Normal & abnormal radiology of brain part ii

Brain tumors, CNS tumors

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

2. Basics of Radiology of Brain

3. Role of Imaging Radiological diagnosis: tumor vs. non-tumor, determine a certain subtype, grading. Take a biopsy to get histopathogical diagnosis. Detect squeal: parenchyma compromise, mass effects Treatment planning: extent of tumor >>> resection Localization for therapeutic modalities: RT, stereotaxic surgery: tumor vs peritumoral edema. Diagnosis Treatment Evaluation of response: residual tumor vs treatment necrosis Monitoring Tumor recurrence Surveillance

4. Imaging of Brain Tumours Primarily of historical interest since the onset of CT in 1974. Rarely necessary. Useful in demonstrating calcification, erosion, or hyperostosis. Most widely used for diagnosis of brain tumors. 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. Skull X-rays CT Preferred for follow-up of most 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

5. Computed Tomography (CT)

6. 1- Density (CT number) Structure/ Tissue Hounsfield units Air -1000 to -600 Fat -100 to -60 Water CSF +8 to 18 White matter +30 to 41 Gray matter +37 to 41 Acute blood +50 to 100 Calcification +140 to 200 Bone +600 to 2000 HYPER HYPO ISO

7. 1- Density (CT number)

8. (A) Hyperdense 5- Acute blood 6- Ocular lens 4- Calcifications 2- Bone 1-Metal (bullets streak artifact) Density>White/Gray matter 3- Contrast (dye) 1- Density (CT number)

9. (B) Isodense Density=White/Gray matter White matter Gray matter (cerebral cortex) Gray matter (basal ganglia) White matter is less dense than gray matter and therefore: white matter is darker than gray matter High attenuation Low attenuation Bright Dark 1- Density (CT number)

10. (C) Hyodense Density<White/Gray matter CSF (water) Fat Air 1- Density (CT number)

11. Manipulation of image gray scale using image’s CT numbers * No additional or new information produced 2- Window

12. * Soft tissues * Brain * Dense structures - Bone Manipulation allows customization of visibility 2- Window

13. Window width (WW) Window level (WL) Range of CT number’s imaged Center or midpoint of CT # range WIDTH BONE MATERIALS 3095 -1000 LEVEL LEVEL WIDTH SOFT TISSUE WATER FAT AIR 2- Window

14. Pixels outside of window displayed as Black or White 255 -1000 1000HU CT Value Window level Grey value Window width 2- Window

15. >200 151-200 101-150 51-100 1-50 (-49)-0 (-99)-(-50) (-149)-(-100) (-199)-(-150) <(-199) 3000 -1000 1000 2000 Window: 400 Level: 0 2- Window

16. Small Window Width 3000 -1000 Window: 400 Level: 0 Short gray scale Small block of CT #’s assigned gray levels Small transition zone of white to black 2- Window

17. 3000 -1000 Window: 400 Level: 0 Used to display soft tissues within structures containing different tissues of similar densities. Level centered near average CT # of organ of interest . Small Window Width 2- Window

18. Large Window Width 1000 Window: 2000 Level: 0 -1000 Long gray scale Large block of CT #’s assigned gray levels Large transition zone of white to black 2- Window

19. Large Window Width 1000 Window: 2000 Level: 0 -1000 Used where large latitude required Used to simultaneously display tissues of greatly differing attenuation. 2- Window

20. Example 1 WL =0 WW = 200 All pixels with CT #’s > 0 +(200/2) = 100: White All pixels with CT #’s < 0 -(200/2) = -100: Black 100 -100 200 2- Window

21. WL = 40 WW = 200 All pixels with CT #’s > 40 + (200/2) = 140: White All pixels with CT #’s < 40 - (200/2) = -60: Black 140 -60 200 40 Example 2 2- Window

22. WL = 0 WW = 400 All pixels with CT #’s > 0 + (400/2) = 200: White All pixels with CT #’s < 0 - (400/2) = -200: Black 200 -200 400 Example 3 2- Window

23. Larger Window Means Obscuring Small Differences in Tissue Attenuation One gray shade encompasses larger range of CT #’s 200 -200 -100 100 20 - 40 40 - 80 20 40 WW=200 WW=400 Range 2- Window

