Normal & abnormal radiology of brain part iv

Brain Tumors, CNS tumors

1. Normal and Abnormal Radiology of CNS ( Part IV) Mohammed Fathy Bayomy, MSc, MD Lecturer Clinical Oncology & Nuclear Medicine Faculty of Medicine Zagazig University

2. Approach To Brain (Intra-Cranial) Tumours

3. ** benign vs. malignant distinction less clinically relevant for intracranial tumors (mass effect, infiltration preventing removal, critical location) Brain Neoplasm Primary Metastatic Extra-axial Intra-axial Neural Glial Meningioma Astrocytoma Ependymoma Oligodendroglioma Lung (50 %) Breast (15%) Melanoma (10%) The most common primary brain tumors are Gliomas (50%) Meningiomas (20%) Pituitary adenomas (15%) Nerve sheath tumors (8%) Classification

4. Classification

5. (I) Primary Brain Tumors (PBT) (A) Brain Gliomas The most common brain tumors are gliomas , which begin in the glial (supportive) tissue. There are several types of gliomas: Astrocytomas arise from small, star-shaped cells called astrocytes. Glioblastoma multiforme (GBM) accounts for about 50% of all astrocytomas Ependymomas: lining of the ventricles. Oligodendrogliomas: the cells that produce myelin. Brain stem gliomas Intra-cranial Tumors

6. Medulloblastomas always located in the cerebellum, These fast-growing high-grade tumors represent about 15 - 20% of pediatric brain tumors and 20% of adult brain tumors. Meningiomas grow from the meninges Schwannomas are benign tumors that begin in Schwann cells, which produce the myelin e.g. Acoustic neuromas Craniopharyngiomas develop in the region of the pituitary gland near the hypothalamus. Pituitary Adenomas . about 10% of PBT &are often benign, slow-growing masses in pituitary gland. (B) Brain Non-Gliomas Intra-cranial Tumors

7. (II) Secondary Brain Tumors (Brain Metastases) Metastatic brain tumors are the most common brain tumors. Characteristics The primary cancer is usually in the lung , breast , colon , kidney , or skin (melanoma), but can originate in any part of the body Most are located in the cerebrum, but can also develop in the cerebellum or brain stem More than half of people with metastatic tumors have multiple lesions (tumors) Intra-cranial Tumors

8. Differential diagnosis & patient age Different incidence of suprasellar lesions between adults & children Common ADULTS Pituitary Macroadenoma Meningioma Schwannoma Saccular aneurysm Craniopharyngioma (squamous papillary) CHILDREN Pilocytic Astrocytoma Craniopharyngioma (adamantinous) Optic pathway glioma Arachnoid cyst Germinoma Metastasis Dermoid & Epidermoid cyst Leukemia & Lymphoma (met) Inflammatory/infective disease Hemangioblastoma Less Common/Rare Hamartoma Inflammatory/infective disease Arachnoid cyst Germinoma Lipoma Pituitary stalk anomalies/Ectopic neurohypophisis Teratoma Aneurysm Pituitary Macroadenoma Leukemia/Lymphoma (1ry)

9. 10 20 30 40 50 60 Oligodendroglioma Ependymoma Colloid cyst Pituitary Schwannoma Ependymoma Medulloblastoma Craniopharyngioma Germinoma Teratoma Choroid plex . pap Astrocytoma Hemangioblastoma Meningioma Metastases Age distribution

10. Common Intra-cranial Tumors Adult: Pediatric: Metastases ++ Gliomas (25%) - Fibrillary Astro - Anaplastic Astro - Glioblastoma Multi - Oligodendroglioma Hemangioblastoma Juvenile Pilocytic Astro PNET (Medulloblastoma) Ependymoma Brainstem Astrocytoma DNET Ganglioglioma Age distribution

11. < 2 years Choroid plexus papillomas. Anaplastic astrocytomas. Teratomas. Medulloblastomas. Astrocytomas. Ependymomas. Craniopharyngiomas. Gliomas. Metastases: very rare (neuroblastoma) Adult Metastases (50%). Astrocytomas ‘‘GBM’’. Meningiomas. Oligodendrogliomas. Pituitary adenomas. Schwannomas. Astrocytomas occur at any age, but GBM is mostly seen in older people. 2-10 years Age distribution

12. Although cancer is rare in children, brain tumors are the most common type of childhood cancer after leukemia and lymphoma. Most of the tumors in children are located infratentorially. Age distribution

