This document provides an overview of MRI protocols for imaging brain tumors and what each sequence reveals. It discusses how conventional sequences can identify tumors versus other lesions and provide histological information. Post-contrast T1-weighted imaging reveals enhancement patterns related to tumor angiogenesis and blood-brain barrier disruption. Perfusion MRI demonstrates neoangiogenesis which correlates with tumor grade. Susceptibility weighted imaging visualizes microvessels and intratumoral susceptibility signals associated with grading. Magnetic resonance spectroscopy identifies metabolite levels indicative of tumor type and grade. Diffusion weighted imaging correlates restricted diffusion with cellularity and tumor aggressiveness.

1. MRI imaging of brain tumors.
A practical approach.
Dr. Hazem Abu Zeid Yousef
Assistant professor of radiodiagnosis.
Assiut University Hospital.

2. Brain tumor imaging objectives
• Tumor versus non tumoral lesion.
• Histological grade.
DIAGNOSIS
• Delineation of the tumor extent.
• Tumor versus peritumoral edema.
TREATMENT
PLAN
• Residual tumor versus treatment
necrosis.
POST TREATMENT
FOLLOW UP

3. What is my job?
• Is this a tumor or something else?
• Is this a benign or malignant tumor?
DIAGNOSIS
• Which part should the surgeon take out?
• Where should be irradiated?
TREATMENT
PLAN
• Recurrent/residual tumor or post
treatment effect?
POST TREATMENT
FOLLOW UP

4. What protocol to use?
• Scout.
• Axial T1W, T2W & FLAIR.
• DWI, ADC & DTI.
• Perfusion.
• SWI.
• Axial, Sagittal & Coronal post Gd T1W.
• Proton MRS SV & Multivoxel.
• 3D T1W volume.

5. What is each sequences tells about the
tumor?
• Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & DTI.

6. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & DTI
Conventional sequences (T1WI, T2WI & FLAIR).

7. Peritumoral edema
• Vasogenic cerebral oedema refers to a type
of cerebral edema in which the blood brain
barrier (BBB) is disrupted (c.f. cytotoxic
edema where BBB is intact). It is an extracellular
oedema which mainly affects the white
matter, through leakage of fluid out of capillaries.
• It may be minor or major, rounded or irregular. It
is most frequently seen around brain
tumors (both primary and secondary) but is may
be seen around non tumorous conditions.

9. Necrosis
• Caused by sudden vascular occlusion.
• Endothelial proliferation and thrombosis are
predisposing factors.
• Poor prognosis in adult glioma.

12. Calcification
• It is usually a sign of slowly growing lesion.
• It is best assessed in CT.

13. Pilocytic astrocytoma
WHO grade I
Ependymoma
WHO grade II
Medulloblastoma
WHO grade IV

14. Cysts
• Neoplastic cysts (arises within the tumor and
has enhancing walls).
• Non neoplastic cysts (reactive, arising in the
neighbouring parenchyma and mural
enhancement is absent).

15. Medulloblastoma
WHO grade IV

16. Ependymoma
WHO grade II

17. Glioblastoma Multiforme
WHO grade IV

18. Hemorrhage
• Due to pathological changes in the tumor
vessels.
• It is rare (0.8-10.2%) and is usually typical of
malignant tumors.

19. Hemorrhagic
metastatic melanoma.

20. • Size.
• Edema.
• Location.
• Necrosis.
• Calcification.
• Hemorrhage.
• Cysts.
Unpredective
of grading

21. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & DTI.
Post contrast T1WI.

22. Post contrast scan
• Contrast material enhancement in the central
nervous system is a combination of two primary
processes: intravascular (vascular) enhancement
and interstitial (extravascular) enhancement.
• Intravascular enhancement may reflect
neovascularity, vasodilatation or hyperemia, and
shortened transit time or shunting. Interstitial
enhancement indicates abnormal BBB.

