XRAY

Question 1

Understand densities on head CT (HU)

Answer 1

Air: -1000 
Fat: -100 
Water: 0 
Brain: 30-40 
Acute Blood	: 60-100 
Calcification: 1000

so anything brighter than brain is hyperdense (bone), anything darker is hypodense (fluid or fat)

Question 2

Magnetic Resonance Spectroscopy (MRS)

Answer 2

Measures brain neurotransmitters and
biochemicals

• Interrogates chemical environment of brain noninvasively
• Metabolites measured: Amino acids, Lipid, lactate, NAA, Choline, Creatine, Myoinositol

• Aids in evaluation of brain tumors,
radiation necrosis, infections, metabolic disease

Question 3

Diffusion Tensor imaging

Answer 3

Allows assessment of
white matter tracts
based on water diffusion characteristics along
these tracts of axons

• Diffusion	sequence used	
to form	3D	image 
• Evaluation	of neurodegenerative	
disease, epilepsy,	
traumatic brain injury, multiple	sclerosis 

• Role in preoperative
evaluation – brain tumors

Question 4

Functional MRI

Answer 4

Functional	MRI	(fMRI) 
• Assess brain metabolic activity	(indirect measure of neuronal	discharge) and	
therefore specific areas	of function 

• Uses BOLD (blood oxygen level dependent) imaging.

• Patient performs a repetitive task, i.e finger tapping
• When brain is activated by a task, increase of blood flow leads to signal
• Used to localize region of sensory function,
motor function, and language

• Role in preoperative evaluation

Question 5

Interventional Neuroradiology

Answer 5

minimally invasive treatment options for conditions involving brain, head and neck, and spine

• microcatheters
• micro-guidewires
• balloon catheters
• embolic material (glue, particles, Guglielmi Detachable Coils)
• detachable balloons
• stents