13. Metastases are by far the most common. It is important to realize that 50% of metastases are solitary. Particularly in the posterior fossa, metastases should be in the top 3 of the differential diagnostic list. Supratentorially, metastases are also the most common tumors, followed by gliomas. Age distribution

14. NON-NEOPLASTIC MASSES CHILDHOOD M-9 yrs, HAMARTOMA Congenital non-neoplastic heterotopias Isotense to grey matter on T1WI & T2WI They do not calcify, enhance, contain fat or have cysts Clinical presentation (precocious puberty and gelastic seizures) F-10 yrs, OPTIC PATHWAY GLIOMA NEOPLASTIC MASSES Frequently associated with NF1 Iso-hypointense on T1WI & moderately hyperintense on T2WI Moderate (variable) contrast enhancement Necrosis, Hge, calcifications are rare Age distribution

15. ADULTS ANY AGE F-50 yrs CRANIOPHARYNGIOMA (Papillary) Usually solid or predominantly solid Suprasellar location Rarely calcifies CHILDREN Mostly cystic/predominantly cystic or rarely mixed solid-cystic Suprasellar or intrasellar/suprasellar 90% calcifies M-15 yrs yrs CRANIOPHARYNGIOMA (Adamantinous) Age distribution

16. It is often not possible to characterize suprasellar masses on the basis of radiological findings alone > > > age and clinical presentation may drive to a diagnosis NEUROFIBROMATOSIS type 1 (von Recklinghausen disease or NF1) Patients with two or more of following findings: Six or more café-au-lait spots; Two or more Lisch nodules (hamartoma) of the iris Two or more neurofibromatosis or one or more plexiform neurofibromas; Axillary/inguinal freckling; One or more bone dysplasia or pseudoarthrosis of a long bone; A first degree relative with NF1 Correleation with clinical data From 15% to 40% of patients with NF1: OPTIC PATHWAY GLIOMAS The involvement of optic chiasma & optic nerves (white arrows) CRANIAL NERVES DYSFUNCTIONS e.g. OCCULMOTOR NERVE PALSY Outward & downward deviation of the eye Ptosis of the eyelid Dilatation of ipsilateral pupil in complete palsy SCHWANNOMA OF III CRANIAL NERVE Intense & Homogenous CE of extra-axial mass localized to site if III CN (white arrow)

17. PRECOCIOUS PUBERTY Appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal (before age 0f 6-8years for girls and before age of 9 years for boys Correleation with clinical data HAMARTOMA The absence of CE of mass localized in the mammillary body (red arrow) KNOWN/UNKNOWN PRIMARY Breast cancer, melanoma, colorectal cancer. Headache, cranial nerves dysfunction, hormonal abnormalities. INFUNDIBULARY METASTASIS FROM BREAST CANCER Intense CE of the mass thickening the stalk (white arrow) GELASTIC SEIZURES Epileptic events characterized by laughter-like vocalization usually combined with facial contraction.

18. OTHER SYSTEMIC DISEASES Children and young adults with involvement of one or more body systems such as bone, lymph nodes, liver, or various soft tissue. Correleation with clinical data LANGERHANS CELL HISTOCYTOSIS The thickened stalk with moderate CE after gadolinium (green arrows) In some case can occur in adults with polycythemia and von Hippel-Lindau syndrome (hemangioblastomas, visceral cysts, and renal cell carcinoma) HEMANGIOBLASTOMA Intense CE (red arrow), the typical T2 signal hyperintensity with characteristics flow voids in the lesion (green arrow) and arterial parenchymal blush in DSA (white arrow)

19. Abnormal Radiology of Brain Mohammed Fathy Bayomy Assistant Lecturer of Clinical Oncology Zagazig University

20. 1- Location Intra- vs. Extra-axial Supra- vs. infra-tentorial. White matter vs. cortical based. Specific anatomic sites: * Sella/suprasellar. * Pineal region. * Intraventricular.