24. As WW increases Contrast decreases Latitude (range of CT #’s imaged) increases As WW decreases Contrast increases Latitude decreases Clinical goal: Largest available contrast at the latitude required by study Window Width & Contrast 2- Window

25. Large window width Different structures more likely to have same gray shade Narrow window width Gray shade differences more likely visible between structures Very narrow window width Small differences in attenuation seen as black & white Window Width & Image Contrast 2- Window

26. Common window settings used when interpreting a normal CT Brain scan: A : Brain window (WW 80, WL 40); B : Bone window (WW 3000, WL 500); C : Soft tissue window (WW 260, WL 80); D : Stroke window (WW 40, WL 40). 2- Window

27. 3- Multiplanar Reconstruction (MPR) Creates non-axial images from stack of contiguous transverse axial scans stack contains 3 dimensional CT data pixels new cut identified & selected from each axial image without scanning

28. Coronal Sagittal Paraxial Oblique Cuts 3- Multiplanar Reconstruction (MPR)

29. Coronal Reconstruction Stack of Axial Slices Reconstructed Slice 3- Multiplanar Reconstruction (MPR)

30. Stack of Axial Slices Reconstructed Slice Coronal Reconstruction 3- Multiplanar Reconstruction (MPR)

31. Stack of Axial Slices Reconstructed Slice Sagittal Reconstruction 3- Multiplanar Reconstruction (MPR)

32. Stack of Axial Slices Reconstructed Slice Oblique Reconstruction 3- Multiplanar Reconstruction (MPR)

33. Enables visualization of specific structures relative to surrounding structures Aids in determining / localizing true extent of Lesions Fractures Bone fragments Foreign bodies Reformatting Advantages 3- Multiplanar Reconstruction (MPR)

34. Reformatting Disadvantages Image quality can be poorer than axial images if plane thickness > pixel size Affects blurring Less problem in spiral scanning 3- Multiplanar Reconstruction (MPR)

35. Reformatting Disadvantages More prone to motion / breathing artifacts Reformatted image taken from many slices Reformatted image represents longer time interval than single slice 3- Multiplanar Reconstruction (MPR)

36. 4- Contrast Physiological contrast enhancement Pituitary gland & its stalk. Dural structures. Arteries and veins especially deep veins and sinuses. Choroid plexus

37. Magnetic Resonance Imaging (MRI)

38. Advantage of MRI No ionizing radiation & no short/long-term effects demonstrated Variable thickness, any plane Better contrast resolution & tissue discrimination Various sequences to play with to characterize the abnormal tissue Many details without I.V contrast No allergy (as with Iodine) Can be used in renal impairment Pregnancy is not a contraindication

39. Caveats of MRI Very sensitive to body movements Produces lots of noise during examination (The noise is due to the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise) Time taking Difficult to perform in claustrophobic pts Expensive Less sensitive for SAH Less sensitive for detection of calcification Relatively insensitive to bony cortical abnormalities Peoples with metallic implants can not be scanned

40. Principle of MRI 1- The Patient Is Placed In A Magnetic Field. 2- A Radio Frequency (RF) Wave Is Sent In. 3- The Radio Frequency Wave Is Turned Off. 4- The Patient Emits A Signal. 5- Which Is Received And Used For Reconstruction Of the Picture

41. MRI Planes

42. MRI Planes

43. MRI Planes

44. MRI Sequences CSF flow studies Diffusion weighted sequences (DWI): apparent diffusion coefficient (ADC), b-values, diffusion tensor imaging (DTI) Echo-planar pulse sequences Fat-suppressed imaging sequences Gradient echo sequences: in-phase and out-of-phase, spoiled gradient echo MRI, steady-state free precession Inversion recovery sequences: short tau inversion recovery (STIR), fluid attenuation inversion recovery (FLAIR), turbo inversion recovery magnitude (TIRM), double inversion recovery (DIR) Metal artifact reduction sequence (MARS) Perfusion-weighted imaging (PWI): dynamic susceptibility contrast (DSC) MR perfusion, dynamic contrast enhanced (DCE) MR perfusion, arterial spin labeling (ASL) MR perfusion, cerebral blood flow (CBF), cerebral blood volume (CBV), k-trans, mean transit time (MTT), negative enhancement integral (NEI), time to peak (TTP) Saturation recovery sequences Spin echo sequences: T1WI, T2WI, fast spin echo (FSE), proton density weighted image Spiral pulse sequences Susceptibility-weighted imaging (SWI) MR angiography (and venography): contrast-enhanced, non-contrast-enhanced MRA (phase contrast imaging, time of flight angiography, TRICKS) MR spectroscopy (MRS)

45. Important MRI Sequences Conventional sequences: T1WI, T2WI, FLAIR, Post contrast T1WI DWI. PWI. DTI. SWI. GRE. MRS. MRA. MRV.

