Magnetic Resonance Imaging: Principles, Clinical Applications, and Problem Solving: A Critical Review

Abstract

Magnetic resonance imaging (MRI) has evolved over the past five decades from an experimental laboratory technique into one of the most versatile and clinically indispensable diagnostic imaging modalities in contemporary medicine. Grounded in the quantum mechanical phenomenon of nuclear magnetic resonance, MRI offers unparalleled soft-tissue contrast, multi-planar capability, and functional sensitivity without the use of ionising radiation. This critical review synthesises the current state of knowledge across the principal domains of MRI science and practice: physical principles including relaxation theory, pulse sequence design, and k-space reconstruction; hardware considerations spanning magnet technology, gradient systems, and radiofrequency coil arrays; and a broad landscape of clinical applications encompassing neuroimaging, cardiovascular assessment, oncological staging, musculoskeletal evaluation, and body imaging. A structured narrative review methodology was employed to identify, screen, and critically synthesise peer-reviewed literature on MRI principles, technologies, safety, and clinical applications published between January 2000 and March 2026 using databases including Web of Science, Scopus, PubMed, Google Scholar, IEEE Xplore, EMBASE, CINAHL, the Cochrane Library, and EUDAMED. Advanced techniques — including diffusion tensor imaging, functional MRI, arterial spin labelling, magnetic resonance spectroscopy, susceptibility-weighted imaging, and quantitative mapping — are examined alongside their translational significance. The review further addresses practical problem solving, with particular attention to artefact recognition and mitigation, radiofrequency and field inhomogeneity, and patient safety considerations relating to implanted devices, gadolinium-based contrast agents, and scanning during pregnancy. Emerging developments — comprising compressed sensing, artificial intelligence–driven reconstruction, ultra-high field MRI at 7 Tesla, portable low-field systems, and MR-guided therapy — are critically assessed in terms of their maturity, limitations, and realistic clinical prospects. The review identifies persistent challenges including acquisition speed, access inequity, artefact burden, and the translation gap between research innovation and routine clinical deployment, and concludes with a synthesis of strategic priorities for advancing MRI science and practice over the coming decade.