1. Brain Tumor Imaging Caribbean Medical Providers Practicing Abroad
June 13, 2015
Asante M. Dickson, MD
CAQ Neuroradiology
Washington Adventist Hospital
Takoma Park, MD

2. Role of Imaging Diagnosis Grade Guide Biopsy
Monitor treatment response and prognosis
Post-operative base-line

3. Imaging Modalities AvailableCT
MRI
PET

4. Pediatric Supratentorial Infratentorial
JPA juvenile pilocytic astrocytoma, Ganglioglioma, PXA pleomorphic xanthoastrocytoma, PNET primitive neuroectodermal tumor, DNT dysembroplastic neuroepithelial tumor
Infratentorial
JPA, Medulloblastoma, ATRT, Ependymoma, Diffuse pontine glioma
(Not usually intra-axial but don’t forget about LCH and Neuroblastoma)

5. Hoag - Medulloblastoma

6. Medulloblastoma

7. 4 year old
Brainstem glioma

8. Brainstem Glioma
Brainstem glioma

9. 26 yo M

10. Craniopharyngioma

11. 56 yo M T2
FLAIR

12. DWI
ADC

13. Intravascular Lymphoma
Post Gad

14. Okay, it’s a brain tumor – But then what ?
WHO divides CNS neoplasms into 9 primary groups and mets
Neuroepithelial tumours (astrocytic, oligo, astroblastoma, ependymal, choroid plexus)
Neuronal, mixed glial-neuronal and neurocytic
Pineal parenchymal tumors
Embryonal tumors (PNET, medullo, ATRT)
Peripheral neuroblastic tumors (neuroblastoma)
Tumors of cranial, spinal or peripheral nerves
Meningeal tumors (meningioma, chondrosarcoma, hemangioblastoma)
Lymphoma, hematopoietic tumors (leukemia, plasmacytoma)
Germ Cell Tumors
Metastases

15. The Approach to Differential Diagnosis
Where is it?
Intra-axial Vs Extra-axial
Cortical, white matter or deep grey matter, Intraventricular
Supra-tentorial or Infra-tentorial
Solitary or Multiple
How old is the patient?
Child, Young Adult, Older Adult, Ready to die of other causes
Primary vs Secondary
Is the patient immunocompromised? Other clinical history...
E.g. Lymphoma
Imaging features – T2, DWI, PWI, MRS, Gad

16. Gamuts Tumors in children <2yo Cortically based tumors
Astrocytoma, CPP, Teratoma, Embryonal tumors
Cortically based tumors
DNET, Ganglioglioma, Oligo, PXA(pleomorphic xanthoastrocytoma)
Intraventricular tumors
Pineal Region tumors
Dural Based tumors
Intracranial extension from extracranial
Chordoma, paraganglioma, carcinomas (NPCA), sarcomas (rhabdo)
Cyst + Nodule
Pilocytic, Craniopharyngioma, Ganglioglioma, Hemangioblastoma

17. Intra-axial vs Extra-axial Features
Surrounded by white matter
Expands cortex
May destroy GM/WM jx
Effaces CSF cisterns
Internal vascular supply
Extra-axial
CSF Cleft
Widening of CSF cisterns
Buckling of grey matter
GM/WM junction preserved
Continuity with bone or falx
Bony changes
External vascular supply

18. 12yoM – Intra or Extra-axial?
Cavernous Hemangioma with Intra-osseous hemangioma

19. Differential Diagnosis – Extra-axial
Skull-base/calvarium
Dural
Sellar/Parasellar/Optic chiasm
Perineural
Intra-ventricular
Central neurocytoma, ependymoma, subependymoma, oligo, pilocytic astro, meningioma, choroid plexus tumour, epidermoid, subependymal giant cell astrocytoma, colloid cyst, arachnoid cyst
Pineal Region
CP Angle

20. Pre T1
Post T1
Post T1
Post T1
Post T1
Post T1
Myxoid chondrosarcoma

21. 56 yo M
Primary CNS Lymphoma

23. Primary CNS Lymphoma

24. Diagnosis – Is it neoplastic?
Mass Lesions – The standard Ddx
(Congenital)
Infectious
Inflammatory
Neoplastic
Vascular – Ischemic, Hemorrhagic
(Toxic, Metabolic)
(Traumatic)
(Degenerative)

25. 56year old male history of lung CA
Abscesses
DWI
ADC
FSE T2
Abscesses
Post-Gad

