MRI PROCEDURE OF BRAIN

1. MRI BRAIN
Presenter :Sujan Karki
B.Sc. MIT 3RD Year
National Academy of Medical Sciences, Bir Hospital

2. Introduction
• Brain is the most frequently imaged organ by MR imaging.
• Technological developments in computer design and processing speeds as
well as hardware developments have enabled significant growth in MR brain
imaging.
• Beyond simple anatomical imaging of the brain, advanced techniques now
include functional MRI (fMRI), 3D proton spectroscopy, diffusion tensor
imaging (DTI), perfusion imaging, and volumetric measurements.
• However, basic techniques remain the foundation for all MR brain imaging.

3. Advantage of MRI over CT in brain imaging
• MRI does not use ionizing radiation, and is thus preferred over CT in
children and patients requiring multiple imaging examinations.
• MRI has a much greater range of available soft tissue contrast, depicts
anatomy in greater detail, and is more sensitive and specific for
abnormalities within the brain itself.
• MRI scanning can be performed in any imaging plane without having to
physically move the patient.
• MRI contrast agents have a considerably smaller risk of causing potentially
lethal allergic reaction.
• MRI allows the evaluation of structures that may be obscured by artifacts
from bone in CT images.

5. Vertebrobasilar Arterial
System(Posterior System)
Internal Carotid Artery
System(Anterior System)

6. Dural venous sinus
• Dural venous sinuses are venous channels
located intracranially between the two
layers of the dura mater and contains
venous blood that originates from major
parts of brain.
• Unlike other veins in the body, they run
alone, not parallel to arteries.
• Furthermore, they are valveless, allowing
for bidirectional blood flow in intracranial
veins.

8. Things to do before MRI examination at waiting room ……
• Review the form with the patient and ask additional questions if they do have any
stimulator (neuro, bone, etc.), aneurysm clips, cardiac valves, pacemakers, and
any type of metallic implants such as cochlear (hearing aid) or ocular.
• If the patient has been or had been held a relevant job such as working in a metal
factory, be extra cautious and question the patient regarding any work-related
accidents.
• Ask patient to change clothes with MR gown and remove any metallic objects
including jewelry, hair pins, watch, mobile devices, etc.
• Is recheck/final check necessary???Scan the patient with a metal detector one
more time before taking them into the MR room
• What about pregnant patient???? decision makers are patients or legal guardians,
but the potential advantages and risks must be explained
• Unconscious patient from Emergency or ICU should be screened carefully to
remove metallic objects such oxygen cylinders
• Take the weight of the patient ????

9. PATIENT PREPARATION FOR MRI :
Things to do during MRI exam at the scanner room
• After the screening if the patient have implants do not take him/her to scanner
room until the implants MR safety is confirmed. If safe to scan then:
• Give and instruct the patient how to insert MR compatible spongy ear plugs to
reduce the noise experienced by the patient.
• When you place coil, straighten the cables to avoid any loop and avoid direct
contact between the cable and bare skin.
• Give the patient the patient alarm bell and explain them that they should press
whenever they feel like they need it (burning sensation, claustrophobia, pain,
nausea, etc.).
• To reduce the potential PNS in MRI, avoid any closed circuits or loops in patient
body resulting from crossing the legs or holding hands above the head.

10. Contrast media in MRI
• Gadolinium-based contrast enhancement is useful in brain imaging.
• Physicians often believe that administration of contrast is indicated for all
lesions.
• Three conditions must meet in order for contrast enhancement to occur:
1. An adequate blood supply to the lesion must exist.
2. Blood-brain barrier breakdown must be present
3. Sufficient extracellular space must be available for the contrast agent to
localize after it has leaked out of the vasculature
• In cases in which lesions do not enhance, the lack of enhancement in and of
itself provides useful clinical information
• IV Gadolinium: 0.1mmol/kg(approx.0.2ml/kg) body weight

11. Most common contraindication for MRI scan

12. T1 WEIGHTED
• RECOGNIZATION
 Fat is hyperintense
 Fluid is hypointense
 New blood is bright
 Moving blood is hypointense
 Paramagnetic substance are hyperintense
 Protein rich lesions are hyperintense
• USEFUL FOR
 Anatomic detail
 disruption of BBB when added contrast
Pathological processes normally increases the water content in tissue. Due to the
added water component most of the pathologies appear hypointense on T1
weighting .

