Mri

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Mri

  1. 1. MRI
  2. 2. Magnetic Resonance Imaging All MRI machines work on hydrogen atom as hydrogen is considered the most common atom in the body, 90% of body is water (H20). The movement of the hydrogen protons in the magnetic field is the basis of MRI imaging. The protons are stimulated by a Radiofrequency (RF) coil and then left to relax in the direction of the magnetic field creating energy that is used for development of the image.
  3. 3. MRI of Spinal Cord and CSF flow Non-invasive –Provides anatomic detail of brain, spinal cord, intravertebral disc spaces, and CSF within subarachnoid space –Does not require intrathecal injection –Does not have bone artifacts Contraindications to MRI • Pacemakers • Ferromagnetic aneurysm clips • Metallic spinal fusion rods
  4. 4. Preference of MRI • MRI is the preferred modality for middle and posterior cranial fossa of brain. – In CT these structures are obscured by bone artifacts • Spinal cord – Allows direct visualization of spinal cord, nerve roots, and surrounding CSF – Can be done in various planes – Aid in diagnosis and treatment of neuro- disorders
  5. 5. Usefulness of MRI • Assessing demyelinating • Herniated disks disease – Such as MS • Congenital abnormalities of vertebral column • Spinal cord compression • Metastatic disease • Post radiation therapy • Para spinal masses changes of spinal cord tumors
  6. 6. Not valuable for diagnosing: • Osseous bone abnormalities of skull • Intracerebral hematomas • Subarachnoid Hemorrhage – CT preferred for these 3 illnesses
  7. 7. MRI Magnetic Resonance Imaging • MRI do not use ionizing radiation [ X-Rays ] for imaging • It can provide 3 dimensional imaging in the axial, sagittal, coronal and oblique projections. • MRI gives high resolution images.Both T1 AND T2 weighted images are essential for diagnosis. • MRI can show the following ; 1. The fractured vertebra and its displacement 2. Ligamentous injury 3. Cord parenchymal lesions [specially in T2 WIs ] 4. Blood collections inside the spinal canal & paravertebrally.
  8. 8. Any MRI examination should include: • T1 weighted images [T1WIs] show (anatomy) • T2 weighted images |T2Wls] show(Pathology) • Contrast used in MRI is Gadolinium PTPA injected in an a dose of 0.1-0.2mL/kgm body weight • MR can obtain sections in any plane as axial, sagittal and coronal.Oblique sections can also be performed
  9. 9. Diagnosis by MRI MRI Sections: • Coronal Like X ray A-P • Sagittal Like X ray lateral. • Axial Like C.T.
  10. 10. T1 T2
  11. 11. Common MR appearance in T1 and T2 WIs 1) Low signal in T1 & low signal in T2 WIs (non mobile protons) a-Cortical bone e.g. edges of vertebrae b- Mature fibrous tissues e.g. ligament and tendons c- Calcifications either normal or pathological 2) High signal in T1 & high signal T2Wis Subacute hematoma
  12. 12. 3) High signal in T1 & low signal in T2 WIs Fat and fat like structure e.g. lipoma 4) Low signal in T1 & high signal in T2 WIs The most common signal behavior Example: CSF, infarction, most of tumors.
  13. 13. Please remember; 1) Bone marrow contains fat so appear bright in T1 and darker in T2 WI 2) Thrombus = Subacute blood so appear white in T1 & White T2 WIs 3) Normal flowing blood gives no signal so appear Black in T1, Black in T2 4) Intervertebral disc: Nucleus pulposus (contains water) black in T1, white T2, Annulus fibrosus (mature fibrous tissue) black in T1, black in T2
  14. 14. Imaging Technology 1. X-RAYS: These show (1) disc narrowing, (2) bone spurs (osteophytes), and (3) vertebrae slipping off another (spondylo-lithesis) 2. CAT SCAN: This is a computerized X ray that shows how much the diameter of the canal is reduced and how far out the discs are 3. M.R.I. (Magnetic Resonance Imaging): It produces picture like the CAT scan but they are generated using a magnetic field (instead of radiation) – not needed if the CAT scan shows the problems. 14
  15. 15. MRI (magnetic resonance imaging): • Image is produced due to reaction between magnetic field inside the body & the magnetic field of the device. • This magnetic field inside the body is produced due to movement of Hydrogen ions as H+ protons are the most found ions in the body.
  16. 16. No image is obtained incase of: 1. Site without hydrogen ions. 2. If the hydrogen ions aren’t moving. There are 2 types of images: 1-T1 image: • All fluids as C.S.F. black • Fats are white • Brain & spinal cord are dark grey
  17. 17. 2-T2 image: • All fluids as C.S.F. is white • Fats are black • Brain & spinal cord are light grey There are 3 views: • Sagittal: as lateral image in x-ray. • Axial: as in CT. • Coronal: used to detect scoliosis, Intraspinal tumor, Para spinal soft tissue N.B. : the slide is taken every 4 mm in the whole column (cervical,dorsal, and lumbar) unlike CT
  18. 18. T1 T2
  19. 19. Types of MRI 1. Open MRI 2. Closed MRI 3. Extremity MRI or for pediatric head. Surface coil: Is a device used for imaging & the patient must lie on it, it is used to produces a large image with high resolution. N.B :There was a coil used for imaging cervical spine but it is not used nowadays as it moves with breathing so the image becomes unclear.
