cns tumors and differentiation by imaging modalities .pptx

Cns tumors and their differentiation based on imaging modalities

1. DR SUMITAVA DE ASST PROFESSOR N R S MEDICAL COLLEGE IMAGING AND BRAIN TUMOR

2.  1895, Wilhelm Roentgen presented his classic written preliminary communication regarding X-rays.  Arthur Schiiller (1874–1957), a Viennese physician, considered as the “father of neuroradiology” studied skull X- rays systematically with various projections  1918, Walter Dandy described diagnostic ventriculography & pneumoencephalography  1927, a Portuguese neurologist, Egas Moniz, first reported the percutaneous technique of cerebral angiography.

3.  Magnetic Resonance phenomenon first described by Felix Bloch and Edward Purcell in 1946. In 1952 they were awarded the Nobel Prize.  1971 - Raymond Damadian showed that the nuclear magnetic relaxation times of tissues and tumors differed, sparking interest in medical uses  1987 –MR angiography developed by Charles Dumoulin.

4. Brain tumor imaging objectives Tumor versus non tumoral lesion. Histological grade. DIAGN O S I S Delineation of the tumor extent. Tumor versus peritumoral edema. TRE A TME NT PLAN Residual tumor versus treatment necrosis. POST TRE A TME NT FOLLOW UP

5. 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? TRE A TMENT PLAN Recurrent/residual tumor or post treatment effect? POST TRE A TMENT FOLLOW UP POINTS TO CONSIDER

6. 1)X - ray Available M o da l it i es 2)CT 3)M R I 4)Nuc l ear Medicine

7. Primarily of historical interest since the onset of CT in 1974. Rarely necessary. Useful in demonstrating calcification, erosion, or hyperostosis Skull X-rays: Will detect >90% of tumors, but might miss: Small Tumors (<0.5 cm) Tumors Adjacent to bone (pituitary adenomas, clival tumors, and vestibular schwannomas) Brain Stem Tumors Low Grade Astrocytomas More sensitive than MRI for detecting acute hemorrhage, calcification, and bony involvement CT: Most widely used for diagnosis of brain tumors More sensitive than CT scans Can detect small tumors Provides much greater anatomic detail Especially useful for visualizing skull base, brain stem, & posterior fossa tumors MRI: Preferred for follow-up of most brain tumors

8. Skull X-rays Full skull ser ies include the four views Lateral projection Occipito frontal projection Half axial antero posterior ( Town’s) Projection Sub mento vertical ( base) Projection

9. X-ray lateral view in a patient with craniopharyngioma showing suprasellar calcification

10. The sella is deepened; a depth of more than 15 mm and an AP diameter of 20 mm are definitely abnormal. The floor may be so demineralised that the tumour actually appears to project into the sphenoid sinus. Irregular growth may cause a step to be visible in the floor of the sella, “Double floor” in a “strict lateral” view

11. MRI is generally preferable to CT for evaluating intracranial neoplasms C T i s preferred for vis u al i zing t umor calcification or intratumor hemorrhage. pref e r r ed me t hod of tumors due to better i magi n g sof t -t i ssue Usu a l l y the intracranial contrast MRI exploits increased water content of many neoplasms. This water content shows up as increased signal on T2 weighted images and decreased signal on T1 Images.

12. MRI has a higher sensitivity in the demonstration of oedema and is better for earlier detection of tumours. Brainstem structures are better identified. It gives a better characterisation of brain tumours MRI has become the most useful pre- operative imaging tool.

