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Fifteen (50) intracranial cystic lesion Dr Ahmed Esawy CT MRI main

Fifteen (50) intracranial cystic lesion dr ahmed esawy ct mri main .
• 1-arachnoid cysts
• 2-porencephalic cyst,
• 4-multicystic encephalomalacia
• 3-hydranencephaly
• 5-holoprosencephaly
• 6-hydrocephalus (aqueduct stenosis)
• 7-periventricular leukomalacia (PVL),
• 8-septum pellucidum changes CSP CV CI
• 9-dandy walker malformation
• 10-dandy walker varaint
• 11-mega cisterna magna
• 12-schizencephaly
• 13-conatal cysts
• 14-subependymal cysts
• 15-encephalomalacia,
• 16-subarachnoid cyst
• 17-cystic lesions after brain surgery
and radiation injury to the brain.
• 18-Leptomeningeal cyst
• 19-Post traumatic porenencephally
• 20-brain abscess
• 21-cysticercosis
• 22-hydatid cyst.
• 23-amoebic abscess
• 24-Aneurysm
• 25-Parenchymal Perianeurysmal Cystic Changes in the Brain
• 26-Vein of Galen malformation
• 27-epidermoid cysts
• 28-dermoid cyst (cystic teratoma)
• 29-craniopharyngioma
• 30-cystic astrocytoma
• 31-cystic meningioma
• 32-cystic shwannoma
• 33-hemangioblastoma
• 34-cystic metastasis
• 35-cystic pituitary adenoma
• 36-Cystic degeneration / necrotic neoplasm
• 37-colloid cysts
• 38-Rathke’s cleft cysts,
• 39-neuroepithelial cysts
• 40-neuroenteric cysts
• 41-pineal cysts.
• 42-Choriod plexus cyst
• 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain
• 44-Trigonal cyst
• 45-Interhemispheric cyst
• 46-Dorsal cyst
• 47-Ependymal cysts
• 48-Enlarged VRS
• 49-Cystic trapped 4th ventricle
• 50-Diverticulation of 3rd , lateral ventricle

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Fifteen (50) intracranial cystic lesion Dr Ahmed Esawy CT MRI main

  1. 1. ‫الرحيم‬‫الرحمن‬‫اهلل‬‫بسم‬ Dr Ahmed Esawy
  2. 2. An Article By Dr. Ahmed Esawy MBBS M.Sc MD Dr Ahmed Esawy
  3. 3. Dr Ahmed Esawy
  4. 4. Congenital cystic lesions • 1-arachnoid cysts • 2-porencephalic cyst, • 4-multicystic encephalomalacia • 3-hydranencephaly • 5-holoprosencephaly • 6-hydrocephalus (aqueduct stenosis) • 7-periventricular leukomalacia (PVL), • 8-septum pellucidum changes CSP CV CI • 9-dandy walker malformation • 10-dandy walker varaint • 11-mega cisterna magna • 12-schizencephaly • 13-conatal cysts • 14-subependymal cystsDr Ahmed Esawy
  5. 5. Post traumatic cystic lesion )sequelae(late • 15-encephalomalacia, • 16-subarachnoid cyst • 17-cystic lesions after brain surgery and radiation injury to the brain. • 18-Leptomeningeal cyst • 19-Post traumatic porenencephally Dr Ahmed Esawy
  6. 6. Inflammatory and infectious cysts: • 20-brain abscess • 21-cysticercosis • 22-hydatid cyst. • 23-amoebic abscess Dr Ahmed Esawy
  7. 7. VASCULAR • 24-Aneurysm • 25-Parenchymal Perianeurysmal Cystic Changes in the Brain • 26-Vein of Galen malformation Dr Ahmed Esawy
  8. 8. Tumors and tumors like cysts 27-epidermoid cysts 28-dermoid cyst (cystic teratoma) 29-craniopharyngioma 30-cystic astrocytoma 31-cystic meningioma 32-cystic shwannoma 33-hemangioblastoma 34-cystic metastasis 35-cystic pituitary adenoma 36-Cystic degeneration / necrotic neoplasmDr Ahmed Esawy
  9. 9. andNonneoplastic cystsinflammatory-non • 37-colloid cysts • 38-Rathke’s cleft cysts, • 39-neuroepithelial cysts • 40-neuroenteric cysts • 41-pineal cysts. • 42-Choriod plexus cyst • 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain • 44-Trigonal cyst • 45-Interhemispheric cyst • 46-Dorsal cyst • 47-Ependymal cysts • 48-Enlarged VRS • 49-Cystic trapped 4th ventricle • 50-Diverticulation of 3rd , lateral ventricleDr Ahmed Esawy
  10. 10. Dr Ahmed Esawy
  11. 11. Congenital cystic lesions Dr Ahmed Esawy
  12. 12. •Arachnoid Cyst Dr Ahmed Esawy
  13. 13. ARACHNIOD VERSUS EPIDERMIOD arachniod CSF density No calcification,no enhancment displace structures CT Low signal like CSFMRI T1 high signal like CSFMRI T2 Low signal like CSFFLAIR DARK hypointensity (free diffusion) DIFFUSION BRIGHT marked hyperintensity like CSF ADC Retrocerebellar,CPA Dr Ahmed Esawy
  14. 14. T2-weighted sagittal MRI image (see Image 2 for axial view) of the brain in a 28-year-old woman with an incidental finding of a cisterna ambiens arachnoid cyst (arrow). 28-year Dr Ahmed Esawy
  15. 15. Unenhanced CT scan of the head in a 26-year-old man with a history of seizures since childhood (same patient as Image 4). The scan shows a large left frontoparietal cyst with a mass effect. Dr Ahmed Esawy
  16. 16. T1-weighted sagittal MRI image of the lumbosacral spine showing an incidental sacral arachnoid cyst.Dr Ahmed Esawy
  17. 17. T2 DIFFUSION autopsied brain ARACHNOID CYSTS Dr Ahmed Esawy
  18. 18. Arachnoid Cyst T2-hyperintense mass in the left cerebellopontine angle (arrow T1-hypointense mass (arrow) DW hypointensity in the mass (arrow) ADC map marked hyperintensity (arrow) similar to that of the CSF Dr Ahmed Esawy
  19. 19. arachnoid cysts Dr Ahmed Esawy
  20. 20. Arachnoid cyst with enlargement of the calvaria T2T1 Non contrast CT Dr Ahmed Esawy
  21. 21. midline Arachnoid cyst Causing dilated OH Coronal gradient echo FLAIRT1 DW CT Dr Ahmed Esawy
  22. 22. 28-year-old woman T2 superior cerebellar cistern arachnoid cyst Dr Ahmed Esawy
  23. 23. 26-year-old man large left frontoparietal cyst Dr Ahmed Esawy
  24. 24. T2 ARACHNIOD CYST T1 FLAIR Dr Ahmed Esawy
  25. 25. • Prenatal coronal T1-left temporal fossa arachnoid cyst. • post natal coronal T2-left temporal fossa arachnoid cyst. • postnatal coronal T1-left temporal fossa arachnoid cyst. Dr Ahmed Esawy
  26. 26. Suprasellar arachnoid cyst in a patient with Mowat-Wilson syndrome (includes agenesis of the corpus callosum) and bradycardia from increased intracranial pressure. The entire fluid collection represents the arachnoid cyst (C) and should not be confused with the third ventricle. T2 Dr Ahmed Esawy
  27. 27. Differential Diagnosis • epidermoid cyst • Chronic subdural hematoma • porencephalic cyst Dr Ahmed Esawy
