Neuroimaging

Question 1

Give the anatomical planes of neuroimaging.

Answer 1

• Sagittal (y-z plane)
• Transverse (axial x-y plane)
• Coronal (x-z plane)

Question 2

List the densities of tissue in order from lowest HU to highest HU.

Answer 2

Air

Fat

Water

CSF

White M

Grey M

Blood clot

Bone

Question 3

What is the unit of measurement for a CT?

Answer 3

Hounsfield Units

Question 4

Which of the following has a range of 50-70 HU on CT?

A. Bone

B. Blood clot

C. Grey matter

D. White matter

Answer 4

B. Blood clot

Question 5

Which of the following has a value of 1000 HU on CT?

A. Bone

B. Blood clot

C. Grey matter

D. White matter

Answer 5

A. Bone

Question 6

Which of the following has a range of 25-30 HU on CT?

A. Bone

B. Blood clot

C. Grey matter

D. White matter

Answer 6

D. White matter

Question 7

Which of the following has a range of 35-45 HU on CT?

A. Bone

B. Blood clot

C. Grey matter

D. White matter

Answer 7

C. Grey matter

Question 8

Which of the following has a range of 15 HU on CT?

A. Bone

B. Blood clot

C. CSF

D. White matter

Answer 8

C. CSF

Question 9

Which of the following has a range of 0 HU on CT?

A. Water

B. Blood clot

C. CSF

D. White matter

Answer 9

A. Water

Question 10

Which of the following has a range of -50 to -100 HU on CT?

A. Water

B. Fat

C. CSF

D. White matter

Answer 10

B. Fat

Question 11

Which of the following has a range of 0 HU on CT?

A. Water

B. Fat

C. CSF

D. White matter

Answer 11

A. Water

Question 12

Which of the following has a range of -50 to -100 HU on CT?

A. Water

B. Fat

C. CSF

D. White matter

Answer 12

B. Fat

Question 13

Which of the following has a range of -1000 HU on CT?

A. Water

B. Fat

C. CSF

D. Air

Answer 13

D. Air

Question 14

What view are CT images taken from?

Answer 14

Caudal View (Feet –> Head)

Question 15

How do you interpret a CT image with regards to the process?

Answer 15

Interpretation: ABCS
• Adequacy/Alignment/Artifact
• Bones/Blood/Brain

• Extra blood: Changes density through consolidation
• Brain parenchyma

Note: EDH and SDH are complete opposites in bleeding shape + intensity/absorption

• Cisterns + Ventricles

• Fluid-filled spaces
• Symmetrical
• Enlarged

• Subcutaneous and surfaces
- Subcutaneous surfaces

Question 16

Outline the process of MRI

Answer 16

Person enters + magnetic field –> atomic nuclei re-orientate along magnetic field –> radiofrequency pulse flips nuclei from orientated position and synchronises precession of spin axis –> receiver measure time until nuclei return to original orientation (structural scans) or desynchronize (functional scan)

Question 17

What view are MRI images taken from?

Answer 17

Caudal view (Feet –> Head)

Question 18

What is a T1 and T2 MRI image used to view predominantly?

Answer 18

• Generated by emission: T1 (CSF black) cf T2 (CSF white)

• -> T1 for structural abnormalities
• -> T2 for inflammation/ischaemia

Question 19

What process can you use to interpret an MRI scan?

Answer 19

• Adequacy + Alignment
• Bone, Blood + Brain
• Cisterns + Ventricles
• Subcutaneous and surfaces

Question 20

What is SPECT?

Answer 20

3D nuclear medicine imaging technique combining information from scintigraphy with CT allowing distribution of radionuclide to be displayed in 3D manner

Question 21

What is PET?

Answer 21

non-invasive imaging technique quantifying radioactivity in vivo using IV injection of positron-emitting radiopharmaceutical then scanning for detection and quantification of patterns of accumulation in the body

Question 22

Outline the process of PET.

Answer 22

Radiolabeled biological compound (e.g. FDG) injected IV –> Uptake by tissues –> FDG to FDG-6-P (cannot be further metabolized in tumour cells) –> accumulation in tumour cells and detected = quantified