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Download ภาพนิ่ง 1 - Walailak University
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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) • Bone, calcification • Metallic Advantage & I/C Adventage - Convenience - Safe - Fast - Availability Indication - Fracture skull - Increase ICP - Intrasellar mass - Osteolytic/ osteoblastic lesion - Calcifying pathology View and positioning 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 Suture Outer table Diploic space Sellar turcica Inner table External occipital protuberance Sphenoid air sinus Caldwell view • Orbital wall • Frontal and ethmoid sinuses • Mandible Maxillary sinus Caldwell view Ethmoid sinus Orbital wall Towne’s view • • • • Occipital bone Lamdoid suture Foramen magnum Petrous ridge และ mastoid sinuses • Zygomotic arch • Mandible ส่ วน 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 Caldwell view Paranasal sinusitis Air-fluid level at both maxillary and both frontal sinuses Linear fracture skull right parietal bone Nasal bone Fx nasal bone Outer table destruction : histiocytosis X Normal sella turcica Anterior clinoid Posterior clinoid 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 : Pituitary tumour CECT CT scan CT /Spiral CT/ MDCT 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 DSA ANGIOGRAM – MCA BIFURCATION ANEURYSM MCA aneurysm 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 machine MRI • Magnet Field : 0.5-3Tesla • Pulse sequences : Spin Echo ( SE) • Parameters : T1 : T2 : TR : TE Advantage MRI 1. Multiplanar imaging ( axial/coronal/sagittal/any planar) 1. No radiation 2. No bony artifact 3. Safer contrast agent (Gadolinium) 4. Best for analysis: posterior fossa and leptomeningeal lesions MRI- three planars Axial Coronal Sagittal Contraindications • • • • • • • • Implantable Cardiac defibrillator Pace Maker wt. > 136 Kg Severe Claustrophobia Pregnancy (+/- ) Cochlear Implant Aneurysm Clips Ferromagnetic eye prosthesis / F.B. SIGNAL INTENSITY(SI) T1W intermediate BRAIN : GM : WM high Muscles intermediate Nerve :dorsal root intermediate :ventral intermediate CSF low Fat high Pituitary: anterior Intermediate posterior high Tissue • • • • • • T2W high low intermediate intermediate high low intermediate high T1WI T2WI MRI of brain tumor T1W T2W T1W-GD
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