neurobrain and spine MRI Flashcards
(20 cards)
what usually causes DWI arttifact
presence of metal e.g implants, makeup
what weighting image is always done for brains + why
t2, good overview, good for anatomy and pathology
pathological processes usually increase water content in tissue so what should you look for on the T1 image
signal loss / dark area
sagittal view particularly useful in MS brains and chair malformation
hippocampus is atrophied in alzheimers
for a brain, what would high DWI, low ADC and low DWI and high ADC be used to find
high DWI and low ADC = tumours
low DWI and high ADC = oedema, treatment response etc
what is CISS
Constructive Interference in Steady State, is a part of fast gradient echo sequences (for brain esp)
when is CISS used
used to investigate wide range of pathologies when routine MRI sequences dont provide desired anatomic info
what is MPR
multiplayer reconstruction
- process of acquiring defined diagnostic slices of information from volumetric data achieved during the scanning process.
what sequence tends to be used for dementia studies
GRE T2* WI
(also known as FFE fast field echo)
what is MRV
magnetic resonance venography,
- 2d technique non contrast
(used to find clots in veins of brain)
why type of suppression sequence is used in c-spine and why
- STIR (supress fat)
- improved lesion detection and visibility over t2 w FSE
why is FLAIR not used in c-spine
it doesnt perform well in spinal cord as it gets hampered by CSF pulsation artifact thus
- poor contrast to noise ration and poor lesion detection
what plane scan is superior for identifying scoliosis
coronal
what is the main sequence / weighting images for spinal scan (that should be prioritised if patient cannot be still)
sag t2’s
(then axial then t1 and stir if possible)
what type of sequence is good for scanning patients with regular movements e.g parkinsons? / what sequence is good for reduction motion artefacts
blade sequence (may also be known as propeller)
(k-space trajectory changed from cartesian sampling to overlapping radial method (blade/propeller))
(by oversampling centre of k-sapce, overall image contrast is im proved and artefacts are minimised)
- can be done with all different types of weightings
note: artefacts from neck braces cause horseshoe shaped darkness
what is a zipper artifact / effecta type of MRI artifact
a type of MRI artifact where one or more spurious bands of electronic noise extends across the image.
(ZIPZ across image seen)
explain why u might see dark bands on axial/oblique imaged at intersecting planes
due to multiplayer acquisition, it can cause saturation of protons in the region where slices intersect
what does CSP stand for and what is it
cavum septi pellucidi (small but important structure in foetal brain)
