Mr imaging of brain

81
MR IMAGING OF BRAIN Muhammad Bin Zulfiqar PGR II SIMS/SHL New Radiology Department

Transcript of Mr imaging of brain

Page 1: Mr imaging of brain

MR IMAGING OF BRAIN

Muhammad Bin Zulfiqar PGR II SIMS/SHL

New Radiology Department

Page 2: Mr imaging of brain

Basics of MR

• MR sequences

• MR signal characteristic

Page 3: Mr imaging of brain

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 )

Page 4: Mr imaging of brain

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

Page 5: Mr imaging of brain

T2WI T1WI

MR signal characteristics

Page 6: Mr imaging of brain

Fat supression Liquid supression

MR signal characteristics

Page 7: Mr imaging of brain

THREE DIMENSIONAL BRAIN ANATOMY

Page 8: Mr imaging of brain

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

Answers1. Cisterna Magna

2. Cervical Cord

3. Nasopharynx

4. Mandible

5. Maxillary Sinus

Page 9: Mr imaging of brain

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

Page 10: Mr imaging of brain

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

Page 11: Mr imaging of brain

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

Answers18. Aqueduct of Sylvius

19. Midbrain

20. Orbits

21. Posterior Cerebral Artery

22. Middle Cerebral Artery

Page 12: Mr imaging of brain

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 theIII Ventricle

Answers23. Occipital Lobe

24. III Ventricle

25. Frontal Lobe

26. Temporal Lobe

27. Sylvian Fissure

Page 13: Mr imaging of brain

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

Page 14: Mr imaging of brain

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

Answers39. Splenium of corpus callosum

40. Choroid plexus within the

body of lateral ventricle

41. Genu of corpus callosum

Page 15: Mr imaging of brain

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

Page 16: Mr imaging of brain

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

Page 17: Mr imaging of brain

Normal anatomical structure of head on MRI

Page 18: Mr imaging of brain

T2WI

Page 19: Mr imaging of brain

T1WI

Page 20: Mr imaging of brain

Flair sequence

Page 21: Mr imaging of brain

T2WI(coronal section )

Page 22: Mr imaging of brain

T1WI ( sagittal section )

Corpus callosum; optic chiasm; pituitary gland; medulla oblongata

Page 23: Mr imaging of brain

MRI diagnosis of brain vascular diseases

• Intra cerebral Hemorrhage

• Cerebral Infarction

• Intracranial Aneurysm

Page 24: Mr imaging of brain

Brain bleed (hemorrhage)

• Causes : high blood pressure, vascular malformation and tumor

• Stage : acute, sub acute, chronic

Page 25: Mr imaging of brain

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.

Page 26: Mr imaging of brain

acute/subacute hemorrhage

acute

subacute T2WI T1WI

Page 27: Mr imaging of brain

Chronic intracranial hemorrhage

Page 28: Mr imaging of brain

MRI diagnosis of cerebral infarction

Page 29: Mr imaging of brain

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.

Page 30: Mr imaging of brain

MR:44396

MR&CT appearances of acute MR&CT appearances of acute cerebral infarctioncerebral infarction

T2WI T1WI Flair

Page 31: Mr imaging of brain

MR:44396

MR&CT appearances of acute cerebral MR&CT appearances of acute cerebral infarctioninfarction

Flair T1WIT2WI

Page 32: Mr imaging of brain

Acute infarction

Page 33: Mr imaging of brain

Acute infarction

Page 34: Mr imaging of brain

Acute infarction DWI

Page 35: Mr imaging of brain

Subacute/chronic infarction—T2WI

Page 36: Mr imaging of brain

T2WI--Coronal

Page 37: Mr imaging of brain

Chronic infarction at brain stem and cerebellum—T2WI

Page 38: Mr imaging of brain

Chronic infarction at brain stem and cerebellum—T1WI

Page 39: Mr imaging of brain

MRI diagnosis of head trauma

Page 40: Mr imaging of brain

The types of head trauma

Skull fracture traumatic cerebral swelling brain contusions Intracranial bleed of trauma

– Epidural hematoma– Subdural hematoma– Subarachnoid hemorrhage– Intracerebral hematoma

Page 41: Mr imaging of brain

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٭

Page 42: Mr imaging of brain

MR FEATURES

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)

Page 43: Mr imaging of brain

Subacute hematoma at left frontal lobe

Page 44: Mr imaging of brain

Subacute hematoma at left frontal lobe

Page 45: Mr imaging of brain

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.