13. Age Location Local tumour spread Solitary or multifocal Specific imaging characteristics Tumour mimics

14. Size. Edema. Location. Necrosis. Calcification. Hemorrhage. Cysts. Un p re d e c t ive of grading

15.  Intra- vs. extra-axial- determine whether the mass arises from within the brain parenchyma (intraaxial) or from outside the brain parenchyma (extra-axial)  Supra- vs. infra-tentorial  White matter vs. cortical based  Specific anatomic sites: Sella/suprasellar Pineal region Intraventricular

16.  In tr a - a x i a l t u m o u rs are t wi ce a s c o m m o n a s ex tr a - a x i al tumours. Signs of extra-axial location:  Widening of the ipsilateral subarachnoid space  Cerebrospinal fluid (CSF) cleft between the mass and the brain parenchyma  Deviation of pial vessels between the mass and the brain tissue  Buckling of the grey matter (GM)/white matter (WM) junction  Broad base along the dural or calvarial surface  Adjacent bony changes such as hyperostosis in meningioma or erosion in acoustic neurinoma.  > 8 % e x t r a- ax ia l t u m ou rs a re e i t h er m e n ing i o ma or schwannoma

17.  Definitive – CSF cleft

18.  Definitive - vessels b/n lesion & brain

19. Intra vs extra axial  Definitive - cortex b/n lesion & brain

20.  Suggestive –broad based towards calvarium

21.  Suggestive - adj bone changes

22.  Suggestive - enhancement of meninges

23.  Invade to & through dura

24. EXTRA AXIAL TUMOR  The T2W images show a schwannoma located in the cerebellopontine angle (CPA).  This case nicely demonstrates the typical signs of an extraaxial tumor.  There is a CSF cleft (yellow arrow).  The subarachnoid vessels that run on the surface of the brain are displaced by the lesion (blue arrow).  There is gray matter between the lesion and the white matter (curved red arrow).  The subarachnoid space is widened because growth of an extraaxial lesion tends to push away the brain.  In the region of the CPA 90% of the extraaxial tumors are schwannomas.

25. Intra-axial Intra-axial is a term that denotes lesions that are within the brain parenchyma Some authors include intraventricular lesions in the intra-axial group as most are lesions that arise from the brain parenchyma and grow exophytically into the ventricular system.

26. INTRA-AXIAL EXTRA-AXIAL Glioma Medulloblastoma Hemangioblastoma Metastases I n farct ion / h e m atoma AVM Abscess/inflammation Meningioma Pituatary adenoma Cranioph a ryng i o m a Schwannoma Chordoma Dermoid/epidermoid cyst Lipoma hematoma, infection

27. Common intra-axial CNS tumours in paediatric age group Supratentorial: Astrocytoma Pleomorphic xanthoastrocytoma PNET DNET Ganglioglioma Infratentorial: Juvenile pilocytic astrocytoma PNET (Medulloblastoma) Ependymoma Brainstem astrocytoma/glioma

28. Common intraaxial tumours in adults Supratentorial Infratentorial Metastases Metastases Gliomas Hemangioblastoma

29.  Most intra-axial tumours are white matter based  Differential diagnosis for cortical based tumours: neuroepithelial DNET (Dysemb r yoplastic tumour) Ganglioglioma

30.  Glioblastoma multiforme (GBM) frequently crosses the midline by infiltrating the white matter tracts of the corpus callosum.  Radiation necrosis mimics GBM and can sometimes cross the midline.  Meningioma can spread along the meninges to the contralateral side.  Lymphoma is usually located near the midline.  Epidermoid cysts can cross the midline via the subarachnoid space.  MS can also present as a mass lesion in the corpus callosum.

31.  Astrocytomas spread along the white matter tracts.  Ependymomas of 4 th ventricle in children tend to extend through the foramen of Luschka to the CP angle and through the foramen of Magendie to the Cisterna Magna  Oligodendroglioma typically show extention to the cortex  Medulloblastoma arising in the cerebellum tend to extend to the upper cervical canal

32.  Primary brain tumors are derived from brain cells and often have less mass effect for their size than expected, due to their infiltrative growth.  Metastases and extra-axial tumors like meningiomas or schwannomas, have more mass effect due to their expansive growth

33.  Met a stases and CNS l y m p h oma, o f ten p resenting with multiple lesions, are rare in children  Seedi n g m etastases m ay b e seen with P N E T - MB (Medulloblastoma) and ependymoma  Multiple brain tumours may occur in phacomatoses: NF I: optic gliomas; astrocytomas NF II: meningiomas; ependymomas; choroid plexus papillomas tubers; ependymomas; Tuberous sclerosis: subependymal intraventricular giant cell astrocytomas Von Hipple Lindau: hemangioblastomas

