Introduction toIntroduction to
NeuroimagingNeuroimaging
Aaron S. Field, MD, PhDAaron S. Field, MD, PhD
NeuroradiologyNeuro...
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Acute Ischemic Stroke ImagingAcute Ischemic Stroke Imaging
 Confirm diagnosisConfirm diagnosis
 Triage for therapy (risk...
CT Signs in Early MCA IschemiaCT Signs in Early MCA Ischemia
Hyperdense MCAHyperdense MCA Insular RibbonInsular Ribbon Len...
Pathophysiology of IschemicPathophysiology of Ischemic
Injury:Injury:
Duration and Degree ofDuration and Degree of ↓↓ CBFC...
MRI in Stroke Intervention
“The 4 P’s”
Pipes → Perfusion → Parenchyma
MRA Perfusion MR Diffusion MR
“Penumbra”Rowley AJNR ...
MCA InfarctMCA Infarct
MCA
PCA InfarctPCA Infarct
PCA
ACA InfarctACA Infarct ACA
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Cerebral HemorrhageCerebral Hemorrhage
• TraumaTrauma
• Ruptured aneurysmRuptured aneurysm
• HypertensiveHypertensive
• He...
Acute intraparenchymal hematomaAcute intraparenchymal hematoma
Cerebral HemorrhageCerebral Hemorrhage
Hemorrhagic melanoma metastasesHemorrhagic melanoma metastases
Cerebral HemorrhageCerebral Hemorrhage
Acute subarachnoid hemorrhageAcute subarachnoid hemorrhage
(and intraventricular)(and intraventricular)
Cerebral Hemorrhag...
Subdural vs. Epidural HematomaSubdural vs. Epidural Hematoma
Acute subdural hematomaAcute subdural hematoma
Cerebral HemorrhageCerebral Hemorrhage
Acute epidural hematomaAcute epidural hematoma
Cerebral HemorrhageCerebral Hemorrhage
Subdural:Subdural: Follows inner layer of duraFollows inner layer of dura
““Rounds the bend” to follow falx or tentoriumRo...
Mixed acute/chronic subdural hematomaMixed acute/chronic subdural hematoma
Cerebral HemorrhageCerebral Hemorrhage
Hematocrit level!Hematocrit level!
Cerebral HemorrhageCerebral Hemorrhage
MRI of HemorrhageMRI of Hemorrhage
MR appearance of hematomas depends on image type.MR appearance of hematomas depends on ...
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
InfectionInfection
• MeningitisMeningitis
• EncephalitisEncephalitis
• Cerebritis and parenchymal abscessCerebritis and pa...
LeptoLeptomeningitis:meningitis:
pia-arachnoidpia-arachnoid
MeningitisMeningitis
PachyPachymeningitis:meningitis: duradura...
HerpesHerpes
EncephalitisEncephalitis
Cerebritis w/ Bacterial AbscessCerebritis w/ Bacterial Abscess
T1 + Gd T2 DiffusionT1 + Gd T2 Diffusion
Cerebritis w/ Subdural EmpyemaCerebritis w/ Subdural Empyema
T1 + Gd T2 FLAIR DiffusionT1 + Gd T2 FLAIR Diffusion
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Brain Tumor ImagingBrain Tumor Imaging
DiagnosisDiagnosis
• Location: Intra- / Extra-axial, Supra- / Infra-tentorial, Grey...
T1 + Gd T2T1 + Gd T2
Intra- or Extra-axial?Intra- or Extra-axial?
Intra- or Extra-axial?
Tumor vs. Other MassesTumor vs. Other Masses
Arachnoid CystArachnoid Cyst
AbscessAbscess
HematomaHematoma
““Tumefactive” M...
Tumor vs. StrokeTumor vs. Stroke
Cytotoxic EdemaCytotoxic Edema Vasogenic EdemaVasogenic Edema
Cellular swellingCellular s...
T1 T1 + Gd
T2
T2 FLAIR
Tumor?
Stroke?
Encephalitis?
3D Imaging for XRT
or Surgical Guidance
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Fractures: CT not MRI !Fractures: CT not MRI !
Traumatic Brain SwellingTraumatic Brain Swelling
CerebellopontineCerebellopontine
angleangle
PontinePontineCerebellomedull...
