Correlation between tumor glucose metabolism and multiparametric functional MRI (IVIM and R2*) metrics in cervical carcinoma: Evidence from integrated 18 F-FDG PET/MR.

BACKGROUND: Multiparameter, multimodality 18 F-FDG PET/MRI holds great potential for the diagnosis of cervical cancer based on the correlation between tumor glucose metabolism and imaging parameters. PURPOSE: To characterize the heterogeneity of tumor glucose metabolism by evaluating the correlation between 18 F-FDG uptake parameters and multiparametric functional MRI metrics in cervical carcinoma. STUDY TYPE: Retrospective. POPULATION: Fifty-four patients with cervical carcinoma. FIELD STRENGTH/SEQUENCE: Hybrid PET/MR (3T), multi-b DWI, and R2* mapping. ASSESSMENT: The maximum and mean standardized uptake values (SUVmax and SUVmean , respectively) from PET and functional MRI metrics (D, D*, f, and R2*) were obtained. Cervical carcinoma tissues also underwent HIF-1α, VEGF, and GLUT-1 immunohistochemical staining. STATISTICAL TESTS: Single-factor Spearman rank and Pearson correlation analysis and multiple linear regression (MLR) analysis were applied. RESULTS: R2*, D, and f have different degrees of correlation (moderate, weak, moderately strong correlation, respectively) with SUVmax and SUVmean (r = 0.530 and 0.527, and P < 0.001 for R2*; r = -0.292 and -0.291, and P < 0.05 for D; r = 0.539 and 0.520, and P < 0.001 for f, respectively). Immunohistochemical staining showed that HIF-1α expression has a moderate degree of correlation with R2* (r = 0.491; P < 0.001); GLUT-1 expression was significantly correlated with SUVmax and SUVmean (r = 0.633 and 0.622; P < 0.001), and VEGF expression had a moderately strong correlation with f (r = 0.457; P = 0.001). If SUVmax is the dependent variable, MLR yields an R-squared value after adjustment (adjusted R-squared) = 0.358, and F = 10.833 (P < 0.001), and the fitting linear equation is Y (SUVmax ) = 9.184 + 0.161X1 (R2*)+50.343X2 (f)-4.780 (D). Otherwise, MLR yields the adjusted R-squared = 0.342, and F = 10.187 (P < 0.001), and the linear regression equation is Y (SUVmean ) = 5.925 + 0.102X1 (R2*)+28.029X2 (f)-2.907X3 (D). DATA CONCLUSION: The functional MRI sequence parameters R2*, f, and D can provide information on the hypoxic condition, blood perfusion, and molecular diffusion of the tumor. 18 F-FDG PET/MR multi-imaging technique can be adopted to evaluate the heterogeneity of glucose metabolism in cervical carcinoma. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:1704-1712.

Progresses of PET and MRI in evaluating expression of tumor hypoxic and downstream molecules / 中国介入影像与治疗学

The growth of solid tumors can lead to changes in the hypoxic microenvironment of local tissues,and the most important regulatory factor is the hypoxia-inducible factors (HIFs).In the case of hypoxia,the downstream target genes regulated by HIF-1α regulation mainly are vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1) genes,etc.In recent years,multimodality PET and MRI imaging technologies have been widely used in diagnosis of tumor diseases,and have confirmed that the parameters obtained by imaging are associated with the expression of tumor hypoxic related molecules.The molecular expression of HIF-1α within the tumor and its downstream target genes VEGF and GLUT-1 detected by PET and multifunctional MRI sequential were reviewed in this article.