What It Is. Magnetic resonance imaging (MRI) of the cervical spine is a safe and painless test that uses a magnetic field and radio waves to produce detailed images of the cervical spine (the bones in the back of the neck). An MRI differs from a CAT scan (also called CT scan or a computed axial tomography scan) because it does not use radiation. An MRI scanner consists of a large doughnut-shaped magnet that has a tunnel in the center. Patients are placed on a table that slides into the tunnel.