(18)F-FDG PET analysis of schwannoma: increase of SUVmax in the delayed scan is correlated with elevated VEGF/VPF expression in the tumors.
OBJECTIVE
In order to clarify the increased 2-deoxy-2-fluoro-(18)F-D: -glucopyranose ((18)F-FDG) accumulation in schwannoma by positron emission tomography (PET) analysis, immunohistochemical analysis for the factors involved in glucose transportation and vascular formation was performed.


METHODS
Twenty-six patients with schwannoma (13 men and 13 women) with ages ranging from 27 to 75 years, who received whole body (18)F-FDG PET scan, were enrolled for the present study. The retention index (RI) was calculated by dividing the increase in the standardized uptake value (SUVmax) at the delayed scan by the SUVmax in the early scan. SUVmax and RI were compared with the histologic variables, including the expression of glucose transporters 1 and 3, hexokinase II, vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), and microvascular density shown by CD31 immunohistochemistry.


RESULTS
Mean SUVmax values in the early and delayed scans were 2.64 +/- 1.47 and 2.71 +/- 1.57 (mean +/- SD), respectively. RI was -2.5 +/- 21 (percentage). SUVmax showed a positive correlation with the tumor size (tumor size <5 cm, 2.06 +/- 0.72; >5 cm, 3.95 +/- 1.89; p < 0.05) and the microvascular density (negative density, 2.16 +/- 1.12; positive density, 3.56 +/- 1.67; p < 0.05). RI correlated with VEGF/VPF expression in the tumors (negative expression, -11 +/- 6.1; positive expression, 13 +/- 8.1; p < 0.05). Other factors showed no correlation with SUVmax or RI.


CONCLUSIONS
Microvascular density and vascular permeability of the tumor are suggested to affect the enhanced (18)F-FDG accumulation in schwannoma.
Hamada
Kenichiro
K
Department of Orthopedic Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan.
Tomita
Yasuhiko
Y
Qiu
Ying
Y
Tomoeda
Miki
M
Ueda
Takafumi
T
Tamai
Noriyuki
N
Hashimoto
Nobuyuki
N
Yoshikawa
Hideki
H
Aozasa
Katsuyuki
K
Hatazawa
Jun
J
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000000981:diagnostic imaging* / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D018709:Statistics, Nonparametric; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D051272:Glucose Transporter Type 1; D019275:Radiopharmaceuticals; D042461:Vascular Endothelial Growth Factor A; D019788:Fluorodeoxyglucose F18; D006593:Hexokinase