34. Fat C a l c if i - cation Cystic mass vs. cyst T1WI signal in t ensi t y T2WI signal in t ensi t y Contrast en h ance- ment A d va n ced MRI

35.  Fat is characterised by low density on CT, high signal on T1 and T2WI, with associated chemical shift artefact  Fat suppression sequences help distinguish from other causes of high signal e.g. melanin, hematoma and slow flow  Masses containing fat include teratoma, lipoma and dermoid cyst

36. In t ra-ax i al: Astrocytoma Oligodendroglioma Ependymoma Choroid plexus papilloma Ganglioglioma Extra-axial: Meningioma Craniopharyngioma

37. Cystic lesions that may simulate tumours include Epidermoid, Dermoid, Arachnoid, Neurenteric and Neuroglial cysts To differentiate cystic masses from cysts: Morphology Fluid/fluid level Content intensity compared to CSF on T1, T2 and FLAIR sequences Restricted flow on DWI

38.  Most tumors have a low or intermediate signal intensity on T1WI.  Exceptions to this rule can indicate a specific type of tumor.

39. PITUTARY apoplexy. The high signal is due to hemorrhage in a pituitary macroadenoma. Glioblastoma multiforme, which caused a hemorrhage in the splenium of the corpus callosum. Metastasis of a melanoma. The high signal intensity is due to the melanin content.

40.  Extra-axial tumours, pituitary, pineal and choroid plexus tumours enhance (outside blood-brain barrier)  Contrast enhancement does not visualise full extent of infiltrative tumours eg gliomas  In gliomas, enhancement indicates higher degree of malignancy  Ganglioglioma and pilocytic astrocytomas are exceptions, low grade tumours that enhance vividly

41. No enh a ncement: Low grade as t r o c y to m a Cystic non- tumoral lesions Homo g ene o us enhancement Germinoma and other pineal tumours Pituitary adenoma Pilocytic astrocytoma(s olid component) and hae m an g iobl a s toma Ganglioglioma M e ningio m a , schwannoma Patchy enh a ncement Radia t ion necrosis Ring enh a ncement High grade glioma Metastases Abscess

42. HOMOGENOUS EN H AN C EME N T

43. PATCHY ENHA N CEMENT  A large tumor with limited mass effect.  This indicates that there is marked infiltrative growth, a characteristic typical for gliomas.  Notice the heterogeneity on both T2WI and FLAIR.  There is patchy enhancement.  All these findings are typical for a GBM.

44. Di f fusion weighted imaging Di f fusion tensor imaging Pe r fusion weighted imaging Magnetic resonance spec t roscopy

45.  Most tumours do show of not sig n i ficant restriction diffusion  High s i gnal on DWI is seen with abscesses, epider m o i d cy s ts and a c ute infarction

46.  Dynamic susceptibility perfusion imaging is based on the premise that contrast material remains within the intravascular compartment.  Signal intensity depends on vascularity, not on breakdown of blood-brain barrier  Better correlation with grade of malignancy than degree of contrast enhancement

47. Grade II astrocytoma. Left, Fluid-attenuated inversion recovery (FLAIR) image demonstrates an area of increased signal intensity in the parietooccipital region. Right, Perfusion MRI demonstrates decreased relative cerebral blood volume (rCBV), consistent with a low-grade neoplasm. The final pathologic diagnosis was a grade II astrocytoma. Axial MRI T1 showing hypointense mass in right frontal lobe which appears hyperintense on T2 and shows increased perfusion values with elevated choline peak values confirming a high grade glioma

48. CT  CT is often the first modality employed to investigate neurological signs or symptoms, and often is the modality which detects an incidental lesion:  non-contrast CT 60% slightly hyperdense to normal brain, the rest are more isodense 20-30% have some calcification  post-contrast CT 72% brightly and homogeneously contrast enhance malignant or cystic variants demonstrate more heterogeneity  hyperostosis (5%) typical for meningiomas that abut the base of the skull need to distinguish reactive hyperostosis from: direct skull vault invasion by adjacent meningioma primary intraosseous meningioma  enlargement of the paranasal sinuses ( pneumosinus dilatans ) has also been suggested to be associated with anterior cranial fossa meningiomas

