Imaging the brain and spinal cord

Question 1

List some imaging modalities for the brain and spinal cord

Answer 1

Computed tomography (CT)
Magnetic resonance imaging (MRI)
X-ray (plain film)

Question 2

List the different cross sections of imaging

Answer 2

Axial
Coronal
Sagittal

Question 3

What is meant by spatial resolution?

Answer 3

Good for looking at bones

Question 4

What is meant by contrast resolution?

Answer 4

Good for looking at different tissues - can distinguish between different types

Question 5

What are the most important MRI images sequences?

Answer 5

T1 and T2

Question 6

What is a T1 weighted MRI scan?

Answer 6

Static fluid appears black

Question 7

What is a T2 weighted MRI scan?

Answer 7

Static fluid is white

Question 8

What static fluid is best to look at to determine the weighting of a MRI scan?

Answer 8

CSF

Question 9

What is contrast?

Answer 9

Used to increase contrast resolution
Given intravenously or enteral before scan
Is either more or less dense than surroundings (CT or X ray) or paramagnetic (MRI)

Question 10

What are the pros of Xray?

Answer 10

Cheap, quick, easy for patient
Good spatial resolution
Low radiation dose

Question 11

What are the cons of Xray?

Answer 11

Poor contrast resolution

Planar imaging

Question 12

What are the pros of CT?

Answer 12

Quick, widely available
Cross sectional images
High contrast resolution

Question 13

What are the cons of CT?

Answer 13

Radiation dose

IV contrast risks

Question 14

What are the pros of MRI?

Answer 14

Contrast resolution
Specific applications
No radiation

Question 15

What are the cons of MRI?

Answer 15

Limited availability
Patient experience
Expense
Magnet/contrast risks

Question 16

Which imaging modalities are used to view the skull?

Answer 16

CT

X-ray

Question 17

Describe a blowout trauma

Answer 17

Soft tissue found in the sinus

Bone fragment displaced

Question 18

What is the falx cerebri?

Answer 18

Separates the cerebral hemispheres

Question 19

What is the tentorium cerebelli?

Answer 19

Separates cerebrum from cerebellum

Question 20

Where are the dural venous sinuses?

Answer 20

Lie between the outer (periosteal) and inner (meningeal) layers of the dura

Question 21

Contrast is not used in which weighted MRI scan?

Answer 21

T2 - fluid is already white

Question 22

What is the function of the cerebral hemispheres?

Answer 22

Language, reasoning, motor and sensory function

Question 23

What comprises the basal ganglia?

Answer 23

Caudate nucleus and lentiform nucleus

Question 24

What is the purpose of the basal ganglia?

Answer 24

Action selection and movement regulation

Question 25

What is the purpose of the thalamus?

Answer 25

Sensory relay station

Question 26

What is the purpose of the cerebellum?

Answer 26

Motor coordination, balance and precision

Question 27

What is the purpose of the brain stem?

Answer 27

Life support: heart rate and breathing

Question 28

What can be seen on a CT scan in the case of a blunt trauma to the head?

Answer 28

``` Extradural haematoma (damage to meningeal artery/vein) Midline shift ```

Question 29

How can a blunt trauma to the head be imaged?

Answer 29

By taking a bone window followed by a soft tissue window

Question 30

Describe the ventricles and their function

Answer 30

4 Ventricles Choroid plexus lines ventricles- production of CSF Ventricles connect with central canal of spinal cord via 4th ventricle allowing CSF circulation Network of 4 cavities in the brain

Question 31

Give an image modality used to view the ventricles

Answer 31

MRI T2 weighted with no contrast - CSF appears white

Question 32

Describe what may be seen in a case of chronic headache using axial CT

Answer 32

Obstructive hydrocephalus with dilatation of both lateral ventricles due to colloid cyst at foramen of monro

Question 33

Describe the arteries of the brain

Answer 33

Aorta - internal carotid arteries and vertebral arteries - circle of willis

Question 34

Describe an image modality used to view the arteries of the brain

Answer 34

MRA (magnetic resonance angiogram) - Angiogram with 3D contrast DSA (digital subtraction angiography) - X-ray with contrast

Question 35

Describe an image modality used to view the veins of the brain

Answer 35

DSA (digital subtraction angiography) - X-ray with contrast

Question 36

What might be seen on a CT scan of a patient with an ischemic MCA stroke?

Answer 36

Cerebral edema | Midline shift

Question 37

What is used to determine the cause of a stroke?

Answer 37

Angiogram (DSA - LATERAL) | Useful for spotting atherosclerotic plaques in the internal carotid artery

Question 38

What is more sensitive than CT for acute stroke?

Answer 38

MRI (diffusion)

Question 39

Which imaging modality is good for assessing the bones in the spine?

Answer 39

X-ray | CT (bones and joints)

Question 40

Which imaging modality is good for assessing the soft tissue detail in the spine?

Answer 40

MRI