Fluid-fluid levels in bone tumours

Dr Aditya Shetty et al.

Fluid-fluid levels in bone tumours is a commonly encountered finding, both in benign as well as malignant bone tumours, and can be used to differentiate between the two.

Method of assessment

On the sagittal T2W image:

  1. measure the length of the largest fluid-fluid level (A)
  2. measure the maximum length of the tumour (B)
  3. calculate A/B ratio


  • an A/B ratio >41.5 means the tumour is more likely to be benign
  • an A/B ratio <41.5 means the tumour is more likely to be malignant 


The rationale behind this unique method of assessment is that areas of necrosis in a malignant tumour are more likely to result in multiple small fluid-fluid levels as compared to a benign tumour.

See also

Share article

Article information

rID: 42596
Section: Approach
Tag: stub
Synonyms or Alternate Spellings:
  • Asssesing fluid-fluid levels in bone tumours
  • Fluid-fluid levels in bone tumors

Support Radiopaedia and see fewer ads

Updating… Please wait.

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.