MRI Brain

Routine Brain protocol

1. 3 plane localizer

2. Sagittal t1 brain

3. Axial T1

4. Axial T2

5. Axial Flair

6. DWI or Diffusion Weighted Images

brain position

head first supine, put head

brain centering

glabella

sagittal brain plotted in

3 planes

Sagittal T1 Brain

Sagittal  T1 is performed not only for diagnosis, it is also used to plot future axial sequences

T1 TR and TE

short TR and short TE

Axial brain plotted off

midline Sag T1

How to plot axial brain

Coverage should be from the top of the brain to below the foramen magnum
The angle is formed by drawing a line from the genu to the splenium of the corpus callosum.

Dark on Axial T1 Brain

CSF 

Increased water- edema, tumor, infarct, inflammation, infection, hemorrhage (hyperacute or chronic)

Low proton density

Flow void

Bright on Axial T1 Brain

Gadolinium

Sub acute hemorrhage

Protein –rich Fluid

Slowly flowing blood

Fat

Laminar necrosis of an infarct 

T2 TR and TE

long TR and Long TE

Dark on Axial T2 Brain

Low proton density, calcification, fibrous tissue

Paramagnetic substances- iron, ferritin.

Protein- rich fluid

Flow void

Bright on Axial T2 Brain

Increased Water- as in edema, tumor, infarct, inflammation, infection, subdural collection.

Subacute hemorrhage

Gray matter is brighter than white.

DWI for what

Diffusion weighted imaging
Allows mapping of the diffusion process of molecules, mainly water.

Diffusion is

Diffusion is the net movement of a substance from a region of high concentration to low concentration.

Diffusion is for

Early identification of ischemic stroke

Differentiation of acute from chronic stroke.

Differentiation of acute stroke from other stroke mimics.

Assessment of active demyelination

FLAIR and does what

Fluid-Attenuated Inversion Recovery
Inversion recovery technique that nulls fluids

ms lesions on flairs

MS lesions periventricular are typically hyperintense bc optimization of TI required to null the signal of water

Dawson plaques

MS plaques in sagittal plane

most effective sequence for MS

Sagittal Flair brain

First symptoms MS and who is it common in

20 and 40, women

symptoms of MS

• Diplopia

• Numbness 

• Tingling

• Optic neuritis

• Unsteady gait

• Fatigue

• Tremors