46. Short TE (echo time). Short TR (repetition time). Better anatomical details. Fluid: dark. Gray matter: gray. White matter: white. T1WI sequence Charactertics Most of pathologies are dark (hypointense) in T1 Bright (hyperintense) in T1 (see below)

47. T2WI sequence Long TE (echo time). Long TR (repetition time). Better pathological details. Fluid: bright. Gray matter: relatively bright. White matter: dark. Charactertics Most of pathologies are bright (hyperintense) in T2 Dark (hypointense) in T2 (see below)

48. FLAIR* sequence Long TE (echo time). Long TR (repetition time). Better pathological details. Fluid: dark (free water suppression). Gray matter: relatively bright. White matter: dark. Charactertics Most of pathologies are bright (hyperintense) in FLAIR Good for lesions near ventricles of sulci * Fluid Attenuated Inversion Recovery Sequences i.e. T2 except fluid inversion

49. T1WI vs T2WI vs FLAIR T1WI T2WI FLAIR TR Short Long Long TE Short Long Long CSF Low High Low Fat High Low Medium Brain Low High High Edema Low High High

50. Contrast Principles of contrast uptake are same in CT and MRI i.e. enhancement of CNS pathology due to disruption of blood brain barrier. Unlike contrast agents used in CT which are directly visualized those used in MRI produce local alteration in the magnetic environment that influences the MRI signal intensity. It is the effect of proton relaxation that appears on MRI and not the contrast itself. Gadolinium is a paramagnetic agent responsible for T1 shortening of MR images Shortening of T1 leads to higher signal intensity on a T1WI hence areas of gad accumulation appear bright on T1 Though it also shortens T2, effect is less as compared to T1 Standard dose of Gad is 0.1 mmol/kg

51. Physiological contrast enhancement Pituitary gland & its stalk. Median eminence Dural structures. Arteries and veins especially deep veins and sinuses. Choroid plexus Contrast

52. Post contrast T1WI sequence Intravascular (vascular) enhancement may reflect neovascularity, vasodilatation or hyperemia, shortened transit time or shunting. Interstitial enhancement indicates abnormal BBB. Enhancement Medulloblastoma

53. DWI* sequence Normally water protons have ability to diffuse extracellularly & loose signal. In most tumors there is no restricted diffusion even in necrotic or cystic components >>> This results in a normal low signal on DWI . Not Restricted * Diffusion Weighted Image High intensity on DWI indicates restriction of ability of water protons to diffuse extracellularly (e.g. Cytotoxic edema, abscess, acute ischemia). Restricted

54. DWI* sequence

55. ADC* sequence * Apparent Diffusion Coefficient Calculated by software. Areas of restricted diffusion are dark True restricted diffusion, the region of increased DWI signal will demonstrate low signal on ADC. T2 shine-through, ADC will be normal or high signal. DWI ADC ADC map ROI

56. PWI* sequence Perfusion imaging can play important role in determining malignancy grade of CNS tumor. Perfusion depends on vascularity of tumor & is not dependent on breakdown of blood-brain barrier. Amount of perfusion shows a better correlation with grade of malignancy of tumor than amount of contrast enhancement. * Perfusion Weighted Image Cerebral Blood Volume (CBV) Cerebral blood flow (CBF) Map Time To Peak (TTP) relative Cerebral Blood Volume (rCBV) Mean Transit Time (MTT)

57. 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. Left, Fluid-attenuated inversion recovery (FLAIR) image demonstrates an area of increased signal intensity in 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. Low Grade High Grade PWI* sequence

58. GRE* sequence * Gradient Recalled Echo FLAIR T1 GRE Generation of gradient echoes as a consequence of echo refocusing. The initial slice selective RF pulse applied to the tissue is less than 90° (typically rotation angles are between 10° and 90°). Immediately after this RF pulse, the spins begin to dephase.

