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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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