  28. 28. ARACHNIOD VERSUS EPIDERMIOD epidermiodarachniod Lower density than CSF May show calcifications invade structures CSF density No calcification,no enhancment displace structures CT LOWER THAN CSFLow signal like CSFMRI T1 HIGHER THAN CSFhigh signal like CSFMRI T2 HIGH SIGNALLow signal like CSFFLAIR BRIGHT typical hyperintensity T2 shine (restricted diffusion) DARK hypointensity (free diffusion) DIFFUSION DARK lower than that of CSF and equal to or higher than that of brain parenchyma BRIGHT marked hyperintensity like CSF ADC Away from midlline CPARetrocerebellar,CPA Dr Ahmed Esawy
  29. 29. posterior fossa cystic malformation destructive lesions porencephalic cyst hydranencephaly multicystic encephalomalacia Dr Ahmed Esawy
  30. 30. • The normal cisterna magna characteristically measures 3–8 mm when measurements are taken in the midsagittal plane from the posterior lip of the foramen magnum to the caudal margin of the inferior vermis Dr Ahmed Esawy
  31. 31. Isolated mega cisterna magna in a patient with trisomy 21 transcranial US /CT Dr Ahmed Esawy
  32. 32. Dandy-Walker malformation three criteria • (a) vermian hypoplasia with cephalad rotation of the vermian remnant, • (b) cystic dilatation of the posterior fossa communicating with the fourth ventricle, and • (c) enlargement of the posterior fossa causing an abnormally high tentorium and torcular, • the latter lying above the level of the lambdoid (ie,torcular-lambdoid inversion) Dr Ahmed Esawy
  33. 33. Dandy-Walker malformation in a full-term 1-day-old neonate retrocerebellar collection of CSF (arrowheads). Coronal US scan shows vermian agenesis and a wide communication with a "keyhole" appearance (arrowheads) between the cyst posteriorly and the fourth ventricle (4) anteriorly . The cerebellar hemispheres (C) are hypoplastic Magnified transmastoid US scanDr Ahmed Esawy
  34. 34. posterior fossa cystic malformation Dandy Walker Dr Ahmed Esawy
  35. 35. Dandy-Walker malformation in a full-term 1-day-old neonate Coronal T2-weighted (d) and sagittal T1- weighted (e) MR images show the Dandy- Walker malformation. Dr Ahmed Esawy
  36. 36. Sagittal T1-weighted image reveals a large posteriorfossa fluid collection that extends to the upper spinal canal. The foramen magnum is enlarged. There is hypoplasia of the inferior vermis of the cerebellum. Superior vermis present in the midline. There is significant decrease in the AP dimension of the medulla Dandy-Walker Variant with No Separate Fourth Ventricle Dr Ahmed Esawy
  37. 37. C. Coronal SPGR image shows asymmetry of the cerebellar hemispheres; the right cerebellar hemisphere is hypoplastic Sagittal T1-weighted image demonstrates a large posterior fossa cyst that communicates with the fourth ventricle elevating the cerebellar vermis and torcular Herophili B. Axial T2-weighted image shows a large CSF- intensity fluid collection that expands the posterior fossa on the right and communicates in the midline with the fourth ventricle (arrow) Dandy-Walker Variant with Elevation of Torcula Dr Ahmed Esawy
  38. 38. T1 Axial transmastoid US T2 Arachnoid cyst and complex posterior fossa malformations in a full-term 1- day-old neonate Dr Ahmed Esawy
  39. 39. Bilateral supraclinoid internal carotid artery occlusions with intact posterior circulation Hydranencephaly in new born an extreme example of porencephaly large cystic space involving the entire supratentorial area bilaterally No cortical rim Dr Ahmed Esawy
  40. 40. B. Axial T1-weighted image shows only portions of temporal lobe and midbrain to be present.Most of the cranium is filled with fluid Hydranencephaly with Microcephaly A. Sagittal T1-weighted image shows portions of frontal lobes, midbrain and cerebellum to be present Dr Ahmed Esawy
  41. 41. Hydranencephaly with increasing head size A. Noncontrast CT through the emporal lobes reveals normal- appearing lower temporal lobes with abnormal CSF collection frontally B. CT image reveals that CSF replaces the hemispheric brain tissue with a thin residual midline and occipital lobe brain C. Sagittal T1-weighted image shows that the areas supplied by posterior cerebral artery are preserved D. T2-weighted image shows normal lower medial temporal and occipital lobes. The thalami are not fuse E. T2-weighted image shows that CSF occupies most of the space normally filled with brain F. Coronal SPGR image shows also that areas supplied by the posterior cerebral artery are preserved. The falx (arrow) is partially normal Dr Ahmed Esawy
  42. 42. B. Axial T2-weighted image shows the brainstem and cerebellum to be present C. Axial T2-weighted image through the expected hemispheres shows a portion of residual temporal lobe on the left A. Sagittal T2-weighted image demonstrates fluid filling most of the cranium in the expected location of the cerebral hemispheres. Only the cerebellum and part of the thalami are present Hydranencephaly with increasing head size Dr Ahmed Esawy
  43. 43. PORENCEPHALIC CYSTS • congenital or acquired cavities within the cerebral hemisphere • cortical or subcortical • unilateral or bilateral . • The location often corresponds to territories supplied by the cerebral arteries . • Congenital porencephalic cysts originate from a fetal or perinatal encephaloclastic process that results from intrauterine vascular or infectious injury . • Acquired cysts are secondary to injury later in life and are usually secondary to trauma, surgery, ischemia, or infection Dr Ahmed Esawy
  44. 44. Coronal T1-MR enlarged left temporal horn (black arrow) that communicates with peripherally located porencephalic cyst (white arrows). Cyst extends to the brain surface Dr Ahmed Esawy
  45. 45. Differential Diagnosis • arachnoid cyst (extra-axial) • schizencephaly • (ependymal cyst) intraventricular with normal surrounding brain tissue ( • encephalomalacia • hydranencephaly Dr Ahmed Esawy
