Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
SlideShare a Scribd company logo

Mri brain anatomy Dr Muhammad Bin Zulfiqar

•Download as PPT, PDF•
•
Dr. Muhammad Bin Zulfiqar
Dr. Muhammad Bin Zulfiqar

Anatomy of Brain by MRI In this presentation we will discuss the cross sectional anatomy of brain. Then we will discuss the Most common diseases to be evaluated by brain imaging. In my opinion this presentation is a road map for beginars.

1 of 81
MR IMAGING OF BRAIN Muhammad Bin Zulfiqar PGR II SIMS/SHL New Radiology Department
Basics of MR • MR sequences • MR signal characteristic
MRI----conventional sequences • SE sequence （ spin echo ） – T1-weighted,T1-WI TR: 200-800ms TE:15-30ms – T2-weighted,T2-WI TR:1500-2000ms TE:60-150ms – Proton Density,N(H) ） TR:1500-2500ms TE:15-30ms • IR sequence （ inversion recovery sequence ） TR （ short ） TE （ short ） TI （ short ）
MR signal characteristics • SE sequences ： – T1-WI: highest signal on fat tissue ,better for showing anatomical structures – T2-WI: highest signal in liquid, better for detecting lesions – N （ H ） Density(H): for characteristics of lesions • GRE sequence ： flip angle ， fast scan • IR sequence ： separation between of fat and liquid
T2WI T1WI MR signal characteristics
Fat supression Liquid supression MR signal characteristics
THREE DIMENSIONAL BRAIN ANATOMY
Fig. 1.1 Post Contrast Axial MR Image of the brain 1 2 3 4 5 Post Contrast sagittal T1 Weighted M.R.I. Section at the level of Foramen Magnum Answers 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx 4. Mandible 5. Maxillary Sinus
Fig. 1.2 Post Contrast Axial MR Image of the brain 7 6 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of medulla Answers 6. Medulla 7. Sigmoid Sinus
Fig. 1.3 Post Contrast Axial MR Image of the brain 15 8 9 10 11 12 13 14 16 17 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Pons Answers 8. Cerebellar Hemisphere 9. Vermis 10. IV Ventricle 11. Pons 12. Basilar Artery 13. Internal Carotid Artery 14. Cavernous Sinus 15. Middle Cerebellar Peduncle 16. Internal Auditory Canal 17. Temporal Lobe
Fig. 1.4 Post Contrast Axial MR Image of the brain 18 19 20 21 22 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Mid Brain Answers 18. Aqueduct of Sylvius 19. Midbrain 20. Orbits 21. Posterior Cerebral Artery 22. Middle Cerebral Artery
Fig. 1.5 Post Contrast Axial MR Image of the brain 23 24 25 26 27 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of the III Ventricle Answers 23. Occipital Lobe 24. III Ventricle 25. Frontal Lobe 26. Temporal Lobe 27. Sylvian Fissure
Fig. 1.6 Post Contrast Axial MR Image of the brain 28 29 30 31 32 38 33 34 36 35 37 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Thalamus Answers 28. Superior Sagittal Sinus 29. Occipital Lobe 30. Choroid Plexus within the occipital horn 31. Internal Cerebral Vein 32. Frontal Horn 33. Thalamus 34. Temporal Lobe 35. Internal Capsule 36. Putamen 37. Caudate Nucleus 38. Frontal Lobe
Fig. 1.7 Post Contrast Axial MR Image of the brain 39 40 41 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Corpus Callosum Answers 39. Splenium of corpus callosum 40. Choroid plexus within the body of lateral ventricle 41. Genu of corpus callosum
Fig. 1.8 Post Contrast Axial MR Image of the brain 42 43 44 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Body of Corpus Callosum Answers 42. Parietal Lobe 43. Body of the Corpus Callosum 44. Frontal Lobe
Fig. 1.9 Post Contrast Axial MR Image of the brain 45 46 Post Contrast sagittal T1 Wtd M.R.I. Section above the Corpus Callosum Answers 45. Parietal Lobe 46. Frontal Lobe
Normal anatomical structure of head on MRI
T2WI
T1WI
Flair sequence
T2WI(coronal section ）
T1WI （ sagittal section ） Corpus callosum; optic chiasm; pituitary gland; medulla oblongata
MRI diagnosis of brain vascular diseases • Intra cerebral Hemorrhage • Cerebral Infarction • Intracranial Aneurysm
Brain bleed (hemorrhage) • Causes ： high blood pressure, vascular malformation and tumor • Stage ： acute, sub acute, chronic
MRI appearances of hemorrhage at different stage • Acute hemorrhage MRI － iso-intensity on T1WI, slightly low or low intensity on T2WI( ideally MR was poor than CT for Acute hemorrhage ). • Sub acute hemorrhage MRI － iso- or high signal intensity on T1WI, iso- or slightly high signal intensity on T2WI. • Chronic hemorrhage MRI － high signal intensity both on T1WI/T2WI.