26. 19 yo Male, Previously well, presents with new onset of seizures x 3

27. MRI Same Day
ADC
GRE
DWI
Katz Demyelination
Post-Gad

28. 5 Days Later
Now Enhances
FSE T2
Post-Gad
Pre-Gad

29. 10 days after presentation
FSE T2
DWI
ADC
Post Gad
Perfusion

30. 15 days after presentation
GRE
FLAIR
Hemorrhagic acute demyelination; Patient received multiple antibiotics and steroids; Radiology DDx – Encephalitis vs Demyelination
Post-Gad

31. Supratentorial Neoplasms – Adults
Metastases
Infiltrative (Diffuse or fibrillary) astrocytic tumours
Astrocytoma, anaplastic astrocytoma, GBM, gliomatosis
Localized/Noninfiltrative astrocytic tumours
(Pilocytic astrocytoma - peds), Pleomorphic xanthoastrocytoma, (supependymal giant cell astrocytoma)
Oligodendroglioma and anaplastic oligo
Neuronal and Glial-neuronal composition
Gangliocytoma and ganglioglioma, (desmoplastic infantile ganglioglioma <1yo), (central neurocytoma), DNT
Primary CNS Lymphoma

32. GBM
GBM

33. Epithelioid Hemangioendothelioma

34. Metastatic Adenocarcinoma
Mets from lung

35. Infratentorial Neoplasms - Adults
Metastases
Hemangioblastoma
Medulloblastoma
(Cerebellar astrocytoma, Ependymoma)

36. JPA

37. Proton MRS
Elevated choline:Creatine ratio and reduced NAA considered “tumor spectrum” but non-specific
Metabolic ratios for glioma grading remains investigational
May be useful to help differentiate high vs low grade gliomas (II vs III/IV)
Lactate (high and low grades, ?radioresistance) vs Mobile Lipids (high grade only) – can’t separate on standard MRS
Imaging brain tumor after therapy – elevated choline (>50% contralateral oe Ch:Cr >2) – moderate to high sensitivity and high specificity for identifying active tumor (but no large series)

38. MRS
TE 144
TE 35
Cho Cr
NAA
Lactate inversion

39. Single Voxel

40. 67 yo M

41. MR Perfusion – elevated relative CBV
Multivoxel
MR Spectroscopy – increased choline, reduced NAA

42. Grading of Brain Tumors
WHO grading revised in 2000
Based on histological appearance
Does not take into account anatomic location and size of tumor which influence resectability
Primary basis for guiding therapy, prognosis, scientific study

43. Diffusion Weighted Imaging and Grade
Tumor grade and cellularity reflected by ADC values
But most astrocytomas are too heterogeneous for ADC values to be helpful
Post-operative injury
Enhancement post-surgery may be subacute infarction
Peritumoral edema
Vasogenic edema (mets and meningiomas) vs Tumoral edema – not so helpful
Integrity and Position of White Matter Tracts (DTI)

44. Tumor grade and cellularity
Higher cellularity, reduced ADC
Minimum ADC may correlate inversely with grade
Limit due to tumor heterogeneity
Non-glial neoplasms – Meningioma, Lymphoma

45. MR Perfusion
Measures Degree of tumour angiogenesis and capillary permeability
CBV is proportional to the area under the contrast agent concentration-time curve
Contrast concentration is proportional to the change in relaxation rate (dR2*)
Assumptions of negligible recirculation and contrast leakage – generally violated
Measurement is relative therefore compare to contralateral white matter

46. MR Perfusion continued
Oligo’s – high CBV regardless of grade
Astrocytomas – higher CBV = high grade
Choroid plexus tumours, some meningiomas, mets – may not return to baseline – contrast leakage/leaky capillaries
CNS Lymphoma – high but not as high as GBM
Tumefactive MS – intralesional venous enhancement, possible mild elevation of CBV

47. Permeability imaging (DCE steady-state T1 measurement or DSC)
Endothelial permeability of vessels in brain tumors gives info about BBB integrity, vascular morphology and nature of neovascularization
Quantitative estimates of microvascular permeability (Ktrans) correlate with brain tumour grade
Ktrans (endothelial transfer coefficient) is a generalized measure to decribe the relationship between the time course of blood plasma Gad concentration (arterial input function) and Gad concentration changes in the voxel
Affected by blood flow, blood volume, endothelial surface area, endothelial permeability

48. Monitoring Response to Therapy
Post-operative Baseline
Tumour recurrence vs radiation necrosis

49. 48year old previously well
FLAIR
DWI
Post-Gad

50. 3 months later - Following one course of steroids

51. following more steroids 11 months after presentation
1 year
following more steroids
11 months after presentation

52. 13 months after initial presentation

53. MR Perfusion 13 months Perfusion 11 months Perfusion
Non-Hodgkings lymphoma Lois Nakamura

54. FDG-18

55. Thank You very much ! Special thanks to Dr. Talia Vertinsky