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 Gradient RF Coil Gradient 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 1 st echo 2 nd echo

Spin-echo Pulse Sequence Dual Echo T2-weighted 1 st echo 2 nd echo RF Signal TR 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 T2WFLAIR 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 T2WIPD/FLAIRT1WI Solid massBright Dark CystBrightDark Subacute bloodBright Acute & chronic blood Dark Gray FatDarkBright

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} 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

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Dx: Amoebic abscesses {Page 3}

History: 62 y.o. man with mumbling speech Case 3

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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 Case 5

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Dx: Brain metastases - Lung carcinoma {Page 4} 10 98

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 Case 8

Confusion and lethargy {Page 2} 3 4

Dx: Herpes simplex encephalitis {Page 3} 6 5

History: 72 y.o. woman with headaches Case 9

Dx: Parasagittal meningioma {Page 2} 54 6

History: 55 y/o female with motor weakness, double vision, & emotional lability 272 Case 10

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Dx: Chronic multiple sclerosis; Incidental sebaceous cyst left posterior scalp {Page 3}

History: 42 y/o female with chronic headaches 549 Case 11

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Dx: TB meningitis - HIV + {Page 3}

History: 75 y.o. male with dysmetria in upper extremities 1 2 Case 12

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Dx: Lipoma {Page 3} 8 6 7

History: Young male with increasing somnolence and irritability 11/

Dx: Planum Meningioma in a dog 4 {Page 2} 6 5