Magnetic Resonance Imaging (MRI) has revolutionized the evaluation of acute ischemic stroke by providing sensitive and specific imaging biomarkers for brain tissue viability. Traditional imaging modalities such as non-contrast computed tomography (NCCT) are limited in early ischemia detection, whereas MRI sequences including diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) allow rapid identification of infarcted core and salvageable penumbra. Additional sequences such as fluid-attenuated inversion recovery (FLAIR), susceptibility-weighted imaging (SWI), and magnetic resonance angiography (MRA) further enhance diagnostic accuracy, treatment planning, and prognostication. This paper provides a theoretical review of diffusion, perfusion, and advanced MRI applications in acute ischemic stroke, comparing their clinical utility, strengths, and limitations.