13. Some examples of hyperintensity in T1 weighting

14. T2 WEIGHTED
• RECOGNIZATION
 fluid is hyperintense
 Fat is hypointense
 flow is dark (blood vessels)

• USEFUL FOR
 Anatomic detail
 most lesions
 Cannot differentiate between lesions from CSF

15. FLAIR(fluid attenuated inversion recovery)
• RECOGNIZATION
 T2 + free flowing Fluid is dark
 Non-free flowing fluid is bright
 Fat is hypointense
USEFUL FOR
Delineation of lesions near ventricles and sulcus
Can improve greywhite differentiation
Edema

16. Value of FLAIR images

17. T2* GRE(SWI)
The principle of Multiecho T2* GRE is similar to conventional
T2 weighting.
T2WI uses the 180∘ refocusing pulse to eliminate the
inhomogeneity
T2* WI dose not use 180 degree refocusing pulse but the
gradient rephasing is used.
T2 reflects the decay of transverse magnetization by tissue
itself but in T2* weighting decay of transverse magnetization is
caused by tissue and inhomogeneity of the main magnetic field.
Paramagnetic substance appears dark( chronic hematoma, other
metal
Useful for the detection of microbleed.

18. Diffusion Weighting Imaging(DWI)
• Random movement of water and small molecules due to thermal collision.
• It is added primarily to basic sequence because it provides sensitivity to
acute/subacute ischemia and requires less than 50 seconds.
• The time cost are minimal for the valuable information gained.
• The utilization of whole body DWI is becoming a standard application in
routine imaging.

19. Formation of DWI image
• Within the spin echo preparation two
strong gradient pulse are played out
around 180 degree pulse.
• The first pulse dephase the
magnetization of hydrogen protons
and then second gradient rephases
them.
• If there is normal diffusion then
during the rephasing the losses their
phase coherence but if there is the
restriction diffusion then the protons
will remain in phase during rephasing
and shows the hyperintense signal.

20. What does B value means ??
• An operator selected parameter that defines gradient strength and duration.
• Determines the degree of the diffusion weighting.
• B value of “0” delivers a T2 weighted EPI image for anatomical reference.
B value : 0 B value: 500 B value: 1000

21. T2 SHINE THROUGH

22. Apparent Diffusion Coefficient (ADC) mapping
• Having measured a set of at least 2 different b-value
images (e.g., b:0 and b: 1000 s/mm²) the system
calculates pixel by pixel the ADC by linear
regression.
• In ADC the T2 shine through effect is diminished
and only the true restriction diffusion is shown
hypodense.
• The ADC image is a calculated parameter map that
computes ADC values on a pixel-by-pixel basis
using data from two or more raw data sets with
different b-values.
• By convention, higher ADC values are displayed as
white while lower ADC values are displayed as
dark.

24. SIGNIFICANCE OF SAGITTAL images
•Anatomic localization
•Corpus callosum delineation
•Craniocervical junction
•Evaluation of venous sinuses
•Pituitary gland

25. SIGNIFICANCE OF CORONAL IMAGES
•Pituitary gland, chiasm,
hypothalamus
•Hippocampal region
•Skull base and posterior fossa
•Trigeminal nerve
•Vascular anatomy

26. Positioning for MRI BRAIN

27. Localizer

28. Planning for Basic Brain sequences
•T2 TSE AXIAL
• SAGITTAL : ANGLE THE BLOCK PARALLEL TO GENUE AND SPLENIUM OF CORPUS CALLOSUM
• CORONAL : PERPENDICULAR TO THE LINE OF 3RD VENTRICLE AND BRAINSTEAM
COVER WHOLE OF THE BRAIN FROM VERTEX TO FORAMENA MAGNUM
TR TE FA MATRIX FOV ST SG NEX
3000+ 100+ 130-150 320X320 210-230mm 5MM 10% 2

29. •T2 FLAIR AXIAL
• SAGITTAL : ANGLE THE BLOCK PARALLEL TO GENUE AND SPLENIUM OF CORPUS CALLOSUM
• CORONAL : PERPENDICULAR TO THE LINE OF 3RD VENTRICLE AND BRAINSTEAM
COVER WHOLE OF THE BRAIN FROM VERTEX TO FORAMENA MAGNUM
TR TE FA MATRIX FOV ST SG NEX
7000+ 110 130-150 320X320 210-230 5MM 10% 2

