FMRI is a functional neuro-
imaging produce using MRI
technology that measures brain
activity in blood flow.
This technique relies on the fact that cerebral blood
flow and neuronal activation are coupled. When an
area of the is in use, blood flow to that region also
The primary form of fMRI uses the Blood-Oxygen-
level dependent (BOLD) contrast discovered by seji
This is a type of specialized brain and body used to map
neural activity in the brain or spinal cord of humans or
other animals by imaging the change in blood flow
(hemodynamic response) related to energy used by brain
BOLD: BOLD is a method used in fMRI to observe
different areas of brain, which are found to be active
at any given time.
A neuron also known as a neuron or nerve cell is an
electrically excitable cells that processes and transmits
through electrochemical cells.
HOW MRI WORKS?
To perform a study the patient is positioned
within an MRI scanner which forms a strong
magnetic field around the area to be
imaged. Most medical application rely on
detecting a radio frequency single emitted
by be exited hydrogen atom in the body using energy from an
oscillating magnetic field applied at the appropriate resonant
frequency. The orientation of the image is controlled by varying the
main magnetic field using gradient coils. As these coils are rapidly
switched on or off they create the characteristics repetitive noises of
an MRI scan. The contrast between different tissues is determined by
rate at which excited atoms returns to the equilibrium state. MRI
requires a magnetic field that is both strong and uniform. The field
strength of the magnet is
measured in tesla.
CONTRAST IN MRI
Image contrast may be
weighted to demonstrate
different anatomical strucu-
res or pathologies. Each
tissues returns to its
equilibrium state after
excitation by the independent processes of T1 and T2
To create a T1-weighted image we wait for different amounts of magnetization to
recover before measuring the MR signal by changing the repetition time (TR). This
image weighting is useful for assessing the cerebral cortex, identifying fatty tissue,
characterizing focal liver lesions and for post-contrast imaging.
To create a T2-weighted image we wait for different amounts of magnetization to
decay before measuring the MR signal by changing the echo time (TE). This image
weighting is useful for detecting edema, revealing white matter lesions and
assessing zonal anatomy in the prostate and uterus.
In 1952, Herman Carr produced a one-dimensional MRI image as reported in his
Harvard PhD thesis.In the Soviet Union, Vladislav Ivanov filed (in 1960) a document
with the USSR State Committee for Inventions and Discovery at Leningrad for a
Magnetic Resonance Imaging device,although this was not approved until the