Premium
Diffusion tensor and tensor metrics imaging in intracranial epidermoid cysts
Author(s) -
Santhosh Kannath,
Thomas Bejoy,
Radhakrishnan Vishnupuri V.,
Saini Jitender,
Kesavadas Chandrasekharan,
Gupta Arun Kumar,
Kapilamoorthy Tirur Raman,
Nair Suresh N.
Publication year - 2009
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21686
Subject(s) - diffusion mri , white matter , fractional anisotropy , anisotropy , nuclear magnetic resonance , diffusion , physics , orientation (vector space) , tensor (intrinsic definition) , chemistry , optics , geometry , mathematics , medicine , magnetic resonance imaging , radiology , thermodynamics
Purpose To explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) in characterizing the structural pathology of epidermoid cysts. DTI gives information about the tissue structure; a high fractional anisotropy (FA) indicates a highly structured orientation of the tissue, fibers, or white matter tracts. Based on the tensor rank, a set of three metrics has been described that can be used to measure the directional dependence of diffusion: linear anisotropy (CL), planar anisotropy (CP), and spherical anisotropy (CS). DTM takes into account the shape of diffusion anisotropy and hence may provide better insight into the orientation of structures than FA. Materials and Methods DTI was performed in three patients with epidermoid cysts. FA, directionally‐averaged mean diffusivity (D av ), exponential apparent diffusion coefficient (eADC), and DTM, such as CL, CP, and CS, were measured from the tumor core as well as from the normal‐appearing white matter. Histopathological correlation was obtained. Results Epidermoid cysts showed high FA with D av values similar to that of normal white matter. eADC maps did not show any restriction of diffusion. FA values were high, but not as high as that for the white matter. CP values were higher and CL values were lower than those obtained for the white matter in various regions. Conclusion High CP values suggest preferential diffusion of water molecules along a two‐dimensional geometry, which could be attributed to the well‐structured orientation of keratin filaments and flakes within the tumor as demonstrated by histopathology. Advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts. J. Magn. Reson. Imaging 2009;29:967–970. © 2009 Wiley‐Liss, Inc.