The radial bands sign refers to linear bands seen on MRI, radiating from the periventricular white matter to the subcortical region, thought to be specific for tuberous sclerosis 1,2.
The exact pathogenesis of radial bands is uncertain, but they are thought to relate to dysfunction of, or injury to, the radial glial fibers (which go on to transform into astrocytes) and form the scaffolding over which neurons migrate from the periventricular germinal matrix to the cortex 2,3.
These radial bands appear as linear regions of signal abnormality extending from the ventricle to the cortex, slightly fanning out as they reach the periphery.
Signal characteristics in adults are 1,2:
- T1: iso to hypointense
- T2 / FLAIR: hyperintense
- T1 C+: occasional enhancement is encountered
In young patients with incomplete myelination, signal characteristic are 2:
- T1: hyperintense to unmyelinated white matter
- T2: iso to hypointense
- 1. Chavhan GB, Shroff MM. Twenty classic signs in neuroradiology: A pictorial essay. Indian J Radiol Imaging. 19 (2): 135-45. doi:10.4103/0971-3026.50835 - Free text at pubmed - Pubmed citation
- 2. Bernauer TA. The radial bands sign. Radiology. 1999;212 (3): 761-2. doi:10.1148/radiology.212.3.r99se17761 - Pubmed citation
- 3. Castillo M. The Core Curriculum. Lippincott Williams & Wilkins. (2002) ISBN:0781736641. Read it at Google Books - Find it at Amazon