Traumatic Brain SwellingTraumatic Brain Swelling
Know your basal cisterns!Know your basal cisterns!
QuadrigeminalQuadrigem...
Effacement of basal cisternsEffacement of basal cisterns
Traumatic brain swelling withTraumatic brain swelling with
downwa...
Traumatic brain swelling
Extra-axial HemorrhageExtra-axial Hemorrhage
Subdural Epidural SubarachnoidSubdural Epidural Subarachnoid
Intra-axial HemorrhageIntra-axial Hemorrhage
Hemorrhagic contusionsHemorrhagic contusions
Intra-axial HemorrhageIntra-axial Hemorrhage
Hemorrhagic contusionsHemorrhagic contusions
Mechanism
Direct contact with sk...
Diffuse Axonal (Shear) Injury (DAI)
Intra-axial HemorrhageIntra-axial Hemorrhage
Diffuse Axonal (Shear) Injury (DAI)
T2: Reveals non-hemorrhagic lesions occult on CT
Diffuse Axonal (Shear) Injury (DAI)
T2*: Increased sensitivity to hemorrhage
DDiffuseiffuse AAxonal (Shear)xonal (Shear) IInjury (njury (DAIDAI))
• Tissues w/ differing elastic properties shear again...
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
DementiaDementia
• Primary role of imaging is toPrimary role of imaging is to
exclude treatable causes, e.g.:exclude treat...
DementiaDementia
Irreversible dementias (imaging non-specific):Irreversible dementias (imaging non-specific):
• Alzheimer’...
Alzheimer’s: Temporal-Parietal Lobe Atrophy (Late)
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Multiple Sclerosis (MS) ImagingMultiple Sclerosis (MS) Imaging
• MRI is the imaging study of choiceMRI is the imaging stud...
MS
Tumefactive MS
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Seizure ImagingSeizure Imaging
• MRI is the imaging study of choiceMRI is the imaging study of choice
• Identify and local...
Congenital anomalies:
Polymicrogyria
Congenital anomalies: Schizencephaly
Mesial Temporal SclerosisMesial Temporal Sclerosis
Most common pathology found inMost common pathology found in
medically ...
Mesial
Temporal
Sclerosis FLAIR
T1
T2
• Atrophy
• Loss gray-white
•↑T2 / FLAIR
Brain Imaging: “The Big 10”Brain Imaging: “The Big 10”
• InfarctionInfarction
• HemorrhageHemorrhage
• InfectionInfection
...
Cranial Nerve ImagingCranial Nerve Imaging
FIESTAFIESTA
CN-5
CN-8
CN-7
Vestibular SchwannomaVestibular Schwannoma
Intracochlear SchwannomaIntracochlear Schwannoma
30 y/o F with
6wk h/o
blurred vision
CraniopharyngiomaCraniopharyngioma
Introduction toIntroduction to
NeuroimagingNeuroimaging
Aaron S. Field, MD, PhDAaron S. Field, MD, PhD
NeuroradiologyNeuro...
