中枢神经系统影像学表现.ppt

Central nervous system,General view,1.conventional x-ray examination:2.modern modalities:computer appears around 1970s.CT in 1969.MRI(magnetic resonance imaging).DSA(digital subtraction angiography),Conventional x-ray examination:.Plain film.Head and spinal column film(Including front and lateral view),Examination Modalityies,Front view,Lateral view,.Angiography internal carotid arteriography vertebral arteriography.Myelography,2.DSA(digital subtraction angiography)IADSA(intrarterial DSA)IVDSA(intravenous DSA),DSA internal carotid arteriography vertebral arteriography,Aneurysm Embolization,3.CT(computed tomography).Plain scan.Contrast enhanced scan.Post contrast examination scan,Scout view,Axial view Coronal view,Plain scan Contrast-enhanced scan,Scout view Axial view,4.MRI(magnetic resonance imaging).Head MRI.Spinal MRI,Brain MRI T1WI T2WI,Normal brain axial views(only two main planes),Pons脑桥,cerebellum小脑,vermis小脑蚓部,Suprasellar cistern鞍上池,Posterior clinoid process后床突,Ambient cistern环池,Anterior horn of lateral ventricle,Head/caput of caudate nucleus,thalamus,lenticular nucleus(put-amen and globus pallidus),External capsule,Posterior limb of internal capsule,Anterior limb of internal capsule,Calcification of pineal body,Genu of corpus callosum,Genu of internal capsule,Trigone of lateral ventricle,Abnormal appearance of head CT,1.Change of density hyperdensity hypodensity isodensity2.Enhancement no enhancement homogeneous enhancement inhomogeneous enhancement annular enhancement,3.Morphology change note:location,size,number,border,middle structure,surrounding tissue,bone structure.,Common Diseases of CNS,Tumor of CNS.primary:glioma,meningioma,pituitary adenoma,craniopharyngioma,acoustic neuroma,pinealoma.secondary:metastatic tumorGlioma(the commonest intracranial tumor)4 types:.astrocytoma(commonest).oligodendroglioma.ependymoma.medulloblastoma,Astrocytoma(incidence:45 percent of intracranial tumor)Grading Kernohans:I(benign)to IV(malignant).WHO-3-tiered system low grade or benign,anaplastic,glioblastoma multiform The new grading scale correlated with kernohans grading:WHO kernohans low grade or benign-grade I,anaplastic-grade glioblastoma multiform-grade IV,Appearance.location:white matter:adult(cerebral hemisphere-supratentorial),children(cerebellum-infratentorial).CT appearance:*low or benign(astrocytoma-grade I,):1.On plain scan:.low ill-defined density lesion(18-24HU)(necrosis,cyst formation,hemorrhage,calcification).Edema(rare).Slight mass effect 2.On contrast enhanced CT,.astrocytoma(grade I)-no or slight enhancement,.astrocytoma(grade II)-enhancement pattern resembles to grade I(no enhancement)or III,IV(strong inhomogenous enhancement)*astrocytoma(grade III,IV)1.Plain scan.well-defined mixed-density lesion(cyst formation,necrosis and hemorrhage calcification).perifocal edema.Severe mass effect 2.On enhancement CT usually strong enhanced inhomogenously,Astrocytoma,plain scan contrast-enhanced scan,meningioma,General view:Arachnoid granulation Linked with dural matterLocation:Parasagittal region,falx,convexity,olfactory groove,tubercle sellae,sphenoid ridge.The first three are the most common places.,CT appearance Typical findings 1.On plain scan.Well-defined and homogenous high density(74.4%)mass abuting dura matter at an obtuse angle calcification(10-20%),hemorrhage,necrosis and cyst formation(usual).surrounding edema(61.3%).mass effect.thickening or destruction of adjacent bone 2.On contrast enhaced CT.strong and homogenous enhancement,Meningioma on plain scan(petrosa),Meningioma on contrast enanced scan(petrosa),Atypical appearance(learn yourself)1.Multiple lesions 2.Resemble to intracerebral tumor 3.Inhomogenous density mass 4.Cystic component dominated mass 5.Total low density with inhomogenous contrast 6.Ossified meningioma 7.Hemorrhage inside the tumor 8.Ring enhancement 9.Nodules on the inner surface of the cyst wall,Metastatic tumor of brain,General view:,CT findings 1.Plain scan.Mutiple nodes or masses with various density on the white and gray matter junction(hemorrhage,necrosis,cystic component,calcification).Striking edema around tumor.Mass effect 2.Contrast enhanced CT.Various enhancement patterns(ring,nodular enhancement),Metastatic tumor in right parietal and occipital lobe on plain scan,Metastatic tumor in right parietal and occipital lobe on CT plain scan,Metastatic tumor in right parietal and occipital lobe on contrast enhanced CT,Metastatic tumor in right parietal and occipital lobe on contrast-enhanced CT,Craniocerebral Trauma,.CT is excellent for detecting detecting and elvaluating the trauma and its prognosis.Usually the craniocerebral trauma can classified into 3 types,and they may appear coincidentally:trauma of scalp(haematoma,laceration)galea aponeurotica trauma of skull trauma of intracranial tissues,Epidural Haematoma(EDH)Pathology Accelerating movement skull fracture-MMA and or its branches tear or rupture-Venous sinus,diploic vein,CT findingsAcute EDH.Biconvex or lentiformshaped shadow with uniform high density(sometimes mixed density)under inner table of the skull.Adjacent brain tissue is compressed and flattened and EDH has the clear and sharp surface with nearby brain Does not crossing the suture With slight occupying effect(adjoining tissues,middle line structures,ventricles,cisterns)Accompanying with skull fracture,Plain scan:acute epidural haematoma,Plain scan:acute epidural haematoma,Plain scan:acute epidural haematoma,Subdural hematoma（sdh）,PathologyDecelerating movement vein or arteriole or bridging vein on the opposite site of the trauma/bridging vein(contre-coup injury,the hedge position)-accompanying with brain contusion and laceration,CT findings Acute SDH crescent homogenous high density(sometimes hypo-or iso-desity due to anemia or CSF mix,sometimes mixed density because of CSF mixing and serum extrusion during clot contraction,)under inner table of the skull.It can spread diffusely even over the affected hemisphere.Cross the suture severe mass effect(lateral ventricles and adjacent brain compression/displacement,shift of midline structure)Accompanying with brain laceration and contusion,or intracerebral haematoma,Plain scan:acute subdural haematoma,Plain scan:acute subdural haematoma,Subacute and chronic SDH(learn yourself after class)ON plain scan crescent or biconvex-shaped shadow with hyper-，hypo-，iso-or mixed density.