How does MRI differentiate between different tissues?

MRI uses magnetic fields and radio waves to differentiate between tissues based on their water content.

Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging technique that uses a strong magnetic field and radio waves to produce detailed images of the body's internal structures. MRI can differentiate between different tissues because the hydrogen atoms in water molecules in the body respond differently to the magnetic field and radio waves.

The magnetic field causes the hydrogen atoms in the body to align in a particular direction. When a radio wave is applied, the hydrogen atoms absorb the energy and flip their alignment. As they return to their original alignment, they emit a signal that is detected by the MRI machine. The strength and duration of the signal depend on the type of tissue and the amount of water present.

Different tissues have different water content, which affects the strength and duration of the signal. For example, tissues with high water content such as cerebrospinal fluid and blood vessels produce bright signals, while tissues with low water content such as bone produce dark signals. By analysing the signals produced by different tissues, MRI can create detailed images of the body's internal structures.

In addition to water content, MRI can also differentiate between tissues based on their chemical composition and physical properties. This allows MRI to detect abnormalities such as tumours, inflammation, and damage to tissues. MRI is a powerful tool for diagnosing and monitoring a wide range of medical conditions.