正常颅脑ct和mri影像表现英文版

CT AND MRI IMAGINGOF NORMAL BRAINNORMAL ANATOMY OF BRAIN Brain is separated from calvarium by three meninges-dura mater,arachnoid membrane and pia mater. Divided into supra tentorial and infra tentorial compartments containing:- Supratentorium: Cerebral hemispheresdiencephalon Infratentorium: Brain stem structures cerebellum Each cerebral hemisphere is further divided in to Frontal,Parietal,Temporal and Occipital lobes by fissures BRAIN ANATOMYSagittal surfaceLat vent GenuFornixPituitary gland Mid brainPonsMedullaCingulate gyrusQuadrigeminalcisternSpleniumColliculi4th ventCerebellumTSagittal surfacei. Pineal glandii. Sup.colliculiiii. Inf. Colliculiiv. Aqueduct of sylviusv. Midbrainvi. Cerebellumvii. 4th ventricleviii.Ponsix. Oculomotor nx. Inter thalamic Inferior surfaceInterhemispheric fissureTemporal lobeMammillary bodies Frontal lobeOlfactory tractOptic tractPit. stalkponsMedulla oblongataCerebellumVBrain stem structuresMid brain: divided into Cerebral peduncles and colliculi. Sup colliculi attached to med.Geniculate Axial sections-TopogramFor CT Axial sections are taken at an angle of10-13degree to the Canthomeatal lineFor MRI sections areparallel to the CT Brain contd Normal HU values in NCCT brain Gray matter:- +36-42 HU White matter:- +26-34 HU CSF:- +4-11HU Bone:- +200 to +1000 HU Calcification:- +100 to +220 HU Blood:-+56-80MRI Imaging Multiplanar modlity so sections can be taken in axial ,coronal and sagittal planes Slice thickness is same as CT imaging. Routinely applied sequences are T1 Weigheted spin echo T2 Weigheted spin echo Proton density images Anatomy of brain is better explained on T1W seq while pathologies are better studied on T2W and Proton density TISSUE CHARACTERISTICSSeq Parameters CSF Gray M WhiteM FatT1W short TR Hypo iso hyper hypershort TE T2W short TR hyper iso hypo iso / long TE hypoProton long TR iso Iso iso/hypo hyperdensity short TE blood vessels appear signal void in all the sequencescalcification and fibrous tissue appear hypointense in all sequences MRI Axial section above foramen magnumMaxillary sinusBasilar A.MedullaCerebellar hemisphereCisterna magnaTonsilsPetrous boneSphenoid sinusNasal cavityZygomatic CT Axial section above foramen magnumFrontal sinusSphenoid sinusTemporal lobeBasilar A.Mastoid cellsCerebellar hemisphereCisterna magnaMedullaOptic nervePituitarySphenoid boneTemporal boneCerebellar MRI Axial Section at 4th VentricleLensOptic nervePituitaryTemporal lobeMiddle cerebellar peduncle4th VentricleMedial rectusLateral rectusPonsPetrous temporal boneCerebellar CT Axial section at 4th ventricleFrontal sinusFrontal boneMid.cerebral ABasilar A.Pons4th ventcerebellumMid cerebellarpedunclePetrous boneTemporal hornAnt.cerebral a Sella turcicaVMRI Axial Se