RT Journal Article SR Electronic T1 Preoperative 18F-FDG PET and MRI parameters in predicting histopathological features of endometrial cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 356 OP 356 VO 61 IS supplement 1 A1 Paola Mapelli A1 Gabriele Ironi A1 Alice Bergamini A1 Paola Maria Rancoita A1 Elena Venturini A1 Valerio Nisi A1 Federico Fallanca A1 Valentino Bettinardi A1 Anna Colarieti A1 Luca Bocciolone A1 Gianluca Taccagni A1 Luigi Gianolli A1 Francesco De Cobelli A1 Maria Picchio YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/356.abstract AB 356Purpose: The aim of the present study is to explore the correlation between PET and MRI parameters of primary tumour and clinicopathological features, and to determine their predictive role in patients with endometrial cancer candidate to surgery. Methods: 27 patients with histologically proven endometrial cancer with preoperative 18F-FDG-PET and MRI scan, performed within one month one from the other, were retrospectively enrolled. The following primary tumour parameters have been considered: SUVmax, SUVmean, MTV and TLG for PET scan; ADCmean and Volume Index for MRI scans. FIGO stage, grade, hystotype (endometrioid vs not-endometrioid), myometrial invasion and lymphovascular space invasion (LVSI) were the histological parameters considered for the analysis. Results: MRI volume index showed a moderate direct correlation with SUVmax (rho=0.673; p<0.001), SUVmean (rho=0.649; p< 0.001), and TLG (rho= 0.669; p< 0.001). A moderate inverse correlation was found between ADCmean and SUVmax (rho=-0.5; p=0.008), SUVmean (rho=-0.545; p=0.003) and TLG (rho=-0.481, p=0.011). MRI Volume index was a good predictor for myometrial invasion (AUC= 0.85; p= 0.003) and a fair predictor of LVSI (AUC= 0.74; p=0.039). Based on ROC curve analysis, a cut-off value of 9.555 for MRI volume index was predictive for deep myometrial invasion (sensitivity=84.6%; specificity= 76.9%); a cut-off higher than 12.165 was predictive for LVSI (sensitivity= 69.2%; specificity= 83.3%). A TLG cut-off value of 26.03 was predictive for myometrial invasion (sensitivity=84.6%; specificity=76.9%). When considering myometrial invasion as a continuous variable, a high direct correlation was found with MRI volume index (rho=0.722; p< 0.001), while significant low direct correlation with SUVmax (rho=0.484; p= 0.012), SUVmean (rho=0.47; p= 0.015), and TLG (rho=0.482; p= 0.013) were identified. SUVmax/ADCmean ratio showed low direct correlation with the percentage of myometrial invasion (rho= 0.467; p= 0.016). Conclusions: MRI volume index and PET TLG are associated with deep myometrial invasion, as well as SUVmax/ADCmean ratio. As myometrial invasion is the conventional index used to predict lymph node involvement in endometrial cancer, the use of these imaging parameters might be suggested to predict lymphnodal metastases.