Low-grade and anaplastic gliomas: differences in architecture evaluated with diffusion-tensor MR imaging.
OBJECTIVE
To prospectively evaluate whether diffusion-tensor magnetic resonance (MR) imaging depicts differences in World Health Organization (WHO) grade II and III glial brain tumors on the basis of tumor architecture and peritumoral tract invasion.


METHODS
The study protocol was approved by the local ethics committee, and written informed consent was obtained. Diffusion-tensor MR imaging was performed in 23 patients (15 men, eight women; mean age, 47 years) with histologically confirmed brain gliomas. Eleven of the 23 tumors were low-grade gliomas (WHO grade II) and 12 were anaplastic gliomas (WHO grade III). Regions of interest were placed in the tumor center, tumor border, normal-appearing white matter (NAWM) adjacent to the tumor, and NAWM of the contralateral hemisphere. fractional anisotropy (FA) ratios were calculated for regions of interest in relation to the NAWM of the contralateral hemisphere. Pairwise comparisons were performed by using the Mann-Whitney U test.


RESULTS
Median FA ratios for grade II versus grade III gliomas were 0.406 versus 0.405, respectively, for tumor center, 0.733 versus 0.449, respectively, for tumor border, and 0.962 versus 0.943, respectively, for NAWM adjacent to the tumor. Differences in FA ratio between low-grade and high-grade tumors were significant in the tumor border only (P = .01). Differences in FA ratio were not significant between low-grade and high-grade gliomas in the tumor center or in the NAWM adjacent to the tumor.


CONCLUSIONS
The periphery of low-grade gliomas contains a considerable amount of preserved fiber tracts. In high-grade gliomas, however, most of these tracts are disarranged. Low FA ratios in the tumor center are consistent with a high degree of disorganization of myelinated fiber tracts in the center of both low-grade and high-grade gliomas.
Department of Neuroradiology, University of Hamburg, Martinistrasse 52, 20251 Hamburg, Germany. goebell@uke.uni-hamburg.de
Einar
E
Goebell
Susanne
S
Paustenbach
Ole
O
Vaeterlein
Xiao-Qi
XQ
Ding
Oliver
O
Heese
Jens
J
Fiehler
Thomas
T
Kucinski
Christian
C
Hagel
Manfred
M
Westphal
Hermann
H
Zeumer
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005910:Glioma / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies