MRI-based decision framework for peritoneal metastases: integrating rPCI, PAUSE, and PROMISE

Peritoneal metastases represent a complex clinical condition in which appropriate patient selection relies on accurate preoperative assessment of disease extent and distribution, as complete cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) may improve survival in selected patients. Computed tomography (CT), although widely available, has limitations in detecting small implants and in evaluating challenging regions such as the mesentery, potentially leading to underestimation of tumor burden and surgical complexity. Magnetic resonance imaging (MRI) enables more accurate evaluation of peritoneal disease, improving detection and characterization of small implants, particularly in surgically critical regions. The radiologic Peritoneal Cancer Index (rPCI) provides a systematic method for quantifying tumor burden; however, tumor burden alone does not reliably predict resectability. The PAUSE framework complements rPCI by incorporating key features that determine surgical feasibility, including unfavorable sites, small bowel and mesenteric involvement, and extra-peritoneal disease. Structured reporting through the PROMISE model ensures that these findings are translated into clinically actionable information. This pictorial essay proposes an MRI-based integrated framework combining rPCI, PAUSE, and PROMISE to improve interpretation, standardize reporting, and support surgical planning. This integrated MRI-based approach supports clinically meaningful patient stratification and improves preoperative decision-making by aligning imaging findings with surgical feasibility.