21. 1- Location Determine whether mass arises from within brain parenchyma (intraaxial) or from outside the brain parenchyma (extra-axial). Extra-axial tumor: mass lies outside the brain, so the tumor not originate from brain but derived from the lining of the brain or surrounding structures, 80% of these extra-axial lesions will be either a meningioma or a schwannoma. Extra-axial vs Intra-axial

22. 1- Location Intra-axial tumor: mass lies inside the brain, so the tumor originate from brain itself, in adult will be a metastasis or astrocytoma in 75% of cases. Extra-axial vs Intra-axial

23. 1- Location Narrows CSF space Displaces cortex toward periphery Widens CSF space Displaces brain deeper Broad base toward dura Extra-axial vs Intra-axial

24. 1- Location Extra-axial vs Intra-axial INTRA-AXIAL EXTRA-AXIAL Glioma Medulloblastoma Hemangioblastoma Metastases Meningioma Pituitary adenoma Craniopharyngioma Schwannoma Chordoma Dermoid/epidermoid cyst Lipoma Metastases

25. 1- Location Extra-axial vs Intra-axial Common Intra-Axial Tumors in Pediatric Supratentorial: Infratentorial: Astrocytoma Pleomorphic xanoastro (PXA) PNET DNET Ganglioglioma Juvenile Pilocytic Astro PNET (medulloblastoma) Ependymoma Brainstem Astrocytoma

26. 1- Location Extra-axial vs Intra-axial Common Intra-Axial Tumors in Adult Supratentorial: Infratentorial: Metastases ++ Gliomas (25%) - Fibrillary Astro - Anaplastic Astro - Glioblastoma Multiformi - Oligodendroglioma Metastases ++++ Hemangioblastoma

27. 1- Location Extra-axial vs Intra-axial Extra-Axial lesions ADULTS Germinoma Craniopharyngioma (squamous-papillary) Leukemia/lymphoma (metastatic) Meningioma Schwannoma Metastasis Epidermoid/dermoid cyst Aneurysm Infectious/inflammatory Pituitary stalk Infundibulum Meninges Vessels CHILDREN Germinoma Craniopharyngioma (adamantinous) Leukemia/lymphoma (primary) Epidermoid/dermoid cyst Aneurysm Infectious/inflammatory Stalk anomalies & ectopic neurohypophisis Intra-Axial lesions Optic chiasma Hypothalamus 3 rd ventricle ADULTS Metastasis Glioma Hemangioblastoma CHILDREN Pilocytic astrocytoma Optic pathway glioma Hamartoma Lipoma

28. 1- Location Extra-axial vs Intra-axial Variable signal, often isotense to brain parenchyma on T1WI & T2WI. Homogenous, intense enhancement. Linear, enhancing dural tail (highly suggestive, not pathognomonic) F-45 years Tuberculum Sellae Meningioma EXTRA-AXIAL ADULTs CHILDREN M-19 years Arachnoid cyst CSF-like signal in all sequences, without CE after gadolinium

29. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Signs of extra-axial location CSF cleft: widens CSF space Displaced and expand subarachnoid space: because growth of an extra-axial lesion tends to push away the brain. Displaced subarachnoid vessels: The subarachnoid vessels that run on the surface of the brain are displaced by the lesion. Cortical gray matter between mass and white matter: displaces brain deeper.

30. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Signs of extra-axial location Broad dural base: broad base toward dura, typically seen in meningiomas. Homogenous enhancement: not derived from brain tissue and do not have a blood-brain-barrier. Bony reaction: are seen in bone tumors like chordomas, chondrosarcomas and metastases, can also be secondary, as is seen in meningiomas and other tumors.

31. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL CSF cleft (Definitive sign)

32. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Vessels b/n lesion & brain (Definitive sign)

33. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Vessels b/n lesion & brain (Definitive sign)

34. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Cortex b/n lesion & brain (Definitive sign)

35. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Broad based towards calvarium (Suggestive sign)

36. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Adjacent bone changes (Suggestive sign)

37. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Adjacent bone changes (Suggestive sign)

38. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Adjacent bone changes (Suggestive sign)

39. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Enhancement of meninges (Suggestive sign) Meningeal tail

40. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Invade to & through dura

41. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL CSF cleft ( yellow arrow ). Subarachnoid vessels that run on surface of brain are displaced by the lesion ( blue arrow ). There is gray matter between lesion & white matter ( curved red arrow ).

42. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Broad dural base Hyperostosis of adjacent bone Homogenous enhancement

43. 1- Location Extra-axial vs Intra-axial EXTRA-AXIAL Differentiation between intra-axial versus extra-axial is usually straight forward, but sometimes it can be very difficult and imaging in multiple planes may be necessary Thought to be a falcine meningioma, i.e. extra-axial: hypointense on T2. However, there is gray matter on the anteromedial and posteromedial side of the lesion (red arrow), this indicates that the lesion is intra-axial. If the lesion was extra-axial the gray matter should have been pushed away.

