Lecture 24: Neuroradiology

Question 1

Whats low and high intensity on CT?

Answer 1

Air, fat = Not dense, dark / black
Bone or muscle = Very dense, white

Grey matter = light grey
Whiter matter = darker grey

Question 2

How does blood appear on CT?

Answer 2

Fresh blood is high intensity (white) on CT

Old blood is lower intesnity

Question 3

When looking at film, whats a good approach:

Answer 3

Identify the type of exam

Read the notes, who is on it, age, what time this occurred, any history, description etc

What side is it on?

Then describe lesion appearance, location and other features.

Question 4

Whats a useful feature of CT?

Answer 4

Can specify at what level the injury is.

Question 5

Describe the appearance of this lesion:

Answer 5

• Biconvex
• Slightly heterogeneous
• Hyperintense lesion
• In anterior cranial fossa
• Extending to the midline
• Causing a midline shift (Space occupying)

Question 6

Recap: How to look at an imaging examination:

Answer 6

1. History and clinical information, Collapse? Strike head? Skin lesion visibile?
2. Read the information on image
3. Look for additional clues on the edge of the image.

Remeber pts left is on your right because looking up from bottom of their feet

Question 7

Whats a consideration when using contrast agents?

Answer 7

The renal function of the patient

Question 8

Whats the process of examining the C spine?

Answer 8

Check: Alignment of vertebral bodies and processess (Ant. and Post. line, then art. facets)

Check soft tissues such as vertebral discs (consistent)

• > Oseteoarthritis
• > Bony spurs or oesteopytes
• > Reduced body height or reduced disc height (Entrapment possible)

Question 9

How can CT be used in stroke management?

Answer 9

Can determine if heamorrhagic or ischeamic.

• ischemic can attempt clot retrieval
• Can use tissue plasminogin activator if ischeamic (not heamohorrhagic tho)
• NB ischeamia will blurr the line between grey and white matter

Question 10

What are the difference between these two bleeds?

Answer 10

Epidural: Between skull and stripped dura. i.e middle miningeal artery. lentiform shape

Subdural: Traumatic injury to veins between dura mater and the arachnoid mater leads to collection of blood in the subdural space. Crescent in shape.

Question 11

What is this?

Answer 11

Subarachnoid space. Check basal cisterns.

Question 12

What are the principles of MRI?

Answer 12

• Protons align under magnet in line with field, act as tiny bar magnets.
• Radiofrequency pulse is applied perpendicular to the main field which flips the direction of the aligned nuclei
• Once pulse is removed nuclei re-align, loose energy and emit their own signal. (Signal varies depending on tissue type, position and pulse sequence used)

Question 13

Describe CSF on T1 and T2 weighted images

Answer 13

T1 = CSF is hypointense 
T2 = CSF is hyperintense 

Bone is black because few mobile protons

Question 14

What are we looking at?

Answer 14

Trauma C4/5 unilateral facet joint dislocation

Question 15

What are we looking at here?

Answer 15

Metasteses sclerotic (vs lytic (completely gone))

Question 16

What are we looking at here?

Answer 16

L1 fracture vertebral body, confirmed with MRI

Question 17

what are we looking at here?

Answer 17

Meningioma

Question 18

What are we looking at here?

Answer 18

Glioblastoma multiforme