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    1. 1. Introduction toIntroduction to NeuroimagingNeuroimaging Aaron S. Field, MD, PhDAaron S. Field, MD, PhD NeuroradiologyNeuroradiology University of Wisconsin–MadisonUniversity of Wisconsin–Madison BRAINBRAIN Updated 3/12/07
    2. 2. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    3. 3. Acute Ischemic Stroke ImagingAcute Ischemic Stroke Imaging  Confirm diagnosisConfirm diagnosis  Triage for therapy (risk /Triage for therapy (risk / prognosis)prognosis)  Rule outRule out hemorrhagehemorrhage  Assess damage: location, pattern,Assess damage: location, pattern, extentextent  Is there salvageable brainIs there salvageable brain (“(“penumbrapenumbra”)?”)?  Follow outcomeFollow outcome
    4. 4. CT Signs in Early MCA IschemiaCT Signs in Early MCA Ischemia Hyperdense MCAHyperdense MCA Insular RibbonInsular Ribbon Lentiform NucleusLentiform Nucleus
    5. 5. Pathophysiology of IschemicPathophysiology of Ischemic Injury:Injury: Duration and Degree ofDuration and Degree of ↓↓ CBFCBF Normal neuronal function Reversible injury (penumbra) Infarction 25 20 15 10 5 0 CBF ml / 100g / min Time (hrs)1 2
    6. 6. MRI in Stroke Intervention “The 4 P’s” Pipes → Perfusion → Parenchyma MRA Perfusion MR Diffusion MR “Penumbra”Rowley AJNR 22(4); 599-601,
    7. 7. MCA InfarctMCA Infarct MCA
    8. 8. PCA InfarctPCA Infarct PCA
    9. 9. ACA InfarctACA Infarct ACA
    10. 10. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    11. 11. Cerebral HemorrhageCerebral Hemorrhage • TraumaTrauma • Ruptured aneurysmRuptured aneurysm • HypertensiveHypertensive • Hemorrhagic transformation ofHemorrhagic transformation of ischemic infarction (esp. venous)ischemic infarction (esp. venous) • Venous infarctionVenous infarction • TumorTumor • Vascular malformationsVascular malformations • Angioinvasive infectionAngioinvasive infection • Amyloid angiopathyAmyloid angiopathy
    12. 12. Acute intraparenchymal hematomaAcute intraparenchymal hematoma Cerebral HemorrhageCerebral Hemorrhage
    13. 13. Hemorrhagic melanoma metastasesHemorrhagic melanoma metastases Cerebral HemorrhageCerebral Hemorrhage
    14. 14. Acute subarachnoid hemorrhageAcute subarachnoid hemorrhage (and intraventricular)(and intraventricular) Cerebral HemorrhageCerebral Hemorrhage
    15. 15. Subdural vs. Epidural HematomaSubdural vs. Epidural Hematoma
    16. 16. Acute subdural hematomaAcute subdural hematoma Cerebral HemorrhageCerebral Hemorrhage
    17. 17. Acute epidural hematomaAcute epidural hematoma Cerebral HemorrhageCerebral Hemorrhage
    18. 18. Subdural:Subdural: Follows inner layer of duraFollows inner layer of dura ““Rounds the bend” to follow falx or tentoriumRounds the bend” to follow falx or tentorium Not affected by sutures of skullNot affected by sutures of skull Tendency forTendency for crescenticcrescentic shapesshapes More mass effect than expected for their sizeMore mass effect than expected for their size Typical source of SDH:Typical source of SDH: cortical veincortical vein Epidural:Epidural: Follows outer layer of dura (periosteum)Follows outer layer of dura (periosteum) Crosses falx or tentoriumCrosses falx or tentorium Limited by sutures of skull (typically)Limited by sutures of skull (typically) Tendency forTendency for lentiformlentiform shapesshapes Typical source of EDH:Typical source of EDH: skull fracture with arterial or sinus lacerationskull fracture with arterial or sinus laceration Subdural vs. Epidural HematomaSubdural vs. Epidural Hematoma *
    19. 19. Mixed acute/chronic subdural hematomaMixed acute/chronic subdural hematoma Cerebral HemorrhageCerebral Hemorrhage
    20. 20. Hematocrit level!Hematocrit level! Cerebral HemorrhageCerebral Hemorrhage
    21. 21. MRI of HemorrhageMRI of Hemorrhage MR appearance of hematomas depends on image type.MR appearance of hematomas depends on image type. Magnetic properties change over time (Hgb breakdownMagnetic properties change over time (Hgb breakdown products), allowing approximate datingproducts), allowing approximate dating T1 T2 T2*T1 T2 T2*
    22. 22. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    23. 23. InfectionInfection • MeningitisMeningitis • EncephalitisEncephalitis • Cerebritis and parenchymal abscessCerebritis and parenchymal abscess • Empyema (subdural/epidural)Empyema (subdural/epidural)
    24. 24. LeptoLeptomeningitis:meningitis: pia-arachnoidpia-arachnoid MeningitisMeningitis PachyPachymeningitis:meningitis: duradura Most common imaging findings in meningitis:Most common imaging findings in meningitis: NONENONE !!!!
