Part V Flashcards

1
Q

phase encoding main gradient coil [..]

A

y-axis

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2
Q

phase encoding [purpose]

A

support flipping M to x and y plane, give pulse/extra energy to enhance gradient coil @ left and right side

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3
Q

[RF ENRGY?] Phase Encoding

A

NONE, during PE if RF is introduced, it will not follow Bo

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4
Q

frequency encoding main gradient coil [..]

A

x-axis

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5
Q

frequency encoding [purpose]

A

SPATIAL DOMAIN -initial appearance and readable app. is in TRAPEZOIDAL

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6
Q

[component] convert signal to readable signal [process]

A

Fourier Transformer
Twisting of Form

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7
Q

[RF ENERGY?] Frequency Encoding

A

YES, include FID -energy transmitted from H atoms

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8
Q

time to give another sequence from first to second

A

TR repetition time

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9
Q

time b/w application of the RF excitation pulse and the peak of the signal induced in the coil

A

TE echo time

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10
Q

most impo plane in spin echo

A

TRANSVERSE - where most energy comes from

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11
Q

Spin echo with multiple 180 deg corresponding pulses

A

Fast Spin Echo

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12
Q

Fast Spin Echo [purpose]

A

lengthen exposure H to RF

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13
Q

Refocusing Pulse [purpose]

A

Give 180 degrees pulse to refocus H, make sure precession is same for increase FID

command it to go back - Rabbit and Turtle Principle

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14
Q

time you suppress signal of a certain poi

A

TI - Inversion time

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15
Q

[reason] signal starts after 90 degrees in inversion recovery sequence

A

only used to remove any signal coming from POI

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16
Q

[characteristics] T1-W Imaging

A

short TR and short TE
(less signal - increase intensity b/w x and y)

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17
Q

[dark-hypointense T1-W Imaging (E.T.H.I.C)

A

Edema
Tumor
Hemorrhage (hyperacute, chronic)
Infection/Inflamm
Calcifications

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18
Q

[bright-hyperintense] T1-W Imaging (F.F.S.M.P.P)

A

Fat
Flowing blood (slow)
Subacute Hemorrhage, Melanin
Protein-rich fluid
Paramagnetic substances (Ga, Cu, Manganese)

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19
Q

[characteristic] T2-W Imaging

A

long TR ang long TE

prolong relaxation = higher signal=brighter

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20
Q

[dark-hypointense] T2-W Imaging (Ca.Fi.P.-PV)

A

Calcification
Fibrous Tissue
Paramagnetic Substances (Deoxyhemoglobin, Ferritin, Melanin)
Protein-rich fluid
Flow Void

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21
Q

[bright-hyperintense] T2-W Imaging [E.T.I.W.S]

A

Edema
Tumor
Infection/Inflamm
Subdural Collection
Water

22
Q

STIR

A

Short TI Inversion Time

23
Q

[purpose] STIR

A

used to null/suppress signal from fat
180 deg first - sppress signal from fat

24
Q

STIR is good for [..]

A

bone marrow edema

25
Q

FLAIR

A

Fluid Attenuated Inversion Recovery

26
Q

IR sequence of FLAIR

A

long TR and TE

27
Q

FLAIR [purpose]

A

nulls/suppress signal from CSF or fluid from poi, heavily T2- W

28
Q

FLAIR is good for [..]

A

detection of hyperintense lesion (adjacent/ near CSF space)

29
Q

FLAIR Structures
[Di.N.G.E.M.Fo.T.E.Ch.S]

A
  1. D. affecting brain parenchyma (demyelinating and atherosclerosis)
  2. Neonates w/ perinatal Hypoxic Ischemic Encephalopathy
  3. Gliomatous cerebri
  4. Extra-axial masses
  5. Mesial Temporal Sclerosis
  6. Focal Cortical Dysplasia
  7. Tuberous Sclerosis
  8. Embolic Infarcts
  9. Chronic Infarcts
  10. Subarachnoid hemorrhage
30
Q

DWI

A

Diffusion Weighted MRI

31
Q

[characteristics] DWI

A

-takes adv of protons’ MOTION to produce signal changes; water=bright
-Stationary water molecules unaffected
-T2
-compare images where there is movement

32
Q

[evaluate] DWI

A

STROKE (cerebrovascular accident)
OLD and NEW Stroke

33
Q

MRS

A

Magnetic Resonance Spectroscpy

34
Q

MRS [purpose]

A

-non-invasive physiologic imaging of the brain
-measures levels of various tissue metabolites

35
Q

MRS [techniques]

A

single -large poi to analyze
multivolume- thinner volume/layer

36
Q

look into indiv H atoms and visualize activity w/in poi

A

MRS

37
Q

MRS [clinical applications classifications]

A

class a
class b
class c

38
Q

MRS- Class A
[Bra.D. Tu.Mo.R]

A
  1. Brain masses
  2. Distinguish neoplastic and non neoplastic masses
  3. Tumor Recurrence vs rad’n necrosis
  4. Monitoring responses to treatment
  5. Research tool
39
Q

MRS-Class B [I.H.E]

A
  1. Ischemia
  2. Hypoxia and related b injuries
  3. Epilepsy
40
Q

MRS- Class C [Hi.N.A.M.P]

A
  1. HIV d and brain
  2. Neurodegenerative disorders
  3. Amyotropic lateral sclerosis
  4. Multiple Sclerosis
  5. Psychiatric Disorders
41
Q

MT MRI

A

Magnetization Transfer MRI

42
Q

macromole involved in MT MRI

A

protein, lipid, nucleic acid, carbohydrates

43
Q

alters contrast of tissue on the basis of macromolecular environment

A

MT MRI

44
Q

MT MRI [Clinical Application]

A

Tuberculoma and Brain Abscess

45
Q

Qualitative Application

A
  1. MR Angio (except cerebral aneurysm)
  2. Post contrast Studies
  3. Spine Imaginh
46
Q

Quantitative Application

A
  1. Multiple Sclerosis
  2. Multiple System Atrophy
  3. Amyotrophic Sclerosis
  4. Schizophrenia
  5. Alzheimer’s D.
47
Q

MRA is used when [..]

A

if BV is tortous

48
Q

MRA Techniques

A

TOF (Time of Flight)
PC (Phase Contrast)
CE (Contrast Enhanced)

49
Q

[MRA technique] no CM is used, detects area where blood flow is present/stenosed

A

Time of Flight (TOF)

50
Q

[MRA technique] measures moving spins; quantification of blood flow and velocity

A

Phase Contrast (PC)

51
Q

[MRA technique] used Gd (reduces T1 relaxation time)

A

Contrast Enhanced (CE)

52
Q

[MRV] used to eval: [..]

A

thrombosis
compression by tumour of the cerebral venous

otitis media
meningitis
sinusitis
confusion w/ headache
seizures
drowsiness