondary HPT c. Tertiary HPT

Answer 12

a. Primary HPT PTH – high Calcium – high Phosphate – low b. Secondary HPT PTH – high Calcium – low Phosphate – normal or low c. Tertiary HPT PTH – high Calcium –high Phosphate – low

Question 13

What are the main consequences of secondary HPT to bone?

Answer 13

Resorption and increased density

Question 14

List 4 types of bone resorption.

Answer 14

Subperiosteal Subchondral Intracortical Brown tumours

Question 15

What are the differences between slow and fast bone loss?

Answer 15

Slow – Involutional Osteoporosis  Bone has time to remodel  Bone loss occurs according to mechanical needs Fast – hyperparathyroidism/disuse osteoporosis  Bone loss is too rapid  Loss does not cater to mechanical needs

Question 16

Describe the radiological features of renal osteodystrophy.

Answer 16

 Subperiosteal bone erosions  Brown tumours  Sclerosis – axial skeleton/vertebral end plates (rugby jersey spine)  Soft tissue calcification (arteries/cartilage)