Magnetic resonance imaging (MRI) is a non-invasive imaging modality widely used in both clinical practice and research for high-resolution visualization of internal body structures. Its primary advantages include excellent soft tissue contrast, the absence of ionizing radiation, and the ability to acquire both anatomical and functional data. MRI is based on the principles of nuclear magnetic resonance, leveraging the magnetic properties of atomic nuclei, primarily hydrogen. An MRI system comprises several key components: the main magnet, which generates a strong static magnetic field, gradient coils for spatial encoding and radiofrequency (RF) coils for signal transmission and reception. MR signal generation relies on the angular momentum (spin) of nuclei, which align under the magnetic field. The Larmor frequency governs the precession rate of these nuclei and depends on magnetic field strength and the gyromagnetic ratio. Following RF excitation, tissue magnetization returns to equilibrium through relaxation processes, as T1 (longitudinal) and T2 (transverse), which generates contrast in standard imaging sequences. Both T1-weighted and T2-weighted images show detailed anatomical structures. T2-weighted images are also sensitive to fluid and pathology. Image reconstruction is achieved through Fourier transformation of spatially encoded signals. Common pulse sequences include spin echo, known for high contrast, and gradient echo, valued for faster acquisition and sensitivity to magnetic susceptibility. MRI plays a vital role in neuroimaging for assessing brain structure and function (functional MRI), and in cardiac imaging for evaluating myocardial anatomy and function. These applications underscore MRI’s versatility and indispensable role across diverse medical and scientific domains.