Cerebral Imaging (13)

Question 1

CT Head: Brain Tissue Algorithm/Windowing

Answer 1

80/30 to match approx HU of brain matter

Question 2

First Imaging Study for initial evaluation of Stroke

Answer 2

CT Head WO

Question 3

Ischemic stroke–definition/cause
(& CT Presentation)

Answer 3

Sudden interruption in blood flow to brain caused by bloackage in artery
(localized areas of hypodensity/darkening)

Question 4

Hemorrhagic Stroke
(& CT presentation)

Answer 4

Sudden interruption in blood flow to the brain caused by intracranial bleeding (noted by localized areas of hyperdensity/brightness)

Question 5

Intracranial hemorrhage: Subdural

Answer 5

Banana-shape
Follows curve of cranium

Question 6

Intracranial hemorrhage: Epidural (2)

Answer 6

Almost always caused by trauma & assoc’d w/skull fracture
Convex shape: bulges out into brain matter

Question 7

Intracranial hemorrhage: Subarachnoid

Answer 7

Usually caused by ruptured aneurysm in the COW

Question 8

Intracranial hemorrhage: Hemorrhagic Stroke

Answer 8

Intracerebral

Question 9

Astrocytoma
Meduloblastoma

Answer 9

Primary malignant brain tumor example

Question 10

Meningioma
Acoustic Neuroma

Answer 10

Most common benign brain tumors

Question 11

CT Angiography (CTA) Head: Purpose

Answer 11

Examine arterial structures in brain, esp Circle of Willis

Question 12

CT Angiography (CTA) Head: Indications (examples)

Answer 12

Vascular abnormalities (e.g., aneurysm, vascular lesion)

Question 13

CT Angiography (CTA) Head: Scan Type

Answer 13

Helical

Question 14

CT Angiography (CTA) Head: Slice Parameters

Answer 14

0.625mm slices w matching/overlapping interval to view small vascular changes

Question 15

CT Angiography (CTA) Head: Gantry Tilt

Answer 15

None

Question 16

CT Angiography (CTA) Head: Contrast
Rate
Direction
Timing

Answer 16

Injected at 4+ mL/sec
Direction of blood flow: inferior to superior
Bolus timing/tracking

Question 17

CT Angiography (CTA) Head: Algorithm

Answer 17

Standard: 400/40
(Does not follow normal windowing for brain d/t interest in vessels, not brain matter)

Question 18

CT Angiography (CTA) Head: Common Reformats/Rendering

Answer 18

Coronal MPR
3D

Question 19

CT Angiography (CTA) Head: Stroke (2)

Answer 19

Not indicated for initial eval since Sx may be caused by vascular changes below head
Commonly requested after CT head WO shows subarachnoid hemorrhaging

Question 20

CT Angiography (CTA) Head & Neck: Purpose (primary arterials)

Answer 20

Examine arterial structures in brain/supplying blood to brain
E.g., Internal carotid, vertebral aa

Question 21

CT Angiography (CTA) Head & Neck: Indications (4)

Answer 21

Suspected stroke
Dissection
Aneurysm
Assess vascular supply after neck trauma
Etc

Question 22

CT Angiography (CTA) Head & Neck: Scan Type

Answer 22

Helical

Question 23

CT Angiography (CTA) Head & Neck: Slice Parameters

Answer 23

1.25mm w matching/overlapping interval to view small vascular changes
(slightly thicker than CTA Head since section scanned is larger)

Question 24

CT Angiography (CTA) Head & Neck: Gantry Tilt

Answer 24

None

Question 25

CT Angiography (CTA) Head & Neck: Contrast Rate Direction Timing

Answer 25

Injected at 4+ mL/sec Scanned in direction of blood flow: inferior to superior Timed using bolus timing/tracking

Question 26

CT Angiography (CTA) Head & Neck: Algorithm

Answer 26

Standard: 400/40

Question 27

CT Angiography (CTA) Head & Neck: Common Reformats

Answer 27

Coronal MPR 3D

Question 28

CT Angiography (CTA) Head & Neck: Vascular Pathologies (4)

Answer 28

Thrombosis Stenosis Aneurysm Dissection

Question 29

CT Angiography (CTA) Head & Neck: Filling Defect (for example: d/t)

Answer 29

Occurs when contrast is not able to completely fill lumen of vessel (e.g., d/t thrombus)

Question 30

MIP

Answer 30

Maximum Intensity Projection: Images display the max HU within the slice instead of the average d/t increased visibility of contrast-filled vessels (creates 3D appearance)

Question 31

VR

Answer 31

Volume Rendering: allows multiple tissues to be displayed together with different colors/transparencies

Question 32

CT Head Venogram: Purpose

Answer 32

Image venous structures of brain: sinuses

Question 33

CT Head Venogram: Indications (4)

Answer 33

Cerebral sinus (venous) thrombosis (primary pathology for CT Head) Stroke (if blood can't flow out of brain correctly, it can't flow in correctly) Mental Status Change Sinusitis

Question 34

CT Head Venogram: Scan Type

Answer 34

Helical

Question 35

CT Head Venogram: Slice Parameters

Answer 35

2.5mm slices w matching interval

Question 36

CT Head Venogram: Gantry Tilt

Answer 36

None

Question 37

CT Head Venogram: Contrast Direction Prep Time

Answer 37

In direction of venous blood flow (superior to inferior) 45sec post injection

Question 38

CT Head Venogram: Algorithm

Answer 38

Standard: 400/40

Question 39

CT Head Venogram: Reformats

Answer 39

Sagittal/Coronal MPR