Difference between MRI and fMRI

MRI and fMRI are used to produce images of the body using magnetic fields and radio waves. MRI creates structural images of the body. where fMRI creates functional images of the brain. The manner in which they are used is another difference. While fMRI is largely used for research, MRI is mostly used for diagnostic purposes.

Read this article to find out more about MRI and fMRI and how they are different from each other.

What is MRI?

MRI uses MRS (Magnetic Resonance Spectroscopy) technology to measure the specific chemical biomarkers that are present inside your body. A sizing magnet, radiofrequency coils, and a computer that controls the imaging process are the components of an MRI machine. The patient is placed on a table that slides into a scanner like a tube to create images of the patient's interior organs using a magnetic field and radio waves.

The protons in the patient's body align with the magnetic field during the MRI scan as a result of the magnetic field. The body is then exposed to radio waves, which cause the protons to resonant and generate a signal that is picked up by the radiofrequency coils. The computer then processes the signal to provide in-depth images of the tissues under image capture.

The following are some of the types of scans available −

  • Brain MRI

  • Spinal MRI

  • Abdominal MRI

  • Breast MRI

What is fMRI?

Functional Magnetic Resonance Imaging (fMRI) uses the principle of MRI. It is used to track detailed brain activity. It also uses a long magnetic field, radio waves, and a computer to measure the blood flow in the brain and take images of the brain.

A huge magnet, radiofrequency coils, and a computer that manages the imaging procedure are all components of the fMRI machine. However, rather than detecting changes in hydrogen atom density and distribution in tissues, fMRI is designed to detect variations in blood flow.

The patient performs particular actions or processes while lying in the scanner during an fMRI scan. Increased neuronal activity in particular brain regions is detected by the scanner as variations in blood oxygenation. These modifications are then used to build maps of brain activity that let researchers determine which parts of the brain are responsible for particular cognitive functions.

Similar to MRI, fMRI is usually regarded as safe but may not be appropriate for people with specific medical issues, like claustrophobia. In addition, correct interpretation of the results from fMRI requires specific knowledge and training.

Difference between MRI and fMRI

The following table highlights the major differences between MRI and fMRI −




Imaging Type

It is used to produce structural images of the body.

It is used to produce functional images of the brain


Produces detailed internal images of the body.

Used to study the activity of the brain


It takes more time to perform the scanning.

It takes less time compared to an MRI to perform the scanning.

Contrast Agents

The MRI scan doesn't require the contrast agents.

The fMRI scan uses the contrast agents to enhance the signals.


High Cost

Low Cost

Safety Concerns

MRIs use strong magnetic fields, which can be dangerous for patients who have implants or medical devices.

fMRI is less dangerous than MRI and is not appropriate for certain medical conditions such as claustrophobia.


The spatial resolution of MRI is very high.

fMRI has a superior temporal resolution.

Suitable Body Parts

It is capable of imaging any part of the body.

It is used to image only the brain.


Useful for identifying bodily defects, injuries, and illnesses.

Useful for mapping the neural networks involved in different tasks and understanding brain function.


MRI and fMRI are both significant imaging methods applied in the medical profession for various objectives. While fMRI is mostly used for research reasons to investigate brain function and activity, MRI is primarily utilised for diagnostic purposes to provide comprehensive structural images of the interior structures of the body, such as the brain, spine, and joints.

Both methods are crucial for improving our knowledge of the human body and brain since they both have particular advantages and disadvantages. In general, the variations between MRI and fMRI highlight the significance of picking the proper imaging method for a certain application or research question.