Parameters of simultaneous 18F-FDG-PET/MRI predict tumor stage and several histopathological features in uterine cervical cancer

Abstract

The purpose of this study was to analyze associations between apparent diffusion coefficient (ADC) and standardized uptake values (SUV) values and different histopathological parameters in uterine cervical cancer. 21 patients with primary uterine cervical cancer were involved into the study. All patients underwent a whole body simultaneous¹⁸F-FDG PET/MRI. Mean and maximum SUV were noted (SUV_mean and SUV_max). In all tumors minimal, mean, and maximal ADC values (ADC_min, ADC_mean, and ADC_max) were estimated. Combined parameters were calculated: SUV_max/SUV_mean, ADC_min/ ADC_mean, SUV_max/ADC_min and SUV_max/ADC_mean. In all cases the diagnosis was confirmed histopathologically by tumor biopsy. Histological slices were stained by hematoxilin and eosin, MIB 1 monoclonal antibody, and p16. All histopathological images were digitalized and analyzed by using a ImageJ software 1.48v. The following parameters were estimated: cell count, proliferation index KI 67, total and average nucleic areas, epithelial and stromal areas. Spearman’s correlation coefficient was used to analyze associations between ADC and SUV values and histological parameters. P values ≤ 0.05 were considered as statistically significant. ADC_min and ADC_min/ ADC_mean were statistically significant lower in N positive tumors. KI 67 correlated statistically significant with SUV_max (r = 0.59, p = 0.005), SUV_mean (0.45, p = 0.04), ADC_min (r = –0.48, p = 0.03), SUV_max/ADC_min (r = 0.71, p = 0.001), SUV_max/ADC_mean (0.75, p = 0.001). SUV_max correlated well with epithelial area (r = 0.71, p = 0.001) and stromal areas (r = –0.71, p = 0.001). SUV values, ADC_min, SUV_max/ADC_min and SUV_max/ADC_mean correlated statistically significant with KI 67 and can be used to estimate the proliferation potential of tumors. SUV values correlated strong with epithelial area of tumor reflected metabolic active areas.