Correlation between standardized uptake value and intravoxel incoherent motion parameters of cervical squamous cell carcinoma with ¹⁸F-FDG PET/MR

Objective: To assess the correlation between standardized uptake value (SUV) and intravoxel incoherent motion (IVIM) parameters of primary cervical squamous cell carcinoma (CSCC) and pelvic metastatic lymph nodes in the use of hybrid PET/MR. Methods: Forty-six CSCC patients in Shengjing Hospital from January 2015 to December 2015 were prospectively enrolled and divided into well-differentiated (G1) group, moderate-differentiated (G2) group and poorly-differentiated (G3) group. PET/MR examination with the multi-b-value diffusion-weighted imaging (DWI) sequence was performed before treatment. Maximum SUV (SUV_max) and mean SUV (SUV_mean) were calculated. IVIM parameters, including the slow diffusion coefficient (D), fast diffusion coefficient (D^*), perfusion fraction (f) were also measured. Pearson correlation analysis was used to evaluate the correlation between IVIM parameters and SUV (SUV_max, SUV_mean). Results: The D of G1, G2, G3 lesions and metastatic lymph nodes were (0.827 ± 0.232) × 10^-3, (0.640 ± 0.153) × 10^-3, (0.563 ± 0.090) × 10^-3 and (0.772 ± 0.246) × 10^-3 mm²/s respectively. The f was 0.310 ± 0.068, 0.348 ± 0.073, 0.287 ± 0.057 and 0.413 ± 0.103 respectively. The D^* was (9.241 ± 2.001) × 10^-3, (9.408 ± 1.927) × 10^-3, (9.715 ± 1.827) × 10^-3 and (8.830 ± 1.632) × 10^-3 mm²/s respectively. The SUV_max was 9.988 ± 3.806, 12.941 ± 5.990, 14.543 ± 7.050 and 9.890 ± 3.906 respectively. The SUV_mean was 5.717 ± 2.830, 7.094 ± 3.518, 8.263 ± 4.124 and 4.952 ± 1.343 respectively. The D of G1 and G2 lesions had negative correlations with SUV_max and SUV_mean (G1, r values: -0.816, -0.842; G2, r values: -0.528, -0.559; all P < 0.05); the f of G2 lesions had positive correlations with SUV_max and SUV (r values: 0.554, 0.550, both P < 0.05). Conclusions: The SUV_max and SUV of the well-moderate differentiated CSCC are consistent with D and f, which reflect the cell density and the microvascular perfusion. PET/MRIVIM could provide important complementary information for treatment-monitoring and prognostic assessment of patients with cervical cancer. (authors)