This document summarizes key aspects of CT and MRI brain imaging techniques. It discusses patient preparation, scan protocols, contrast administration, and interpreting images. CT provides anatomical details while MRI allows for tissue characterization and multiplanar imaging without bone artifacts. MRI protocols include T1, T2, and FLAIR weighted sequences which appear different based on proton behavior. Interpreting signals relies on identifying normal structures and understanding common signal intensities on different sequences. Anatomical details and pathology can be clearly visualized.

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

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

20. Corona Radiata

21. Corona Radiata

22. CT Vascular Anatomy

23. 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
BRAIN MRI

26. CLOSED MAGNET

27. CLOSED MAGNET

28. OPEN MAGNET

29. OPEN MAGNET

30. EXTERMITY MAGNET

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

33. • T1 WIs (TR< 800 msec TE 20 msec)
• T2 WIs (TR> 1000 msec TE> 80 msec)
• PD WIs (TR> 1000 msec TE= 20 msec)
• T1 WIs [CSF BLACK ]
• T2 WIs [CSF BRIGHT ]
• FLAIR WIs [ CSF BLACK ]
BRAIN MRI

34. BRAIN MRI
PROTOCOL

35. T1 T2 FLAIR

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

38. 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
How to interpret MR Images ?!

39. 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……..

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

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

42. 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

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

47. Amegdala , hippocampus, superior vermis

48. Hippocampal region

49. Mesial temporal
sclerosis

50. Choroidal fissure , Hippocampal tail , Vein of Galen

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

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

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

56. MRI Vascular Anatomy

60. ‫اليك‬‫نتوب‬‫و‬‫نستغفرك‬‫انت‬‫اال‬‫اله‬‫ال‬‫ان‬‫نشهد‬‫بحمدك‬‫و‬ ‫اللهم‬‫سبحانك‬
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