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Imaging of the CNS. Contents. Diagnostic tools Anatomical localization: Brain Diseases: - Infection - Tumor - Trauma - Stroke - Cord compression. Tools. Plain film CT MR Angiography. Plain radiography. 5 densities. Air Fat Soft tissue (water,muscles,etc)
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Contents • Diagnostic tools • Anatomical localization: Brain • Diseases: - Infection - Tumor - Trauma - Stroke - Cord compression
Tools • Plain film • CT • MR • Angiography
5 densities • Air • Fat • Soft tissue (water,muscles,etc) • Bone, calcification • Metallic
Adventage - Convenience - Safe - Fast - Availability Indication Fracture skull Increase ICP Intrasellar mass Osteolytic/ osteoblastic lesion Calcifying pathology Advantage & I/C
PA • Petrous pyramid อยู่ภายในกระบอกตา • Frontal bone and parietal bone • Frontal sinus • Nasal cavity • Mandible • Roof of orbits
Lateral skull • Cranial vault • Suture : coronal and lambdoid • Occipital bone • Sellar turcica • Floor of cranial fossa • Clivus • Nasopharyngeal soft tissue • Sphenoid air sinus • lateral of calvarium • lateral of mandible • Cervical spine 1st-2nd
Lateral Outer table Suture Diploic space Sellar turcica Inner table External occipital protuberance Sphenoid air sinus
Caldwell view • Orbital wall • Frontal and ethmoid sinuses • Mandible
Caldwell view Ethmoid sinus Maxillary sinus Orbital wall
Towne’s view • Occipital bone • Lamdoid suture • Foramen magnum • Petrous ridge และ mastoid sinuses • Zygomotic arch • Mandible ส่วน head, neck และ rami
Waters’ view • Facial bone • Orbital roof • Maxillary, frontal and ethmoid sinus
Waters’ view Frontal sinus Orbital wall Maxillary sinus
Paranasal sinuses Water’ s view Caldwellview
Paranasalsinusitis Air-fluid level at both maxillary and both frontal sinuses
Nasal bone Fx nasal bone Outer table destruction : histiocytosis X
Normal sella turcica Anterior clinoid Posteriorclinoid Dorsum sellae Floor of sella
ICP “loss of dorsum sella sign”
Pituitary tumor “Double floor sign”
Large intrasella mass 1 3 2 “ballooning sella”
CT scan Advantage - Axial imaging - Reconstruction, reformatted to coronal, sagittal planes - Providing contrast- noncontrast study - Differentiation tissues by densities(HU) - Additional software: CTA, CTV, 3D, CTP etc.
Indication • Trauma case • 1st line imaging of Stroke • Infection • Tumor • Intracranial calcification • C/I: pregnancy, contrast enhancement injection: limited in patient with azotemia
Attenuation number of CT (HU)Hounsfield Units • CSF = 0-20 HU. • Gray matter = 40 HU. • White matter = 23-46 H • Clot blood & hematoma = 70-100 HU. • Calcification and bone = +100-200 HU. • Fat = -100-200 HU. • Air = >- 600 HU. • Density ของ lesion ใดๆจะดูเทียบกับ gray matter
Normal CT brain Gray matter White matter Basal ganglia cerebellum Thalamus
Normal CT brain : Ventricular system Temporal horn Frontal horn Lateral ventricle 4th ventricle Occipital horn
Physiologic calcification • Pineal gland • Age > 10 year • Size < 10 mm. • Basal ganglia • Middle aged • Young aged : hypoxia or abnormal serum Calcium • Choroid plexus • Dura • Falx cerebri • Calcification of diaphragmatic sellae
Enhancement by contrast media • Abnormal blood brain barrier (BBB) • Identify vascular and dural structures • Differential pathology by pattern of enhancement
25-YEAR-OLD NORMOTENSIVE MAN WITH UNEXPLAINED ICH LT ICA ANGIOGRAM – AVM
Indication • Gold standard for vascular imaging ( ex. Aneurysm, AVM) • Arterial / venous • Risk=1% • C/I : azotemia, pregnancy
MRI • Magnet Field : 0.5-3Tesla • Pulse sequences : Spin Echo ( SE) • Parameters : T1 : T2 : TR : TE
Advantage MRI • Multiplanar imaging ( axial/coronal/sagittal/any planar) • No radiation • No bony artifact • Safer contrast agent (Gadolinium) • Best for analysis:posterior fossa and leptomeningeal lesions
MRI- three planars Axial CoronalSagittal
Contraindications • Implantable Cardiac defibrillator • Pace Maker • wt. > 136 Kg • Severe Claustrophobia • Pregnancy (+/- ) • Cochlear Implant • Aneurysm Clips • Ferromagnetic eye prosthesis / F.B.
BRAIN : GM : WM Muscles Nerve :dorsal root :ventral CSF Fat Pituitary: anterior posterior T1WT2W intermediate high high low intermediate intermediate intermediate intermediate intermediate low high high low Intermediate intermediate high high SIGNAL INTENSITY(SI) Tissue
MRI of brain tumor T2W T1W-GD T1W