59. SWI* sequence * Susceptibility weighted imaging Originally called BOLD venographic imaging MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo (GRE) pulse sequence to acquire images. Glioblastoma multiforme (a) T1WI+C (b, c) SWI

60. MRS* * Magnetic Resonance Spectroscopy Non-invasive physiological imaging of brain that measure relative of various tissue metabolites. Used to complement MRI in characterization of various tissues 4 3 2 1 ppm NAA Glx Cr Cho ml Differentiate Neoplasms from Nonneoplastic Brain Masses Radiation Necrosis versus Recurrent Tumor

61. Resonating Normal function Change Lipids 0.9 & 1.3 Cell membrane  High grade neoplasia Metabolite Lactate 1.3 Anaerobic glycolysis  Neoplasia, necrosis Alanine 1.5 Amino acid  Meningioma Acetate 1.9 Anabolic precursor  Neoplasia NAA 2 Neural marker  Neoplasia, necrosis Creatine 3.03 Cell energy marker  Neoplasia Choline 3.2 Marker of cell memb . turnover  Neoplasia MRS

62. Normal NAA/Cr 2.0 Metabolite Ratios NAA/Cho 1.6 Cho/Cr 1.2 Cho/NAA 0.8 Myo /NAA 0.5 Abnormal <1.6 <1.2 >1.5 >0.9 >0.8 Cho/Cr Myo /NAA Cho/NAA NAA/Cr Lipid/lactate Indicate Malignancy MRS

63. MRA* * Magnetic Resonance Angiography

64. MRV* * Magnetic Resonance Venography

65. Normal Radiology of Brain Mohammed Fathy Bayomy Assistant Lecturer of Clinical Oncology Zagazig University

66. Structures

67. 1- Skull Bones and Sutures Bone windows Bones of the skull are assessed viewing the 'bone window' CT images Note that no detail of brain structure is provided on these window settings

68. 1- Skull Bones and Sutures Bone windows Bones of the skull are assessed viewing the 'bone window' CT images Note that no detail of brain structure is provided on these window settings

69. 2- Cranial Fossae

70. 2- Cranial Fossae

71. 3- Meninges & Dural folds

72. 3- Meninges & Dural folds

73. Tentorium cerebelli 3- Meninges & Dural folds

74. Tentorium cerebelli 3- Meninges & Dural folds

75. Tentorium cerebelli 3- Meninges & Dural folds

76. Tentorium cerebelli 3- Meninges & Dural folds

77. Falx cerebri 3- Meninges & Dural folds

78. Falx cerebri 3- Meninges & Dural folds

79. Falx and tentorium 3- Meninges & Dural folds

80. Falx and tentorium 3- Meninges & Dural folds

81. 4- CSF spaces The brain is surrounded by cerebrospinal fluid (CSF) within Subarachnoid spaces , Cisterns . CSF is also found centrally within the ventricles .

82. 4- CSF spaces 1- Subarachnoid spaces, 2- Cisterns, 3- Ventricles. Together form the 'CSF spaces', also known as the 'extra-axial spaces'.

83. CSF is of lower density than the grey or white matter of the brain, and therefore appears darker on CT images. An appreciation of the normal appearances of the CSF spaces is required to allow assessment of brain volume. 4- CSF spaces

