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Skull & Brain. Imaging Techniques Plain……..M.M. before MRI for intra- occular metalic FB CT & MRI …standard investig . US Angiography….Limited to stenosis. aneurysm & AVM. Imaging Techniques. Plain …. - PowerPoint PPT Presentation
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Skull & BrainSkull & BrainImaging TechniquesImaging Techniques
Plain……..M.M. before MRI for Plain……..M.M. before MRI for
intra-occular metalic intra-occular metalic FBFB
CT & MRI …standard investig.CT & MRI …standard investig.
USUS
Angiography….Limited to Angiography….Limited to stenosis. stenosis.
aneurysm & aneurysm & AVMAVM
Imaging TechniquesImaging Techniques
Plain ….Plain …. Normal….inner & outer tables (compact)Normal….inner & outer tables (compact) Diploic space ( spongy bone )Diploic space ( spongy bone ) Sutures remain visible even Sutures remain visible even after fusion. after fusion. Metopic suture. InconstantMetopic suture. Inconstant
Lytic & sclerotic lesions in the Lytic & sclerotic lesions in the skullskull
Lytic lesionsLytic lesions Metast. & M.M.Metast. & M.M. Geographic skull in histiocytosis X.Geographic skull in histiocytosis X.
Sclrotic lesionsSclrotic lesions
Localized sclerosis… metastasesLocalized sclerosis… metastases
CT BrainCT Brain
Normal CT Normal CT Abnormal CT cardinal signsAbnormal CT cardinal signs
-abnormal tissue density-abnormal tissue density
high density…recent hge, calcified high density…recent hge, calcified and contrast enhancementand contrast enhancement
low density….neoplasm, infarct, low density….neoplasm, infarct, oedema oedema
Abnormal CT…cont.Abnormal CT…cont.
Mass effect ..compressed or displacedMass effect ..compressed or displaced lateral ventricleslateral ventricles Midline shiftMidline shift
Dilatation of ventricular systemDilatation of ventricular system -CT with contrast; CT angio-CT with contrast; CT angio
MRI of brainMRI of brain
Multiplanar capability….extent of Multiplanar capability….extent of tumor.tumor.
esp. for post. Fossa & craniovertebral esp. for post. Fossa & craniovertebral junction.junction.
Disadvantage; inability to show Disadvantage; inability to show calcification and bone details calcification and bone details
long scan timelong scan time
difficulty in monitoring critical patientsdifficulty in monitoring critical patients
MRI BrainMRI Brain
ContrastContrast
GadoliniumGadolinium
MRA severe stenosis & aneurysmMRA severe stenosis & aneurysm
MRV venous sinusesMRV venous sinuses
MRI BrainMRI Brain
It is more often possible to make a It is more often possible to make a specific diagnosis with MRI than CT.specific diagnosis with MRI than CT.
Demyelinating plaques of MSDemyelinating plaques of MSAVM AVM
NeurosonographyNeurosonography
HydrocephalusHydrocephalusHemorrhageHemorrhageCongenital abnormalities.Congenital abnormalities.
Brain TumorsBrain Tumors GliomaGlioma
Solitary irregular massSolitary irregular mass
surrounded by edemasurrounded by edema
may compress or displace ventricle.may compress or displace ventricle.
usually hypodense usually hypodense
may be hyper or mixed.may be hyper or mixed.
may calcifymay calcify
most show partial enhancement.most show partial enhancement.
may be ring enhancement.may be ring enhancement.
Low in T1 , high in T2Low in T1 , high in T2
MetastasesMetastases
may be of high or low density.may be of high or low density.
surrounded by edemasurrounded by edema
typically multiple typically multiple
a solitary metast. could not be diff. a solitary metast. could not be diff. fromfrom
a primary neither by CT nor by MRIa primary neither by CT nor by MRI
MeningiomaMeningioma arise from meninges of the vault, falx arise from meninges of the vault, falx
& tentorium.& tentorium. commonest sites are parasagittal commonest sites are parasagittal
region over the cerebral convexities & region over the cerebral convexities & sphenoid ridge.sphenoid ridge.
