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 (SUV _max and SUV _mean , 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 SUV _max and SUV _mean (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 SUV _max and SUV _mean (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 SUV _max 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 (SUV _max ) = 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 (SUV _mean ) = 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.
(© 2018 International Society for Magnetic Resonance in Medicine.)