84. 4- CSF spaces

85. Lateral Ventricles 4- CSF spaces

86. Lateral Ventricles 4- CSF spaces

87. Third Ventricle 4- CSF spaces

88. Third Ventricle 4- CSF spaces

89. Fourth Ventricle 4- CSF spaces

90. Fourth Ventricle 4- CSF spaces

91. Subarachnoid spaces 4- CSF spaces

92. Subarachnoid spaces 4- CSF spaces

93. Subarachnoid spaces 4- CSF spaces

94. Subarachnoid spaces 4- CSF spaces

95. Subarachnoid spaces 4- CSF spaces

96. Subarachnoid spaces 4- CSF spaces

97. Cisterns 4- CSF spaces Pentagon Cistern Basal Cistern Perimesencephalic cistern

98. Cisterns 4- CSF spaces

99. Cisterns 4- CSF spaces

100. Cisterns 4- CSF spaces Sylvian cistern Lamina terminalis cistern Interpeduncular cistern Pentagon Cisterns

101. Cisterns 4- CSF spaces Perimesencephalic Cisterns

102. Cisterns 4- CSF spaces Pericallosal cistern

103. Cisterns 4- CSF spaces Lamina terminalis cistern

104. Cisterns 4- CSF spaces Suprasellar (Chiasmatic) cistern

105. Cisterns 4- CSF spaces Interpeduncular Cistern

106. Cisterns 4- CSF spaces Pontine Cistern

107. Cisterns 4- CSF spaces Crual Cistern

108. Cisterns 4- CSF spaces Ambient Cistern

109. Cisterns 4- CSF spaces Sylvian Cistern

110. Cisterns 4- CSF spaces Supracerebellar Cistern

111. Cisterns 4- CSF spaces Quadrigeminal Cistern * *

112. Cisterns 4- CSF spaces Cisterna Magna (Cerebellomedullary cistern) *

113. Grey matter vs white matter 5- Brain parenchyma

114. Grey matter vs white matter 5- Brain parenchyma

115. Brain lobes 5- Brain parenchyma

116. Brain lobes 5- Brain parenchyma

117. Brain lobes 5- Brain parenchyma

118. Brain lobes 5- Brain parenchyma

119. Lobes vs regions 5- Brain parenchyma CT does not clearly show the anatomical borders of the lobes of the brain. For this reason radiologists often refer to 'regions', such as the 'parietal region' or 'temporal region', rather than lobes. If more than one adjacent region needs to be described then conjoined terms can be used such as ' temporo -parietal region' or ' parieto -occipital region'

120. Lobes vs regions 5- Brain parenchyma

121. Lobes vs regions 5- Brain parenchyma

122. Cerebral cortex 6- Gray Matter structures

123. Cerebral cortex 6- Gray Matter structures

124. Insula 6- Gray Matter structures

125. Insula 6- Gray Matter structures

126. Basal ganglia and thalamus 6- Gray Matter structures

127. Basal ganglia and thalamus 6- Gray Matter structures

128. Basal ganglia and thalamus 6- Gray Matter structures

129. Internal Capsules & Corpus Callosum 6- White Matter structures

130. Internal Capsules & Corpus Callosum 6- White Matter structures

131. Corpus Callosum 6- White Matter structures

132. Corpus Callosum 6- White Matter structures

133. Corpus Callosum & Corona Radiata 6- White Matter structures Corpus callosum - clinical significance Malignant lesions of the brain can grow from one brain hemisphere to the other via the corpus callosum Elsewhere the falx acts as a relative barrier to direct invasion

134. Corpus Callosum & Corona Radiata 6- White Matter structures Corpus callosum - clinical significance Malignant lesions of the brain can grow from one brain hemisphere to the other via the corpus callosum Elsewhere the falx acts as a relative barrier to direct invasion

