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@ARTICLE{Stegmayr:827963,
author = {Stegmayr, Carina and Oliveira, Dennis and Niemietz, Nicole
and Willuweit, Antje and Lohmann, Philipp and Galldiks,
Norbert and Shah, N. J. and Ermert, Johannes and Langen,
Karl-Josef},
title = {{I}nfluence of bevacizumab on blood-brain barrier
permeability and {O}-(2- 18 {F}-fluoroethyl)-{L}-tyrosine
uptake in rat gliomas},
journal = {Journal of nuclear medicine},
volume = {58},
number = {5},
issn = {2159-662X},
address = {New York, NY},
publisher = {Soc.},
reportid = {FZJ-2017-01991},
pages = {700-705},
year = {2017},
abstract = {Restoration of the blood–brain barrier (BBB) after
antiangiogenic therapy of gliomas with bevacizumab may
result in a decrease in contrast enhancement on MRI despite
tumor progression. This so-called pseudoresponse is
difficult to differentiate from a true tumor response with
conventional MRI. Initial patient studies have indicated
that PET using O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET)
may be helpful for solving this diagnostic problem. This
study was performed to investigate the effects of
bevacizumab on BBB permeability and 18F-FET uptake in a
human xenograft model. Methods: Human U87 glioblastoma cells
were implanted into the striatum of immunodeficient RNU
rats. 18F-FET PET scans and ex vivo autoradiography were
performed in animals receiving a single high dose of
bevacizumab (45 mg/kg 2 d before PET; n = 9) or in animals
receiving 2 lower doses (10 mg/kg 9 and 2 d before PET; n =
10) to evaluate short-term and long-term effects on the BBB,
respectively, and in control animals without bevacizumab
treatment (n = 8). Time–activity curves, slope, and
tumor-to-brain ratios of 18F-FET uptake (18–61 min after
injection) were evaluated using a volume-of-interest
analysis. After PET scanning, Evans blue dye (EBD) was
injected into animals, and cryosections of the brains were
evaluated by autoradiography, by histology, and for EBD
fluorescence to assess BBB permeability. Results: Compared
with the control, short-term bevacizumab therapy resulted in
a trend toward BBB restoration (P = 0.055) and long-term
therapy resulted in a significant decrease (P = 0.004) in
BBB permeability, as assessed by EBD fluorescence. In
contrast, no significant differences in tumor-to-brain
ratios or slope of 18F-FET uptake were observed in PET and
autoradiography (P > 0.05). Conclusion: 8F-FET uptake in
glioblastomas seems to be largely independent of BBB
permeability and reflects the viability of tumor tissue
during antiangiogenic therapy more reliably than
contrast-enhanced MRI},
cin = {INM-3 / INM-4 / INM-5},
ddc = {610},
cid = {I:(DE-Juel1)INM-3-20090406 / I:(DE-Juel1)INM-4-20090406 /
I:(DE-Juel1)INM-5-20090406},
pnm = {573 - Neuroimaging (POF3-573)},
pid = {G:(DE-HGF)POF3-573},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000400633500008},
doi = {10.2967/jnumed.116.187047},
url = {https://juser.fz-juelich.de/record/827963},
}