44. 1- Location Extra-axial vs Intra-axial INTRA-AXIAL Intra-axial is a term that denotes lesions that are within the brain parenchyma Some authors include intra-ventricular lesions in the intra-axial group as most are lesions that arise from the brain parenchyma and grow exophytically into ventricular system.

45. 1- Location Extra-axial vs Intra-axial A linear ependymal enhancement is evident in III ventricle anterior recesses. Pineal recess nodular localization & leptomeningeal spread F-45 years, Metastatic Ependymal intraventricular spread (melanoma) INTRA-AXIAL ADULTs CHILDREN M- 2 years, pilocytic astrocytoma Solid & cystic mass. Solid portion T1-hypointense, T2-hyperintense with strong enhancement. Cystic portion present variable T1 & T2 signal according to protein content.

46. 1- Location Supratentorial vs Infratentorial Common Intra-Axial Tumors in Pediatric Supratentorial: Infratentorial: Astrocytoma Pleomorphic xanoastro (PXA) PNET DNET Ganglioglioma Juvenile Pilocytic Astro PNET (medulloblastoma) Ependymoma Brainstem Astrocytoma

47. 1- Location Common Intra-Axial Tumors in Adult Supratentorial: Infratentorial: Metastases ++ Gliomas (25%) - Fibrillary Astro - Anaplastic Astro - Glioblastoma Multiformi - Oligodendroglioma Metastases ++++ Hemangioblastoma Supratentorial vs Infratentorial

48. 1- Location Suprasellar SUPRASELLAR LESIONS Neoplastic & Non-neoplastic masses -Macroadenoma -Meningioma -Schwannoma -Craniopharyngioma -Pilocytic astrocytoma -Optic pathways glioma -Metastasis -Lymphoma & Leukemia -Arachnoid cyst -Dermoid cyst -Epidermoid cyst -Ectopic neurohypophysis -Hemangioblastoma Infectious & inflammatory lesions -Granulomatous diseases -Abscesses/ Hypophyisitis Vascular anomalies -Aneurysm Most Common diagnosis (big five: >75% of all suprasellar masses) -Macroadenoma -Meningioma -Aneurysm -Craniopharyngioma -Pilocytic astrocytoma

49. 1- Location Pineal Region Common Pineal Region Tumors Pineocytoma Germ cell tumours PNET Tectal Glioma Meningioma Dermoid Arachnoid cyst

50. 1- Location Pineal Region Differential diagnosis -Pineocytoma -Pineoblastoma -Papillary tumor of pineal gland -Astrocytoma of pineal gland -Meningioma near pineal gland

51. 1- Location Pineal Region Differential diagnosis -Pineocytoma -Papillary tumor of pineal gland -Germinoma -Astrocytoma of pineal gland -Pineal cyst

52. 1- Location Intraventricular Common Intraventricular Tumors Ependymoma Subependymoma Central Neurocytoma Meningioma Giant cell Astrocytoma Choroid plexus papilloma Colloid cyst

53. 1- Location Differential diagnosis -Ependymoma -Intraventricular meningioma -Subependymal giant cells astrocytoma -Choroid plexus papilloma -Choroid plexus carcinoma -Oligodendroglioma Intraventricular

54. 1- Location Differential diagnosis -Central Neurocytoma -Choroid plexus papilloma -Choroid plexus carcinoma Intraventricular

55. 1- Location Posterior Fossa Posterior Fossa Tumours in Pediatric Brainstem: Glioma Ganglioglioma Astrocytoma Tectum/Cerebellum: Pilocytic Astrocytoma Medulloblastoma Hemangioblastoma Fourth Ventricle: Medulloblastoma Ependymoma Choroid Plexus Papilloma CP Angle: Acoustic neuroma Meningioma Choroid Plexus Papilloma Epidermoid Cyst

56. 1- Location CP Angle Common CP Angle Tumors Schwannoma Meningioma Epidermoid Arachnoid Cyst Paraganglioma Metastasis

57. 1- Location Fourth Ventricle Common Fourth Ventricle Tumors Astrocytoma Medulloblastoma Ependymoma Brainstem gliomas (Exophytic) Metastases Hemangioblastoma Choroid Plexus Papilloma Dermoid & Epidermoid

58. 1- Location Skull Base Common Skull Base Tumors Chordoma Chondrosarcoma Esthesioneuroblastoma Lymphoma Metastases Myeloma Paraganglioma Sinonasal Carcinoma

59. 2- Peritumoral edema Vasogenic cerebral oedema : a type of cerebral edema in which blood brain barrier (BBB) is disrupted (N.B.  cytotoxic edema  where BBB is intact). Extracellular oedema which mainly affects the white matter, through leakage of fluid out of capillaries. May be minor or major Rounded or irregular Most frequently seen around brain tumors (both primary & secondary) but is may be seen around non tumorous conditions.

