Magnetic resonance imaging in peritoneal carcinomatosis: protocol and structured reporting

Peritoneal carcinomatosis represents a diagnostic and therapeutic challenge in advanced abdominal tumors. Although computed tomography remains the most widely used method, its sensitivity significantly decreases in critical regions such as the pelvis, lesser omentum, mesentery, or in mucinous disease. Magnetic resonance imaging (MRI), with its superior soft tissue contrast, functional sequences, and absence of radiation, emerges as a key tool for preoperative staging. This iconographic essay presents a comprehensive approach to MRI evaluation of peritoneal carcinomatosis, based on a dedicated technical protocol and a structured reading model combining the PAUSE and PROMISE systems. Through representative cases, we illustrate tumor dissemination patterns such as mesenteric disease, surgically unfavorable sites, ascites, extraperitoneal lesions, and mucinous content, emphasizing their relevance in surgical planning. The goal is to provide a practical, reproducible, and educational tool for radiologists, oncologic surgeons, and multidisciplinary care teams. This structured approach promotes systematic interpretation, improves study indication, and enhances interdisciplinary communication, directly impacting the selection of patients suitable for cytoreductive surgery.