  46. 46. 1-day-old term infant Porencephaly (no communication with the ventricles) CT no C calcifications along the margins of the cavity (arrowheads). These are probably sequelae of a remote infarct in the distribution of the middle cerebral artery. Dr Ahmed Esawy
  47. 47. Porencephaly in a 26-week gestation premature neonate Dr Ahmed Esawy
  48. 48. CT scan at the age of 13 years showing the porencephalic cyst in left cerebral hemisphere. Dr Ahmed Esawy
  49. 49. • the midline cavities and their positions in the sagittal plane (top) and coronal plane (bottom). • supratentorial cystic lesions in a periventricular location, Dr Ahmed Esawy
  50. 50. 28-week gestation neonate Dr Ahmed Esawy
  51. 51. Cavum veli interpositium. 33 weeks of gestation Dr Ahmed Esawy
  52. 52. Differential diagnosis Periventricular Location • periventricular leukomalacia (PVL), • connatal cyst (CC), • subependymal cyst (SC) • anatomic locations. Dr Ahmed Esawy
  53. 53. • Connatal cysts in a 30-week gestation preterm infant. just lateral to the frontal horn and body of the lateral ventricle. connatal cysts are coarctation of the lateral ventricles and frontal horn cysts sequelae of ischemic insults Dr Ahmed Esawy
  54. 54. Bilateral connatal cysts in a 3-week-old full-term neonate along superolateral angles of the lateral ventricles (arrows). Dr Ahmed Esawy
  55. 55. Subependymal Cysts • acquired, posthemorrhagic cyst • congenital and is related to germinolysis. Dr Ahmed Esawy
  56. 56. Acquired subependymal cyst due to an evolving subependymal hemorrhage caudothalamic groove T2 T1 Dr Ahmed Esawy
  57. 57. Open lip schizencephaly (type II) T1 T2 T2 T2 FLAIR Dr Ahmed Esawy
  58. 58. Periventricular Leukomalacia • Periventricular leukomalacia (PVL) refers to white matter necrosis in a characteristic distribution. • The distribution pattern is dorsal and lateral to the external angles of the lateral ventricles • involves particularly the centrum semiovale and the optic (trigone and occipital horns) and acoustic (temporal horn) radiations . • PVL most frequently occurs in premature infants of less than 32 weeks gestation due to the unique anatomic features of the brain at this age. Dr Ahmed Esawy
  59. 59. • Extensive cystic PVL in a 29-week gestation premature neonate. extensive multiseptate cystic areas located superiorly to the frontal horns (arrows). There is ex vacuo dilatation of the ventricles secondary to white matter loss. Dr Ahmed Esawy
  60. 60. Unilateral periventricular leukomalacia Gray matter indents the ventricle wall (arrow) due to severe white matter loss on right. Corpus callosum is thin. The right hemisphere is smaller than the left. Typical undulation of ventricular wall is present Dr Ahmed Esawy
  61. 61. B. DW image shows hypointensity in right hemisphere cystic lesions Multicystic Encephalomalacia A.T1-weighted image shows a thin corpus callosum Dr Ahmed Esawy
  62. 62. E. T2-weighted image shows diffuse hyperintense cysts throughout the right hemisphere that is smaller C. Axial FLAIR image reveals small right hemisphere and multiple CSF containing spaces with dilated lateral ventricle D. Coronal FLAIR image confirms the encephalo-malacia and ex vacuo atrophy displacing the midline to right Multicystic Encephalomalacia Dr Ahmed Esawy
  63. 63. Multicystic Encephalomalacia F. T1-weighted image shows hypointensity in the right cerebral hemisphere. This is consistent with an area of encephalomalacia and gliosis due to a prior insult such as infarct or infection. Minimal hyperintensity is noted in the area of encephalomalacia consistent with mineralization H. CT at the age of 3years shows multicystic encephalomalacia with small right hemicranium G. T1-FLAIR image shows multiple CSF containing cysts. The thin cortex is better appreciated in this sequence Dr Ahmed Esawy
  64. 64. Schizencephaly with bilateral clefts in a 36- week gestation preterm infant. Dr Ahmed Esawy
  65. 65. Severe obstructive hydrocephalus due to aqueductal stenosis. large fluid-filled space posteriorly which represents a markedly dilated lateral ventricle that simulates a large cyst. choroid plexus (CP) • thalami (T) Dr Ahmed Esawy
  66. 66. Holoprosencephaly spectrum disorder in a newborn. a) Midline sagittal US scan shows a large monoventricle (arrows). The third and fourth ventricles are normal (b) Coronal US scan shows an absent septum pellucidum, the large monoventricle (arrows), and partially fused thalami (T). Dr Ahmed Esawy
  67. 67. (b) Sagittal T2-weighted MR image shows the shieldlike appearance of forebrain structures and the monoventricle (arrowheads). A-Axial T2-weighted MR image shows partial fusing (arrowheads) of the thalami (T) and the large monoventricle posteriorly Holoprosencephaly spectrum disorder in a newborn.Dr Ahmed Esawy
  68. 68. Sagittal T1-weighted image shows hypoplastic cerebellar hemisphere (arrow), small brainstem and a large posterior CSF space. There is also a prominent CSF space anterior to the pons. Corpus callosum is thin and splenium absent Chiari III Dr Ahmed Esawy
  69. 69. Holoprosencephaly/ aqueductal stenosis • The key is in the appearance of the thalami and third ventricle: holoprosencephaly exhibits fused thalami and an absent third ventricle,while aqueductal stenosis will show splayed thalami and a dilated third ventricle Dr Ahmed Esawy
  70. 70. Left frontal intraparenchymal hematoma in a newborn with increasing thrombocytopenia T1 Spontaneous Intracranial Hematoma Dr Ahmed Esawy
  71. 71. Spontaneous intracranial hematoma in a 2-month-old infant with an inherited thrombophilic disorder. Dr Ahmed Esawy
  72. 72. Temporal lobe cysts and fetal alcohol syndrome Parasagittal T1- T2-bitemporal intraparenchymal cysts (arrows). FLAIR Dr Ahmed Esawy
  73. 73. Temporal lobe cysts and fetal alcohol syndrome MRS Dr Ahmed Esawy
  74. 74. Inflammatory and infectious intracranial cysts • 20-brain abscess • 21-cysticercosis • 22-hydatid cyst. • 23-amoebic abscess Dr Ahmed Esawy
  75. 75. Brain Abscess Dr Ahmed Esawy
