Bone & Spine Flashcards
Normal red marrow MRI signal characteristics ( contains small amounts of fat)
T1 - slightly hyper - iso to muscle / disc
STIR - hyper to FAT ( compare with T2)
In/out MRI- signal decrease
Abnormal marrow may not be darker when early or haemorrhage.
Compare T2 with STIR to assess suppression - abnormal does not suppress
Normal marrow red –> fat conversion order sequence
appendicular> axial
distal > proximal
Epiphyses and apophyses > diaphyses> distal metaphyses> proximal metaphyses
Reversed order in reconversion.
Epiphyses usually not involved in reconversion.
Red marrow present in subchondral epiphyses
Marrow reconversion
Causes
7
Obese females Smokers Haemolytic anaemia High altitude Athletes Marrow stimulating meds eg GCSF ( can mimic reconv or myeloprolif) Replacement/des of normal marrow
Marrow depletion causes
3
T1/T2 - similar to fat
Aplastic anaemia
Radiation
Chemotherapy
Marrow oedema due to hyperaemia or ischaemia
Focal
Trauma Osteonecrosis Transient oedema Regional migratory oedema inflammatory arthritis
Miscellaneous marrow disorders
5
Gaucher Haemosiderin Serous atrophy Paget Osteopetrosis
Features of benign vertebral #
usually anterior column
posterior concave margin is preserved
retropulsion can occur
Visible fracture line surrounded by oedema
Features of pathologic vertebral #
Expanded vertebral body with convex margins involved pedicles soft tissue mass abnormal signal throughout body no fracture line ( late to #) destroyed trabeculae
Multiple myeloma
Marrow patterns 4
Normal
Focal ( plasmacytoma)
Diffuse homogeneous - non specific : conf low T1/high T2//STIR
Micronodular/peppered - somewhat specific
Mixed patterns
Marrow changes associated with radiation
after 2 weeks
Red marrow preferentially destroyed Focal Abrupt margin at edges T1/T2/STIR high Regeneration at periphery
Spine: distinguish pial vessels vs meningeal mets
Pial vessels post Gad will washout early
Pial vessels at 12-6 o’clock positions
