Imaging in Hyperthermic Intraperitoneal Chemotherapy.

Hyperthermic intraperitoneal chemotherapy (HIPEC) combined with cytoreductive surgery (CRS) (CRS-HIPEC) has revolutionized the management of peritoneal malignancies, pivoting from a palliative care approach to a treatment strategy tailored to improve overall survival. This procedure is based on the principle that local instillation of heated chemotherapeutic agents augments their cytotoxic effects, which target and eradicate microscopic disease. Imaging is integral to the management of patients undergoing HIPEC, having multiple roles that range from patient selection, preoperative assessment, and determining treatment effectiveness to postprocedural surveillance. Various imaging modalities can be used for radiologic assessment and include CT, dual-energy CT, MRI, fluorine 18-fluorodeoxyglucose PET/CT, and PET/MRI. A crucial step in assessing the feasibility of CRS-HIPEC is estimation of the peritoneal carcinomatosis index, which enables one to determine the total peritoneal disease burden and is essential for effective multidisciplinary management. Following HIPEC, the completeness of cytoreduction score and residual disease score provide a robust framework for assessing treatment efficacy and strategically guiding subsequent management and surveillance protocols. Imaging facilitates accurate evaluation of complications, as well as early recognition of residual or recurrent peritoneal disease. The authors provide a comprehensive overview of HIPEC therapy, focusing on the role of imaging in the management of patients with peritoneal malignancies, delving into the nuances of this procedure, and discussing crucial aspects related to patient selection, surgical complexity, and prediction of outcomes. RSNA, 2025 See the invited commentary by Wasif in this issue.