Bone metastases — lytic, sclerotic, mixed, and the fracture risk

CT · MRI

First and second year — the floor first, then every step

Report the number and distribution of lesions, their character (lytic, sclerotic, mixed), and the ones that threaten: cortical destruction in weight-bearing long bones, spinal instability (SINS) and epidural cord compression.

Orient first

  • Sclerotic: prostate, breast (treated); lytic: renal, thyroid, lung; mixed: breast, lung.
  • Response on CT is hard: healing lytic metastases become sclerotic and can look like progression (flare).
  • Mirels score for long bones and SINS for the spine structure the fracture risk (verify the versions in use).

Acquire the study

  • Staging CT with bone window review and sagittal and coronal reformats of the spine and pelvis.

The manoeuvre

  • Bone window, axial and sagittal reformats: every lesion — lytic, sclerotic, mixed; size in mm.
  • Long bones: cortical destruction as a percentage of the circumference; axial cortical involvement over 30 mm.
  • Spine: vertebral collapse, posterior element involvement, alignment — SINS components.
  • Compare with the prior study: new lesions vs sclerosis of known ones.

What confirms it

  • Multiple characteristic lesions in a patient with a known primary; biopsy when solitary or the primary is unknown.

What licenses you to exclude it

  • A normal whole-spine T1 excludes spinal metastases of detectable size; CT misses marrow-only disease.

The classic misread

  • Calling a healing flare progression.
  • Not stating the epidural extent in the spine.
  • Missing a lytic lesion in the femoral neck on a staging CT.

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