Biomed Imaging MRI

mri

magnetic resonance imaging

mri is based on sophisticated technology that excites and detects the ____ in the change in the directional axis of ______ found in the water than makes up living tissues

change, protons

time and amount of energy released from protons during realignment is dependent on

environment and chemical nature of molecules

mri contrast usually contains

gadolinium

contrast alters the magnetic properties of

water molecules

contrast enhances the visibility of

tumors, inflammation, infection, blood vessels

contrast is delivered via

iv

mri can detect

joint problems, spinal disc abnormalities, structural problems, tumors

9 types of mri sequences

t1 weighted, t2 weighted, t2 fluid attenuated inversion recovery, diffusion weighted imaging, perfusion weighted imaging, susceptibility weighted imaging, magnetic resonance angiography, diffusion tensor imaging, functional mri

emphasize fat and protein content, good for visualizing anatomy and highlighting fat containing tissues

t1 weighted

sensitive to water content, useful for detecting fluid and edema, higher resolution than t1w seq

t2 weighted

suppresses signal from cerebral spinal fluid, making it excellent for visualizing subtle changes in brain parenchyma

flair

measures the movement of water molecules, allowing for the detection of tissue damage and ischemia, particularly in the brain

dwi

assesses blood flow to tissues and organs

pwi

technique that enhances the visualization of small blood vessels and iron deposits

swi

images blood vessels

mra

uses directional movement of water molecules to visualize white matter tracts and assess brain connectivity

dti

measures brain activity by detecting changes in blood flow

fmri

subsequence of dwi

apparent diffusion coefficient maps

adc maps

quantify mobility of water molecules in tissues

hypointense

restriction of water

hyperintense

flow of water

subsequence of dti

fractional anisotropy maps

fa maps

water diffusivity that reflects white matter properties

red

transverse fibers

green

anteroposterior fibers

blue

craniocaudal fibers

what is this an mri of

ischemic stroke

limitations and risks of mri

exerts powerful forces on iron objects, loud, contrast sensitivity

things to take into consideration about patients

patients with implants, noise sensitivity, nerve sensitivities, contrast sensitivity, pregnancy, claustrophobia