60. 2- Peritumoral edema

61. 3- Effect on surroundings Primary brain tumors are derived from brain cells and often have less mass effect for their size than you would expect, due to their infiltrative growth . This is not case with metastases and extra-axial tumors like meningiomas or schwannomas, which have more mass effect due to their expansive growth .

62. 3- Effect on surroundings EXPANSIVE GROWTH PATTERN INFILRATIVE GROWTH PATTERN VS INTRA-AXIAL EXTRA-AXIAL Intra-axial or extra-axial bulky lesion, with usually well-defined margins, compressing adjacent structure: (a) Craniopharyngioma (papillary variant) wedging in to foramina of Monro & displace nerves & Chiasma. (b) Tuberculum Sellae Meningioma displacing the fronto-basal parenchyma & splaying the optic nerves. INTRA/EXTRA-AXIAL Lesions with ill-defined margins that predominantly infiltrate rather than compress structure: (c) Hypothalamus, pituitary stalk, suprasellar and interpeduncular cistern invasion from infiltrative high grade diencephalic glioma.

63. 3- Effect on surroundings (A) Tumor Spread Along the white matter tracts spread: astrocytomas have infiltrative growth that do not respect boundaries of lobes >>>> the tumor is actually larger than can be depicted with MRI. Trans-foramens extension: ependymomas of fourth ventricle in children tend to extend through the foramen of Magendie to cisterna magna & through the lateral foramina of Luschka to cerebellopontine angle. Cortical extension: oligodendrogliomas typically show extension to the cortex.

64. 3- Effect on surroundings (A) Tumor Spread Extension into foramen magnum ( red arrow ). Extension to prepontine area ( blue arrows ).

65. 3- Effect on surroundings (A) Tumor Spread Subarachnoid seeding: some tumors show subarachnoid seeding and form tumoral nodules along brain & spinal cord. This is seen in PNET , ependymomas , GBMs , lymphomas , oligodendrogliomas , choroid plexus papillomas . Primitive neuroectodermal tumours (PNET) form a rare group of tumors, which develop from primitive or undifferentiated nerve cells. These include medulloblastomas and pineoblastomas.

66. 3- Effect on surroundings (A) Tumor Spread Extracranial extension: one of the most important roles of imaging is to assess extracranial extent of a tumor. Patient who presented with left multiple cranial nerve abnormalities. On the images we see an extra-axial tumor in region of left cavernous sinus. There is homogeneous enhancement with a broad dural tail. This is typical for meningioma. Only by studying all the images we do appreciate that actual extent of the tumor is greater than expected. The tumor is situated in pterygopalatine fossa & extends into orbit. It also spreads anteriorly into middle cranial fossa

67. 3- Effect on surroundings (B) Mass Effect The effect of a growing mass (or of the edema surrounding the mass) compressing (and infiltrating) brain structures. Mechanical displacement of adjacent brain Compression foramina of Monro & Ventricles Obstructive Hydrocephalus Midline Shift/Brain Herniation MASS (large or small with or without EDEMA) Compression of pituitary gland & adjacent cerebral parenchyma (Diencephalon, temporal & frontal lobes

68. 3- Effect on surroundings (B) Mass Effect PILOCYTIC ASTROCYTOMA CRANIOPHARINGIOMA (Sq. papillary) PILOMYXOID ASTROCYTOMA

69. 3- Effect on surroundings (B) Mass Effect Minimal mass effect: occur in diffusely infiltrating intra-axial tumors, with variable enhancement pattern e.g. astrocytomas Low grade astrocytoma shows typical infiltrative growth occupying most of the right hemisphere with only a minimal mass effect.

70. 3- Effect on surroundings (B) Mass Effect Midline crossing: ability of tumors to cross midline:- Glioblastoma multiforme (GBM) frequently crosses midline by infiltrating white matter tracts of corpus callosum. Radiation necrosis can look like recurrent GBM & can sometimes cross midline. Meningioma is an extra-axial tumor and can spread along the meninges to the contralateral side. Lymphoma is usually located near midline. Epidermoid cysts can cross midline via subarachnoid space. MS can also present as mass lesion in corpus callosum.