  76. 76. Brain abscess.. poorly defined area of posterior parietal brain edema (arrows). Early cerebritis may not outline a focal mass clearly Dr Ahmed Esawy
  77. 77. Brain abscess. a poorly defined pattern of mass effect and low attenuation in the left temporal lobe. Of early cerebritis Dr Ahmed Esawy
  78. 78. Brain abscess. An area of ring like enhancement (yellow arrow) is noted within a much larger pattern of edema (white arrow). The central core of the abscess (black arrow) does not enhance (central necrosis) Dr Ahmed Esawy
  79. 79. temporal lobe abscess, extracranial, subdural, and intracerebral abscesses Dr Ahmed Esawy
  80. 80. Brain abscess. depressed skull fracture. The left parietal cranial injury an abscess of the subgaleal space (SGA) the epidural space (EDA) the left cerebral hemisphere (CA). Dr Ahmed Esawy
  81. 81. Brain abscess. Axial T1 +C ,T2-weighted MRI in a patient with a right frontal abscess. Dr Ahmed Esawy
  82. 82. The right frontal lobe of the brain is shifted across the midline (double arrow) by an intracranial abscess (single black arrow) that has extended upward from the medial right orbit and medial ethmoid air cells (curved dotted arrow). T1-contras Brain abscess T1-contras the enhancement within the right ethmoid sinuses from which the infection arose. The medial superior right maxillary sinus has been destroyed (yellow arrow). T1-contras An abscess is noted within the medial inferior right orbit. The right maxillary sinus (double white arrows) contains infected secretions and mucusDr Ahmed Esawy
  83. 83. Brain abscess. (FLAIR) MRI in a patient with abscess of the cerebellar vermis (black arrow). T2- MRI abscess of the midline cerebellum. the large area of increased signal, both within the abscess and within the surrounding cerebellum (black arrow). Dr Ahmed Esawy
  84. 84. Brain abscess. T1-enhanced central zone of enhancement within the abscess, with a zone of decreased brightness (edema, white arrow). Brain abscess. T1enhanced enhanced mass within the right medial cerebellum (yellow arrow). The thick- walled cystic mass was opened. Dr Ahmed Esawy
  85. 85. CEREBRAL ABSCESS ON DW MRI On trace DWI abscesses are typically hyperintense, indicating decreased diffusion of water. – This is secondary to increased viscosity of pus which contains, in addition to cellular debris and bacteria, large molecules such as fibrinogen, which bind water molecules and add to the effect of restricted diffusion. – This can be confirmed with an apparent diffusion coefficient (ADC) map where abscesses are of low signal ,markedly reduced ADCDr Ahmed Esawy
  86. 86. Diffusion-weighted Imaging ADC maps are of great value in distinguishing neoplasms in ADC maps is more often have facilitated diffusion, Dr Ahmed Esawy
  87. 87. CEREBRAL THALAMIC ABSCESS ON MRI Post-Gd T1WI: WI2T DWI Dr Ahmed Esawy
  88. 88. Left and right frontal abscesses: 35-year-old male. DWI ADCWI2TWI1T Dr Ahmed Esawy
  89. 89. Pyogenic Abscess T2 T1 T1/Gd DWI bright on DWI Dr Ahmed Esawy
  90. 90. Abscess (purulent) ADC decreased dark on ADC mapDr Ahmed Esawy
  91. 91. 7. 8. DD : tumour central hypointensity on diffusion-weighted image and hyperintensity on ADC map, consistent with the diagnosis of tumor. Dr Ahmed Esawy
  92. 92. 7. 8. DD : tumour Central hypointensity is seen on the diffusion-weighted image and hyperintensity on the ADC map, consistent with the diagnosis of tumor. Dr Ahmed Esawy
  93. 93. Brain abscess primary and secondary (daughter Fluid and necrotic tissue (bright area) . edema surrounds the abscess cavities (black arrows). surrounding the abscess does not enhance (white arrows). DWI T1/Gd Dr Ahmed Esawy
  94. 94. Brain abscess (FLAIR) left occipital-parietal brain abscess. Dr Ahmed Esawy
  95. 95. MRI Brain abscess T1/Gd T2 well-defined hypointense capsule DWI Dr Ahmed Esawy
  96. 96. MR Spectroscopy • .Typical MR spectroscopic features of brain abscesses include • elevated peaks of amino acid, lactate, alanine, acetate, pyruvate, and succinate • absent signals of NAA, creatine, and choline. Dr Ahmed Esawy
  97. 97. MR spectroscopy • shed light on which organism is responsible for the abscess • because the presence of anaerobic bacteria tends to cause elevated acetate and succinate peaks. Dr Ahmed Esawy
  98. 98. DD : NEOPLASM • Elevation of choline and absence of signal from a variety of amino acids, acetate and succinate favours neoplastic process Dr Ahmed Esawy
  99. 99. Dr Ahmed Esawy
  100. 100. Dr Ahmed Esawy
  101. 101. necrotic or cystic neoplasmsPyogenic brain abscesses Elevated choline , decrease NAA elevated peaks of amino acid, lactate, alanine, acetate, pyruvate, and succinate absent signals of NAA, creatine, and choline MRS facilitate diffusion dark restricted diffusion bright DW Bright on ADC map The walls of necrotic or cystic tumors have a lower ADC value than of an abscess markedly reduced ADC maps.ADC wall of necrotic or cystic neoplasms tends to have higher rTBV capsule of an abscess tends to have lower rTBV MR PERFUSION Dr Ahmed Esawy
  102. 102. Signal volume MR spectra of abscess Short-echo MRS shows depression of the NAA, choline (Cho) and creatine (Cr) as well as elevation of the amino acid, lactate (Lac), acetate and succinate.Dr Ahmed Esawy
  103. 103. T2 T1+C Single voxel MRS peaks representing alanine, lactate and amino acids DW hyperintense signal in centre ADC decrease signal in centre Brain abscess Dr Ahmed Esawy
  104. 104. brain abscess Dr Ahmed Esawy
  105. 105. Brain abscess in a 28-week gestation preterm newborn well-defined cystic structure with low- level echoes (arrowheads) in the left posterior parietal region abscess has ring enhancement (arrowheads).Dr Ahmed Esawy
  106. 106. cysticercosis Dr Ahmed Esawy
  107. 107. Cystercercus cellulosae - (3-20 mm) regular round thin walled cyst, produces only mild inflammation larva in cyst Dr Ahmed Esawy
  108. 108. Calcification in cysticercosis • Calcification in burned out residues of cysticercosis scattered throughout the brain in later stagesDr Ahmed Esawy