    25. 25. HerpesHerpes EncephalitisEncephalitis
    26. 26. Cerebritis w/ Bacterial AbscessCerebritis w/ Bacterial Abscess T1 + Gd T2 DiffusionT1 + Gd T2 Diffusion
    27. 27. Cerebritis w/ Subdural EmpyemaCerebritis w/ Subdural Empyema T1 + Gd T2 FLAIR DiffusionT1 + Gd T2 FLAIR Diffusion
    28. 28. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    29. 29. Brain Tumor ImagingBrain Tumor Imaging DiagnosisDiagnosis • Location: Intra- / Extra-axial, Supra- / Infra-tentorial, Grey /Location: Intra- / Extra-axial, Supra- / Infra-tentorial, Grey / white matter, etc.white matter, etc. • Single or multiple?Single or multiple? • Tumor or tumor-like alternatives?Tumor or tumor-like alternatives? • Histology: Type and grade?Histology: Type and grade? Treatment PlanningTreatment Planning • Surgery, radiation, chemo txSurgery, radiation, chemo tx • Functional MRI for eloquent brain mappingFunctional MRI for eloquent brain mapping • 3D scans to guide surgery, radiation3D scans to guide surgery, radiation Follow-upFollow-up • Stable vs. recurrence / progressionStable vs. recurrence / progression • ComplicationsComplications
    30. 30. T1 + Gd T2T1 + Gd T2 Intra- or Extra-axial?Intra- or Extra-axial?
    31. 31. Intra- or Extra-axial?
    32. 32. Tumor vs. Other MassesTumor vs. Other Masses Arachnoid CystArachnoid Cyst AbscessAbscess HematomaHematoma ““Tumefactive” MSTumefactive” MS GBMGBM
    33. 33. Tumor vs. StrokeTumor vs. Stroke Cytotoxic EdemaCytotoxic Edema Vasogenic EdemaVasogenic Edema Cellular swellingCellular swelling Gray-white margin lostGray-white margin lost Leaky capillariesLeaky capillaries Gray matter is sparedGray matter is spared
    34. 34. T1 T1 + Gd T2 T2 FLAIR Tumor? Stroke? Encephalitis?
    35. 35. 3D Imaging for XRT or Surgical Guidance
    36. 36. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    37. 37. Fractures: CT not MRI !Fractures: CT not MRI !
    38. 38. Traumatic Brain SwellingTraumatic Brain Swelling CerebellopontineCerebellopontine angleangle PontinePontineCerebellomedullaryCerebellomedullary (Cisterna Magna)(Cisterna Magna) Know your basal cisterns!Know your basal cisterns!
    39. 39. Traumatic Brain SwellingTraumatic Brain Swelling Know your basal cisterns!Know your basal cisterns! QuadrigeminalQuadrigeminal InterpeduncularInterpeduncularSuprasellarSuprasellar AmbientAmbient
    40. 40. Effacement of basal cisternsEffacement of basal cisterns Traumatic brain swelling withTraumatic brain swelling with downward herniationdownward herniation Traumatic Brain SwellingTraumatic Brain Swelling
    41. 41. Traumatic brain swelling
    42. 42. Extra-axial HemorrhageExtra-axial Hemorrhage Subdural Epidural SubarachnoidSubdural Epidural Subarachnoid
    43. 43. Intra-axial HemorrhageIntra-axial Hemorrhage Hemorrhagic contusionsHemorrhagic contusions
    44. 44. Intra-axial HemorrhageIntra-axial Hemorrhage Hemorrhagic contusionsHemorrhagic contusions Mechanism Direct contact with skull Shear-strain deformation Lesion locations Commonly located along inferior, lateral, and anterior frontal and temporal lobes Often above bony prominences (petrous pyramid, sphenoid wing, orbital roof) Appearance of cortical contusions Overlying cortex, by definition, always involved (vs. DAI) “Salt and pepper” appearance due to intermixed hemorrhage and edema Non-hemorrhagic contusions often not initially seen on CT scans Lesions often more visible days after injury as edema and hemorrhage increase Acute lesions much more conspicuous on T2 or T2-FLAIR MRI
    45. 45. Diffuse Axonal (Shear) Injury (DAI) Intra-axial HemorrhageIntra-axial Hemorrhage
    46. 46. Diffuse Axonal (Shear) Injury (DAI) T2: Reveals non-hemorrhagic lesions occult on CT
    47. 47. Diffuse Axonal (Shear) Injury (DAI) T2*: Increased sensitivity to hemorrhage