30. •T1 CORONAL
• SAGITTAL : POSITION THE BLOCK PARALLEL TO THE BRAINSTEAM
• AXIAL : POSITION THE BLOCK PERPENDICULAR TO MIDLINE OF BRAIN
COVER WHOLE OF BRAIN FROM FRONTAL SINUS TO THE LINE OF OCCIPITAL PROTUBERANCE
TR TE FA MATRIX FOV ST SG NEX
400-600 15+ 90 320X320 210-230 5MM 10% 2

31. TR TE FA MATRIX FOV ST SG NEX
3000+ 100+ 130-150 320X320 210-
230mm
5MM 10% 2
T2 SAGITTAL
CORONAL : PARALEEL TO THE LINE ALONG THE 3RD VENTRICLE AND BRAINSTEAM
AXIAL : PARALLEL TO THE MIDLINE OF THE BRAIN
SLICE MUST BE SUFFICIENT TO COVER THE BRAIN FROM TEMPORAL LOBE TO TEMPORAL LOBE

32. •DWI (EPI)
• SAGITTAL : ANGLE THE BLOCK PARALLEL TO GLABELLA AND FORAMENA MAGNUM (this
angle will reduce the artefacts from the paranasal sinuses)
• CORONAL: PERPENDICULAR TO THE LINE OF 3RD VENTRICLE AND BRAINSTEAM
COVER WHOLE OF THE BRAIN FROM VERTEX TO FORAMINA MAGNUM
TR TE FA MATRIX FOV ST SG NEX B VALUE
7000+ 110+ 130-150 192X192 210-230 5MM 10% 4 0,1000

33. Appearance of clotted blood on MRI

34. Sequences for hemorrhage
- Routine protocol
- SWI(Axial T2*GRE)
- DWI
- MRA
IF given contrast then post contrast T1 axial ,T1coronal T1sagittal and
CE flair may be taken

35. Stroke
• A stroke occurs when the blood supply to part of brain is
interrupted or reduced, preventing brain tissue from getting
oxygen and nutrients.
• It is the No. 5 cause of death and a leading cause of disability
in the United States.
• Broadly, there are three types of stroke, ischemic (in 85% of
cases) or haemorrhagic (in 15%)and transient ischemic stroke
(a mini stroke).
• About 1.9 millions of neuros per minutes are irreversibly lost
in the initial phase of acute ischemic stroke.
• Protocols should therefore be as short as possible without
compromising in information needed for patient
management.
• No universally accepted MRI protocol exists for AIS
imaging.

36. Stroke protocols
• Sequences :-
Routine Protocol
SWI(T2*)
DWI
Perfusion
MRA
IF given contrast then post contrast T1 axial ,T1coronal
T1sagittal and CE flair may be taken .

37. Cranial Nerves(Trigeminal NERVE)
• For optimal demonstration of cranial nerve
anatomy along their entire course to detect any
pathology, injury, infection, tumor and any
clinical condition related to possible dysfunction
of the nerve.
• Trigeminal nerve is the fifth cranial nerve
responsible for the sensation nof the face.
• Sometime compression of the trigeminal nerve
by the artery most commonly superior
cerebellar artery may cause irritation to the
nerve and cause excessive pain at the face .

38. •T2 STIR COR 3MM
• ON SAGITTAL : PERPENDICULAR TO HARD PALATE
• ON AXIAL: PERPENDICULAR TO NASAL SEPTUM
COVERAGE FROM NOSE TO 4TH VENTRICLE
TR TE FA MATRIX FOV ST SG NEX
4000-5000 110 130 256x256 170-180 3MM 10% 3

39. •T1 TSE COR 3MM
• SAGITTAL : PERPENDICULAR TO HARD PALATE
• AXIAL: PERPENDICUAL TO NASAL SEPTUM
COVERAGE FROM NOSE TO 4TH VENTRICLE
TR TE FA MATRIX FOV ST SG NEX
400-600 15-25 140 256x256 170-180 3MM 10% 2

40. • T2 3D SPACE OR CISS AXIAL 0.9MM
• SAGGITAL: PARALLEL TO HARD PALATE
• CORONAL: PARALLEL TO RT AND LT IAM
COVER FROM GLABELLA TO HARD PALATE
TR TE FA MATRIX FOV ST SG NEX
2000-2200 250-300 30 320x320 170-200 0.9MM 10% 2

