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 retrospectively review the PET/CT imaging features of sarcoidosis and improve the diagnostic accuracy of this benign disease.Methods The PET/CT imaging characteristics and clinical data, including lesion size, distribution, standardized uptake value (SUV) and the ratio of misdiagnosis, of 11 sarcoidosis patients (5 confirmed pathologically and 6 clinically) were retrospectively analyzed.Results (1) Eleven patients had lymph node involvement:mediastinum and hilar lymphadenopathy in 11/11, supraclavicular fossa lymphadenopathy in 8/11, retroperitoneal lymphadenopathy in 8/11, pelvic cavity lymphadenopathy in 3/11.(2) Extrathoracic lesions were found in 7/11 with 4 lung involvement, 2 liver involvement, 1 parotid gland and temporalis involvement and 1 bilateral iliac and sacral bone involvement.(3) The size of the lesions ranged from 1.0 to 4.6 cm and the CT density ranged from 30 to 40 HU.The lesions in the lung are hypodense and in the liver are slightly hypo-or iso-dense.18F-fluorodeoxyglucose (FDG) uptake of all lesions was definitely increased in 6 cases; 18F-FDG uptake of some lesions was moderately or definitely increased in 2 cases, and slightly increased uptake in 3 cases.(4) The PET/CT diagnosis was consistent with the final diagnosis in 6/11.The 5 cases of misdiagnosis were malignant lymphoma (4/11) and lung cancer ( 1/11 ).Conclusions Differentiation between sarcoidosis and lymphoma in patients presenting with hilar lynphadenopathy can be difficult.Whole-body PET/CT may be helpful in the differentiation of the two diseases.