Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

C2 Modules CLINICAL > CT and MR angiography > Flashcards

CT and MR angiography Flashcards

1
Q

Where does the vertebral arteries run up through?

A

Transverse foramina of the cervical vertebrae and up through the foramen magnum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What branch does vertebral arteries give rise to?

A

Posterior Inferior Cerebellar Arteries (PICA)

and anterior spinal arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What branch does PICA give rise to?

A

Posterior spinal arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When vertebral arteries come together and fuse what will it form?

A

Basilar arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What branches does basilar arteries give rise to?

A

Anterior Inferior Cerebellar arteries at the level of pons

and pontine branches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What supplies the top of the cerebellum?

A

Superior Cerebellar Arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does basilar arteries feed into?

A

Posterior part of Circle of Willis: Posterior cerebral arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the branches within the middle cerebral arteries?

A

Anterior choroidal artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are arteries that goes to the lentiform nucleus?

A

Lenticulostriate arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is found within the optic chiasm?

A

Anterior communicating artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the venous system?

A

Part of circulation in which the blood is transported from periphery back to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are dural sinuses?

A

Veins found within space between periosteal layer and meningeal layer of dura mater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is the inferior sagittal sinus located within?

A

lower part of the falx cerebri

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the superior sagittal sinus?

A

Unpaired area along the attached margin of the falx cerebri

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where will the inferior sagittal sinus empty into?

A

sagittal sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is opthalmic vein located in?

A

orbital cavity and facial vein drain into the cavernous sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What two branches does cavernous sinus give off?

A
  1. Superior petrosal sinus

2. Inferior petrosal sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does the sigmoid sinus empty into?

A

Internal Jugular vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the clinical indications include?

A
  1. Ischemic stroke
  2. Transient Ischemic attack
  3. Subarachnoid haemorrhage
  4. Cerebral parenchymal haemorrhage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are examples of ischemic stroke?

A

Detect occlusion, thrombus, dissection and collaterals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is an example of TIA?

A

Carotid artery stenosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is an example of subarachnoid haemorrhage?

A

Aneurysms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is example of cerebral parenchymal hemorrhage?

A

Vascular malformation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is CT angiography technique?

A

Uses injection of contrast material into blood vessels and CT scanning to help diagnosis and evaluate blood vessel disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What do angiography exams produce?

A

Pictures of major blood vessels throughout body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does CTA combine?

A

CT scan with injection of dye

27
Q

What are characteristics of CT angiography?

A
  1. Helical CT acquisition
  2. IV injection of iodinated contrast
  3. Dose, weight, number of detectors
  4. Timing: Fixed scan delay, test bolus injection, automated bolus tracking
  5. Administration rate
28
Q

What are the clinical use of CTA?

A
  1. Fast diagnosis of major vessel occlusion
  2. Fast diagnosis of presence of aneurysm
  3. Screening of carotid stenosis
29
Q

What are the CTA post-processing?

A
  1. Axial source data
  2. Isotropic voxels
  3. Multiplanar reformats
  4. Maximum intensity projections
  5. 3D volume rendering
  6. Curved planar reformats
30
Q

What is multiplanar reformats?

A
  1. Axial/coronal/sagittal

2. Thickness

31
Q

What is maximum intensity projections?

A

Projecting the voxel with the highest attenuation value on every view throughout the volume onto 2D image

32
Q

What is 3D volume rendering?

A

3D volume reconstruction method that allows every voxel in the volume data to contribute to the reconstructed image

33
Q

What is Magnetic Resonance Angiography (MRA)?

A

Uses powerful magnetic field, radiowaves and computer to evaluate blood vessels and help identify abnormalities

does not use radiation

34
Q

MRA contrast material

A

less likely to cause an allergic reaction

35
Q

What are the MRA techniques?

A
  1. Time of Flight (TOF)
  2. Contrast enhanced (CEMRA)
  3. Phase contrast (PC)
  4. Other: ASL MR angiography
36
Q

What is TOF?

A

Measuring distance between a sensor and an object based on time difference between emission of signal and its reutn to the sensor after being reflected by an object

37
Q

What is CEMRA?

A
  1. Gadolinium-based agent is injected

2. Inject a compact bolus of contrast into central circulation with clearing all contrast from proximal veins

38
Q

What is phase contrast?

A
  1. Looking at both positive and negative velocities

2. Visualise moving fluid

39
Q

What is MRA TOF?

A
  • Technique to visualise flow within vessels without the need for contrast
  • 2D or 3D Gradient Echo sequence
  • Based on flow related enhancement on imaging slice
  • Manipulates MR environment so only spins within flowing blood generates signal
  • Stationary spins saturated – low MR signal
  • Fresh unsaturated spins carried in by flowing blood
40
Q

What is TOF principles?

A
  • Radiofrequency pulses suppress slice
  • Flowing blood not suppressed
  • Slice perpendicular to the flow
  • Saturation pulse – saturate blood from distal – doesn’t corrupt the images, if flow is too slow – suppression occurs
41
Q

Saturation of MRA TOF?