41. • T1 TSE AXIAL 3MM
• SAGITTAL : PARALLEL TO HARD PALATE
• CORONAL : PARALLEL TO RT AND LT IAM
COVER FROM GLABELLA TO ANGLE OF JAW
TR TE FA MATRIX FOV ST SG NEX
400-600 15-25 140 256x256 170-180 3MM 10% 2

42. Internal Auditory Meatus(IAM)
• Generally done for the indication of
• Bell’s palsy
• Vertigo
• Ringing in the ear
• Acoustic neuroma(Vestibular Schwannoma)
• Sensorineural hearing loss(damage to the structures
in inner ear or auditory nerve)
• Generally done for cranial nerve 7 and 8
related pathologies.
• T1 axial and T1 coronal are required for the
contrast study in case of tumors.

43. Schwannoma
• Tumor that develops from Schwan
cells(benign)
• Categorized as glial cells which surrounds
and supports the neurons
• In peripheral nervous system Schwann
cell synthesize a fatty substance called
myelin which acts as a insulation sheath.
• Vestibular schwannoma is the
compression of seventh cranial nerve
causing hearing loss on one side, ringing
of the ear, balance problem .
•

44. •T2 TSE AXIAL
• SAGITTAL : ANGLE THE BLOCK PARALLEL TO GENUE AND SPLENIUM OF CORPUS CALLOSUM
• CORONAL : PERPENDICULAR TO THE LINE OF 3RD VENTRICLE AND BRAINSTEAM
COVER WHOLE OF THE BRAIN FROM VERTEX TO FORAMENA MAGNUM
TR TE FA MATRIX FOV ST SG NEX
3000+ 100+ 130-150 320X320 210-230 5MM 10% 2

45. •T2 TSE CORONAL
• AXIAL : Parallel to the line along RT and LT IAM
• SAGITTAL : parallel to brainstem
• Cover IAM from the posterior border of sphenoid sinus upto the line of 4th
ventricle.
TR TE FA MATRIX FOV ST SG NEX
3000-4000 110 130-140 256x256 150-180 3MM 10% 2

46. • 3D CISS (3D SPACE OR 3D FIESTA) AXIAL
• CORONAL :Parallel to RT and LT IAM
• SAGITTAL: Perpendicular to the brainstem
• Cover IAMS from the hippocampus up to the line of the C1 vertebral
body.
TR TE FA MATRIX FOV ST SG NEX
12-15 6-7 80 384x320 210-230 0.8MM 10% 1

47. Intracranial Space Occupying Lesions

48. • Evaluation of the intraparenchymal space occupying lesions
as tumors, metastases, abscesses etc.
• For localization, complication and management, meningeal
disease and post op follow up of these cases.
• Sequences
- Routine protocol
- DWI
- Axial ,coronal and sagittal T1 + contrast

49. Pituitary gland
• MRI is the examination of choice for sellar and
parasellar pathologies due to its superior soft
tissue contrast, multiplanar capability and lack
of ionizing radiation.
• In sagittal image anterior and posterior
pituitary gland can be clearly differentiated
because posterior pituitary appears
hyperintense on T1 because it contains more fat
and triglyceride.
• Pituitary Adenomas
Adenomas measuring more than 1 cm are
called macroadenomas.
Adenomas measuring less than 1cm are called
microedenomas.
Microadenoma
Macroadenoma
Macroadema

50. •T2 TSE COR 3MM
• SAGITTAL: PERPENDICULAR TO SELLA TURCICA
• AXIAL : PERPENDICULAR TO CEREBRAL MIDLINE
COVER WHOLE OF PITUTARY GLAND FROM ANTRIOR BORDER OF SPHENOID SINUS TO THE
ANTERIOR BORDER OF PONS.
TR TE FA MATRIX FOV ST SG NEX
3000+ 110 130 256X256 110-130 3MM 10% 3

51. •T1 TSE SAGITTAL FAT SATURATED 3MM
• CORONAL :PARALLEL TO THE LINE ALONG THE 3RD VENTRICLE AND MIDBRAIN
• AXIAL: POSITION THE BLOCK PARALLEL TO SELLA TURCICA
COVER WHOLE OF THE PITUTARY GLAND FROM RT AND LT INTERAL CAROTID
ARTERY
TR TE FA MATRIX FOV ST SG FATSAT NEX
400-500 15 130 256X256 110-130 3MM 10% YES 4

