Barbell sign (progressive multifocal leukoencephalopathy)

Last revised by Lachlan McKay on 19 Mar 2024

Citation, DOI, disclosures and article data

Citation:

Smith D, McKay L, Sharma R, et al. Barbell sign (progressive multifocal leukoencephalopathy). Reference article, Radiopaedia.org (Accessed on 25 Apr 2024) https://doi.org/10.53347/rID-65769

DOI:

https://doi.org/10.53347/rID-65769

Permalink:

https://radiopaedia.org/articles/65769

rID:

65769

Article created:

22 Jan 2019, Derek Smith ◉

Disclosures:

At the time the article was created Derek Smith had no recorded disclosures.

View Derek Smith's current disclosures

Last revised:

19 Mar 2024, Lachlan McKay ◉

Disclosures:

At the time the article was last revised Lachlan McKay had no financial relationships to ineligible companies to disclose.

View Lachlan McKay's current disclosures

Revisions:

7 times, by 6 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Signs

Tags:

signs, cases

Synonyms:

Barbell sign (PML)
Bar-bell sign
Barbell sign (progressive multifocal leucoencephalopathy)

The barbell sign is a radiological sign present in progressive multifocal leukoencephalopathy (PML) on MRI brain.

This describes confluent T2/FLAIR parieto-occipital abnormalities with a thin continuation of signal abnormality across the splenium ^1,2. 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 ¹. 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.