MRI stands for Magnetic Resonance Imaging, which by its powerful magnetic field and radio waves, produces detailed images of structures inside the body. Its operating principle involves aligning hydrogen atoms in the body with a magnetic field and exciting them with radio waves. Then, it senses the energy they emit as the atoms relax back to their previous alignment.
Basic Principles
An MRI scan is a form of imaging because of the unique make-up that the human body has. We are all composed of cells which all have water – composed of hydrogen ions (H2O).
The magnetic field produced by the MRI machine can affect such positively charged hydrogen ions (H+ ions) favorably, causing them to ‘spin’ similarly. We are capable of varying the strength and orientation of such a magnetic field in order to control the ‘spin’ of the protons, which we can use to develop layers of information.
Precession is how the protons get back to the original state when the magnet is removed.
Basically, the different tissues in the body take longer to return to their original states, which is how we’re able to see the different tissues in the body.
Strong Magnetic Fields
MRI machines generate a strong magnet, and they have an extremely strong magnetic field. It aligns the magnetic moments of hydrogen atoms (protons) in your body, and causes them to spin in a similar fashion.
Radio Frequency Pulses
The MRI machine then sends out radio waves that provide an impetus for the protons. The radio waves are at a frequency that can flip the aligned protons out of equilibrium.
Imaging
The type and strength of the signals, which one observes, depends on the kind of tissue and proton environment. Different tissues and structures of the body have different relaxation rates, and the MRI scanner will create complex images of each tissue because it is capable of separating them.
Computer Processing
The signals that are received are translated into a digital image that is observable on the monitor, or printed. The computer uses complicated algorithms that put the data together, reconstruct the image, then make it visual for the user to interpret the patient’s internal body parts.
In short, MRI is a technique that uses the natural magnetic properties of the body to generate a diagnostic image with incredible detail easily, with no need for ionizing radiation, unlike X-ray imaging. It is a safe diagnostic tool that is very effective.
Relaxation And Signal Detection
Turning the radio waves off, the protons return to the base state, releasing energy in the form of radio waves. The energy is received by the MRI machine, with a computer being used to rearrange the signals.
Conclusion
The probe or protons are influenced by the magnetic field when they are at the equilibrium position. Then, a pulse of radio frequency energy, known as the energy in the radio frequency range, is introduced into the patient body to disturb the equilibrium position with a highly controlled energy called a radio frequency pulse. The radio frequency pulse is used to excite the protons to another position that is not in line with the magnetic field. The radio frequency pulse has a short life span, followed by a time interval for the protons to return to the equilibrium position.
Frequently Asked Questions
Q. How Does Magnetic Resonance Imaging (MRI) Work?
MRI works by using a strong magnet, radio waves, and a computer to generate detailed pictures of organs and tissues by making use of the water content in your body.
Q. What Is The Principle Of Magnetic Resonance Imaging?
Magnetic Resonance Imaging works by the alignment of protons in the body (mostly in water) by the use of a powerful magnetic field and radio waves, then sent out of alignment by a radiofrequency pulse.
Q. What Is The Contrast Mechanism In MRI?
The disorganized protons within the water nuclei of the tissue of interest are aligned using a strong, stable external magnetic field.
Q. Why Is MRI So Loud?
Most of the typically heard noise during an MRI scan is produced by the rapid changes of the magnetic fields of the gradient coils.
Q. Why Is It Not Allowed To Drink Water Prior To An MRI?
Water is often allowed before an MRI scan, but do follow instructions.
