Barbell sign (progressive multifocal leukoencephalopathy)

Dr Ammar Haouimi and Dr Derek Smith et al.

The barbell sign has been described in a short series of patients with progressive multifocal leukoencephalopathy (PML) 1.

This describes confluent FLAIR / T2w parieto-occipital abnormalities with a thin continuation of signal abnormality across the splenium.

Given the lack of mass effect typically exhibited in PML this appears as a thin band between the abnormal regions, similar to a barbell/dumbbell. This should be discriminated from the enlargement of the splenium in other inflammatory or neoplastic processes.

Case series have found this sign in immunocompromised patients (both HIV and non-HIV associated), all with visual disturbance 1.

Article information

rID: 65769
Section: Signs
Synonyms or Alternate Spellings:
  • Barbell sign (progressive multifocal leucoencephalopathy)
  • Bar-bell sign
  • Barbell sign (PML)

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Updating… Please wait.

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

     Thank you for updating your details.