MRI machines are big, non-invasive machines that employ radio waves and a strong magnetic field to provide detailed images of inside organs and tissues. MRI machines are big, non-invasive machines that employ radio waves and a strong magnetic field to provide detailed images of inside organs and tissues. MRI machines are big, non-invasive machines that employ radio waves and a strong magnetic field to provide detailed images of inside organs and tissues.MRI machines are big, non-invasive machines that employ radio waves and a strong magnetic field to provide detailed images of inside organs and tissues.