MBD - Radiology Flashcards
Radiographic signs of MBD?
These are signs NOT diseases:
Osteopenia
• ‘poverty of bone’ - reduced mineral content of bone (NOT as bad as osteoporosis)
• seen in BOTH osteoporosis & osteomalacia
Osteosclerosis
• abnormal hardening of bone
AND
• increased bone density
Radiographic tools that can be used to see MBD?
X-rays = alpha-density
Bone Densitometry (DEXA) = alpha density/attenuation
CT Scans = alpha density/attenuation
MRI Scans = alpha chemical/water content
Radiological features of osteoporosis?
Decreased quantity of bone (bone mass)
BUT
NORMAL microstructure
- normal biochemistry
- fragility fractures
- deformity
- pain
What causes osteomalacia (& rickets)?
Due to VitD deficiency
- Biochemistry = low VitD, low/normal Ca2+, high PTH
- Inadequate/delayed mineralisation of bone
Relationship between radiology & osteomalacia?
Radiology is proportional to age/growth plate closure
• Too little mineral = osteopenia & soft bones bend and deform
• Too MUCH osteoid = Looser’s zones (and fractures)
If Ca2+ stays low, 2o hyperparathyroidism can develop
What are Looser’s zones?
Pseudo-fractures
• show narrow lucency and are perpendicular to bone cortex
• occur in
- pubic rami, proximal femur, scapula & lower ribs
What is meant by codfish vertebrae?
Biconcave deformity of vertebrae (loss of height)
• osteopenia and a ‘pencilled-in margin’
Seen in osteoporosis & osteomalacia
Osteomalacia vs. Osteoporsis
LUDLEY!
Less mineral vs. less bone
Osteopenia vs. Osteopenia
Bend & bow before breaking vs. Breaks
Feature ‘codfish vertebrae) vs. Anterior wedging
- uniform spine deformity
Osteomalacia vs. Rickets
LUDLEY!
Changes in mature bone vs. Changes before growth plate closure
Osteopenia vs. Changes related to growth plates dominates
Looser’s zones vs. Changes of osteomalacia co-exist
Feature codfish vertebrae
Bending deformities
Main radiological sign of rickets?
Metaphysis (area between epiphysis & diaphysis)
• has the most rapid growth
SO
• shows the most obvious changes
FRAYED metaphyseal margin
• SO metaphysis in indistinct
Other radiological signs of rickets?
Widened growth plate (no calcification)
Splaying/cupping metaphyseal due to weight bearing
‘Rickets rosary’ = enlargement of anterior ends of ribs
Bowing of weight-bearing legs
Osteopenia
Types of hyperparathyroidism?
1o - PTH adenoma
• high PTH
• high Ca2+
• low phosphate
2o - VitD deficiency (renal failure, impaired liver, rickets/osteomalacia etc.)
• high PTH
• low/normal Ca2+
• low/normal phosphate
3o - autonomous production of PTH
• high PTH
• high Ca2+
• low phosphate
Radiological sign of hyperparathyroidism?
1o (high Ca2+)
• bone resorption
2o (low/normal Ca2+)
• renal osteodystrophy
• resorption AND increase density (due to PTH features)
Different types of bone resorption in HPT?
Sub-periosteal
• affects radial aspect of middle & ring finger phalanges
Sub-chondral
Intra-cortical
Brown tumours
Bone loss can be both slow and fast - explain how
Slow - involutional osteoporosis
• bone has time to remodel (bone loss occurs due to mechanical needs)
Fast - HPT, disuse osteoporosis
• bone loss is TOO RAPID
• loss does NOT cater to mechanical needs