135. 7- Posterior Fossa

136. 7- Posterior Fossa

137. 7- Posterior Fossa

138. 7- Posterior Fossa

139. 8- Calcified Structures Calcified choroid plexus

140. 8- Calcified Structures Calcified choroid plexus

141. 8- Calcified Structures Calcified pineal gland

142. 8- Calcified Structures Calcified pineal gland

143. 8- Calcified Structures Calcified basal ganglia

144. 8- Calcified Structures Calcified basal ganglia

145. 8- Calcified Structures Calcified falx cerebri

146. 8- Calcified Structures Calcified falx cerebri

147. Normal CT Atlas

148. Level of above Corpus Callosum Axial

149. Level of above Corpus Callosum CT-Axial

150. Level of above Corpus Callosum CT-Axial

151. Level of above Corpus Callosum CT-Axial

152. Level of above Corpus Callosum CT-Axial

153. Level of above Corpus Callosum CT-Axial

154. Level of above Corpus Callosum CT-Axial

155. Level of above Corpus Callosum CT-Axial

156. Level of above Corpus Callosum CT-Axial

157. Level of above Corpus Callosum CT-Axial

158. Level of above Corpus Callosum CT-Axial

159. Level of above Corpus Callosum CT-Axial

160. Level of above Corpus Callosum CT-Axial

161. Level of above Corpus Callosum CT-Axial

162. Level of above Corpus Callosum CT-Axial

163. Level of above Corpus Callosum CT-Axial

164. Level of above Corpus Callosum CT-Axial

165. Level of body Corpus Callosum CT-Axial

166. Level of Mid-ventricle CT-Axial

167. Level of Mid-ventricle CT-Axial

168. Level of Thalamus CT-Axial

169. Level of Thalamus CT-Axial

170. Level of Thalamus CT-Axial

171. Level of Thalamus CT-Axial

172. Level of Thalamus CT-Axial

173. Level of Third ventricle CT-Axial

174. Level of Third ventricle CT-Axial

175. Level of Third ventricle CT-Axial

176. Level of Third ventricle CT-Axial

177. Level of Midbrain CT-Axial

178. Level of Midbrain CT-Axial

179. Level of Midbrain CT-Axial

180. Level of Pons CT-Axial

181. Level of Pons CT-Axial

182. Level of Pons CT-Axial

183. Level of Pons CT-Axial

184. Level of Pons CT-Axial

185. Level of Medulla CT-Axial

186. Level of Medulla CT-Axial External Auditory canal Fourth Ventricle

187. Level of Medulla CT-Axial

188. Level of Medulla CT-Axial

189. Level of Medulla CT-Axial

190. Level of foramen magnum CT-Axial

191. Level of foramen magnum CT-Axial

192. Normal MRI Atlas

193. Level of above Corpus Callosum T1WI – Axial Frontal Lobe Parietal Lobe

194. Level of above Corpus Callosum T2WI – Axial Frontal Lobe Parietal Lobe

195. Level of Body of Corpus Callosum T1WI – Axial Body of corpus callosum Frontal Lobe Parietal Lobe

196. Level of Body of Corpus Callosum T2WI – Axial Body of corpus callosum Frontal Lobe Parietal Lobe

197. Level of Mid-ventricle T1WI – Axial Genu of corpus callosum Splenium of corpus callosum Choroid plexus éin body of lateral ventricle Septum Pallicidum

198. Level of Mid-ventricle T2WI – Axial Genu of corpus callosum Splenium of corpus callosum Choroid plexus éin body of lateral ventricle Septum Pallicidum

199. Level of Thalamus T1WI – Axial Frontal horn Frontal Lobe Caudate nucleus Putamen Internal capsule Thalamus Choroid plexus éin occipital horn Temporal Lobe Superior Sagittal Sinus

200. Level of Thalamus T2WI – Axial Frontal horn Frontal Lobe Caudate nucleus Putamen Internal capsule Thalamus Choroid plexus éin occipital horn Temporal Lobe Superior Sagittal Sinus Retrothalamic Cistern Supracerebellar Cistern

201. Level of Third Ventricle T1WI – Axial Frontal Lobe Sylvian fissure Insular Cortex Temporal Lobe Occipital Lobe Third ventricle Occipital horn Supracerebellar cistern

202. Level of Third Ventricle T2WI – Axial Frontal Lobe Sylvian fissure Insular Cortex Temporal Lobe Occipital Lobe Third ventricle Occipital horn Sup. cerebellar cistern

203. Level of Midbrain T1WI – Axial Orbit Optic chiasma Infundibulum Suprasellar cistern Midbrain Aqueduct of Sylvius Ambient cistern Quadrigeminal cistern Cerebellum Sup. cerebellar cistern Hippocampus

204. Level of Midbrain T2WI – Axial Orbit Optic chiasma Infundibulum Suprasellar cistern Midbrain Ambient cistern Quadrigeminal cistern Cerebellum Sup. cerebellar cistern Temporal horn Hippocampus

205. Level of Pons Vermis IV Ventricle Pons Basilar A. ICA Cavernous sins Middle cerebellar peduncle Internal Auditory canal Temporal lobe T1WI – Axial

206. Level of Pons Vermis IV Ventricle Pons Basilar A. ICA Cavernous sins Middle cerebellar peduncle Temporal lobe T2WI – Axial

207. Level of Medulla T1WI – Axial Maxillary Sinus Flow void of vertebral A. Medulla oblongata Cerebellum

208. Level of Medulla T2WI – Axial Flow void of vertebral A. Medulla oblongata Cerebellum

209. Level of Forman Magnum T1WI – Axial Cisterna Magna Cervical cord Mandible Nasopharynx Maxillary Sinus

210. Appendix