acute/subacute hemorrhage acute subacute T2WI T1WI
Chronic intracranial hemorrhage
MRI diagnosis of cerebral infarction
MR appearances of cerebral infarction • High signal intensity at Acute , subacute and chronic stage on T2WI because of increment of fluid at infarction. • Iso-intensity at acute stage , iso- or slightly low intensity at subacute stage, low intensity at chronic stage on T1WI. • Flair and DWI sequences are more sensitive for detecting acute infarction.
MR:44396 MR&CT appearances of acuteMR&CT appearances of acute cerebral infarctioncerebral infarction T2WI T1WI Flair
MR:44396 MR&CT appearances of acute cerebralMR&CT appearances of acute cerebral infarctioninfarction FlairT1WIT2WI
Acute infarction
Acute infarction
Acute infarction DWI
Subacute/chronic infarction—T2WI
T2WI--Coronal
Chronic infarction at brain stem and cerebellum—T2WI
Chronic infarction at brain stem and cerebellum—T1WI
MRI diagnosis of head trauma
The types of head trauma  Skull fracture  traumatic cerebral swelling  brain contusions  Intracranial bleed of trauma – Epidural hematoma – Subdural hematoma – Subarachnoid hemorrhage – Intracerebral hematoma
MR diagnosis of cranial trauma Epidural hematoma ： ‫٭‬ direct violence on skull ‫٭‬skull fracture and deformation ‫٭‬direct laceration or tearing of meningeal arteries ‫٭‬ local hematoma ,not across cranial suture ‫٭‬shape of duple convex mirror
MR appearances ‫٭‬ shape of hematoma is biconvex ‫٭‬ signal intensity of hematoma varies greatly depending on times. ‫٭‬ at acute stage （ 0~2 days ）， iso-intensity on T1WI ， low intensity on T2WI. ‫٭‬at subacute stage （ 3~14 days ）， becoming high signal intensity from rim to center on T1WI, still low signal intensity at 6~8 days and high signal intensity after 8 day on T2WI. ‫٭‬ at chronic stage (14 days later) , high signal intensity on both T1WI and T2WI for quite long times (may be several months)
Subacute hematoma at left frontal lobe
Subacute hematoma at left frontal lobe
Subdural hematoma ‫٭‬Location: supratentorial convexity. ‫٭‬ Caused by stretching and tearing of bridging veins. ‫٭‬ Hematoma is located between dura mater and arachnoid. Often quite large extent , across cranial suture. ‫٭‬ MR appearances ： shape of hematoma semilunar ， signal changes of hematoma similar to epidural hematoma at different stages.
Subacute Subdural Hematoma Axial T1-weighted magnetic resonance imaging demonstrates bilateral subacute subdural hematomas with increased signal intensity. Areas of intermediate intensity represent more acute hemorrhage into the subacute collections. T2-weighted magnetic resonance imaging in a patient with subdural hematoma shows blood products of differing ages.
Subacute subdural hematoma at left frontal-temporal area
Subacute subdural hematoma at left frontal-temporal area
MR Features of brain contusion ‫٭‬ Often involve the temporal and frontal lobe. • Temporal lobe lesions tend to lie just above the petrous bone or posterior to the greater sphenoid wing. • Frontal lobe lesions occur just above the cribriform plate, orbit, planum sphnoidale, and lesser sphenoid wing.
MR appearances ‫٭‬ MR is more sensitive than CT to find small contusion because of easy to find edema caused by contusion. ‫٭‬hemorrhagic foci appear petechia or multiple confluent regions with high signal intensity. ‫٭‬ easy to find contusion at brain stem.
