Magnetic Resonance Imaging

Magnetic resonance imaging, or MRI, is a non-invasive technique with wide applications in neuroradiology and musculoskeletal radiology.

While performing MRI, the patient is placed in a strong external magnetic field. It aligns the randomly oriented hydrogen nuclei of water in the patient's body in the direction of the field.

After this, an external radiofrequency pulse is applied, which is absorbed by the hydrogen nuclei, disturbing their alignment.

Once the pulse stops, these nuclei release the absorbed energy realigning with the magnetic field. These emitted signals are picked up by the MRI machine to generate a gray-scale image of the tissue.

The image contrast can be improved by the intravenous injection of gadolinium-based contrast agents. For example, in this image, bone metastasis is clearly visible when gadolinium is used.

Unlike CT and X-ray, MRI allows better visualization of soft tissue structures, such as the delicate spinal cord inside the vertebral column, brain anomalies, and ligament tears.

MRI has the advantage of providing anatomical details for all three planes: axial, sagittal, and coronal.