How does an MRI work? The basics explained

How does an MRI work? The basics explained

How does an MRI work? The basics explained

Magnetic resonance imaging (MRI) is a medical imaging technique used to visualize detailed internal structures of the body. It is based on the physical properties of hydrogen atoms in the body and the interactions of these atoms with strong magnetic fields and radio waves. This article explains the basics of MRI, how it works, its applications, and its advantages and disadvantages.

What is an MRI?

An MRI machine consists of a strong magnet, a transmitting coil, a receiving coil and a computer. The magnet creates a strong, constant magnetic field around the patient's body. The transmitting coil sends radio waves into the body and the receiving coil detects the signals emitted by the hydrogen atoms. The computer processes these signals and creates high-resolution images of the inside of the body.

How does imaging work?

MRI imaging is based on the phenomenon of magnetic resonance. Hydrogen atoms, which are abundant in the body, are composed of a proton, which has a positive charge, and an electron, which has a negative charge. When the body is placed in the MRI machine's strong magnetic field, the hydrogen atoms are aligned so that their protons point in the same direction.

Magnetization and relaxation

This state of alignment of the protons is called magnetization. When the transmitter coil sends radio waves into the body, the protons are excited by the energy of the radio waves and begin to rotate. In doing so, they absorb the energy from the radio waves. When the radio waves are turned off, the protons return to their original alignment, emitting energy in the form of radio waves.

Signal acquisition and image construction

The receiving coil detects the emitted radio waves and forwards them to the computer. The computer analyzes the signals and creates an image that represents different types of tissue and anatomical structures in the body. Different types of scans are used, such as the T1-weighted or the T2-weighted sequence, to make different tissue properties visible.

Applications of MRI

MRI has found wide application in medical diagnostics. It can be used to examine many areas of the body, including the brain, heart, joints, spine, abdominal organs, and more. It enables a detailed assessment of tissue structures, inflammation, tumors, blood vessels and other pathological changes.

The advantages of MRI

MRI offers several advantages over other imaging techniques such as X-rays or CT scans. It does not use ionizing radiation, making it a safe choice for many patients, especially children and pregnant women. It also offers high resolution and can distinguish tissue types well. It also allows for the assessment of soft tissue that is difficult to visualize using other techniques.

The disadvantages of MRI

Despite its numerous advantages, MRI also has some disadvantages. It can be noisy and patients may have to lie still during the exam, which can be uncomfortable for some. In addition, MRI can be expensive and require longer examination times than other imaging techniques. Patients with metal implants or other metal objects may not be able to undergo an MRI scan due to complications or danger.

Frequently asked questions

Ask:How long does an MRI scan take?

Answer:The length of an MRI scan varies depending on the area being examined, but can typically range from 30 minutes to an hour.

Ask:Is an MRI scan painful?

Answer:The MRI scan is usually painless. However, some patients may experience a slight tingling or warm feeling during the scan.

Ask:How can I prepare for an MRI scan?

Answer:Before an MRI scan, you may need to remove jewelry, metal objects, or clothing containing metal as they may interfere with the scanning process. You may also be given instructions about fasting before the exam.

Ask:Can an MRI scan be performed on every patient?

Answer:Most patients can have an MRI scan. However, there are some contraindications, especially for patients with implanted pacemakers, metal braces or artificial joints.

Ask:Are there any side effects or risks associated with an MRI scan?

Answer:The MRI scan is generally safe and has no side effects. However, rare cases of allergic reactions to intravenously administered contrast media may occur.

Conclusion

Magnetic resonance imaging (MRI) is a modern and advanced imaging technique that provides a detailed view of the body's internal structures. It is based on the physical properties of hydrogen atoms and the interactions of these atoms with strong magnetic fields and radio waves. MRI has found wide application in medical diagnostics and provides a safe and detailed assessment of various areas of the body. Although it has some disadvantages, its advantages outweigh them, making it an important diagnostic method in modern medicine.