  109. 109. NEUROCYSTICERCOSIS Multiple neurocysticercosis cysts of various sizes. Some contain visible scolices (arrows). MR image shows T1 innumerable tiny low-signal-intensity neurocyticercosis cysts in brain parenchyma and subarachnoid spaces. Most contain small “dot” that represents the scolex (arrows Dr Ahmed Esawy
  110. 110. Intraparenchymal cysticercal cyst Scolex within each cyst Dr Ahmed Esawy
  111. 111. Differential Diagnosis • abscess (T2-hypointense rim ( • Tuberculosis (profoundly hypointense on T2 ,meningitis) • toxoplasmosis • neoplasm primary or metastatic • enlarged PVSs same appearance as CSF at all MR sequences and do not enhance) • NEUROCYSTICERCOSIS characteristic “cyst with dot” appearance . Dr Ahmed Esawy
  112. 112. multiloculated amebic abscess partially cystic mixed-signal-intensity subcortical mass (arrow)T1. some enhancement around complex cystic mass (arrow)T1+CONTRASTDr Ahmed Esawy
  113. 113. Differential Diagnosis • Complex conglomerated parasitic cysts of any origin may mimic primary or metastatic brain tumor . Dr Ahmed Esawy
  114. 114. hydatid cyst CT Unilocular cyst CSF density No edema no enhancement ± calcification MRI low signal T1 , high signal T2Dr Ahmed Esawy
  115. 115. hydatid cyst T1+C T1 T2 Dr Ahmed Esawy
  116. 116. HYDATID CYSTS • 5 year child very large nonenhancing cystic mass without surrounding edema (arrows). Dr Ahmed Esawy
  117. 117. Differential Diagnosis • arachnoid cyst • epidermoid cyst • neurocysticercosis Dr Ahmed Esawy
  118. 118. Tuberculous abscesses T1- multiple scattered ring-enhancing lesions Dr Ahmed Esawy
  119. 119. MRS • Tuberculous abscesses typically have high lipid and lactate peaks. • These abscesses have no peaks for amino acids (leucine, isoleucine, and valine) at 0.9 ppm, succinate at 2.41 ppm, acetate at 1.92 ppm, and alanine at 1.48 ppm, • in contrast to pyogenic abscesses, which have peaks for all these metabolites. Dr Ahmed Esawy
  120. 120. VASCULAR CYSTIC INTRACRANIAL LESION Dr Ahmed Esawy
  121. 121. VASCULAR • 24-Aneurysm • 25-Parenchymal Perianeurysmal Cystic Changes in the Brain • 26-Vein of Galen malformation Dr Ahmed Esawy
  122. 122. Vein of Galen malformations (VOGMs) • The aneurysm of the vein of Galen represents a rare intracranial arteriovenous malformation Dr Ahmed Esawy
  123. 123. CT scan in a 3 month old child with vein of Galen malformation a: Plain axial CT scan of the brain showing a rim of calcification located along the wall of the venous sac Dr Ahmed Esawy
  124. 124. Fetal MRI imaging of aneurysm of vein of Galen Dr Ahmed Esawy
  125. 125. CT scan with contrast medium. Note the enlarged lateral ventricles and the large well-defined globular mass in the pineal region. Contrast enhancementDr Ahmed Esawy
  126. 126. MRI; midline sagittal projection. T1-weighted image shows the spheroidal lesion with a signal void that is typical of a high flow arteriovenous malformation. The aneurysm causes a mass-efect on the aqueductus of Silvius, the posterior part of the third ventricle and the splenium of the corpus callosum.Dr Ahmed Esawy
  127. 127. MRI of a thrombosed vein of Galen mlaformation: : Plain T2 weighted sagittal scan of the brain revealing the characteristic location of the lesion Plain T1 weighted axial scan of the brain revealing the presence of thrombus at various st ages within the venous sac Dr Ahmed Esawy
  128. 128. Lateral MR venogram Vein of Galen malformation. T1- The dilated vein of Galen communicates with a persistent falcine sinus (arrow). pericallosal branches (P). Dr Ahmed Esawy
  129. 129. vein of Galen malformation neonate Transcranial color Doppler ultrasonography aneurysmal dilatation of the median prosencephalic vein of Markowski (black arrows). Dr Ahmed Esawy
  130. 130. Two year old Vein of Galen malformation. Dr Ahmed Esawy
  131. 131. Plain radiograph of the skull showing calcification of the wall of the venous sac of a vein of Galen malformation Dr Ahmed Esawy
  132. 132. Differential diagnosis midline cystic cerebral lesions • Arachnoid cysts • Porencephalic cysts • Choroid plexus cysts • Choroid papilloma • Intracranial teratomas • Congenital dural arteriovenous fistula Dr Ahmed Esawy
  133. 133. Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  134. 134. large (2.0-cm- diameter) right posterior cerebral artery aneurysm (arrow) with an adjacent cluster of various sized cysts (arrowheads). Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  135. 135. T2- perianeurysmal cysts in the left basal ganglia (arrowhead). Coronal T1+C aneurysm of the left internal carotid artery Several small cysts (arrowheads) are seen superior to the aneurysm(arrow) Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  136. 136. • T1 enhanced multiple small cysts (arrowheads) around the large (1.9-cm-diameter) aneurysm (arrow) of the right posterior cerebral artery. Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  137. 137. right anterior cerebral artery aneurysm (arrow) as hyperintense. The adjacent cyst (arrowhead) is unilocular and irregular in shape Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  138. 138. • CT scan shows a giant (4.0-cm-diameter) aneurysm (arrow) with prominent thrombosis and calcifications. Perianeurysmal cyst (arrowhead) and edema are depicted in the left frontal lobe. Parenchymal Perianeurysmal Cystic Changes in the Brain Dr Ahmed Esawy
  139. 139. blood within an arachnoid cyst at the tip of the left temporal lobe with a degree of ventricular dilatation Posterior communicating artery aneurysm presenting with haemorrhage into an arachnoid cyst Dr Ahmed Esawy
  140. 140. Nonneoplastic & noninflammatory intracranial cysts Dr Ahmed Esawy
  141. 141. andNonneoplastic cystsinflammatory-non • 37-colloid cysts • 38-Rathke’s cleft cysts, • 39-neuroepithelial cysts • 40-neuroenteric cysts • 41-pineal cysts. • 42-Choriod plexus cyst • 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain • 44-Trigonal cyst • 45-Interhemispheric cyst • 46-Dorsal cyst • 47-Ependymal cysts • 48-Enlarged VRS • 49-Cystic trapped 4th ventricle • 50-Diverticulation of 3rd , lateral ventricleDr Ahmed Esawy