71. 3- Effect on surroundings (B) Mass Effect

72. 4- Single vs Multiple Single tumors: typically in primary brain tumors Multiple tumors: meningiomas & schwannomas can be multiple tumors especially in NFII Multiple lesions: usually indicate metastatic disease. Multifocal tumors: may occur in brain lymphomas, multicentric glioblastomas gliomatosis cerebri. Seeding metastases: medulloblastomas (PNET-MB), ependymomas, GBMs, oligodendrogliomas.

73. 4- Single vs Multiple Metastases Multiple meningiomas and a schwannoma in a patient with Neurofibromatosis II

74. 4- Single vs Multiple Multiple brain tumors can be seen in phacomatoses : Neurofibromatosis I: optic gliomas & astrocytomas Neurofibromatosis II: meningiomas, ependymomas, choroid plexus papillomas Tuberous Sclerosis: subependymal tubers, intraventricular giant cell astrocytomas, ependymomas Von Hippel Lindau: hemangioblastomas

75. 5- Cortical based tumors Most intra-axial tumors are located in WM. Some tumors spread to or are located in GM. Differential diagnosis: pilocytic astrocytoma, oligodendroglioma, ganglioglioma, Dysembryoplastic Neuroepithial Tumor (DNET). Patients with a cortically based tumor usually present with complex seizures.

76. 5- Cortical based tumors Non-enhancing, cortically based tumor (ganglioglioma).

77. 5- Cortical based tumors CT shows a mass with calcifications, which extends all the way to cortex. Although this is a large tumor there is only limited mass effect on surrounding structures, which indicates that this is an infiltrating tumor.

78. 6- CT Density For example: fat containing tumors lipomas, dermoid cysts, teratomas CT: low density on CT (- 100HU). MRI: high signal intensity on both T1- & T2WI while low on fat suppression Coronal T1WI CT without contrast For example: lymphoma, colloid cyst , PNET-MB (medulloblastoma). *High density:- *Low density:-

79. 7- MR signal intensity Most tumors have a low/intermediate signal intensity on T1WI. Exceptions to this rule can indicate a specific type of tumor. Calcifications are mostly dark on T1WI, but depending on matrix, they can sometimes be bright on T1. If you only do an enhanced scan, remember that high signal is not always enhancement. (A) High on T1WI

80. 7- MR signal intensity (A) High on T1WI High Intensity on T1WI Met-hemoglobin: e.g. hemorrhagic tumors or metastasis High protein: e.g. dermoid cyst Fat: e.g. Lipoma, dermoid cyst Cholesterol: e.g. Colloid cyst Melanin: e.g. Melanoma metastases Flow effects: e.g. Slow flow Paramagnetic cations: e.g. Cu, Mn, ……… etc

81. 7- MR signal intensity (A) High on T1WI Pituitary Macroadenoma with hemorrhage GBM with hemorrhage Metastasis of melanoma

82. 7- MR signal intensity Most tumors will be bright on T2WI due to high water content. When tumors have low water content they are very dense & hypercellular & cells have a high nuclear-cytoplasmasmic ratio >>>> dark on T2WI, e.g. CNS lymphoma & PNET (hyperdense on CT). Calcifications are mostly dark on T2WI. (B) Low on T2WI

83. 7- MR signal intensity Paramagnetic effects cause signal drop and are seen in tumors that contain hemosiderin. Proteinaceous material can be dark on T2 depending on content of protein itself, e.g. colloid cyst. Flow voids are also dark on T2 & indicate presence of vessels or flow within lesion, seen in tumors that contain a lot of vessels like hemangioblastomas, but also in non-tumorous lesions like vascular malformations. (B) Low on T2WI

84. 7- MR signal intensity (B) Low on T2WI Low Intensity on T2WI Hyper-cellularity: e.g. lymphoma, Meningioma, PNET, Germinoma, GBM, Oligodendroglioma, Mucinous adeno- metastases (GI, Lung, Breast, GU) Calcification: see calcification Blood: e.g. old hemorrhage or vascular mal. Protein: e.g. colloid cyst Melanin: e.g. Melanoma metastases Flow-void: e.g. Hemangioblastoma, vascular mal.