Contusion and epidural hemorrhage at both temporal lobe and frontal lobe
Contusion and epidural hemorrhage at both temporal lobe and frontal lobe
Multiple contusions at both sides of frontal and temporal lobes
Multiple contusions at both sides of frontal and temporal lobes
INTRACRANIAL TUMORS ‫٭‬ primary (80%) :originating from cranial bone, cranial meninges, brain tissues, vessels, cranial nerves, pituitary gland, etc. glioma(50%) , meningioma(14%) , pituitary tumor (11%) , acoustic neuroma(7%) ‫٭‬secondary (20%) : metastasis , involved by tumor from near structures.
The types of intracranial tumors • Intraaxial brain tumors ： 1.glioma( astrocytoma and oligodendroglioma) 2.ependymoma 3.medulloblastoma 4.hemangioblastoma 5.papilloma choroideum 6.metastases
The types of intracranial tumors • Extraaxial brain tumors 1.meningioma 2.craniopharyngioma 3.pituitary tumor 4.nerve sheath tumors-acoustic schwannoma 5.epidermorid cyst, dermoid cyst and hamartomas
Direct signs 1. tumor or occupying lesion. 2. abnormal density or signal. 3. enhancement in different degree on enhanced scan. CT and MRI Signs for diagnosis of intracranial tumors 、、
Indirect signs 1. shift of near structures 2. edema in brain tissue near tumor 3. Intratumoral bleed 4. Intratumoral calcification 5. bone changes
Astrocytoma lower grading of astrocytoma ， grading I or II ． • Often in adult （２０～４０ years ） -- more occult in cerebral hemisphere ， grading II ， solid • child– less seen ， more in cerebellum ， grading I, cyst
Astrocytoma MR ： Isointensity on T1WI ， unclear border , high or slightly high signal intensity on T2WI no or slight occupying effect , no or slight enhancement.
Grade I Astrocytoma T1WI T2WI
Grade II astrocytoma T2W Gd+ Gd+ MR:39547
Astrocytoma high grading （ grading III or IV) • Fast growing • Occur in any age
Imaging appearances of high grading astrocytoma • Obvious occupying effects ,infiltrating growing with unclear margin , growing across lobe and hemisphere. • Necrosis, cyst , bleed. • Obvious brain edema around tumor. • Obvious uneven or ring-like enhancement.
Grade IV astrocytoma MR:39985 T2W T1W Gd+
Grade IV astrocytoma MR:39985 T2W Gd+ T2W Gd+
MR ： 53847 Grading IV astrocytoma
Brain metastasis • Old age • Single or multiple • Multiple appearances on CT or MR, but often shown in nodule • Heterogeneous density or signal, central necrosis with lower density or signal on T1WI. • Ring-like or even enhancement • Obviously finger-like peritumoral edema
Multiple metastases
Metastasis from lung cancer uncontrast contrast
Metastasis from lung cancer uncontrast contrast
Imaging of meningioma • Round or hemishere mass occur mostly in convexity of brain , especially sagittal sinus. • Mass with clear margin which was encysted with cerebral spinal fluid and/or vessels. • Iso- or slightly high density on plain CT and low signal on T1WI, iso- or slightly high signal on T2WI, which was enhanced obviously and evenly. • A broad thickened dural-based margin which was called “tail sign” . • Edema may be not or obvious. • Local bone changes including destruction, thin or thickness.
Right parietal meningioma Plain T1WI Contrast T1WI
T2WI AND contrast T1WI
Meningioma T2WI T1WI Gd-T1W
Acoustic schwannoma • Benign tumor, occur mostly at middle age people, approximately 7 ~8 of all primary intracranial neoplasms.﹪ ﹪ • Ovoid or tubular tumors may occur in the internal auditory canal and cerebellopontine angle cistern . • Tumor may be part of solid and cystic . • On Plain CT, solid part of tumor was iso-density ,and cystic part was low density. • Iso-intensity or low signal intensity were seen in solid or cystic part of tumor on T1WI, but high or very high signal intensity on T2WI,. • Obvious enhancement was seen on solid tumor. • Enlargement of internal auditory canal.
