MRI scans work by using strong magnetic fields and radio waves to produce detailed images of the organs and tissues within the body. Here's a breakdown of the process:
1. Strong Magnetic Field Alignment
- The MRI scanner is essentially a powerful magnet. When you lie inside the scanner, the strong magnetic field aligns the protons (tiny particles within atoms) in your body. Think of them as tiny compass needles all pointing in random directions, which then get aligned to point in either the same direction as the strong magnetic field or the opposite direction.
2. Radiofrequency (RF) Pulses
- Radio waves are then emitted into the body. These radio waves briefly knock the aligned protons out of alignment. Specifically, the radio waves provide energy that changes the orientation of some of the protons.
3. Proton Relaxation and Signal Detection
- When the radio waves are turned off, the protons gradually realign with the magnetic field, releasing energy in the form of radio signals. This process is called relaxation.
- The MRI scanner has sensitive coils that detect these emitted radio signals.
4. Signal Processing and Image Creation
- The detected radio signals vary depending on the type of tissue and its environment.
- A computer processes these signals using complex mathematical algorithms to create cross-sectional images of the body. These images can be viewed from different angles.
- The contrast in the image is determined by how quickly the protons realign and the strength of the signal they emit. Different tissues have different relaxation times, which is what allows the MRI to distinguish between them.
In summary:
The process involves aligning protons using a strong magnetic field, disrupting this alignment with radio waves, detecting the signals emitted as the protons realign, and using these signals to create detailed images of the body's internal structures.