    48. 48. DDiffuseiffuse AAxonal (Shear)xonal (Shear) IInjury (njury (DAIDAI)) • Tissues w/ differing elastic properties shear against each other, tearing axons • Caused by rapid deceleration/rotation of head • Locations: • Cerebral hemispheres near gray-white junction • Basal ganglia • Corpus callosum, especially splenium • Dorsal brainstem • High morbitity & mortality – common cause of post-traumatic vegetative state • Initial CT often normal despite poor GCS • Lesions often non-hemorrhagic and seen only on MRI
    49. 49. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    50. 50. DementiaDementia • Primary role of imaging is toPrimary role of imaging is to exclude treatable causes, e.g.:exclude treatable causes, e.g.:  HydrocephalusHydrocephalus  Subdural hematomaSubdural hematoma  NeoplasmNeoplasm
    51. 51. DementiaDementia Irreversible dementias (imaging non-specific):Irreversible dementias (imaging non-specific): • Alzheimer’s diseaseAlzheimer’s disease • Multi-infarct dementiaMulti-infarct dementia • Dementias associated with Parkinson’s disease and similarDementias associated with Parkinson’s disease and similar disordersdisorders • AIDS dementia complexAIDS dementia complex
    52. 52. Alzheimer’s: Temporal-Parietal Lobe Atrophy (Late)
    53. 53. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    54. 54. Multiple Sclerosis (MS) ImagingMultiple Sclerosis (MS) Imaging • MRI is the imaging study of choiceMRI is the imaging study of choice • Help establishHelp establish ““dissemination of lesions indissemination of lesions in time and spacetime and space”” • Estimate disease burdenEstimate disease burden • Identify acute (inflammatory) vs. chronicIdentify acute (inflammatory) vs. chronic lesions (enhancement = activelesions (enhancement = active inflammation)inflammation)
    55. 55. MS
    56. 56. Tumefactive MS
    57. 57. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    58. 58. Seizure ImagingSeizure Imaging • MRI is the imaging study of choiceMRI is the imaging study of choice • Identify and localize offending lesionIdentify and localize offending lesion • New onset vs. chronic epilepsyNew onset vs. chronic epilepsy • Younger vs. older patientsYounger vs. older patients • Search may be guided by EEG / clinical sxSearch may be guided by EEG / clinical sx • Preoperative planningPreoperative planning e.g. language lateralization before temporal lobectomye.g. language lateralization before temporal lobectomy
    59. 59. Congenital anomalies: Polymicrogyria
    60. 60. Congenital anomalies: Schizencephaly
    61. 61. Mesial Temporal SclerosisMesial Temporal Sclerosis Most common pathology found inMost common pathology found in medically refractory epilepsy patientsmedically refractory epilepsy patients Rare under age 10 or with new seizuresRare under age 10 or with new seizures Pathogenesis unknownPathogenesis unknown - Post ictal / kindling?- Post ictal / kindling? Pathology:Pathology: Hippocampal atrophy / gliosisHippocampal atrophy / gliosis
    62. 62. Mesial Temporal Sclerosis FLAIR T1 T2 • Atrophy • Loss gray-white •↑T2 / FLAIR
    63. 63. Brain Imaging: “The Big 10”Brain Imaging: “The Big 10” • InfarctionInfarction • HemorrhageHemorrhage • InfectionInfection • TumorTumor • TraumaTrauma • DementiaDementia • MSMS • EpilepsyEpilepsy • Cranial neuropathyCranial neuropathy • Orbits / Ophtho dxOrbits / Ophtho dx
    64. 64. Cranial Nerve ImagingCranial Nerve Imaging FIESTAFIESTA CN-5 CN-8 CN-7
    65. 65. Vestibular SchwannomaVestibular Schwannoma
    66. 66. Intracochlear SchwannomaIntracochlear Schwannoma
    67. 67. 30 y/o F with 6wk h/o blurred vision CraniopharyngiomaCraniopharyngioma
    68. 68. Introduction toIntroduction to NeuroimagingNeuroimaging Aaron S. Field, MD, PhDAaron S. Field, MD, PhD NeuroradiologyNeuroradiology University of Wisconsin–MadisonUniversity of Wisconsin–Madison BRAINBRAIN
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