Left acoustic schwannoma
Left acoustic schwannoma T2WI T1WI Contrast T1WI
Left acoustic schwannoma
Mri brain anatomy Dr Muhammad Bin Zulfiqar

More Related Content

Mri brain anatomy Dr Muhammad Bin Zulfiqar

  • 1. MR IMAGING OF BRAIN Muhammad Bin Zulfiqar PGR II SIMS/SHL New Radiology Department
  • 2. Basics of MR • MR sequences • MR signal characteristic
  • 3. MRI----conventional sequences • SE sequence （ spin echo ） – T1-weighted,T1-WI TR: 200-800ms TE:15-30ms – T2-weighted,T2-WI TR:1500-2000ms TE:60-150ms – Proton Density,N(H) ） TR:1500-2500ms TE:15-30ms • IR sequence （ inversion recovery sequence ） TR （ short ） TE （ short ） TI （ short ）
  • 4. MR signal characteristics • SE sequences ： – T1-WI: highest signal on fat tissue ,better for showing anatomical structures – T2-WI: highest signal in liquid, better for detecting lesions – N （ H ） Density(H): for characteristics of lesions • GRE sequence ： flip angle ， fast scan • IR sequence ： separation between of fat and liquid
  • 5. T2WI T1WI MR signal characteristics
  • 6. Fat supression Liquid supression MR signal characteristics
  • 8. Fig. 1.1 Post Contrast Axial MR Image of the brain 1 2 3 4 5 Post Contrast sagittal T1 Weighted M.R.I. Section at the level of Foramen Magnum Answers 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx 4. Mandible 5. Maxillary Sinus
  • 9. Fig. 1.2 Post Contrast Axial MR Image of the brain 7 6 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of medulla Answers 6. Medulla 7. Sigmoid Sinus
  • 10. Fig. 1.3 Post Contrast Axial MR Image of the brain 15 8 9 10 11 12 13 14 16 17 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Pons Answers 8. Cerebellar Hemisphere 9. Vermis 10. IV Ventricle 11. Pons 12. Basilar Artery 13. Internal Carotid Artery 14. Cavernous Sinus 15. Middle Cerebellar Peduncle 16. Internal Auditory Canal 17. Temporal Lobe
  • 11. Fig. 1.4 Post Contrast Axial MR Image of the brain 18 19 20 21 22 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Mid Brain Answers 18. Aqueduct of Sylvius 19. Midbrain 20. Orbits 21. Posterior Cerebral Artery 22. Middle Cerebral Artery
  • 12. Fig. 1.5 Post Contrast Axial MR Image of the brain 23 24 25 26 27 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of the III Ventricle Answers 23. Occipital Lobe 24. III Ventricle 25. Frontal Lobe 26. Temporal Lobe 27. Sylvian Fissure
  • 13. Fig. 1.6 Post Contrast Axial MR Image of the brain 28 29 30 31 32 38 33 34 36 35 37 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Thalamus Answers 28. Superior Sagittal Sinus 29. Occipital Lobe 30. Choroid Plexus within the occipital horn 31. Internal Cerebral Vein 32. Frontal Horn 33. Thalamus 34. Temporal Lobe 35. Internal Capsule 36. Putamen 37. Caudate Nucleus 38. Frontal Lobe
  • 14. Fig. 1.7 Post Contrast Axial MR Image of the brain 39 40 41 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Corpus Callosum Answers 39. Splenium of corpus callosum 40. Choroid plexus within the body of lateral ventricle 41. Genu of corpus callosum
  • 15. Fig. 1.8 Post Contrast Axial MR Image of the brain 42 43 44 Post Contrast sagittal T1 Wtd M.R.I. Section at the level of Body of Corpus Callosum Answers 42. Parietal Lobe 43. Body of the Corpus Callosum 44. Frontal Lobe
  • 16. Fig. 1.9 Post Contrast Axial MR Image of the brain 45 46 Post Contrast sagittal T1 Wtd M.R.I. Section above the Corpus Callosum Answers 45. Parietal Lobe 46. Frontal Lobe
  • 17. Normal anatomical structure of head on MRI
  • 18. T2WI
  • 19. T1WI
  • 22. T1WI （ sagittal section ） Corpus callosum; optic chiasm; pituitary gland; medulla oblongata
  • 23. MRI diagnosis of brain vascular diseases • Intra cerebral Hemorrhage • Cerebral Infarction • Intracranial Aneurysm
  • 24. Brain bleed (hemorrhage) • Causes ： high blood pressure, vascular malformation and tumor • Stage ： acute, sub acute, chronic
  • 25. MRI appearances of hemorrhage at different stage • Acute hemorrhage MRI － iso-intensity on T1WI, slightly low or low intensity on T2WI( ideally MR was poor than CT for Acute hemorrhage ). • Sub acute hemorrhage MRI － iso- or high signal intensity on T1WI, iso- or slightly high signal intensity on T2WI. • Chronic hemorrhage MRI － high signal intensity both on T1WI/T2WI.