  142. 142. Colloid cystColloid cyst Dr Ahmed Esawy
  143. 143. • MRI appearance • : variable signals depending on the contents T1 hyperintense or hypo intense T2 hyperintense or hypo intense Colloid cystColloid cyst Dr Ahmed Esawy
  144. 144. colloid cysts Dr Ahmed Esawy
  145. 145. Colloid cyst Characteristic site anterior 3rd ventricle Characteristic contents dense viscid mucoid material (old blood, cholesterol crystals, CSF,various ions) • CT: hyper dense midline lesion no enhancement Dr Ahmed Esawy
  146. 146. Colloid cyst Unenhanced CT. There is a dense, rounded mass in the region of the foramen of Monro causing enlargement of the lateral ventricles, and indenting the anterior aspect of the third ventricle.Dr Ahmed Esawy
  147. 147. COLLOID CYSTS • Transverse nonenhanced CT scan shows classic hyperattenuated colloid cyst at foramen of Monro (arrow (Dr Ahmed Esawy
  148. 148. Differential Diagnosis • CSF flow artifact (MR pseudocyst( • neurocysticus cyst may occur at the foramen of Monro. • Neoplasms such as subependymoma or choroid plexus papilloma Dr Ahmed Esawy
  149. 149. Rathke cleft cyst T2 smoothly marginated cystic mass (arrows) within and projecting above the pituitary gland. The cyst appears slightly hyperintense relative to gray matter on both T1-weighting (B) and T2-weighting (A). There is no contrast enhancement of its contents or margins T1 -c Dr Ahmed Esawy
  150. 150. RATHKE CLEFT CYSTS • Sagittal postcontrast • cyst has moderately high protein content and is isointense with brain, not CSF. Location is typical for a Rathke cleft cyst ,Dr Ahmed Esawy
  151. 151. Differential Diagnosis • Craniopharyngioma • cystic pituitary adenoma • nonneoplastic cysts Unlike Rathke cleft cysts Dr Ahmed Esawy
  152. 152. • Enhanced CT scan demonstrates an extra-axial cystic lesion over the left frontal convexity with two small nodules of rim calcification. There is no contrast enhancement of the cyst. Intracranial laterally based supratentorial neurenteric cyst Dr Ahmed Esawy
  153. 153. Choroids Plexus Cysts • Choroid plexus cysts are usually a few millimeters in diameter and are commonly located within the body of the plexus. Choroid plexus cysts may be limited within the body itself or may protrude into the ventricular cavity . Isolated choroid plexus cysts occur in about 1% of all pregnancies. Dr Ahmed Esawy
  154. 154. Choroids Plexus Cyst Dr Ahmed Esawy
  155. 155. Choroids Plexus Cyst Dr Ahmed Esawy
  156. 156. Multiple small choroid plexus cysts in a normal infant.. Dr Ahmed Esawy
  157. 157. CHOROID PLEXUS CYSTS Transverse contrast-enhanced T1-weighted bilateral CPCs with peripheral and nodular enhancement (arrows). Most CPCs are actually degenerative xanthogranulomas. Dr Ahmed Esawy
  158. 158. Differential Diagnosis • ependymal cyst do not enhance • villous hyperplasia of the choroid plexus enhances strongly and relatively uniformly. • Disturbed CSF flow and pseudolesions • Colloid cysts should not be mistaken for CPCs Dr Ahmed Esawy
  159. 159. T2 multiple bizarre-appearing cysts (arrows) in centrum semiovale and subcortical white matter of both hemispheres. The cysts vary in size and focally expand but otherwise spare the overlying cortex. T1+C nonenhancing enlarged PVSs in right basal ganglia Enlarged PVSs, Virchow-Robin spaces isointense to CSF at all pulse sequences Dr Ahmed Esawy
  160. 160. Differential Diagnosis • multiple lacunar infarcts • cystic neoplasms • infectious cysts (Neurocysticercosis cysts ) . Dr Ahmed Esawy
  161. 161. EPENDYMAL CYSTS • FLAIR MR • enlarged atrium of the left lateral ventricle (open arrow). Signal intensity was isointense to CSF at all pulse sequences. Note lateral displacement of choroid plexus (solid arrow) Dr Ahmed Esawy
  162. 162. Differential Diagnosis • CPC • arachnoid cyst • neurocysticercosis • asymmetric ventricles Dr Ahmed Esawy
  163. 163. Neuroepithelial (ependymal) cyst Intraventricular cysts 5-year-old male T2- T2- cyst within the right lateral ventricle with signal intensity isointense to CSF in all pulse sequences T2- Dr Ahmed Esawy
  164. 164. NEUROGLIAL CYSTS • neuroglial cyst (straight arrow) adjacent to left temporal horn . • isointense to CSF at all sequences . • neuroglial cyst in the choroid fissure (arrow . AXIAL FLAIR MR Dr Ahmed Esawy
  165. 165. Differential Diagnosis • enlarged PVS • infectious cyst • porencephalic cyst • arachnoid cyst Dr Ahmed Esawy
  166. 166. PINEAL CYSTS postmortem slice Sagittal contrast-enhanced T1 classic benign pineal cyst (straight arrows) with rim enhancement and mild mass effect (note slight compression, displacement of tectal plate [curved arrow).(] Dr Ahmed Esawy
  167. 167. Differential Diagnosis • benign pineal parenchymal neoplasm called a pineocytoma . • Other cysts in the quadrigeminal cistern that mimic pineal cysts include arachnoid cysts (no calcium) and, rarely,epidermoid cysts Dr Ahmed Esawy
  168. 168. NEURENTERIC CYSTS • Sagittal T1 small well-delineated ovoid mass in front of pontomedullary junction (arrow). Mass is hyperintense compared to CSF. Location and configuration are typical for a neurenteric cyst Dr Ahmed Esawy
  169. 169. Differential Diagnosis • epidermoid cyst • arachnoid cyst • endodermal cysts (Rathke and colloid) Dr Ahmed Esawy
  170. 170. The Virchow–Robin spaces (VRS) • perivascular compartments surrounding small blood vessels as they penetrate the brain parenchyma • Three types IMAGING CHARACTER • Characteristic site • The content of the cysts is CSF-like. • The adjacent brain parenchyma has normal signal intensity. • No solid components are identified. • no enhancement • Enlarged cause pressure changes Dr Ahmed Esawy
