中枢神经系统影像学表现.ppt

Central nervous system General view1.conventional x-ray examination:2.modern modalities: computer appears around 1970s .CT in 1969 .MRI(magnetic resonance imaging) .DSA(digital subtraction angiography)1.Conventional x-ray examination: . Plain film .Head and spinal column film (Including front and lateral view) 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 T2WIPons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 ventricleHead/caput of caudate nucleusthalamuslenticular nucleus(put-amen and globus pallidus)External capsulePosterior limb of internal capsuleAnterior limb of internal capsuleCalcification of pineal bodyGenu of corpus callosumGenu of internal capsuleTrigone of lateral ventricle1.Change of density hyperdensity hypodensity isodensity2.Enhancement no enhancement homogeneous enhancement inhomogeneous enhancement annular enhancement3. Morphology change note: location, size, number, border, middle structure, surrounding tissue, bone structure.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 IVAppearance.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 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 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 scanMetastatic tumor in right parietal and occipital lobe on CT plain scanMetastatic tumor in right parietal and occipital lobe on contrast enhanced CTMetastatic tumor in right parietal and occipital lobe on contrast- enhanced CT. 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 tissuesEpidural 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(som