Page 46: Mr imaging of brain

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.

Page 47: Mr imaging of brain

Subacute subdural hematoma at left frontal-temporal area

Page 48: Mr imaging of brain

Subacute subdural hematoma at left frontal-temporal area

Page 49: Mr imaging of brain

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.

Page 50: Mr imaging of brain

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 ٭

Page 51: Mr imaging of brain

Contusion and epidural hemorrhage at both temporal lobe and frontal lobe

Page 52: Mr imaging of brain

Contusion and epidural hemorrhage at both temporal lobe and frontal lobe

Page 53: Mr imaging of brain

Multiple contusions at both sides of frontal and temporal lobes

Page 54: Mr imaging of brain

Multiple contusions at both sides of frontal and temporal lobes

Page 55: Mr imaging of brain

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.

Page 56: Mr imaging of brain

The types of intracranial tumors

• Intraaxial brain tumors : 1.glioma( astrocytoma and oligodendroglioma)

2.ependymoma

3.medulloblastoma

4.hemangioblastoma

5.papilloma choroideum

6.metastases

Page 57: Mr imaging of brain

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

Page 58: Mr imaging of brain

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

、、

Page 59: Mr imaging of brain

Indirect signs

1. shift of near structures 2. edema in brain tissue near tumor 3. Intratumoral bleed 4. Intratumoral calcification 5. bone changes

Page 60: Mr imaging of brain

Astrocytoma

lower grading of astrocytoma , grading I or II .

• Often in adult (20~40years ) -- more occult in cerebral hemisphere , grading II , solid

• child– less seen , more in cerebellum , grading I, cyst

Page 61: Mr imaging of brain

Astrocytoma MR : Isointensity on T1WI , unclear border , high or slightly high signal intensity on T2WI no or slight occupying effect , no or slight enhancement.

Page 62: Mr imaging of brain

Grade I Astrocytoma

T1WI T2WI

Page 63: Mr imaging of brain

Grade II astrocytoma

T2W Gd+ Gd+

MR:39547

Page 64: Mr imaging of brain

Astrocytomahigh grading ( grading III or IV)

• Fast growing

• Occur in any age

Page 65: Mr imaging of brain

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.

Page 66: Mr imaging of brain

Grade IV astrocytoma

MR:39985

T2W T1W Gd+

Page 67: Mr imaging of brain

Grade IV

astrocytoma

MR:39985

T2W Gd+

T2W Gd+

Page 68: Mr imaging of brain

MR : 53847

Grading IV astrocytoma

Page 69: Mr imaging of brain

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

Page 70: Mr imaging of brain

Multiple metastases

Page 71: Mr imaging of brain

Metastasis from lung cancer

uncontrast contrast

Page 72: Mr imaging of brain

Metastasis from lung cancer

uncontrast contrast

Page 73: Mr imaging of brain

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.

Page 74: Mr imaging of brain

Right parietal meningioma

Plain T1WI

Contrast T1WI

Page 75: Mr imaging of brain

T2WI AND contrast T1WI

Page 76: Mr imaging of brain

Meningioma

T2WI

T1WI

Gd-T1W

Page 77: Mr imaging of brain

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.

Page 78: Mr imaging of brain

Left acoustic schwannoma

Page 79: Mr imaging of brain

Left acoustic schwannoma

T2WI T1WI Contrast T1WI

Page 80: Mr imaging of brain

Left acoustic schwannoma

Page 81: Mr imaging of brain