(sometimes it presents you with upper part low density and lower part high-density owe to clot precipitation.)calcification.can cross the suture obvious mass effect(lateral ventricles and adjacent brain compression/displacement,shift of midline structure)on contrast-ehanced CT enhanced blood vessels of brain surface is displaced from the inner table of skull,contrasted SDHs capsule(capillary-rich membrane),Plain scan:subacute subdural haematoma,Contrast-enhanced scan:subacute subdural haematoma,subarachnoid hemorrhage(SAH),General view traumatic spontaneous(aneurysm),Pathology.non-bacterial meningitis(oxyhemoglobin).cerebral spasm brain edema,encephalomalacia,.Hydrocephalus(arachnoid granulation block),CT appearance.increased density in sulci and CSF cisterns(interhemispheric cistern).Cerebral infarction.Hydrocephalus(late stage),Acute subarachnoid hemorrhage,cerebral contusion and laceration,General view.Cerebral contusion refers to edema,swelling,small hemorrhage of the brain cortex and deep brain.Cerebral laceration means the blood vessel tear in brain and pia mater.,Pathlogy.early stage(within several days)hemorrhage,swelling and edema,necrosis.middle stage(several daysseveral weeks)liquefaction of necrosis areas and replaced by scar tissues.Small lesion is substituted by gliocytes and granulation tissue for large one.late stage(several weeks several years)small lesion is repaired by scar tissues,large lesion is replaced by cyst accompanying with atrophy of adjacent brain and meninges thickening/adhesion,CT findings1.Focal and ill-defined low density.Sometimes very wide.It recovers to normal brain density after several days or several weeks.If it becomes lower that means ncephalomalacia is present.Cyst formation will occur in the late stage.2.Small hemorrhage,.vary in size and shape.Absorb from 3-7 days after damage,and becomes low density 1-2months later 3.Mass effect(cerebral ventricles and adjacent brain compression/displacement,shift of midline structure,brain hernia)4.Sometimes Accompanying with subarachnoid hematoma,intracranial or extrocranial hematoma,skull fracture.5.Late stage,local brain atrophy occurs(suli becomes wide,brain cisterns enlarges),Acute brain contusion and laceration,Brain vascular diseasesIntracerebral hemorrhage1.General view:common reasons(hypertension,aneurysm,malformation of cerebral blood vessels,post-infarction)the first is commonest one.Basal nucleus area is the common site.2.CT findings(based on the hematomas age),Intracerebral hemorrhage,Intracerebral hemorrhage,Intracerebral hemorrhage,Cerebral infarction,General view It can be divided into 3 partterns:the ischemic,the hemorrhagic,the lacunar.The common reasons are cerebral artery embolism as a result of atherosclerosis,Ischemic infarction CT findings.low density areas:.no positive foundings within 24 hours.Or ill-defined low density.in early stage we still can find some signs:a.hyperdense(hyperattenuating)artery sign:increased density of affected artery due due to the intraluminal thrombus,usually happens in middle cerebral artery(MCA).,b.insular ribbon sign:In the early phase of MCA embolism,the gray-white mater interface loss in the area of insular lobe,claustrum and extreme capsule.,.after 24 hours,a low density area conforms in shape to the affected artery distibution involving gray and white matter.2-3 weeks later,fogging effect appears because of macrophage invasion and perifocal edema loss.the lesion present you with isodensity.in late stage,the lesion appears low density owe to necrosis and cyst formation.,edema and mass effect:2 days 15days after infarction onset,edema peak will reach.mass effect can be found,brain atrophy 1 months later,in affected area,sulci widen,ventricle enlarges,middle structure shift to affected side.,on contrast-enhanced CT 3days-6 weeks after ictus,inhomogenous enhancement(round,nodular,gyral enhancement)will appear,because of blood brain barrier rupture,over-perfusion in affected areas,newborn capillaries,Ischemic infarction,Ischemic infarction,3.Hemorrhagic infarction(after thrombolytic therapy,the reopened blood vessel ruptures,leading hemorrhage in same infarcted region)CT findings.Usually in cortex and basal ganglia region,.large patchy low density with high hemorrhage density in it.edema and space-occupying effect,Hemorrhagic infarction,Hemorrhagic infarction,4.Lacunar infarction penetrating artery occlusion/embolism results in small patch of deep cerebral infarction,which commonly occurs in basal ganglia and thalamus area about 0.5-1.5cm in diameter.CT findings.low density 0.5-1.5cm in diameter in basal ganglia and thalamus area.with or without slight edema and mass effect,Lacunar infarction,Lacunar infarction,Thank you,