ABSTRACT
ObjectiveTo study the relationship between 18F-FDG uptake and tumor cell density,glucose transporter expression,cellular proliferation and angiogenesis before and after radiotherapy in C6 glioma rats.MethodsThirty C6 glioma-bearing male SD rats were randomly divided into three groups:A,B and C ( 10 rats in each group).Two weeks later,18F-FDG PET/CT was performed in group A.In groups B and C,18 F-FDG PET/CT was performed at 48 h and 1 week after radiotherapy,respectively.The ratio of SUVmax of tumor to muscle (T/M) was calculated.HE staining,immunohistochemical staining and Western blot were used to measure tumor cell density,Ki67 labeling index ( LI),microvessel density ( MVD),Glut-1 and VEGF expression quantitatively.The one-way analysis of variance and bivariate correlation analysis were used to compare the changes of each indicator and evaluate the correlation between T/M and biological indicators,respectively.Results Significant differences of T/M,tumor cell density,Ki67 LI,MVD,Glut-1 and VEGF among groups A,B and C were observed ( F =6.77,60.66,104.56,95.49,9.13,24.48,respectively,all P ＜0.05).Least significant difference (LSD) test showed that there was no significant difference between group A and B in T/M,tumor cell density and Ki67 LI ( 10.86 ± 3.31,730.50 ± 78.93,20.02 ± 2.14 vs 9.23 ± 4.56,672.70 ± 92.98,18.56 ± 2.26).However,the indicators of group C (5.16 ± 2.52,355.60 ± 72.62,7.81 ± 1.76 ) were significantly decreased compared with those of groups A and B (all P ＜0.05 ).MVD and Glut-1 expression of group B increased slightly compared with those of group A ( 19.50 ± 1.96,0.20 ± 0.09 vs 17.90 ± 2.02,0.15 ± 0.04),but the difference was not statistically significant.Nevertheless,the two indicators were significantly decreased in group C ( 8.40 +1.84 and 0.07 ±0.06,P ＜0.05).VEGF expression in group B (0.42 ±0.13) was significantly higher than that in groups A and C (0.17 ±0.04 and 0.16 ± 0.09) ( both P ＜ 0.05 ).The changes of T/M were positively correlated with the changes of tumor cell density between groups A and B ( r =O.81,P ＜ 0.05 ).Changes of T/M were positively correlated with the changes of tumor cell density,Ki67 LI,MVD and Glut-1 between groups A and C (r =O.83,0.71,0.68,0.62,all P ＜ 0.05 ).ConclusionsThe changes of 18 F-FDG uptake in C6 glioma rats were only correlated to the changes of tumor cell density at 48 h after radiotherapy.However,the changes of 18F-FDG uptake closely correlate to the changes of a variety of biological indicators at 1 week post radiotherapy.
ABSTRACT
Objective To investigate the correlation between ~(18)F-fluorodeoxyglucose (FDG) uptake and hypoxia inducible factor1α (HIF-1α) level,microvessel density (MVD) in human gliomas.Methods ~(18)F-FDG PET scan was performed preoperatively in 41 patients with gliomas (including 23 highgrade and 18 low-grade tumors).The ratios of maximum standardized uptake value(SUV_(max))between tumor (T)and contralateral white matter (WM) were calculated (T/WM).Immunohistochemical stain methods were used to evaluate the level of HIF-1α and measure the MVD in tumors.Correlation analysis between SUV_(max) of T/WM and HIF-1α level,MVD wag performed.The t-test,one-way ANOVA test,Spearman rank correlation and Wilcoxon signed-rank test were calculated using SPSS 11.5 software.Results (1)The SUV_(max) of T/WM,HIF-1α level and MVD in high-grade and low-grade tumors groups were 3.39±1.43,95.7% and 44.13±16.1 vs 1.46±0.55.55.6% and 18.83±7.07,respectively.The difierences of SUV_(max) of T/WM,HIF-1α level and MVD between two groups were statistically significant (t=-5.921,z=-3.938,t=-6.745,all P＜0.05).(2)Among 41 gliomas,the strong positive expression of HIF-1α was observed in 8,mederate in 9,weak in 15 and negative expression was found in 9,SUV_(max) of T/WM and MVD increased with increasing HIF-1α level.The differences of SUV_(max) of T/WM and MVD among 4 different groups were statistically significant (F=7.41,P＜0.05).(3) The MVD of all gliomas was ranged from 9.76 to 94.52,which correlated with SUV_(max) of T/WM(r=0.759,P＜0.05).Conclusions The SUV_(max) of T/WM correlates with HIF-1α level and MVD in gliomas.Therefore,~(18)F-FDG PET provides preoperatively a noninvasive assessment of hypoxia or angiogenesis in human glionma.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the value of (18)F-FDG and (11)C-MET PET-CT scan in differentiation of brain ringlike-enhanced lesions on MRI imaging.</p><p><b>METHODS</b>Forty-one brain ringlike-enhanced lesions on MRI imaging including 30 brain tumors and 11 non-neoplastic lesions confirmed pathologically or clinically underwent (18)F-FDG and (11)C-MET PET-CT brain scan. Among them, 15 patients who were suspected to have brain metastasis received body scan by (18)F-FDG PET-CT. Both images were analyzed visually and semi-quantitatively.</p><p><b>RESULTS</b>Visual analysis: for brain tumors the diagnostic sensitivity, specificity and accuracy of (18)F-FDG PET-CT was 53.3%, 72.7%, 58.5%, versus 96.7%, 90.9%, 95.1% of (11)C-MET PET-CT, respectively. All the primary foci in 9 patients with brain metastases were detected by body (18)F-FDG PET-CT scan. Semiquantitative analysis: There was a significant difference in the uptake between highly differentiated malignant and poorly differentiated tumors as well as non-neoplastic lesions for both tracers (P < 0.01), while between low-grade malignant tumors and non-neoplasm lesions, there was a difference in uptake only by (11)C-MET (P < 0.01). No significant difference between the uptakes in brain metastasis and glioblastomas was found by both tracers (P > 0.05).</p><p><b>CONCLUSION</b>Both (18)F-FDG and (11)C-MET PET-CT are useful in differentiation of brain ringlike-enhanced lesions on MRI imaging. (11)C-MET PET-CT is more helpful than (18)F-FDG PET-CT in differential diagnosis of low-grade neoplastic from non-neoplastic lesions. Combination of (18)F-FDG and (11)C-MET PET-CT scans can improve the accuracy of differential diagnosis for brain ringlike-enhanced lesions on MRI imaging.</p>