Week Six - Multimodal Medical Image Computing Flashcards
What is the difference between imaging and computing?
Imaging - acquisition of images.
Computing - computational analysis of images.
What does MIC stand for?
Medical image computing
What is back-projection in regards to CT?
Involves smearing back the projection across the image at the angle it was received to reconstruct the image.
What is EEG?
Electroencephalography. Measures voltage fluctuations resulting from the ionic current within the neurons of the brain.
What is MEG?
a cool kid.
Magnetoencephalography.
Measures magnetic fields produced by electric currents in the brain.
Why would you perform both an EEG and a MEG?
Individually poorly detect activity below the cortex - but with different errors - so when combined noise is somewhat corrected.
Name the six types of MRI.
T1-weighted T2-weighted Proton density weighted FLAIR dMRI fMRI
What is the T1 time?
Time taken for excited spins to recover and be available for the next excitation.
Short T1 = bright (fat)
Long T1 = dark (CSF)
What is the T2 time?
How quickly an MR signal fades after excitation.
Short T2 = dark (fat)
Long T2 = bright (CSF)
What does T1 contrast enhanced MRI involve?
Injection of a contrast agent - gadolinium.
What does proton density weighted MRI involve?
Less protons = low signal = dark
More protons = cool signal = bright
What is FLAIR?
Fluid attenuated inversion recovery. A pulse sequence used in MRI that nulls fluids.
What is FLAIR used for?
Commonly used in the brain and spinal cord where lesions are normally covered by bright cerebrospinal fluid signals.
Describe dMRI.
Estimates the orientation of axonal fibre bundles based on the fact that water diffuses most rapidly along the length of axons.
What does fMRI involve?
Relies on the fact that cerebral blood flow and neuronal activation are coupled - when an area of the brain is in use, blood flow to that region increases.