49. T2 T1 T1 isointense to grey matter (60-90%) hypointense to grey matter (10-40%) particularly fibrous, psammomatous variants T1 C+ (Gd): usually intense and homogeneous enhancement T2 isointense to grey matter (~50%) 3,8,13 hyperintense to grey matter (35-40%) usually correlates with soft texture and hypervascular tumours very hyperintense lesions may represent the microcystic variant 12 hypointense to grey matter (10-15%): compared to grey matter and usually correlates with harder texture and more fibrous and calcified contents

50. T2 Contrasted T1 Perfusion-Weighted

51. A number of helpful imaging signs have been described, including:  CSF vascular cleft sign , which is not specific for meningioma, but helps establish the mass to be extra-axial; loss of this can be seen in grade II and grade III which may suggest brain parenchyma invasion  Dural tail seen in 60-72% (note that a dural tail is also seen in other processes)  Sunburst or spokewheel appearance of the vessels  Arterial narrowing Typically seen in meningiomas which encase arteries Useful sign in parasellar tumours, in distinguishing a meningioma from a pituitary macroadenoma ; the later typically does not narrow vessels

52. The spoke wheel sign refers to the pattern of vessels coursing through meningiomas , when seen in cross-section. It is the result of the same phenomenon which results in the sunburst pattern AXIAL T1W T1C+

53. 60 year-old lady with anosmia and short term memory loss. A well defined strikingly enhancing (arrows) classic meningioma is seen involving the floor of the anterior cranial fossa, particularly involving the PLANUM SPHENOIDALE and OLFACTORY GROOVE , finding responsible for anosmia. Olfactory groove Meningioma

54. A dural-based intensely enhancing (arrows) meningioma arising from the right side of the falx. Falcine Meningioma

55. MRI images of a large sphenoidal wing meningioma. (A) Enplaque, (B) Globular MRI gadolinium. (A) Axial, (B) Coronal, (C) Sagittal images showing a pterional meningioma

56. MENINGIOMA Alanine – Doublet at 1.47 ppm Inverts at long TE Decreased NAA, Cr Increased Glx Increased mI Presence of Choline Variable Lactate Minimal lipids

57. MRI gadolinium images of rarer meningiomas: (A) Falcotentorial meningioma, (B) Torcular meningioma, (C) Middle fossa meningioma extending through the foramen ovale, (D) Meningioma with pituitary microadenoma, (E) Cystic meningioma with a dural tail, (F) Multiple meningiomas A B C

58.  Epi: 15% of Astrocytomas Young Adults  Facts : Best diagnostic clue: Focal or diffuse nonenhancing white matter (WM) mass  Location Cerebral hemispheres, supratentorial 2/3 Frontal lobes 1/3, temporal lobes 1/3 Relative sparing of occipital lobes Infratentorial1/3 Brainstem (50% of brain stem "gliomas" are low-grade astrocytoma) Occur in pons and medulla of children/ adolescentsWidely Infiltrate surrounding tissue C y st T1 weighted T2 weighted On Imaging: CT: Well circumscribed, non enhancing, hypodense or isodense lesion MRI: MRI more sensitive than CT – useful for identification and establishing extent T1 image shows abnormal areas of decreased signal T2 image shows abnormal areas of increased signal Usually no enhancement

59. Low grade glioma CT: Well circumscribed, non enhancing, hypodense or isodense lesion

60. Low grade glioma CT: Well circumscribed, non enhancing, hypodense or isodense lesion

61. Low grade glioma CT: Well circumscribed, non enhancing, hypodense lesion WITH cyst S/O pilocytic astrocytoma

62. TlWI Homogeneous hypointense mass May expand white matter and adjacent cortex Appears circumscribed, but infiltrates adjacent brain Ca++ and cysts uncommon Hemorrhage or surrounding edema (rare) TI C+ Usually no enhancement Enhancement suggests progression to higher grade

