Department of RadiologyUniversity of California

San Diego

John R. Hesselink, M.D.

MR ImagingMR Imaging of the Brain

MR System Components

Computer

Gradient Amplifier

Receiver

Transmitter

Digitizer

RF Coil

Gra

die

nt

RF Coil

Grad

ient

Magnet

MR Imaging

Proton density

T1 relaxation time

T2 relaxation time

Flow effects

Source of Signal and Contrast

Spin-echo Pulse SequenceSingle Echo T1-weighted

RF

Signal

TR

TE

1st

echo2nd

echo

Spin-echo Pulse SequenceDual Echo T2-weighted

1st

echo2nd

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 ofMR Signal ofBrain LesionsBrain Lesions

SolidBrainLesion PDW

T2W T1W

CysticLesion

T2W

T1W

FLAIR

236

SubacuteHemorrhage

PDW

T1W

T2W

AcuteHemorrhage

T2W

FLAIR

T1WGRE

History: 9 y/o boy with prior head trauma

466

Hemorrhage SequenceGradient-echo

PDW

Fator

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 SequenceDiffusion 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. manwith headaches & increasing confusion

21

T2W PDW

{Page 2}

5

34

T1W

T1W / Gd

T1W

Dx: Meningioma & right MCA infarct

Increasing confusion {Page 3}

76

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

21

Case 3

{Page 2}

3 4

Mumbling speech {Page 3}

5 6

Dx: Enhancing subacute infarct

{Page 4}

87

21

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

12

Case 5

{Page 2}

43

{Page 3}

7

6

5

Dx: Brain metastases - Lung carcinoma

{Page 4}

10

98

History: 36 y.o. man with seizures

21

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 headachesCase 7

Dx: Arachnoid cyst

{Page 2}

History: 27 y.o. man with increasing confusion & lethargy

5

21

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

21

Case 9

Dx: Parasagittal meningioma

{Page 2}

54

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. malewith 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