  • 28. MRI diagnosis of cerebral infarction
  • 29. MR appearances of cerebral infarction • High signal intensity at Acute , subacute and chronic stage on T2WI because of increment of fluid at infarction. • Iso-intensity at acute stage , iso- or slightly low intensity at subacute stage, low intensity at chronic stage on T1WI. • Flair and DWI sequences are more sensitive for detecting acute infarction.
  • 30. MR:44396 MR&CT appearances of acuteMR&CT appearances of acute cerebral infarctioncerebral infarction T2WI T1WI Flair
  • 31. MR:44396 MR&CT appearances of acute cerebralMR&CT appearances of acute cerebral infarctioninfarction FlairT1WIT2WI
  • 37. Chronic infarction at brain stem and cerebellum—T2WI
  • 38. Chronic infarction at brain stem and cerebellum—T1WI
  • 39. MRI diagnosis of head trauma
  • 40. The types of head trauma  Skull fracture  traumatic cerebral swelling  brain contusions  Intracranial bleed of trauma – Epidural hematoma – Subdural hematoma – Subarachnoid hemorrhage – Intracerebral hematoma
  • 41. MR diagnosis of cranial trauma Epidural hematoma ： ‫٭‬ direct violence on skull ‫٭‬skull fracture and deformation ‫٭‬direct laceration or tearing of meningeal arteries ‫٭‬ local hematoma ,not across cranial suture ‫٭‬shape of duple convex mirror
  • 42. MR appearances ‫٭‬ shape of hematoma is biconvex ‫٭‬ signal intensity of hematoma varies greatly depending on times. ‫٭‬ at acute stage （ 0~2 days ）， iso-intensity on T1WI ， low intensity on T2WI. ‫٭‬at subacute stage （ 3~14 days ）， becoming high signal intensity from rim to center on T1WI, still low signal intensity at 6~8 days and high signal intensity after 8 day on T2WI. ‫٭‬ at chronic stage (14 days later) , high signal intensity on both T1WI and T2WI for quite long times (may be several months)
  • 45. Subdural hematoma ‫٭‬Location: supratentorial convexity. ‫٭‬ Caused by stretching and tearing of bridging veins. ‫٭‬ Hematoma is located between dura mater and arachnoid. Often quite large extent , across cranial suture. ‫٭‬ MR appearances ： shape of hematoma semilunar ， signal changes of hematoma similar to epidural hematoma at different stages.
  • 46. Subacute Subdural Hematoma Axial T1-weighted magnetic resonance imaging demonstrates bilateral subacute subdural hematomas with increased signal intensity. Areas of intermediate intensity represent more acute hemorrhage into the subacute collections. T2-weighted magnetic resonance imaging in a patient with subdural hematoma shows blood products of differing ages.
  • 47. Subacute subdural hematoma at left frontal-temporal area
  • 48. Subacute subdural hematoma at left frontal-temporal area
  • 49. MR Features of brain contusion ‫٭‬ Often involve the temporal and frontal lobe. • Temporal lobe lesions tend to lie just above the petrous bone or posterior to the greater sphenoid wing. • Frontal lobe lesions occur just above the cribriform plate, orbit, planum sphnoidale, and lesser sphenoid wing.
  • 50. MR appearances ‫٭‬ MR is more sensitive than CT to find small contusion because of easy to find edema caused by contusion. ‫٭‬hemorrhagic foci appear petechia or multiple confluent regions with high signal intensity. ‫٭‬ easy to find contusion at brain stem.