63. TlWI Homogeneous hypointense mass May expand white matter and adjacent cortex Appears circumscribed, but infiltrates adjacent brain Ca++ and cysts uncommon Hemorrhage or surrounding edema (rare) TI C+ Usually no enhancement Enhancement suggests progression to higher grade

64. Grade II astrocytoma in a 30-year- old man. Nonenhanced T2- weighted MRI shows a well- circumscribed area of increased signal intensity in the left temporal lobe. Grade II astrocytoma. Left, Fluid-attenuated inversion recovery (FLAIR) image demonstrates an area of increased signal intensity in the parietooccipital region. Right, Perfusion MRI demonstrates decreased relative cerebral blood volume (rCBV), consistent with a low-grade neoplasm. The final pathologic diagnosis was a grade II astrocytoma.

65. Anaplastic astrocytoma (M) Hemispheric WM lesion, usually non enhancing Focal or diffuse mass May be ind i stingu i shable without biopsy Ischemia Vascular territory (MCA, ACA, PCA), acute onset Diffusion restriction (a c ut e / e arly subacute) Often wedge- shaped, involves GM & WM Cerebritis Edema, patchy enhancement characteristic Usually shows restricted diffusion Typically more acute onset O l igoden d r ogl i o ma Cort i c a l l y -b a sed mass with variable enhancement Ca++ common May be ind i stingu i shable

66. Most common of all primary intracranial neoplasms. Location- Supratentorial white matter most common Frontal, temporal, parietal lobes. Tumor may cross white matter tracts to involve contralateral hemisphere like Corpus callosum (butterfly glioma). May be multifocal, multicentric. Presentation- Varies with location: Seizures, focal neurologic deficits common, Increased intracranial pressure, mental changes. Age:- Peak 45-70 years but may occur at any age. Patterns of dissemination- Most common: Along white matter tracts, perivascular spaces.Less common: Ependymal/subpial spread, CSF Metastases.

67.  On Imaging: Variable CT  Irregular thick margins: iso to slightly hyperattenuating (high cellularity)  Irregular hypodense centre representing necrosis  Marked mass effect  Surrounding vasogenic oedema  Haemorrhage occasionally seen  Calcification is uncommon  I n ten s e irregu l a r , h e tero g ene o us enhan c e m ent o f t h e margins is almost always present

68. Non contrast axial CT CECT Axial

69.  MRI  T1 hypo to isointense mass within white matter central heterogeneous signal (necrosis, intratumoural haemorrhage)  T1 C+ (Gd) enhancement is variable but is almost always present typically peripheral and irregular with nodular components usually surrounds necrosis  T2/FLAIR hyperintense

70. Axial T2WI MR shows a heterogeneous hyperintense mass with central necrosis and surrounding signalabnormality likely related to tumor extension and edema. Typical imaging of GBM. Axial T1 C+ MR shows peripheral enhancement with central necrosis and extension across the splenium of the corpus callosum, characteristic of GBM.

71. Axial (a) and coronal (b) fluid-attenuated inversion recovery MR images demonstrate the mass with a large amount of surrounding T2 prolongation, a finding that suggests edema.

72. T h e � bu t t erfly glio m a � ref e rs t o a hig h grade astr o cytoma , usually a GBM, which crosses the midline via the corpus callosum. Most frequently this occurs in the frontal lobes

73. Axial CECT shows a peripherally enhancing, centrally necrotic mass with surrounding mass effect and midline shift. There is uncal herniation and early entrapment of the ventricular system. GBM. Single voxel MRS shows elevated Cho and decreased NAA. Note the lactate doublet at 1.33 (arrow), typical of high grade tumors. Patient with a history of AA that progressed to GBM.

