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Mri brain anatomy Dr Muhammad Bin Zulfiqar
The document discusses various aspects of magnetic resonance imaging (MRI) of the brain, including MR sequences, signal characteristics, and imaging techniques for diagnosing brain vascular diseases, head trauma, and intracranial tumors. It outlines the appearances of conditions like intracerebral hemorrhage, cerebral infarction, and different types of brain tumors, emphasizing the importance of MRI in identifying and differentiating these conditions based on specific imaging characteristics. Additionally, it provides detailed descriptions of normal anatomical structures and various MRI findings relevant to brain pathology.
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- 1. MR IMAGING OFBRAIN Muhammad Bin Zulfiqar PGR II SIMS/SHL New Radiology Department
- 2. Basics of MR •MR sequences • MR signal characteristic
- 3. MRI----conventional sequences • SEsequence （ 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 signalcharacteristics
- 6. Fat supression Liquidsupression MR signal characteristics
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- 8. Fig. 1.1 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 PostContrast 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 structureof head on MRI
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- 22. T1WI （ sagittalsection ） Corpus callosum; optic chiasm; pituitary gland; medulla oblongata
- 23. MRI diagnosis ofbrain 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 ofhemorrhage 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.
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- 28. MRI diagnosis ofcerebral infarction
- 29. MR appearances ofcerebral 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 ofacuteMR&CT appearances of acute cerebral infarctioncerebral infarction T2WI T1WI Flair
- 31. MR:44396 MR&CT appearances ofacute cerebralMR&CT appearances of acute cerebral infarctioninfarction FlairT1WIT2WI
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- 37. Chronic infarction atbrain stem and cerebellum—T2WI
- 38. Chronic infarction atbrain stem and cerebellum—T1WI
- 39. MRI diagnosis ofhead trauma
- 40. The types ofhead trauma Skull fracture traumatic cerebral swelling brain contusions Intracranial bleed of trauma – Epidural hematoma – Subdural hematoma – Subarachnoid hemorrhage – Intracerebral hematoma
- 41. MR diagnosis ofcranial 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 ٭ shapeof 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)
- 43. Subacute hematoma at leftfrontal lobe
- 44. Subacute hematoma at leftfrontal lobe
- 45. Subdural hematoma ٭Location: supratentorialconvexity. ٭ 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 AxialT1-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 hematomaat left frontal-temporal area
- 48. Subacute subdural hematomaat left frontal-temporal area
- 49. MR Features ofbrain 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 ٭ MRis 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 epiduralhemorrhage at both temporal lobe and frontal lobe
- 52. Contusion and epiduralhemorrhage at both temporal lobe and frontal lobe
- 53. Multiple contusions atboth sides of frontal and temporal lobes
- 54. Multiple contusions atboth 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 ofintracranial tumors • Intraaxial brain tumors ： 1.glioma( astrocytoma and oligodendroglioma) 2.ependymoma 3.medulloblastoma 4.hemangioblastoma 5.papilloma choroideum 6.metastases
- 57. The types ofintracranial 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. tumoror 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. shiftof near structures 2. edema in brain tissue near tumor 3. Intratumoral bleed 4. Intratumoral calcification 5. bone changes
- 60. Astrocytoma lower grading ofastrocytoma ， 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 onT1WI ， unclear border , high or slightly high signal intensity on T2WI no or slight occupying effect , no or slight enhancement.
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- 63. Grade II astrocytoma T2WGd+ Gd+ MR:39547
- 64. Astrocytoma high grading （grading III or IV) • Fast growing • Occur in any age
- 65. Imaging appearances ofhigh 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.
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- 68. MR ： 53847 GradingIV astrocytoma
- 69. Brain metastasis • Oldage • 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
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- 71. Metastasis from lungcancer uncontrast contrast
- 72. Metastasis from lungcancer 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 PlainT1WI Contrast T1WI
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- 77. Acoustic schwannoma • Benigntumor, 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.
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- 79. Left acoustic schwannoma T2WIT1WI Contrast T1WI
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