The primary difference between traditional MRI, or magnetic resonance imaging scanners, and open MRI systems is open MRI devices have an open bed for the patient to lay in during the scan rather than the closed tube of a traditional scanner. While many patients prefer open MRI due to the high noise levels and close confines of a traditional MRI, most open MRI devices cannot achieve the same level of resolution as traditional systems, explains Health Diagnostics.
MRI imaging works by using strong magnetic fields to polarize hydrogen atoms in the water molecules contained in the body, reports Abi Berger for the British Medical Journal. When the magnetic field is removed, the hydrogen atoms return to their ground state and emit radio waves. By polarizing the atoms at several different angles, MRI systems are able to reconstruct images of body tissues based on these patterns of radio emissions. However, this requires repositioning of the magnetic field in the MRI to capture all the necessary angles for reconstruction, leading to the traditional enclosed tube design of MRI scanners.
Open MRI scanners avoid the need for an enclosed tube by using a pair of magnets that move around a patient on an open bed, according to medical imaging service OpenSided MRI. Using an open MRI can help alleviate the feelings of extreme claustrophobia some patients experience in traditional MRIs. Though the resolution of open MRI systems is not as good as the most powerful traditional MRI units, the imaging quality is sufficient for the majority of diagnostic uses.