74. Differential diagnosis  Abscess - Ring-enhancement typically thinner than GBM.T2 hypointense rim, diffusion restriction + typical.  Metastasis - Typically multiple lesions at gray-white junctions. Round> infiltrating lesion. Primary tumor often known  Primary CNS lymphoma - Periventricular enhancing mass.Often crosses corpus callosum. Typically isointense/hypointense on T2W.Necrosis common in AIDS related lymphoma.  Anaplastic astrocytoma (AA) - Often nonenhancing white matter mass. Enhancement may indicate degeneration to GBM.

75.  On Imaging: CT: Well circumscribed, hypodense lesions with heavy calcification Cystic degeneration is common but hemorrhage & edema are uncommon MRI: Hypointense or isointense on T1-weighted images Hyperintense on T2-weighted images with variable enhancement

76.  T2* GRE: Ca++ seen as areas of "blooming"  DWI: No diffusion restriction is typical  TI C+:Heterogeneous enhancement is typical. Approximately 50% enhance Rarely, leptomeningeal enhancement is seen. Axial NECT shows a calcified cortically-based frontal mass (arrow). Calcification is seen in the vast majority of oligodendrogliomas, typicallynodular or clumped.. Axial T2WI MR in the same case shows a heterogeneously hyperintense cortically- based mass with infiltration into the subcortical white matter. Cystic change is seen, but the Ca++is not visualized

77. 55 yr old male with h/o seizures 1year and rt sided paresis CECT brain s/o hetrogenously enhancing calcified mass with perilesional edema in left frontoparietal lobe s/o oligodendroglioma

78. 55 yr old male with h/o seizures 1year and rt sided paresis CECT brain s/o hetrogenously enhancing calcified mass with perilesional edema in left frontoparietal lobe s/o oligodendroglioma

79.  Dis t inct ty p e o f ( usu a l l y) b e nign s u prat e n t orial a s trocytoma found almost exclusively in young adults. Presentation  Major i ty with l o n g - s t an d i n g e pileps y , often part i al co m plex seizures (temporal lobe)  Other signs/symptoms: Headache, focal neurologic deficits Age  Tumor of children/young adults  2/3 < 18 years. Location  Periph e ra l ly loca t e d he m i s p h er i c m a s s, of t en i n v o l v e s cort e x and meninges.  98% supratentorial-Temporal lobe most common.

80. General Features  Best diagnostic clue- Supratentorial cortical mass with adjacent enhancing dural "tail“.  Cyst and enhancing mural nodule typical. CT Findings  Cystic/solid mass: Hypodense with mixed density nodule  Solid mass: Variable; hypodense, hyperdense or mixed. Minimal or no edema is typical. Ca++, hemorrhage, frank skull erosion rare. tu m o r  S t rong, s o m e ti m e s h e te ro g eneo u s en h anc e m e n t of nodule. MR Findings  TlWI-Mass is hypointense or isointense to gray matter.  T2WI-Hyperintense or mixed signal intensity mass  Cystic portion isointense to CSF. Surrounding edema rare

81.  T1 C+- Enhancement usually moderate/strong, well-delineated  Enhancement of adjacent meninges, dural"tail"common (approximately 70%)  Enhancing nodule often abuts pial surface.

82. Axial and coronal FLAIR, T2W and T1C+ scans showing solid cystic mass with ehhancing mural nodule.

83. Ganglioglioma Cortically based hemispheric mass, solid/cystic or solid Mural nodule typical, often not adjacent to meninges Variable enhancement, no enhancing dural "tail" Ca++ is common; may remodel calvarium Pilocytic astrocytoma Supratentorial location other than hypothalamus/chiasm rare Typically solid and cystic or solid mass Enhancement but no dural "tail" D y sembr y opla s tic neuroepithelial tumor (DNET) Superficial cortical tumor, well demarcated Multicystic "bubbly" ,appearance

84.  W ell di f ferent i ated, slo w ly gro w ing neur o e p i the l ial t u m or composed of neoplastic ganglion cells and neoplastic glial cells  Most common cause of temporal lobe epilepsy (TLE). Presentation  Chronic temporal lobe epilepsy (approximately 90%)  Often partial complex seizures  Other signs/symptoms: Headache, signs of raised ICT. Age  Tumor of children, young adults.80% of patients < 30 yrs. Location  Can occur anywhere but m ost co mm o nly sup e rfi c ial hemispheres(temporal lobe).

