MRI BRAIN

• MRI of the Head & Neck


  • MRI Brain (routine)
  • MRI Sella
  • MRI IAC
• Indications for MRI Brain (routine)


  • Tumour of the brain/meninges
  • Inflammation of the brain/meninges
  • Encephalopathy
  • Encephalitis
  • Venous sinus thrombosis
  • Haemorrhage
  • Epilepsy
  • Chronic stroke/infarct
  • Post-operative follow-up

  
• Indications for MRI Sella


  • Pituitary adenoma
  • Pituitary microadenoma
  • Pituitary macroadenoma
  • Hypopituitarism
  • Prolactinoma
  • Cushing's diseases
  • Diplopia
  • Ptosis
• Indications for MRI IAC


  • Acoustic neuroma
  • Schwannoma
  • Post-operative of cochlear implant
  • Mastoiditis
  • Unexplained hearing loss
  • Significant tinnitus
  • Dizziness
  • Vertigo
  • Sensorineural hearing loss (SNHL)
• Positioning for MRI


  1. Supine, head-first

  2. Hand by side

  3. Head matrix coil with mirror mounted

  4. Make sure head symmetry

  5. CR = glabella

  6. Cushion under knee

  7. Earplug or headphone

  8. Emergency buzzer

  9. Cover patient with blanket
• Scout images


  1. Three planes (axial, coronal, sagittal)

  2. Used for planning of the scan

  3. Can check the FOV, artifact & positioning

  4. Identify anatomy structure to be scanned

  5. Acquisition time (TA) in about 10 s

  6. Suggested parameter (ST = 8 mm, DF = 20%, FOV 230 mm × 230 mm, TR = 7 ms, TE = 2.95 ms)
• MRI Brain (routine) Protocol/Images/Sequence


  • T1 Axial
  • T2 Axial
  • FLAIR Coronal
  • T1 Sagittal
  • T2 Sagittal
  • T1 Axial (post-contrast)
  • T1 Coronal (post-contrast)
  • T1 Sagittal (post-contrast)

  
• MRI Sella Protocol/Images/Sequence


  • FLAIR Axial (whole brain)
  • T1 Sagittal (sella)
  • T2 Sagittal (sella)
  • T1 Coronal (sella)
  • T2 Coronal (sella)
  • T1 Axial (whole brain, post-contrast)
  • T1 Coronal (sella, post-contrast)
  • T1 Sagittal (sella, post-contrast)
  • T1 Coronal (sella, dynamic study with ST = 1 mm, pre & post-contrast)
• MRI IAC Protocol/Images/Sequence


  • T2 Axial (whole brain)
  • T1 Axial (IAC)
  • T2 Axial (IAC)
  • T2 Coronal (IAC)
  • T1 Axial (whole brain, post-contrast)
  • T1 Axial (IAC, post-contrast)
  • T1 Coronal (IAC, post-contrast)
• There is no sagittal images required for IAC
• Axial


  Plan in sagittal & coronal scout images, parallel to corpus callosum, FOV = vertex to foramen magnum, ST = 3 mm, T1-weighted uses short TR & TE, T2-weighted uses long TR & TE
• Coronal


  Plan in sagittal & axial scout images, perpendicular to corpus callosum, FOV = frontal sinus to occipital, ST = 3 mm, long TR & long TE, additional inversion time (TI) parameter for FLAIR = 2500 ms
• Sagittal


  Plan in axial & coronal scout images, parallel to interhemispheric fissure, FOV = Rt to Lt parietal bones, ST = 3 mm, T1-weighted uses short TR & TE, T2-weighted uses long TR & TE
• Axial whole brain


  Plan in sagittal & coronal scout images, parallel to corpus callosum, FOV = vertex to foramen magnum, ST = 3 mm, long TR & long TE, additional inversion time (TI) parameter for FLAIR = 2500 ms

  
• Sagittal sella


  Plan in axial and coronal scout images at the cavernous sinuses/sella/pituitary, parallel to midline, FOV = cavernous sinuses region, ST = 3 mm, T1-weighted uses short TR & TE, T2-weighted uses long TR & TE
• Coronal sella


  Plan in sagittal and axial scout images that show pituitary gland (mid-sagittal), perpendicular to sellar floor & parallel to pituitary stalk, FOV = orbital apex to petrous region, ST = 3 mm, T1-weighted uses short TR & TE, T2-weighted uses long TR & TE
• Axial IAC


  Plan in sagittal & coronal scout images at the IAC, parallel to hard palate in sagittal & parallel to temporal lobes in coronal, FOV = pons & whole IAC, ST = 3 mm, T1-weighted uses short TR & TE, T2-weighted uses long TR & TE
• Coronal IAC


  Plan in axial scout images that shows symmetrical right and left IAC, parallel to line connecting both right and left IAC, FOV = cover whole IAC and anterior half of the pons, T2-weighted images show hyperintense (bright) structures containing fluid like ventricle and eyeball
• CSF in T2-weighted images appears bright/hyperintense
• Body position of routine MRI brain

  Supine (head first)
• Centre of laser beam for routine MRI brain


  At the MSP and acanthion
• Planning the MRI procedure

  1. Localizer (scout) image must be taken in 3 planes (axial, sagittal & coronal)

  2. Normally at the mid plane
• Standard routine /screening MRI brain scanning require multiple set of images such as T1 axial, T2 axial, FLAIR coronal and all planes post contrast (if needed)

  
• FLAIR sequence of MRI


  Good to evaluate the diseases surrounding the structure that contains fluids (CSF) such as ventricles of the brain

  
• Producing AXIAL images for standard routine /screening MRI brain scanning

  1. Align the slice line/box parallel to the genu and splenium of corpus callosum at the midsagittal localizer

  2. Check the coverage from vertex to foramen magnum included on both midsagittal and midcoronal plane localizers

  
• Producing CORONAL images for standard routine /screening MRI brain scanning

  1. Align the slice line/box perpendicular (90 degree) to the genu and splenium of corpus callosum at the midsagittal localizer

  2. Check the coverage from frontal sinus to cerebellum/occipital lobe included on both midsagittal and axial plane localizers

  
• Producing SAGITTAL images for standard routine /screening MRI brain scanning

  1. Align the slice line/box parallel to interhemispheric fissure at the axial localizer

  2. Check the coverage from right to left parietal lobes (whole brain) included on both axial and midcoronal plane localizers

  
• For MRI brain of stroke, 3 additional sequences normally required, which are GRE (FLASH), DWI & TOF MRA circle of Willis
• For MRI brain tumour, 3 additional sequences normally required, which are GRE (FLASH), DWI & 3D MPRAGE sagittal (post-contrast)

  
• For MRI brain to rule out epilepsy, the axial slices must be parallel with temporal lobes of brain

  
• The planning for temporal lobes can be acquire from para-midsagittal localizer
• Acoustic neuroma (vestibular schwannoma)


  A benign tumor that best diagnosed using MRI IAC