Diffusion-weighted magnetic resonance imaging in peritoneal carcinomatosis from suspected ovarian cancer: Diagnostic performance in correlation with surgical findings

Purpose: Ovarian cancer (OC) is the commonest cause of death by gynaecological cancer in developed countries. Peritoneal carcinomatosis (PC) complete debulking without residual disease of >1 cm is the best prognostic predictor in advanced OC. PC is assessed with Computed tomography (CT). CT accuracy and cytoreduction success predictive ability are limited. PET/CT is not an imaging standard for PC. PC shows high signal foci in Diffusion-weighted magnetic resonance imaging (DWI MRI). We assessed the diagnostic performance (DP) and tumour burden correlation of Whole body DWI with background suppression MRI (WB-DWIBS/MRI) in PC of suspected OC using the Peritoneal Cancer Index (PCI), referring to cytoreduction surgery as the standard reference. Method: Fifty patients with suspicion of disseminated OC underwent cytoreduction and WB-DWIBS/MRI. The PCI scores tumour burden (0–3) in 13 anatomical regions (global range of 0–39). Two radiologists (Rad1/Rad2) assessed the PCI preoperatively and with surgical findings. We evaluated regional and global DP, the interobserver agreement (Cohen´s kappa coefficient), statistical differences (McNemar test) and tumour burden (Pearson's test). Results: 72% (36/50) were epithelial OC and 78% (39/50) achieved complete cytoreduction. Global-PCI correlation was 0.762 (Rad1) with DP: Sensitivity 0.84, specificity 0.89, accuracy 0.89, and kappa 0.41. Average global-PCI was 7. The pelvis and right hypochondrium showed the highest positive rate and DP, while the intestinal regions presented the lowest. Previous studies reported higher sensitivity than CT or PET/CT, although only a few used the PCI. Conclusions: WB-DWIBS/MRI is reliable to depict, quantify and to predict complete cytoreductive surgery in OC PC.