  171. 171. Virchow-Robin Spaces TYPE 1 Proton density FALIR DWI ADC Bilateral type I VR spaces in a 6-year-old boy anterior perforated substance on both sides The signal intensity of the surrounding brain parenchyma is normal Dr Ahmed Esawy
  172. 172. Virchow-Robin Spaces TYPE 11 Proton density FALIR Type II VR spaces in a 73-year-old woman hyperintense foci in the centrum semiovale in both hemispheres The signal intensity of the surrounding brain parenchyma is normal FLAIR show old lacunar infarctions(arrow) Dr Ahmed Esawy
  173. 173. Type II dilated VR spaces in a 6-year-old boy FALIRT2 punctate hyperintense areas around the occipital horns Dr Ahmed Esawy
  174. 174. Type III VR spaces in a 68-year-old man Proton density FALIR T2 multiple punctate hyperintense areas in the brainstem ON T2 hypointenese on FLAIR Dr Ahmed Esawy
  175. 175. Giant VR spaces in the mesencephalothalamic region in a 19-year-old man. T2 T1+C multicystic lesion in the mesencephalothalamic region Dr Ahmed Esawy
  176. 176. DIFFERENTIAL DIAGNOSIS of VRS • Lacunar infarction • Cystic periventricular leukomalacia • Ovoid MS lesion of the centrum semiovale • Parenchymal neurocysticercosis in the vesicular stage • Hurler syndrome (mucopolysaccharidosis type I) • Desmoplastic pilocytic astrocytoma • Arachnoid cyst in the perisellar cistern area • Neuroepithelial cyst of the thalamus • Choroidal fissure cyst Dr Ahmed Esawy
  177. 177. MR Imaging of CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain Dr Ahmed Esawy
  178. 178. T1 T2 Left choroidal fissure cyst (arrows) in 36- year-old man Dr Ahmed Esawy
  179. 179. T1 Right choroidal fissure cyst 31 y right temporal lobe lesion (arrowheads) Dr Ahmed Esawy
  180. 180. T2 T1 T1 Right choroidal fissure cyst 31 y right temporal lobe lesion (arrowheads) Dr Ahmed Esawy
  181. 181. • Left choroidal fissure cyst (arrows) • 13-year-old girl • cyst between mesial temporal lobe and brainstem is seen on T1 T2 Dr Ahmed Esawy
  182. 182. • Right choroidal fissure cyst in 74-year-old woman with cerebral atrophy • Large cyst (arrows) medial to temporal tip of lateral ventricle (arrowheads) , no enhancement of lesion. T1+C T1 Dr Ahmed Esawy
  183. 183. T2 Right choroidal fissure cyst (arrowheads) in 27-year-old man Dr Ahmed Esawy
  184. 184. Left juxtasylvian cyst in 49-year-old woman loop of middle cerebral artery (small curved arrow) indenting cyst (large arrow). No enhancment T2 T1+C Dr Ahmed Esawy
  185. 185. T2 T1 T1 Right juxtasylvian cyst (arrows) in 54-year-old man Note similarity in shape and location to Branch of middle cerebral artery indents Dr Ahmed Esawy
  186. 186. T2 T1 T1 Right thalamic multiseptated cyst (arrows) in 66-year-old woman isointensity of cyst with CSF. Dr Ahmed Esawy
  187. 187. Interhemispheric cysts associated with callosal agenesis Dr Ahmed Esawy
  188. 188. Dr Ahmed Esawy
  189. 189. The most important condition that must be distinguished from interhemispheric cysts is the alobar form of holoprosencephaly because to treat them as early as possible in order to prevent gross developmental deficits Dr Ahmed Esawy
  190. 190. Tumors and tumors like cysts intracranial Dr Ahmed Esawy
  191. 191. ARACHNIOD VERSUS EPIDERMIOD epidermiod Lower density than CSF May show calcifications invade structures CT LOWER THAN CSFMRI T1 HIGHER THAN CSFMRI T2 HIGH SIGNALFLAIR BRIGHT typical hyperintensity T2 shine (restricted diffusion) DIFFUSION DARK lower than that of CSF and equal to or higher than that of brain parenchyma ADC Away from midlline CPA , supra and parasellar region middle cranial fossa and cisterna magna LOCATION Dr Ahmed Esawy
  192. 192. T2 CT+no C CT+C EPIDERMIOD AT CPA Dr Ahmed Esawy
  193. 193. T2 T1+C DIFFUSION Epidermoid tumour Dr Ahmed Esawy
  194. 194. Epidermoid, brain. CT+no C , located in the middle cranial fossa with extension into the suprasellar cistern.. Dr Ahmed Esawy
  195. 195. Epidermoid, brain. T2T1+no C DIFFUSION FLAIR Dr Ahmed Esawy
  196. 196. epidermoid cysts Dr Ahmed Esawy
  197. 197. EPIDERMOID CYST diffusion-shows markedly restricted diffusion (arrows.( Dr Ahmed Esawy
  198. 198. T2WIT1WI DWI ADC End of images EPIDERMOID CYST B 1000 ADC Dr Ahmed Esawy
  199. 199. ARACHNIOD VERSUS EPIDERMIOD epidermiodarachniod Lower density than CSF May show calcifications invade structures CSF density No calcification,no enhancment displace structures CT LOWER THAN CSFLow signal like CSFMRI T1 HIGHER THAN CSFhigh signal like CSFMRI T2 HIGH SIGNALLow signal like CSFFLAIR BRIGHT typical hyperintensity T2 shine (restricted diffusion) DARK hypointensity (free diffusion) DIFFUSION DARK lower than that of CSF and equal to or higher than that of brain parenchyma BRIGHT marked hyperintensity like CSF ADC Away from midlline CPARetrocerebellar,CPA Dr Ahmed Esawy
  200. 200. Differential Diagnosis • arachnoid cyst. Arachnoid cysts are isointense to CSF at all sequences, including FLAIR. They displace rather than invade structures such as the epidermoid. Finally, arachnoid cysts do not restrict on diffusion-weighted image . • Dermoid cysts are typically located along the midline and resemble fat, not CSF . • Cystic neoplasms often enhance and do not resemble CSF . • Neurocysticercosis cysts often enhance and demonstrate surrounding edema or gliosis . Dr Ahmed Esawy
  201. 201. Dermoid cyst location Midline plane, posterior fossa, suprasellar area and Intraventricular MRI: high signal in T1 [ fat ] Dr Ahmed Esawy
  202. 202. CT: fat density ± calcification, no enhancement Dermoid cyst Dr Ahmed Esawy
  203. 203. Dermoid tumor 26-Y M cystic lesion is present in the right temporal lobe+ peripheral marginal calcification in the lesion partial marginal enhancement T1+C multiple small foci of hyperintense signal are present along the sulci of the right temporal lobe. These represent fat droplets in the subarachnoid space from the focal rupture of the dermoid tumor. T1+C T1+NO C Dr Ahmed Esawy
  204. 204. Rupture intraventricular or subarachnoid → fat /fluid level Dr Ahmed Esawy
