An Open MRI uses the same technology as a Closed MRI, but has a much larger opening compared to a Closed MRI. In recent years Open MRI technology has made huge improvements in magnet power, computing capacity, and image construction that Open High Field MRIs such as the Hitachi Oasis can produce images on par with Closed High Field MRIs. Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures that are inside the body. MRIs allow physicians to see extremely detailed images of the inside of the human body that cannot be seen with other diagnostic imaging. An MRI is one of the safest, most comfortable imaging techniques available.