85. General Features  Best diagnostic clue: Partially cystic, enhancing,cortically-based mass in child/young adult with TLE. CT Findings isoden se  4 % hyp o dense , 30 % mi x ed hypo d ense (cy s t), (nodule),15% isodense or hyperdense  Ca++ common, 35-50%  Superficial lesions may expand cortex, remodel bone  Approximately 50% enhance  • Varies from moderate, uniform to heterogeneous. MR Findings  TIWI-Mass is hypo to isointense to gray matter.  T2WI-Hyperintense, heterogeneous.  Tl C+:Variable enhancement, usually moderate

86. Axial FLAIR MR shows a cortically- based hyperintense mass in the right frontal lobe. Note the lack of edema and mass effect. Coronal T1 C+ MR shows a temporal lobe circumscribed cystic and solid mass with intense enhancement of the mural nodule (arrow). Long history of temporal lobe epilepsy. Ganglioglioma.

87. (Left) Axial T2WI MR shows a hyperintense temporal lobe mass without significant edema or mass effect. Temporal lobe is the most common location for ganglioglioma. Patient with temporal lobe epilepsy. (Right) Axial T1 C+ MR shows a cystic and solid temporal lobe mass with marked enhancement of the solid portion, a typical enhancement pattern of ganglioglioma.

88. Best diagnostic clue: Well-demarcated, wedge-shaped "bubbly" intracortical mass in young patient with longstanding partial seizures Location Temporal lobe (often amygdala/hippocampus) most common site Parietal cortex, caudate nucleus, septum pellucidum also frequent sites Intracortical mass scallops inner table of skull and "points" towards ventricle Size  Variable: Small (involving part of a gyrus)

89.  CT Findings NCCT  Wedge-shaped low density area -Cortical/subcortical lesion  Extends towards ventricle in 30%  Scalloped inner table in 44-60+%  Calcification in 20-36%  May resemble stroke on initial CT BUT no temporal evolution to atrophy CECT Usually non enhancing Faint nodular or patchy enhancement in 20% Slightly higher risk of recurrence if enhancement CTA: Avascular MR Findings  TlWI Pseudocystic, multinodular ("bubbly") mass Hypointense on Tl  T2WI Very hyperintense on T2 Multinodular or septated appearance well seen on T2WI

90. Non-enhanced CT scan reveals a parietal lesion with calcific hyperdensity. Calvarial remodeling is evident on bone window CT scan.

91. MRI axial images showing multicystic lesion in the right temporal lobe which appears (A) hypointense on T1, (B and C) Hyperintense on T2 and FLAIR, (D) No significant enhancement on contrast imaging A B C D

92. DNET Axial T2WI MR in a 5 year old with seizures shows multicentric, "bubbly", DNET with involvement of the body of the caudate nucleus (arrow). Axial T2WI MR shows bubbly temporal lobe DNET expanding involved gyri and remodeling the inner calvarial table (arrow).

93. 106 General characteristics Solid, cystic, or combination Classically described as g lo b ular/ exop h ytic suprasellar mass CT Low-density to isodense Intense enhancement with contrast MRI T1: Low-intensity with marked g a dol i ni u m enhancement- tubular or fusiform nerve in axial T2: Hyperintense mass Found to grow postero-superiorly with invagination of the third ventricle With lateral progression, may involve the Circle of Willis 23 May 2016

94. Radiology ©R

95.  Age and clinical feature should always considered.  Neuroradiology provides details of the structural pathology, the functional and physiological data.  MRI is the choice of neuroimaging; CT still has a role.  MRI (FLAIR) increases the conspicuity of lesions at brain- CSF interfaces.  MRI (STIR) suppresses fat, which is useful for skull base and orbital imaging.  fMRI and DTI decide the surgical approach.  Advanced imaging helps in narrowing the D/Ds  Good preoperative work up & team approach is key to success.