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HSC3007 MRI > Week 8 > Flashcards

Week 8 Flashcards

1
Q

bandwidth is __ proportional to sampling time

A

inversely

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2
Q

high bandwidth RF pulse causes __

A

higher SAR = thicker slice thickness and reduced TEs & TRs

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3
Q

purpose of birdcage coil

A

provides best RF homogeneity & transceiver coil to image head

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4
Q

FLAIR

A

Fluid Attenuated Inversion Recovery

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5
Q

FLAIR nulls fluid signal by __

A

long inversion time

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6
Q

SWI

A

Susceptibility Weighted Imaging

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7
Q

SWI uses __ to generate unique contrast

A

magnetic susceptibility differences such as deoxygenated blood, Fe2+, & Ca2+

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8
Q

SWI is useful for __

A

microbleeds, calcifications, microhemorrhage

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9
Q

SWI images obtained are __

A
  • Magnitude image
  • Phase image
  • SWI
  • minIP
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10
Q

whole brain scans include __

A
  • localizer
  • axial T1 / T2 / FLAIR / DWI / SWI
  • coronal T1
  • sagittal T2
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11
Q

coronal brain scans are aligned to __

A

frontal sinus to line of occipital protuberance

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12
Q

coverage of whole brain scans

A

vertex to foramen magnum

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13
Q

whole brains scans are aligned to __

A

Anterior Commissure – Posterior Commissure (AC-PC) line

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14
Q

coronal epilepsy range is __

A

whole temporal lobe

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15
Q

coronal epilepsy scans are __

A

angled perpendicular to brain midline, tilted to hippocampus

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16
Q

orbit scans done include __

A
  • localizer
  • T1 coronal
  • T2 axial / sagittal
  • STIR axial / coronal
17
Q

T1 coronal orbit scans are aligned __

A

Perpendicular to optic nerve, Position block parallel to eye lenses

18
Q

T2 axial orbit scan position block are aligned __

A

parallel to optic nerve

19
Q

T2 sagittal oblique orbits are aligned __

A

Parallel to line along superior & inferior rectus muscle; position block parallel to optic nerve

20
Q

why is CT the 1st modality for emergencies instead of MRI

A

speed / availability / contraindications for MRI

21
Q

common artifacts seen in time of flight MRA

A
  • Venetian blind artifact due to overlapping adjacent slabs acquired separately then fused together
  • Imperfect slab superimposition causes multiple overlapping thin slab acquisition which causes tortuous vessels being cut off and ‘stenosis’ appearance
22
Q

how does time of flight work

A

Rapid RF pulses to saturate stationary protons in a slice before they can fully recover longitudinal magnetization

Surround tissues saturated using short TR to prevent T1 recovery and appears dark

Flowing blood unsaturated and appears bright

Moving protons do not experience saturation pulses & have longitudinal magnetization available for signal generation

23
Q

subdural hemorrhage appears __

A

biconcave & venous blood

24
Q

epidural hemorrhage appears __

A

biconvex & arterial blood

25
Q

types of aneurysms

A

berry [bulges from 1 side of artery]

fusiform [bulges from all sides of artery]

mycotic [infected artery wall]

26
Q

vascular diseases include __

A

aneurysm, arterial venous malformation, arterial venous fistula

27
Q

what is multiple sclerosis

A

Autoimmune disease attacks protective sheath that covers nerve fibers & causes problems between brain & body

28
Q

MRI face protocols

A
  • localizer
  • Axial T1 / STIR / DWI
  • Sagittal T2
  • Coronal T1 / STIR
  • 3D T1
29
Q

MRI face axial scan targets are __

A
  • Position block parallel to hard palate
  • Perpendicular to nasal septum
  • Glabella down to larynx
30
Q

MRI face sagittal position block parallel to __

A

nasal septum

31
Q

MRI face coronal aligned __

A
  • Perpendicular to nasal septum
  • Positioning block perpendicular to hard palate
32
Q

tongue sagittal range are __

A
  • AP range = sphenoid sinus to clear nose tip
  • RL range = entire oral cavity
33
Q

MRI neck scans include

A
  • localizer
  • axial T1 / STIR / DWI
  • sagittal T2
  • coronal T1 / STIR
34
Q

MRI neck axial scans are __

A
  • Perpendicular to cervical spine
  • Parallel to hard palate in chin down position
  • Range = neck soft tissue from frontal sinus to line of SC joint
35
Q

MRI neck sagittal scans are __

A
  • Range = entire neck from frontal sinus to clavicle
  • Parallel to cervical spine
  • Right to left pinna
36
Q

MRI neck coronal scans are __

A
  • Perpendicular to nasal septum
  • Range = nose tip up to line of spinous process
  • Patient must not swallow for sequence acquisition; 30s provided after scan to swallow saliva
37
Q

where is the target for whole brain scans

A

glabella

HSC3007 MRI (10 decks)

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