  20. 20. What is seen in MRI 1. Bone: vertebral endplate is black while in CT is white 2. Disc 3. Paravertebral soft tissue 4. Bone marrow indicated for MRI only 5. Spinal cord indicated for MRI only N.B.: MRI takes slides from left to right, so when we detect the midline image we choose the picture which contains the clearest image of spinal cord & conus medularis & what is before it is left & what is after it is right.
  21. 21. 1. Spinal canal (in axial image) If the thecal sac is circled & the epidural fat is found normal. 2. Cauda Equina (in axial image) Is more obvious in T2 more than T1 as in T2 C.S.F is white & nerve roots are grey in colour as well as it‘s not obvious in CT. 3. Spinal cord (in sagittal image) Spinal cord must be enveloped with C.S.F. anteriorly & posteriorly Mild stenosis: if C.S.F is found in one direction only anterior Or posterior. Moderate stenosis: C.S.F isn’t found at all.
  22. 22. 4. Bone marrow Contains fat & fat is white in T1 & black in T2 5. Disc (in midline sagittal T2 image) IF: a. Disc contains water it is white & it’s edge is within the vertebral edgeNORMAL. b. Disc doesn’t contain water (becomes black) & it’s still within the vertebral edge DEGENERATED. c. Disc doesn’t contain water (becomes black) & it’s edge isn’t within the vertebral edge it may be PROTRUDED OR HERNIATED.
  23. 23. Spinal degenerative diseases 1) Spinal canal stenosis 2) Disc lesions 3) Bone marrow changes 4) Ligamentous pathology 5) Osseous changes 6) Spondylolisthesis 7) Cord pathology
  24. 24. 1. spinal canal stenosis: (SCS) a) Idiopathic or Congenital SCS: < 13 mm reduced sagittal diameter Relative 11-12 mm / Absolute 8-9-10 mm b) Developmental SCS: Increases by time inspite of normal diameter which due to i) Hypertrophy of the lamina (becomes thick & short) & the angle becomes acute instead of being obtuse ii) Articular facet hypertrophy iii) Ligamentum flava hypertrophy
  25. 25. c- Acquired not discogenic: as there are many causes I) Disc lesions ii) Osteophytes Usually the patient has all types of spinal canal stenosis N.B. Captious spinal canal: very wide canal The canal diameter > 21 mm & it’s painful also as the thecal sac becomes more free instead of being fixed I can appreciate SCS of lumbar spine in axial more sagittal view .
  26. 26. -Ligaments, tendons and cortical bone are usually black in T1 & T2 images as they contain a lot of hydrogen ions but they aren’t moving that is why they are black all the time. -Ligamentum flava appears normally as a thin rope & appears abnormally as a thick rope. - Lateral recess measurement normally it measures about 0.5 cm or 5 mm if there is narrowing it compresses the nerve roots.
  27. 27. Cervical spinal canal stenosis We can detect it in sagittal T2 MRI image 1. Normally there’s C.S.F anterior & posterior to the cord 2. Mild there’s C.S.F only anterior or posterior to the cord 3. Moderate No C.S.F anterior or posterior to the cord 4. Severe No C.S.F & the cord is compressed as well But in CT Normally the cord is kidney shaped & there’s no idiopathic SCS Developmental SCS no disc & no C.S.F Acquired SCS C.S.F disappears due to disc
  28. 28. Spinal Stenosis  Spinal stenosis is a progressive narrowing of the opening in the spinal canal, which places pressure on the spinal cord (nerve roots)  Pressure on nerve roots causes  chronic pain, and  loss of control over some functions because communication with the brain is interrupted
  29. 29. Spinal Stenosis  Cervical spinal stenosis: Stenosis (narrowing) is located in the neck  Lumbar Spinal Stenosis: Stenosis is located on the lower part of the spinal cord  75% of cases of spinal stenosis occur in the low back (lumbar spine), and legs are affected  Produce pain in the legs with walking, and the pain is relieved with sitting
  30. 30. Summary  Disc Space Narrowing may be due to bulging and herinated discs  Posterior osteophytes – bone spurs  Posterior Apophyseal Arthropathy – abnormal growth on facet joints  Spondylolisthesis – vertebral slippage We detect these conditions using X ray
  31. 31. MRI Lumbar spine T2WI
  32. 32. T2WI MRI dorsal spine
  33. 33. MRI lumbar T1WI
