Advanced Mri techniques overview notes
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Overview
This lecture covered advanced MRI techniques, focusing on functional MRI
(fMRI), BOLD imaging, diffusion and perfusion imaging, spectroscopy, and
diffusion tensor imaging (DTI), including key concepts, clinical applications, and
keywords for exam questions.
Functional MRI & BOLD Imaging
• Functional MRI measures brain activity by detecting regions using more
oxygen during tasks.
• BOLD stands for Blood Oxygen Level Dependent, sensitive to the
paramagnetic properties of O₂ in blood.
• Active brain areas receive more oxygen, leading to signal changes (usually
dark) due to susceptibility effects.
• BOLD imaging is used to map specific brain functions and is useful in
patients who cannot communicate.
Diffusion MRI & ADC Mapping
• Diffusion MRI detects Brownian motion (random movement) of water
molecules, especially after stroke.
• Key term: Brownian motion refers to water molecule movement in interstitial
spaces.
• During stroke, damaged cells allow water inside, changing normal diffusion
patterns.
• The B value measures diffusion sensitivity; higher B value increases
sensitivity but lowers SNR.
• Bright areas on B=1000 that are dark on ADC maps indicate pathology
(stroke).
• T2 shine-through artifact: areas remaining bright on both B=1000 and B=0
are likely artifacts, not pathology.
• Hyperintense = bright; hypointense = dark; isointense = similar signal as
surroundings.
Created with Coconote - https://coconote.app
Overview
This lecture covered advanced MRI techniques, focusing on functional MRI
(fMRI), BOLD imaging, diffusion and perfusion imaging, spectroscopy, and
diffusion tensor imaging (DTI), including key concepts, clinical applications, and
keywords for exam questions.
Functional MRI & BOLD Imaging
• Functional MRI measures brain activity by detecting regions using more
oxygen during tasks.
• BOLD stands for Blood Oxygen Level Dependent, sensitive to the
paramagnetic properties of O₂ in blood.
• Active brain areas receive more oxygen, leading to signal changes (usually
dark) due to susceptibility effects.
• BOLD imaging is used to map specific brain functions and is useful in
patients who cannot communicate.
Diffusion MRI & ADC Mapping
• Diffusion MRI detects Brownian motion (random movement) of water
molecules, especially after stroke.
• Key term: Brownian motion refers to water molecule movement in interstitial
spaces.
• During stroke, damaged cells allow water inside, changing normal diffusion
patterns.
• The B value measures diffusion sensitivity; higher B value increases
sensitivity but lowers SNR.
• Bright areas on B=1000 that are dark on ADC maps indicate pathology
(stroke).
• T2 shine-through artifact: areas remaining bright on both B=1000 and B=0
are likely artifacts, not pathology.
• Hyperintense = bright; hypointense = dark; isointense = similar signal as
surroundings.
