Colorectal liver metastases: imaging strategies for diagnosis, local treatment planning and systemic treatment response.

Colorectal liver metastases (CRLM) remain a major cause of cancer-related mortality, with imaging playing a critical role in diagnosis, treatment planning, and surveillance. CT and MRI are the mainstays of lesion detection, with MRI offering higher sensitivity, particularly for small or treated lesions. PET/CT and diffusion-weighted imaging (DWI) complement anatomical techniques, especially in surgical planning and treatment response assessment. Beyond RECIST 1.1, morphologic tumor response criteria such as Chun and mRECIST incorporate morphologic and functional changes to potentially reflect therapeutic efficacy more accurately. This review summarizes international guidelines and literature on optimal imaging for CRLM, covers the imaging features of common histologic subtypes, post-treatment appearances, and highlights key points for locoregional therapy, surgical planning, and recurrence detection. Finally, we highlight emerging technologies including circulating tumor DNA, artificial intelligence and radiomics, which may enhance diagnostic precision and enable personalized treatment approaches in CRLM.