Diffusion tensor imaging analysis of optic radiation using readout-segmented echo-planar imaging.
OBJECTIVE
To investigate the diffusion tensor imaging parameters of the optic radiation and surrounding structures using the high-resolution readout-segmented diffusion tensor imaging method.


METHODS
Coronal readout-segmented diffusion tensor images were acquired in 15 healthy volunteers. On three slices of each image, eigenvalue 1, fractional anisotropy, radial diffusivity, apparent diffusion coefficient, and signal intensity on T2-weighted images were measured in the lateral inferior longitudinal fasciculus, external and internal layers of the optic radiation, and the tapetum within regions of interest delineated by two independent observers. Profile curve analysis of regions of interest across the optic radiation and surrounding structures was performed for a representative typical case.


RESULTS
Significant differences in fractional anisotropy, radial diffusivity and apparent diffusion coefficient were observed between external and internal layers of the optic radiation, while there was no significant difference in eigenvalue 1. In fractional anisotropy maps, two low signal bands were observed between the inferior longitudinal fasciculus, the optic radiation and the tapetum. Profile curve analysis showed a minimum on the fractional anisotropy and eigenvalue 1 images and a maximum in the radial diffusivity image.


CONCLUSIONS
Readout-segmented diffusion tensor imaging revealed significant differences in the diffusion tensor imaging parameters between internal and external layers of the optic radiation.
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan.
Hirofumi
H
Yamada
Akira
A
Yamamoto
Tomohisa
T
Okada
Mitsunori
M
Kanagaki
Yasutaka
Y
Fushimi
Taha Mohamed
TM
Mehemed
David A
DA
Porter
Kaori
K
Togashi
D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D005829:Geniculate Bodies / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated; D015588:Observer Variation; D009900:Optic Nerve / Q000033:anatomy & histology*; D012016:Reference Values; D014795:Visual Pathways / Q000033:anatomy & histology