BRAIN IMAGING CT & MRI

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

2 Patient Preparation Patient position Technique Scanogram [frontal, lateral] Scan intervals Orbito-meatal line: From External Canthus To Ext. Auditory meatus

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

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

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10 Post. Fossa level Basilar Art. Prepontine Cistern Ambean Cistern Pones Middle Cerbellar Peduncle 4 th Ventricle Cerebellar Hemispheres Vermis

11 Medulla Oblongata 4 th Ventricle Vallecula Cisterna Magna

12 Aqueduct of Sylvius Midbrain Cerebellar Folia Quadrigeminal Cistern

13 Quadrigeminal Cistern Occipital horn, Calc. pineal body Ventricular anatomy

14 External Capsule Internal Capsule Basal Ganglia Head of caudate Lentiform nucleus Insula Thalamus 3 rd Ventricle Quadrigeminal Cistern

15 Quadrigeminal Cistern

16 Pineal body Inter. Cerebr. veins Vein of Galen Retro-thalamic Cistern Vellum interpositum Retro-thalamic Cistern Sup.cerebellar Cistern Pineal body Inter. Cerebr. veins Quadrigeminal Cistern Retro-thalamic Cistern

17 Septum Pleusedum Body of caudate

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

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20 Corona Radiata

21 Corona Radiata (deep) Centrum Semi-ovale (superf.)

22 CT Vascular Anatomy MCA A. Communicating A. ACA (a2) ACA (a1) ICA P. Comm. A. PCA Basilar A.

23 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

24 Subarachnoid Cisterns Cavum velum interpositum Quadrigeminal Cistern Interpeduncular Cistern Prepontine Cistern Cisterna Magna Suprasellar Cistern

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26 CLOSED MAGNET

27 OPEN MAGNET

28 OPEN MAGNET

29 EXTERMITY MAGNET

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

32 BRAIN MRI 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 ]

33 BRAIN MRI PROTOCOL

34 T1 T2 FLAIR

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

37 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

38 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..

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

40 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] ++

41 Gadolinium DTPA 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

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44 Trigeminal n.

45 Gyrus rectus Optic tract,mamillary body, cerebral peduncle, substantia negra

46 Quadrigeminal Cistern Interpeduncular Cistern Temporal Horn Amegdala, hippocampus, superior vermis Hippocampal Formation (epilepsy)

47 Hippocampal region

48 Mesial temporal sclerosis

49 Choroidal fissure, Hippocampal tail, Vein of Galen (Retrothalamic Cistern)

50 Verchaw Robben s spaces (dilated perivascular spaces) Seen in T1WIs Not seen in FLAIR No clinical correlation Anatomic sites

51 Grey matter : Whitish White matter: Greyish

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

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

55 MRI Vascular Anatomy

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58 Thank you سبحانك اللهم و بحمدك نشهد ان ال اله اال انت نستغفرك و نتوب اليك

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