23. Diffuse astrocytoma
WHO grade II

24. Dysembryoplastic Neuroepithelial Tumor (DNET)
WHO grade I

25. GBM
WHO grade IV
Primary CNS lymphoma
WHO grade IV

26. Meningioma
WHO gradeI
Choroid plexus papilloma
WHO grade I

27. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & DTI.
Perfusion MRI.

28. Perfusion MRI
• Perfusion imaging allows some insight into
angiogenesis “development of new arteries
from pre-existing arteries” , a process
essential for neoplastic growth. Neoplastic
induced angiogenesis results in structurally
abnormal vessels that tend to be leaky, and
thus neoplasms have increased permeability
parameters on perfusion MR images.

29. The more aggressive a neoplasm
The more abnormal its vascularity.
Greater vascular tortuosity.
Greater vascular density.
Greater permeability.
Higher tumor blood volume.

30. Representative CBV maps from (A) a grade II fibrillary astrocytoma, (B) a grade III anaplastic
astrocytoma, and (C) a grade IV glioblastoma multiforme.
©2005 by American Society of Neuroradiology Tufail F. Patankar et al. AJNR Am J Neuroradiol
2005;26:2455-2465

31. WHO Grade II astrocytoma

32. WHO Grade III anaplastic astrocytoma

33. WHO Grade IV GBM

34. WHO Grade I meningioma

35. Primary CNS lymphoma WHO grade IV

36. Perfusion MRI
Predective of
grading
Neoangiogenesis is
one of the key
features of high
grade tumours.

37. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & DTI.
SWI.

38. Susceptibility weighted imaging (SWI)
• SWI is a technique that exploits the
susceptibility difference between tissues to
provide contrast for different regions of the
brain. In essence, it uses the deoxygenated
hemoglobin of veins, hemosiderin of
hemorrhage, etc. as intrinsic contrast agents,
allowing for much better visualization of blood
and microvessels even without administration
of an external contrast agent.

39. • SWI is an innovative new technique to
demonstrate microvessels and tumor
neoangiogenesis in exquisite detail based on
the presence of ITSS (intratumoral
susceptibility signals) thereby aiding in tumor
grading. Higher the ITSS score higher the
tumor grade.

40. Grade I astrocytoma

41. Oligodendroglioma grade II

42. Glioblastoma multiforme WHO grade IV

43. Glioblastoma multiforme WHO grade IV

44. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & TWI.
MRS.

45. MR Spectroscopy
Proton magnetic resonance spectroscopy
(MRS) provides a noninvasive method for
characterizing the cellular biochemistry which
underlies brain pathologies, as well as for
monitoring the biochemical changes after
treatment in vivo.

46. The brain metabolites that are commonly seen
on the MR spectrum are

52. Glioblastoma multiforme WHO Grade IV showing “sky high”
choline.

53. Cerebellar grade
I astrocytoma

54. • Conventional sequences (T1WI, T2WI & FLAIR).
• Post contrast T1WI.
• Perfusion MRI.
• SWI.
• MRS.
• DWI & TWIDWI & DTI.

55. Diffusion weighted imaging (DTI)
• The degree of restriction to water diffusion is
correlated with tissue cellularity and integrity
of cell membranes. Generally, malignant
tumors have enlarged nuclei and show
hypercellularity. These characteristics reduce
the extracellular matrix and the diffusion
space of water protons in the extracellular
areas, with a resultant decrease in the ADC
value.

56. ADCvalue

57. AnaplasticastrocytomaIII

58. MedulloblastomaWHOIV

59. DWI of ring enhancing lesions
• The necrotic component of brain tumor (GBM
and metastases) show marked hypo intensity
on DW images and increased ADC values due
to increased free water. This finding can be
used to differentiate necrotic tumors from
cerebral abscess, which demonstrates marked
diffusion restriction.

62. Hypercellularity is
one of the key
features of high
grade tumours.
Predective of
grading

63. Diffusion tensor (tractography)

64. Radiology Vol. 243, No. 2: 539-550
©RSNA, 2007

65. Thank
you