Department of Radiology

University of California

San Diego

John R. Hesselink, M.D.

MR Imaging

of the Brain

MR System Components

Computer

Gradient Amplifier

Receiver

Transmitter

Digitizer

RF Coil

Gra

die

nt

RF Coil

Magnet

MR Imaging

Proton density

T1 relaxation time

T2 relaxation time

Flow effects

Source of Signal and Contrast

Spin-echo Pulse Sequence

Single Echo T1-weighted

RF

Signal

TR

TE

1st

echo

2nd

echo

Spin-echo Pulse Sequence Dual Echo T2-weighted

1st

echo

2nd

echo

RF

Signal

TR

TE

TE

T2-Weighted Images

Proton Density Weighted Images

Normal FLAIR Images

TR = 6000 msec, TI = 2000 msec, TE = 102 msec

T1-Weighted

Images

MR Signal of

Brain Lesions

Solid

Brain

Lesion PDW

T2W T1W

Cystic

Lesion

T2W

T1W

FLAIR

236

Subacute

Hemorrhage

PDW

T1W

T2W

Acute

Hemorrhage

T2W

FLAIR

T1W GRE

History: 9 y/o boy with prior head trauma

466

Hemorrhage Sequence Gradient-echo

PDW

Fat

or

Lipoma

T2W

T1W

MR Signal Intensities

T2WI PD/FLAIR T1WI

Solid mass Bright Bright Dark

Cyst Bright Dark Dark

Subacute blood Bright Bright Bright

Acute & chronic

blood Dark Dark Gray

Fat Dark Bright Bright

Acute Stroke Sequence Diffusion Weighted Imaging

MR Angiography

Dx: Anaplastic astrocytoma > GBM

MR Spectroscopy

Brain Screening Protocol

Sagittal T1-weighted images

Axial T2-weighted images

Axial FLAIR images

Diffusion-weighted images

Gradient-echo images

Axial T1-weighted images

Gadolinium: Axial & Coronal T1

History: 46 y.o. man

with headaches & increasing confusion

2 1

T2W PDW

{Page 2}

5

3 4

T1W

T1W / Gd

T1W

Dx: Meningioma & right MCA infarct

Increasing confusion {Page 3}

7 6

Student Cases

"May the FORCE be with you!"

History: 69 y/o man with nausea

& memory deficits for several weeks

413

Case 1

Dx: Glioblastoma

{Page 2}

History: 5 y/o girl with seizures

361

Case 2

{Page 2}

Dx: Amoebic abscesses

{Page 3}

History: 62 y.o. man with mumbling speech

26

2 1

Case 3

{Page 2}

3 4

Mumbling speech {Page 3}

5 6

Dx: Enhancing subacute infarct

{Page 4}

8 7

2 1

History: 48 y.o. male with a

sensorineural hearing loss

Case 4

Dx: Acoustic neuroma

{Page 2}

5

4

3

History: 48 y.o. man with

headaches & confusion

32

1 2

Case 5

{Page 2}

4 3

{Page 3}

7

6

5

Dx: Brain metastases -

Lung carcinoma

{Page 4}

10

9 8

History: 36 y.o. man with seizures

2 1

Case 6

History: Seizures

{Page 2}

5

4

3

Dx: AVM & basilar

tip aneurysm

{Page 3}

8

7

6

History: 62 y/o woman with headaches Case 7

Dx: Arachnoid cyst

{Page 2}

History: 27 y.o. man with

increasing confusion & lethargy

5

2 1

Case 8

Confusion and lethargy {Page 2}

3 4

Dx: Herpes simplex

encephalitis

{Page 3}

6

5

History: 72 y.o. woman

with headaches

49

3

2 1

Case 9

Dx: Parasagittal

meningioma

{Page 2}

5 4

6

History: 55 y/o female with motor

weakness, double vision, & emotional lability

272

Case 10

{Page 2}

Dx: Chronic multiple sclerosis;

Incidental sebaceous cyst

left posterior scalp

{Page 3}

History: 42 y/o female with chronic headaches

549

Case 11

{Page 2}

Dx: TB meningitis - HIV+

{Page 3}

History: 75 y.o. male

with dysmetria in upper extremities

1 2

Case 12

{Page 2}

3

5

4

Dx: Lipoma

{Page 3}

8

6

7

History: Young male with increasing

somnolence and irritability

11/20 -

2

1

3

Dx: Planum Meningioma

in a dog

4

{Page 2}

6

5