85. 7- MR signal intensity (B) Low on T2WI Melanoma Met. PNET GBM Oligodendroglioma Ependymoma Mucinous Carcinoma Lymphoma Lymphoma-FLAIR Meningioma

86. 8- Solid vs Cystic Is the lesion Solid, Mixed solid-cystic, Cystic or Vascular? Optic pathway glioma (pilocytic/pilomyxoid astrocytoma Craniopharyngioma Hamartoma Schwannoma Meningioma Ectopic posterior pituitary Metastasis Granulomatous diseases Adenoma Craniopharyngioma Optic pathway glioma (pilocytic/pilomyxoid astrocytoma Arachnoid cyst Epidermoid cyst Dermoid cyst Craniopharyngioma SOLID MIXED CYSTIC-SOLID CYSTIC Aneurysm VASCULAR

87. 8- Solid vs Cystic (A) Cystic Mass There are many cystic lesions that can simulate a CNS tumor. These include epidermoid, dermoid, arachnoid, neuroenteric and neuroglial cysts. Enlarged perivascular spaces of Virchow Robin can simulate a tumor. To determine whether a lesion is a cyst or cystic mass look for the following characteristics: • Morphology • Fluid/fluid level • Content usually isointense to CSF on T1, T2 & FLAIR • DWI: restricted diffusion

88. 8- Solid vs Cystic (A) Cystic Mass T2W FLAIR DWI T1C+ EPIDERMOID CYST Isointense to CSF in T1WI and T2WI without CE after gadolinium T2-FLAIR high signal & DWI restricted diffusivity due to desquamating epithelium/cholesterol accumulation FLAIR T2W T1C+ DWI ARACHNOID CYST Signal and diffusivity equal to CSF. No CE. CSF containing cyst with thin walls T2W DWI T1C+ T1W Hyperintense to CSF in T1WI and hypointense in T2WI >>>> (crankcase) like oily material (cholesterol, protein, blood product) Cyst walls enhance. DWI MR typically presents a low signal CRANIOPHARYNGIOMA Variable Signal Intensity according to content of cyst

89. 8- Solid vs Cystic (A) Cystic Mass Medulloblastoma WHO grade IV Ependymoma WHO grade II Neoplastic cysts (arises within tumour & has enhancing walls ). Non-neoplastic cysts (reactive, arising in neighbouring parenchyma & mural enhancement is absent ).

90. 8- Solid vs Cystic (A) Cystic Mass Craniopharyngioma Neurentric Cyst GBM Enhancing rim surrounding cystic component Contents of which have the same signal intensity as CSF Central cystic component & irregular enhancement

91. 8- Solid vs Cystic (A) Cystic Mass Glioblastoma Multiforme WHO grade IV

92. 8- Solid vs Cystic (B) Solid lesions

93. 9- Necrosis Caused by sudden vascular occlusion. Endothelial proliferation and thrombosis are predisposing factors. Poor prognosis in adult glioma.

94. 10- Calcification It is usually a sign of slowly growing lesion. It is best assessed in CT. When we think of a calcified intra-axial tumor, we think oligodendroglioma since these tumors nearly always have calcifications. Intraaxial calcified tumor in brain is more likely to be an astrocytoma than a oligodendrogliomas , since astrocytomas , although less frequently calcified, are far more common. Pineocytoma itself does not calcify, but instead it 'explodes' calcifications of pineal gland.

95. 10- Calcification Tumors Associated with Calcification Intra-axial tumours: Astrocytomas (20%) Oligodendrogliomas (90%) Metastases Ependymoma (50%) Choroid Plexus Papilloma (25%) Ganglioglioma Extra-axial tumours: Meningioma (25%) Craniopharyngioma (90%) Chordomas Chondrosarcomas

96. 10- Calcification Oligodendroglioma PDWI CT Ependymoma Medulloblastoma (A) Calcification in Intra-axial Tumours Pilocytic Astrocytoma

97. 10- Calcification (B) Calcification in Extra-axial Tumours Craniopharyngioma Meningioma T1W Coronal T1W Sagittal CT

98. 11- Hemorrhage Due to pathological changes in the tumor vessels. It is rare (0.8-10.2%). Usually typical of malignant tumors Hemorrhagic metastatic melanoma Stage Hyperacute Acute Early Subacute Late Subacute Chronic Time <24hrs 1-3 d 3-7 d >7d >14d T1 Iso Iso Hyper Hyper Iso, Hypo T2 Hyper Hypo Hypo Hyper Hypo

99. 12- Enhancement The brain has a unique triple layered blood-brain barrier (BBB) with tight endothelial junctions in order to maintain consistent internal milieu. Contrast will not leak into brain unless this barrier is damaged. Enhancement is seen when CNS tumor destroys BBB. Extra-axial tumors not drive from brain cells >>> not have a blood-brain barrier >>> enhance. No blood-brain barrier in pituitary, pineal choroid plexus regions.