  • 51. Contusion and epidural hemorrhage at both temporal lobe and frontal lobe
  • 52. Contusion and epidural hemorrhage at both temporal lobe and frontal lobe
  • 53. Multiple contusions at both sides of frontal and temporal lobes
  • 54. Multiple contusions at both sides of frontal and temporal lobes
  • 55. INTRACRANIAL TUMORS ‫٭‬ primary (80%) :originating from cranial bone, cranial meninges, brain tissues, vessels, cranial nerves, pituitary gland, etc. glioma(50%) , meningioma(14%) , pituitary tumor (11%) , acoustic neuroma(7%) ‫٭‬secondary (20%) : metastasis , involved by tumor from near structures.
  • 56. The types of intracranial tumors • Intraaxial brain tumors ： 1.glioma( astrocytoma and oligodendroglioma) 2.ependymoma 3.medulloblastoma 4.hemangioblastoma 5.papilloma choroideum 6.metastases
  • 57. The types of intracranial tumors • Extraaxial brain tumors 1.meningioma 2.craniopharyngioma 3.pituitary tumor 4.nerve sheath tumors-acoustic schwannoma 5.epidermorid cyst, dermoid cyst and hamartomas
  • 58. Direct signs 1. tumor or occupying lesion. 2. abnormal density or signal. 3. enhancement in different degree on enhanced scan. CT and MRI Signs for diagnosis of intracranial tumors 、、
  • 59. Indirect signs 1. shift of near structures 2. edema in brain tissue near tumor 3. Intratumoral bleed 4. Intratumoral calcification 5. bone changes
  • 60. Astrocytoma lower grading of astrocytoma ， grading I or II ． • Often in adult （２０～４０ years ） -- more occult in cerebral hemisphere ， grading II ， solid • child– less seen ， more in cerebellum ， grading I, cyst
  • 61. Astrocytoma MR ： Isointensity on T1WI ， unclear border , high or slightly high signal intensity on T2WI no or slight occupying effect , no or slight enhancement.
  • 63. Grade II astrocytoma T2W Gd+ Gd+ MR:39547
  • 64. Astrocytoma high grading （ grading III or IV) • Fast growing • Occur in any age
  • 65. Imaging appearances of high grading astrocytoma • Obvious occupying effects ,infiltrating growing with unclear margin , growing across lobe and hemisphere. • Necrosis, cyst , bleed. • Obvious brain edema around tumor. • Obvious uneven or ring-like enhancement.
  • 68. MR ： 53847 Grading IV astrocytoma
  • 69. Brain metastasis • Old age • Single or multiple • Multiple appearances on CT or MR, but often shown in nodule • Heterogeneous density or signal, central necrosis with lower density or signal on T1WI. • Ring-like or even enhancement • Obviously finger-like peritumoral edema
  • 71. Metastasis from lung cancer uncontrast contrast
  • 72. Metastasis from lung cancer uncontrast contrast
  • 73. Imaging of meningioma • Round or hemishere mass occur mostly in convexity of brain , especially sagittal sinus. • Mass with clear margin which was encysted with cerebral spinal fluid and/or vessels. • Iso- or slightly high density on plain CT and low signal on T1WI, iso- or slightly high signal on T2WI, which was enhanced obviously and evenly. • A broad thickened dural-based margin which was called “tail sign” . • Edema may be not or obvious. • Local bone changes including destruction, thin or thickness.
  • 74. Right parietal meningioma Plain T1WI Contrast T1WI
  • 77. Acoustic schwannoma • Benign tumor, occur mostly at middle age people, approximately 7 ~8 of all primary intracranial neoplasms.﹪ ﹪ • Ovoid or tubular tumors may occur in the internal auditory canal and cerebellopontine angle cistern . • Tumor may be part of solid and cystic . • On Plain CT, solid part of tumor was iso-density ,and cystic part was low density. • Iso-intensity or low signal intensity were seen in solid or cystic part of tumor on T1WI, but high or very high signal intensity on T2WI,. • Obvious enhancement was seen on solid tumor. • Enlargement of internal auditory canal.
  • 79. Left acoustic schwannoma T2WI T1WI Contrast T1WI