Faria A. V., de Macedo F. C. Jr, Ferreira M. M. C., Marsaioli A J., Cendes F., "In vitro biochemical classification of brain tumors by high field 1H MRS". Águas de Lindóia, SP, Brazil, 10-15/09/2006: 10th International Conference on Chemometrics in Analytical Chemistry (CAC-2006, CAC-X), Book of Abstracts (2006) P070. Poster 070.
10th International Conference on Chemometrics in Analytical Chemistry P070
In vitro biochemical classification
of brain tumors by high field 1H
MRS
Andréia Vasconcellos1*,
Fernando César de Macedo Júnior3,
Márcia M. C. Ferreira3,
Anita Jocelyne Marsaioli3,
Fernando Cendes2
1Department of
Radiology and 2Neurology, Faculty of Medical
Sciences, State University of Campinas
(UNICAMP), Campinas, SP,
Brazil
3Chemistry Institute,
State University of Campinas (UNICAMP), Campinas, SP, Brazil
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Hydrogen magnetic resonance spectroscopy (1H
NMR) performed at low fields is a
non-invasive
method and a useful tool
for the diagnosis of tumors in vivo. High field 1H
MRS, on the other hand, has
been used to study biochemical
changes in distinct pathologies in vitro based on the pattern of metabolite
distribution in
tissue extracts. It is also useful for identifying
the distinct metabolic profiles of specific
histological subtypes of
brain tumors, aiming for the optimization of the
in vivo 1H NMR
spectroscopy
protocols. The accurate
analysis and classification of different spectra, however, remains
a challenge. In
this work, brain tissue
samples from patients with various types of brain
tumors were analyzed by high
field (B0
= 11.7 T) 1H MRS in the region 1.22 - 4.25
ppm. Spectra were corrected to phase shift, baseline
corrected using a
linear fit and point wise scaled by the sum of
all intensities (normalized to unit area).
Partial Least Square Discriminant Analysis (PLS-DA) on autoscaled
data revealed a tendency of high-
grade neuroglial tumors
in increasing glycine and glutamine/glutamate
and decreasing myo-inositol.
Creatine and
NAA were clearly decreased in non-neuroglial tumors
and alanine was higher in non-
neuroglial tumor
followed by high-grade neuroglial tumors.
Choline compounds had a particular
distribution in metastasis
and non-neuroglial tumors with increasing of GPC peak and decreasing
of PC
peak when compared with
neuroglial tumors and control. None or at most one sample was
misclassified
during the leave-one-out
crossvalidation procedure. These results allowed brain tumors
to be grouped
according to
their specific histological subtypes and
degree of agressiveness, reflecting particular
characteristics of tumor
original cell and neoplastic cells' metabolic abnormalities possibly related
to high
turnover, resistance to
apoptosis, osmotic stress and their tendency to aerobic glycolysis.
Acknowledgment. FAPESP,
CNPq.
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