Slightly hyperdense on native CTSlightly hyperdense on native CT marked enhancementmarked enhancement
Acoustic neuroma;Acoustic neuroma; in the CPA near in the CPA near IAM.IAM.
Pit. Tumors:Pit. Tumors:
microadenoma < 10mmmicroadenoma < 10mm
macroadenoma.> 10mmmacroadenoma.> 10mm
MRIMRI
Cerebral infarction & hemorrhageCerebral infarction & hemorrhage
Clinically similarClinically similar
CT is the initial exam.CT is the initial exam.
Hge….high density surrounded by Hge….high density surrounded by edema.edema.
May be SAH or intraventricular.May be SAH or intraventricular.
In Infarction ….CT normal initially.In Infarction ….CT normal initially.
MRI diffusion Weighted Images.MRI diffusion Weighted Images.
SAH SAH usually due to rupture usually due to rupture aneurysm.aneurysm.
CT is the best initial exam.CT is the best initial exam.
The large aneurysms are seen by CT.The large aneurysms are seen by CT.
MRA can show smaller aneurysms.MRA can show smaller aneurysms.
Arteriography is the best.Arteriography is the best.
AVMAVM may present with Hge….CT can may present with Hge….CT can show the AVM esp. with contrast.show the AVM esp. with contrast.
But MRI is better even without But MRI is better even without contrast.contrast.
AbscessAbscess
Low density with ring enhancementLow density with ring enhancement
Head Injury:Head Injury:FracturesFractures# more translucent# more translucent# may branch abruptly# may branch abruptly
Suture in known anatomical positions.Suture in known anatomical positions.Depressed #....dense.Depressed #....dense.
EDH can result from # through MMA groove.EDH can result from # through MMA groove.
CT in head injuryCT in head injuryCT should be done when there is:CT should be done when there is:-deterioration in the conscious level.-deterioration in the conscious level.-worsening of neurological deficits.-worsening of neurological deficits.
Extracerebral lesionsExtracerebral lesions-EDH.. -EDH.. biconvex. Associated with #biconvex. Associated with # High density for 2Wks.High density for 2Wks.After 3-4Wks…..hypodenseAfter 3-4Wks…..hypodenseIsodense in between. Isodense in between.
-SDH-SDH…….concavoconvex…….concavoconvex
Fractures of the base & vault are easily Fractures of the base & vault are easily seen in bone windowseen in bone window
Intracerbral lesions:Intracerbral lesions:-Edema- -Edema- homogenous low density.homogenous low density.-Contusions- -Contusions- patchy low density areaspatchy low density areas-Intracerebral hematoma-Intracerebral hematoma
Severe head injury can exist with no Severe head injury can exist with no abnormal CTabnormal CT
2020
Cerebral infarction with mass effectCerebral infarction with mass effect
2121
Intracerebral hemorrhageIntracerebral hemorrhage (hyperdense lesion in CT scan)(hyperdense lesion in CT scan)
2222
Acute epidural hematomaAcute epidural hematoma(lenticular shaped clot)
2323
Subarachnoid hemorrhageSubarachnoid hemorrhage(hyperdensity in Sylvain fissures and (hyperdensity in Sylvain fissures and interhemispheric fissures in CT scan)interhemispheric fissures in CT scan)
Subdural hematomaSubdural hematoma((crescentic collection over the convexity of the crescentic collection over the convexity of the
hemispherehemisphere))
2424
2525
MCA aneurysm MCA aneurysm
2626
MeningiomaMeningioma
Brain abscessBrain abscess
2727
2828
MeningiomaMeningioma
2929
Pituitary adenomaPituitary adenoma
Multiple osteolytic lesionsMultiple osteolytic lesions(multiple myeloma)(multiple myeloma)
3030
3131
Multiple brain secondariesMultiple brain secondaries