A
  1. Background tissue suppression
  2. Blood in slice taking too long (disadvantage)
  3. Worse with thick slabs
42
Q

Intravoxel dephasing of MRA TOF?

A
  • Different velocities within voxel – turbulent flow, stenosis, corners
  • Susceptibility induced – field inhomogeneities, transitions e.g. skull base
  • Worse with big voxels
43
Q

What is the main use of CEMRA?

A

Extracanial MRA

44
Q

What are the characteristics of CEMRA?

A
  1. 3D spoiled gradient echo sequence
  2. Flip angle: 25-50 degrees
  3. Gadolinium injection - shorten T1
  4. Blood high signal
  5. Rapid acquisition
  6. Arterial phase - timing of acquisition is important
  7. synchronised with first pass
  8. Images in long axis of vessel e.g. cornonal
  9. not reliant on inflow or new spins
  10. more efficient data acquisition
  11. substraction
45
Q

What is the main use of MRA phase contrast?

A
  1. Visualise moving fluids,

2. MRV

46
Q

What are the characteristics of MRA phase contrast?

A
  • No contrast required
  • Spins passing along the direction of the magnetic field gradient acquire phase change
  • Measures phase change
  • Proportional to distance travelled along gradient (i.e. velocity)
  • Provide quantitate and directional data
47
Q

What is Arterial Spin labelling

A
  • Flowing blood is tagged with RF-Pulses to have high magnetization, whilst stationary tissue is suppressed
  • Assess cerebral vasculature and hemodynamics
  • Conditions exhibiting delayed arterial transit time and collateral flow pathways
48
Q

What are the advantages of CTA?

A
  1. Availibility of MDCT
  2. Rapid: limits motion artefact
  3. Patient tolerance
  4. No flow related artefacts
  5. calcification well seen
  6. Wide range of reformations
  7. Whole head and neck circulation
  8. Imaging of non-vascular structures
49
Q

What are the limitations of CTA?

A
  1. Ionizing radiation
  2. Iodinated contrast
  3. Streak artefacts
  4. Lower resolution
  5. Acquisition limit evaluation of flow
50
Q

What are consequence of iodinated contrast?

A
  1. Invasive
  2. Reactions
  3. Acute kidney injury at risk patients
51
Q

What are examples of streak artefacts?

A
  1. Dental amalgam
  2. Metallic implants
  3. Dense contrast
52
Q

What is consequence of lower resolution?

A

Difficulty evaluating subtle well changes e.g. vasculitis

53
Q

What are the pitfalls of CTA?

A
  1. windowing
  2. Suboptimal opacification
  3. Vessel segment hidden by bone at skull base
  4. Over zealous post processing
54
Q

What are the advantages of MR ?

A
  1. No ionizing radiation
  2. Combined with other sequences
  3. Post-processing
55
Q

What are the limitations of MR?

A 
•	Susceptible to artefacts
•	Long acquisition times
•	Patient compliance – claustrophobia
•	MR safety
-	Pacemakers, certain implants, aneurysm clips
•	Physics support
•	Expensive
56
Q

What are advantages of 2D TOF?

A 
•	Individual slices
-	Minimal saturation of blood
-	Coverage expandable by adding more slices
•	Sensitivity to slow flow
•	Sat band prior to each slice 
-	Good venous saturation
57
Q

What are disadvantages of 2D TOF?

A
  • Large voxels, Long TE intravoxel dephasing
  • Relatively poor resolution
  • Poor suppression of short T1 tissues
58
Q

What are advantages of 3D TOF?

A
  • High spatial resolution
  • Small voxel – minimises intravoxel dephasing
  • Short TE (less dephasing)
  • High SNR (3D)
  • Isotropic voxels – Multiplanar Reformations
59
Q

What are disadvantages of 3D TOF?

A
  • Slab saturation – slab boundary artefact
  • Less effective venous suppression
  • Poor suppression of short T1 tissues
  • Motion artefact corrupt all slices
  • Slightly longer acquisition than 2D
60
Q

What are advantages of CEMRA?

A
  • Low intravoxel dephasing – short TR
  • Low saturation – Gadolinium
  • Short acquisition – low motion
  • Less Artefacts
61
Q

What are disadvantages of CEMRA?

A
  • Gadolinium
  • Cannot be repeated
  • Synchronisation
  • Short acquisition – resolution challenge
  • Subtraction – reduced SNR
62
Q

What are advantages of ASL MRA?

A
  • Covers entire vasculature
  • Non-invasive
  • No contrast agents
  • No ionizing radiation
  • Vessel selection
  • Can be quantitative
63
Q

What are the artefact of ASL MRA?

A
  • Require high arterial velocities
  • Presumes the flow direction is known, which is not always the case
  • Potential partial labeling of vessels in close proximity to selected vessel
  • Small signal variations within vessels affect assessment of partial stenosis

C2 Modules CLINICAL (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions