Magnetic Resonance Imaging (MRI) works by using strong magnetic fields and radio waves to create detailed images of the inside of the body. Here's how the process works:
- The MRI machine contains powerful magnets that produce a strong, uniform magnetic field around the part of the body being scanned. This magnetic field causes the protons in hydrogen atoms (mainly found in water and fat in the body) to align with the field, similar to tiny magnets lining up in the same direction
- Once aligned, the machine sends short pulses of radiofrequency (RF) waves to the body. These pulses temporarily knock the protons out of alignment by exciting them to a higher energy state
- When the RF pulses are turned off, the protons relax back to their original aligned state, releasing energy in the form of radio signals
- These emitted signals are detected by receiver coils in the MRI machine. The signals vary depending on the type of tissue and its environment, because different tissues cause protons to relax at different rates (known as relaxation times)
- By applying magnetic field gradients, the MRI system localizes the signals to specific locations within the body, allowing the computer to construct detailed cross-sectional images of organs and tissues based on the density and properties of hydrogen atoms
- The resulting images provide excellent contrast between different soft tissues, which is why MRI is especially useful for imaging the brain, muscles, heart, and internal organs without using ionizing radiation like X-rays
In summary, MRI leverages the magnetic properties of hydrogen protons in the body, manipulating their alignment and detecting the signals they emit as they return to equilibrium, then converting these signals into detailed anatomical images
