1. BRAIN IMAGING CT & MRI Mamdouh Mahfouz MD Professor of Radiology Cairo University

2. Patient Preparation Patient position Technique
Scanogram [frontal, lateral]
Scan intervals

3. Patient Preparation Fasting 4- 6 hours Contrast material
[ Urographin, Telebrix,…] 1-2 ml/kg
Anesthesia
Children, Uncooperative patients

4. Contrast material administration
Traumatic cases, CVS
Cold cases [headache, epilepsy, signs of increased ICT, …] NO
YES

11. Vallecula

13. Ventricular anatomy

15. Quadrigeminal Cistern

16. Quadrigeminal Cistern
Vellum interpositum
Retro-thalamic Cistern
Retro-thalamic Cistern
Sup.cerebellar Cistern
Quadrigeminal Cistern

18. F T T O F F F F P T P P P O O O

20. Corona Radiata

21. Corona Radiata

22. CT Vascular Anatomy

23. Strong magnetic field and Radiofrequency (RF) coils
BRAIN MRI
Strong magnetic field and Radiofrequency (RF) coils
Imaging are created by the motion of hydrogen protons in response to the applied radiofrequency
Multiplanar imaging [ axial, sagittal, coronal ]
Any MR examination should include T1 and T2 Weighted images

26. CLOSED MAGNET

27. CLOSED MAGNET

28. OPEN MAGNET

29. OPEN MAGNET

30. EXTERMITY MAGNET

32. O H N K Na H H H P C H H H H H H

33. Water represents 75-80% of the human body
H2O H H O

34. Hydrogen Atom [proton]
MR Imaging
Magnet
Radio frequency coil H H H H H H H H
Hydrogen Atom [proton]

35. Hydrogen Atom [proton]
MR Imaging H H H H H H H H
Hydrogen Atom [proton]

36. MR Imaging H H H H H H
SIGNAL H H
Hydrogen Proton

37. H SIGNAL Adequate Mobile DARK, HYPOINTENSE LOW INTERMEDIATE
GRAY, ISOINTENSE
BRIGHT, HYPERINTENSE
HIGH

38. The creation of MR images depend on
Hydrogen
Proton
Amount
Motion

39. H Amount Motion Minimal hydrogen [air] → no signal
Non mobile hydrogen [cortical bone] → no signal
Fast hydrogen [flowing blood] → no signal

40. Non mobile hydrogen
Cortical bone
Mature fibrous tissue
Calcifications

41. Minimal hydrogen
AIR
Lung
Sinuses
Intestine

42. characteristic signal
Fluid T2 T1
Fat

43. characteristic signal
Fluid T1 T2
Fat

44. characteristic signal
Air
Cortical bone
Fibrous tissue
Calcifications
Flowing blood T2

45. Each structure [lesion] in the human body has a characteristic signal
Subacute blood

46. T1 T2
Fat T1 T2
Blood

47. MR advantages Multiplanar imaging Tissue characterization
No bone artifacts
Shows blood vessels without contrast

48. BRAIN MRI T1 WIs (TR< 800 msec TE 20 msec)
PD WIs (TR> 1000 msec TE= 20 msec)
T1 WIs [CSF BLACK ]
T2 WIs [CSF BRIGHT ]
FLAIR WIs [ CSF BLACK ]

49. BRAIN MRI
PROTOCOL

50. T1 T2
FLAIR

52. Signal intensity Low signal lesion = hypointense = dark
High signal lesion = hyperintense = bright
Intermediate signal = isointense = Gray

53. How to interpret MR Images ?!
Identify T1 weighted images (CSF low signal) and T2 Weighted images (CSF high signal)
Assess the signal intensity of the structure or lesion in both T1 and T2 weighted images
Follow the well known common signal behavior

54. T1[low signal] T2[low signal] [Non mobile protons]
Cortical bone
Mature fibrous tissue ( ligaments and tendons)
Calcifications ( physiological, pathological)
Flowing blood in the vessels ( fast moving protons) (signal void)
Air in the sinuses, lungs,…( minimal hydrogen protons)
Others……..

55. T1[High signal] T2[High signal]
Subacute blood [met Hb]
Others….
T1[High signal] T2[Low signal]
Fat ( subcutaneous fat, dermoid cyst,…)
Others….

56. T1[Low signal] T2[High signal]
Any structure or lesion not listed before
Fluids ( CSF, urine, pleural effusion, ascites.,…)
Edema and infarctions
Most of tumors
Contrast injection [ Gd- DTPA] ++

57. Gadolinium – DTPA 0.1 – 0.2 mmol/kg body weight
Only T1 weighted images are obtained after Gd- DTPA injection
Differentiate SOLs
Assess activity of some lesions like MS
Assess post operative tumour recurrence

61. Gyrus rectus
Optic tract ,mamillary body, cerebral peduncle, substantia negra

62. Amegdala , hippocampus, superior vermis

63. Hippocampal region

64. Mesial temporal sclerosis

65. Choroidal fissure , Hippocampal tail , Vein of Galen

66. Verchaw – Robben’s spaces
Seen in T1WIs
Not seen in FLAIR
No clinical correlation
Anatomic sites

68. Value of sagittal images
Anatomic localization [Lobes]
Corpus callosum delineation
Cranio cervical junction
Evaluation of the venous sinuses
Pituitary gland

71. Value of coronal images
Pituitary gland, chiasm, hypothalamus
Hippocampal region
Skull base and posterior fossa
Trigeminal nerve
Vascular anatomy

72. MRI Vascular Anatomy

73. Normal Venous Anatomy MR angiogram Angiogram TO= torcular herophili
TH= thalamostriate
R=basal vein of rosenthal
L = vein of labbe
SPS = superior petrosal sinus
I = ISS
S= straight sinus
MR angiogram
Angiogram
Normal Venous Anatomy

78. Thank you
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