title: Magnetic resonance diffusion tensor imaging and tractography of intracranial cavernous malformations: preliminary observations and characterization of the hemosiderin rim.
abstract: OBJECTIVE
  Cavernous malformations (CMs) can cause symptoms that appear out of proportion to the lesion size, leading one to hypothesize that they may have an effect on adjacent white matter that is not fully explained by local mass effect. The goal of this study was to investigate the diffusion tensor (DT) properties of CMs, the hemosiderin rim, and normal-appearing adjacent white matter.
  
  
  METHODS
  Eighteen cavernous malformations were characterized using standard MR imaging sequences as well as 6-direction DT imaging with single-shot echo planar-gradient echo imaging at 3 tesla.
  
  
  RESULTS
  Diffusion tensor imaging demonstrated that CMs have a characteristic signature on DT imaging, with low fractional anisotropy (FA) and high mean diffusivity centrally within the lesion. The hemosiderin rim had a high FA value relative to the central lesion or adjacent white matter. Tractography revealed that tracts neatly deviate around CMs. Tracts were typically seen to pass through the hemosiderin rim.
  
  
  CONCLUSIONS
  The hemosiderin rim of CMs was intimately associated with white matter tracts that were deviated by the central lesion. These findings are consistent with histopathological reports that the hemosiderin rim is composed of blood breakdown products deposited in viable white matter.
authors.affiliation: Department of Radiology, Division of Neuroradiology, University of Massachusetts Medical Center, Worcester, Massachusetts 01655, USA. keithcauley@hotmail.com
authors.forename: Keith A
authors.initials: KA
authors.lastname: Cauley
authors.forename: Trevor
authors.initials: T
authors.lastname: Andrews
authors.forename: Jay V
authors.initials: JV
authors.lastname: Gonyea
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Filippi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D056324:Diffusion Tensor Imaging; D017352:Echo-Planar Imaging; D005260:Female; D020786:Hemangioma, Cavernous, Central Nervous System / Q000378:metabolism* / Q000473:pathology*; D006485:Hemosiderin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D010865:Pilot Projects
chemical_list: D006485:Hemosiderin