  205. 205. Dermoid tumor. The high signal intensity areas in the subarachnoid space of the Sylvian fissures and ambient cisterns represent lipid material from the tumor that has contaminated the CSF Dr Ahmed Esawy
  206. 206. Suprasellar rupture dermoid tumours T1W Fat globules, which have spilled into the subarachnoid space, are seen as high signal foci in the left Sylvian fissure Dr Ahmed Esawy
  207. 207. posterior fossa lesion with posterior mural nodule Unusual Imaging Appearance of an Intracranial Dermoid Cyst Dr Ahmed Esawy
  208. 208. Ruptured dermoid cyst • mixed-signal-intensity lesion in the pineal region (straight arrow) with multiple hyperintense droplets scattered through the subarachnoid space (curved arrows). Moderate hydrocephalus is present .. T1+no C Dr Ahmed Esawy
  209. 209. Differential Diagnosis • Epidermoid (typically resemble CSF (not fat), lack dermal appendages, and are usually located off midline) • Craniopharyngioma (suprasellar, with a midline location, and demonstrate nodular calcification. craniopharyngiomas are strikingly hyperintense on T2 enhance strongly. • teratoma • lipoma . Dr Ahmed Esawy
  210. 210. CT +no C epidermiod tumour (inclusion cyst) of Quadrigeminal cistern Quadrigeminal cistern cyst Dr Ahmed Esawy
  211. 211. CT +C epidermiod tumour (inclusion cyst) of Quadrigeminal cistern displacment of choriod plexus and the body of lateral ventricle Dr Ahmed Esawy
  212. 212. MRI T1+C epidermiod tumour (inclusion cyst) of Quadrigeminal cistern Compression of quadrigeminal plate and cereberal aqueduct Dr Ahmed Esawy
  213. 213. MRI T2 Quadrigeminal cistern Dr Ahmed Esawy
  214. 214. Differential Diagnosis of Quadrigeminal cistern cyst • Arachniod • Teratoma • Cystic pineal tumour Dr Ahmed Esawy
  215. 215. craniopharyngioma Dr Ahmed Esawy
  216. 216. CT+C large suprasellar cyst with several nodular calcifications of varying size (arrow) in the wall of the cyst T1+C cystic intra-/suprasellar mass with strong contrast enhancement of the cyst wall (arrow). The cyst contents are isointense with gray matter, reflecting their high protein content. T2-strongly hyperintense homogeneous cyst contents. The well circumscribed cyst (arrow) displaces the anterior cerebral arteries anteriorly and the middle cerebral arteries bilaterally Craniopharyngioma in a child Dr Ahmed Esawy
  217. 217. Craniopharyngioma in an adult T2 T1+C Dr Ahmed Esawy
  218. 218. cystic astrocytoma Dr Ahmed Esawy
  219. 219. hemangioblastoma Dr Ahmed Esawy
  220. 220. postcontrast T1 facial schwannoma associated with large arachnoid cyst)(open arrow.( postcontrast T1 large pituitary macroadenoma with multiple cysts (arrows) surrounding the suprasellar component trapped PVSs NEOPLASM-ASSOCIATED BENIGN CYSTS Dr Ahmed Esawy
  221. 221. cystic metastasis NEOPLASM-ASSOCIATED BENIGN CYSTS Dr Ahmed Esawy
  222. 222. T1W post-contrast i dark DW bright on the ADC map Cystic metastasis from CA breast unrestricted diffusion in the center of the mass Dr Ahmed Esawy
  223. 223. large right cerebellopontine angle tumour with a medial cystic component. Cystic vestibular schawannoma T2W Dr Ahmed Esawy
  224. 224. Cystic astrocytoma Dr Ahmed Esawy
  225. 225. II- Magnetic resonance imaging: • MRI emerged as the imaging modality of choice for most intracranial abnormalities. This is especially true for lesions located in the posterior fossa, where the sensitivity of CT is limited by beam- hardening artifacts from the petrous bone. Dr Ahmed Esawy
  226. 226. • If metastases are to be excluded, heavily T1-weighted pre- and post-contrast images can be obtained. Intravenous contrast is a routine for tumor and infection investigation. Dr Ahmed Esawy
  227. 227. • A potential drawback of SE images is that they may not reliably show the internal architecture or morphology of cystic masses. If the solid portion does not enhances with contrast material, it difficult to determine whether the mass is simple cyst or a cyst with solid component. Dr Ahmed Esawy
  228. 228. • Fluid-attenuation inversion-recovery (FLAIR) MRI belongs to a family of inversion-recovery sequences, that generates heavily T2-weighted images with nulling/subtraction of the CSF sign and enable improved characterization of complex cystic masses. Dr Ahmed Esawy
  229. 229. Functional studies of cystic brain lesion Dr Ahmed Esawy
  230. 230. N-acetylaspartate (NAA) creatine-phosphocreatine(Cr) choline (Cho). amino acid, lactate, alanine, acetate, pyruvate, and succinate MR spectroscopy Dr Ahmed Esawy
  231. 231. primary cystic neoplasm versus metastases primary cystic neoplasm choline Cystic metastases where no choline resonance is seen Dr Ahmed Esawy
  232. 232. necrotic or cystic neoplasmsPyogenic brain abscesses Elevated choline , decrease NAA elevated peaks of amino acid, lactate, alanine, acetate, pyruvate, and succinate absent signals of NAA, creatine, and choline MRS facilitate diffusion dark restricted diffusion bright DW Bright on ADC map The walls of necrotic or cystic tumors have a lower ADC value than of an abscess markedly reduced ADC maps.ADC wall of necrotic or cystic neoplasms tends to have higher rTBV capsule of an abscess tends to have lower rTBV MR PERFUSION Dr Ahmed Esawy
  233. 233. CT and MR stereotactic biopsy: Solid contrast enhancing areas are preferred for biopsy rather than cystic, necrotic, or hemorrhagic tumor regions. Cystic brain lesion biopsy and treatment Dr Ahmed Esawy
  234. 234. Image guided therapy: CT and MRI have revolutionized the diagnosis and management of brain abscesses. If excisional neurosurgery is not immediately or otherwise indicated an attempt at abscess aspiration should be made usually guided by CT when the lesion is accessible. Also intraoperative imaging using MR allows for precise localization of the lesion and its relationship. Dr Ahmed Esawy
  235. 235. THANK YOU Dr Ahmed Esawy
  236. 236. THANK YOU Dr Ahmed Esawy

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