  34. 34. MRI dorsal
  35. 35. MRI dorsal
  36. 36. T1WI MRI cervical
  37. 37. MRI cervical
  38. 38. T1WI T2WI MRI brain
  39. 39. MRI- LUMBAR SPINE SAGITTAL L-3 – L-4 DISC L-4 - L-5 DISC L- 5 S- 1
  40. 40. MRI- LUMBAR SPINE SAGITTAL L-3 – L-4 DISC L-4 - L-5 DISC L- 5 S- 1
  41. 41. MRI– LUMBAR SPINE SAGITTAL SPINAL CORD BULGING DISC
  42. 42. MRI – LUMBAR SPINE NERVE ROOTS FORAMEN AXIAL VIEW
  43. 43. MRI – LUMBAR SPINE THECAL SAC NERVE ROOTS AXIAL VIEW
  44. 44. MRI – LUMBAR SPINE AXIAL VIEW DISC FACET JOINTS LAMINA
  45. 45. MRI—CERVICAL SPINE SAGITTAL-lateral FACET JOINTS
  46. 46. MRI– CERVICAL SPINE SAGITTAL-midline C-7 T-1
  47. 47. MRI—CERVICAL SPINE SAGITTAL-midline THECAL SAC SPINAL CORD DISC
  48. 48. MRI– CERVICAL SPINE AXIAL FORAMEN FORAMEN DISC FACET JOINT FACET JOINT SPINOUS PROCESS
  49. 49. MRI– CERVICAL SPINE AXIAL THECAL SAC CORD
  50. 50. CT coronal MRI sagittal
  51. 51. T2WI MRI cervical
  52. 52. Cervical Spinal Stenosis (MRI) T2WI
  53. 53. Cervical Herniated Disc (MRI) T1WI T2WI
  54. 54. MRI of the spine T1WI T2WI
  55. 55. T2WI MRI
  56. 56. MRI of lumbar spine (T2WI) Disc bulge
  57. 57. T2WI T1WI Lumbar
  58. 58. Lung Metastasis. Post-contrast axial CT image showing a lung metastasis in the right hemisphere adjacent to the falx with surrouding edema and effacement of the sulci in the right hemisphere secondary to the mass effect.
  59. 59. MRI showing wedge # (T2WI)
  60. 60. Burst # of the spine
  61. 61. Subdural Hematoma on MRI
  62. 62. T2 MRI Lumbar spine
  63. 63. T2WI MRI of cervical spine
  64. 64. Cervical Herniated Disc (MRI) T2WI T1WI
  65. 65. Lumbar Herniated Disc (MRI)
  66. 66. Cervical Spinal Stenosis (MRI)
  67. 67. Thoracic Spine Compression Fx MRI
  68. 68. Olfactory Groove Meningioma. Post-contrast CT with multiple views displaying a large olfactory meningioma expanding around the internal carotids and as far as the clivus. Note the mass effect displacing the corpus callosum superiorly and posteriorly and erosion of the anterior fossa floor
  69. 69. Posterior Fossa Meningioma. T1-weighted coronal MRI with contrast. A large tumour is highlighted in the right posterior fossa and bilateral dilatation of the lateral ventricles is evident (likely secondary to compression of the 4th ventricle or Sylvian aqueduct)
  70. 70. Cauda Equina. T2-weighted axial MRI image showing a central disc herniation compressing the cauda equina.
  71. 71. Cauda Equina. T2-weighted sagittal MRI showing a L4-5 disc herniation compressing the cauda equina.
  72. 72. Central Disc Herniation. T2-weighted axial MRI showing a central disc herniation compressing the cord (note the minimal amount of CSF and change in cord morphology)
  73. 73. Cord Compression. T2-weighted sagittal MRI showing compression of the L1 vertebra with posterior displacement vertebral body disrupting the posterior spinal line
  74. 74. Far Lateral Disc Herniation. T2-weighted axial MRI image showing a right-sided far lateral disc herniation compressing the nerve root
  75. 75. Idiopathic Syrinx. T2-weighted sagittal MRI image showing a hyperintense signal within the spinal cord
  76. 76. Subarachnoid hemorrhage. Axial CT image with blood filling the suprasellar cistern, ambient cisterns, interhemispheric fissure, and sylvian fissures in the classic star pattern
  77. 77. Subarachnoid hemorrhage and Aneurysm. Axial non-contrast CT image showing a SAH and right MCA aneurysm with mild hydrocephalus seen by the prominent temporal horns of the lateral ventricles
  78. 78. Acute Subdural Hematoma. Non-contrast axial CT showing a left hemispheric subdural hematoma with some blood tracking along the falx and concurrent intracerebral hemorrhage on the right. Some compression is seen on the left with decreased visibility of sulci and soft tissue swelling on the posterior left occipital lobe
  79. 79. Chronic Subdural Hematoma. Axial CT image showing left hemispheric chronic subdural hematoma with neomembrane and compression of the left hemisphere.
  80. 80. Chronic Subdural Hematoma.
  81. 81. Chronic Subdural Hematoma.
  82. 82. Subdural hematoma

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