100. 12- Enhancement High grade gliomas: infiltration of surroundings >>> Break BBB >>> Enhancement Low grade tumors: no infiltration of surroundings >>> No Break BBB >>> No Enhancement Ganglioglioma & pilocytic astrocytomas are exceptions to this rule: they are low-grade tumors, but they enhance vividly .

101. 12- Enhancement Contrast Enhancement Extra-axial tumors: Meningioma, Schwannoma High grade gliomas Low grade gliomas: ganglioglioma, pilocytic astrocytoma Lymphoma Metastases Non-tumoral: infection, abscess, MS, infarction

102. 12- Enhancement Meningioma WHO grade I Schwannoma

103. 12- Enhancement GBM WHO grade IV

104. 12- Enhancement Ganglioglioma Pilocytic astrocytoma

105. 12- Enhancement Primary CNS lymphoma

106. 12- Enhancement Choroid plexus papilloma WHO grade I

107. 12- Enhancement Dysembryoplastic Neuroepithelial Tumor (DNET)  WHO grade I

108. 12- Enhancement Low-grade astrocytoma of temporal lobe no enhancement & DWI was normal

109. 12- Enhancement Contrast enhancement cannot visualize full extent of tumor in cases of infiltrating tumors, like gliomas >> reason for this is that tumor cells blend with normal brain parenchyma where the blood brain barrier is still intact . Tumor cells can be found beyond enhancing margins of tumor & beyond any MR signal alteration -even beyond area of edema.

110. 12- Enhancement In gliomas - like astrocytomas, oligodendrogliomas glioblastoma multiforme - enhancement usually indicates a higher degree of malignancy. Therefore when during follow up of low-grade glioma tumor starts to enhance , it is a sign of malignant transformation . Tumor angiogenesis as shown by perfusion MR correlates better with tumor grade than enhancement after administration of intravenous contrast.

111. 12- Enhancement Contrast enhancement patterns No Enhancement Homogeneous Enhancement Patchy Enhancement Ring Enhancement Low grade astrocytoma Cystic non-tumoral lesions Germinoma Pineal tumours Pituitary adenoma Pilocytic astrocytoma (solid component) Haemangioblastoma Ganglioglioma Meningioma Schwannoma Radiation necrosis High grade glioma Metastases Abscess

112. 12- Enhancement (A) No enhancement Low grade astrocytomas Cystic non-tumoral lesions: Dermoid cyst Epidermoid cyst Arachnoid cyst T1WI T1WI+C T2WI Diffuse Infiltrative Astrocytoma (WHO grade II)

113. 12- Enhancement (A) No enhancement Low grade astrocytomas Cystic non-tumoral lesions: Dermoid cyst Epidermoid cyst Arachnoid cyst T1WI T1WI+C T2WI Diffuse Infiltrative Astrocytoma (WHO grade II) T2WI T2WI T1WI+C T1WI+C Low-grade astrocytoma

114. 12- Enhancement (B) Homogeneous enhancement Metastases Meningioma Pituitary macroadenoma Pilocytic astrocytoma (solid part) Pineal gland tumors Lymphoma Germinoma Ganglioglioma Hemangioblastoma (solid part) Schwannoma

115. 12- Enhancement (B) Homogeneous enhancement Meningioma Schwannoma Lymphoma Hemangioblastoma Pilocytic Astrocytoma Ganglioglioma Choroid plexus papilloma

116. 12- Enhancement (C) Patchy enhancement Metastases Oligodendroglioma Glioblastoma multiforme Radiation necrosis T1WI+C FLAIR Glioblastoma multiforme (GBM) Partial enhancement Cystic component with ring enhancement

117. 12- Enhancement (C) Patchy enhancement FLAIR T1WI+C T1WI+C T1WI T2WI Glioblastoma multiforme (GBM) Large tumor with limited mass-effect Heterogeneity on both T2WI & FLAIR. There is patchy enhancement.

118. 12- Enhancement (D) Ring enhancement Metastases Glioblastoma multiforme Abscess, Infectious disease Multiple sclerosis Chronic hematoma GBM Metastases Abscess