Magnetic resonance imaging (MRI) is a diagnostic tool. Images are created using an electro-magnet. The images obtained are based on water content of tissues. A neck or back MRI does not involve radiation. It is used to image many parts of the spine such as discs, facet joints, spinal nerves, tumors, infections, cysts and other structures. A neck or back MRI provides more images from more views than traditional x-rays. These detailed and varied images may provide your doctor information not available by other tests.