Magnetic Resonance Imaging (MRI) plays a pivotal role in evaluating treatment response following radiation-based therapies for hepatocellular carcinoma (HCC). As radiation modalities such as stereotactic body radiotherapy (SBRT) and transarterial radioembolization (TARE) gain prominence, understanding the underlying mechanisms of radiation-induced cellular senescence is essential for accurate interpretation of imaging. The physiological changes of radiation treatment manifest as altered diffusion characteristics and delayed regression of enhancement and tumor volumes on MRI, challenging conventional response criteria. Herein, functional and temporal imaging biomarkers are necessary. However, current imaging strategies lack standardization and robust validation, underscoring the need for prospective studies to correlate MRI findings with treatment outcomes. This review synthesizes emerging evidence on MRI-based evaluation of radiation-treated HCC, explores the physiological rationale linking senescence to imaging phenotypes, and advocates for optimized imaging protocols and criteria to enhance post-treatment surveillance and therapeutic decision-making.