52. •T1 FAT SATURATED CORONAL
• AXIAL : PERPENDICULAR TO CEREBRAL MIDLINE
• SAGITTAL: PERPENDICULAR TO SELLA TURCICA
COVER WHOLE OF PITUTARY GLAND FROM ANTRIOR BORDER OF SPHENOID SINUS TO THE
ANTERIOR BORDER OF PONS.
TR TE FA MATRIX FOV ST SG FATSAT NEX
400-500 15 130 256X256 110-130 3MM 10% YES 4

53. Dynamic imaging of pituitary gland
• Method for acquiring a series of MR images in
rapid succession following the administration of
contrast.
• viewing the "wash-in" and "wash-out" of contrast
on MRI may improve the detection and
delineation of tumors and vascular lesions.
• A dose of 0.1mmol/kg of gadolinium injected
intravenously is usually adequate.
• After a bolus injection of intravenous gadolinium,
six consecutive sets of three images are obtained
in coronal plane every 10 seconds.
• The peak enhancement of the pituitary adenomas
occurs at 60-200 seconds, usually after the most
marked enhancement of the normal pituitary
gland,

54. • Middle pink portion of the k space contains the low spatial frequency information
–overall darkness and brightness and general shape.
• The periphery portion contains high spatial frequency information .
• When contrast passes through the anatomy of interest, only the general brightness
or darkness change significantly

55. Epilepsy and Seizure
• A seizure is a sudden uncontrolled electric
disturbance in the brain.
• It can cause change in the behavior,
movements or feelings and in the level of
consciousness.
• Reoccurring and unpredictable seizures is
epilepsy.
• During seizure cluster of neurons in brain
become temporarily impaired and either
causes to much excitation or tool little
inhibition.

56. •T2 TSE CORONAL OBLIQUE 3MM
• AXIAL : PERPENDICUALR TO THE MIDLINE OF THE BRAIN
• SAGITTAL: PERPENDICULAR TO THE LONG AXIS OF HIPPOCAMPUS
(COVER WHOLE OF THE TEMPORAL LOBE)
TR TE FA MATRIX FOV ST SG NEX
3000-4000 100-120 130-150 320X320 180-200 2MM 10% 4

57. •T1 TSE CORONAL OBLIQUE 3MM
• AXIAL : PERPENDICUALR TO THE MIDLINE OF THE BRAIN
• SAGITTAL: PERPENDICULAR TO THE LONG AXIS OF HIPPOCAMPUS
(COVER WHOLE OF THE TEMPORAL LOBE)
TR TE FA MATRIX FOV ST SG NEX
400-600 15-25 140 320X320 180-200 2MM 10% 4

58. Multiple sclerosis
• Demyelinating disease of central nervous system.
• Exact cause is unknown but linked on genetic and
environmental factors .
• Flair is superior to PD in the supratentorial white
matter but the opposite is true for posterior fossa
lesions, where PD holds a significant advantage.
• In PD grey matter, white matter and CSF have similar
signal but lesions such as MS plagues have higher
signals.
• The role of Gd-enhanced imaging remains
controversial in management and diagnosis of MS
but,
-recent consensus statement advocates that “enhanced
MRI is recommended for suspected MS for initial
diagnostic evaluation and diagnosis.

59. •Protocol:
•Best with sagittal FLAIR
•Administration of contrast .
•Sequences:
- Routine protocol
- 3D Sagittal FLAIR
- Axial T1 FS + contrast
- Axial FLAIR + contrast
- Coronal T1 FS + contrast

60. Brain MRI Protocols of BIR HOSPITAL
Basic Sequence Screening Sequence
SURVEY SURVEY
T2 TSE AXIAL T2 FLAIR AXIAL
DWI AXIAL T2 TSE AXIAL
T1 SE AXIAL
T1 SAGITTAL
FLAIR AXIAL
T2 CORONAL
T2 GRE AXIAL

61. REFERENCES
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• MRI Handbook MR Physics, Patient Positioning, and Protocols Muhammed Elmao lu
Ayazma Caddesi
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• Diffusion-weighted MRI: a new functional clinical technique for tumour imaging 1 D-M
KOH, MRCP, FRCR and 2 A R PADHANI, FRCR, FRCP
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Doring, MScd,e
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Chen,1 Xiao Ming Zhang,1 and Xiao Hua Huang
• www.mrimasters.com
• www. questions and answers in MRI