Spine Magnetic Resonance Imaging (MRI)

MRI was initially developed in the late 1970s and early 1980s. This technique offers superior soft tissue contrast resolution compared to CT and X-ray imaging. MRI operates on the principle of nuclear magnetic resonance (NMR), which involves the manipulation of hydrogen nuclei (abundant in water and fat) using magnetic fields to generate an electromagnetic signal. MRI scanners use a powerful magnet to create a magnetic field and radio waves.  By modifying the radio wave pulses, hydrogen atoms throughout the body emit signals with frequencies corresponding to the tissue density in which they are located. These signals are recorded by the scanners receiving coils and then processed by a computer to produce high-resolution 2D and/or 3D images. 

Indications: radiculopathy, vertebral disc herniation, congenital malformations, spine infection/abscess, spine tumors or metastatic disease, epilepsy, chronic headaches, dementia, and demyelination (characteristic of multiple sclerosis and other autoimmune diseases). 

Advantages: superior soft tissue resolution and contrast compared to CT and X-ray makes pathology easier to identify,  images are 2D and/or 3D, no use of ionizing radiation, and programmable MRI protocols can assess blood flow and diffusion of water (helpful for stroke detection). 

Disadvantages: expensive, less widely available, much longer scan times compared to CT, tight space of MRI scanner may cause claustrophobia, images may be altered by patient movement, and safety issues caused by MRI magnet.