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Skull & Brain Imaging Techniques Plain……..M.M. before MRI for

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Presentation on theme: "Skull & Brain Imaging Techniques Plain……..M.M. before MRI for"— Presentation transcript:

1 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

2 Imaging Techniques Plain …. Normal….inner & outer tables (compact)
Diploic space ( spongy bone ) Sutures remain visible even after fusion. Metopic suture. Inconstant

3 Lytic & sclerotic lesions in the skull
Lytic lesions Metast. & M.M. Geographic skull in histiocytosis X. Sclrotic lesions Localized sclerosis… metastases

4 CT Brain Normal CT Abnormal CT cardinal signs -abnormal tissue density
high density…recent hge, calcified and contrast enhancement low density….neoplasm, infarct, oedema

5 Abnormal CT…cont. Mass effect ..compressed or displaced
lateral ventricles Midline shift Dilatation of ventricular system -CT with contrast; CT angio

6 MRI of brain Multiplanar capability….extent of tumor.
esp. for post. Fossa & craniovertebral junction. Disadvantage; inability to show calcification and bone details long scan time difficulty in monitoring critical patients

7 MRI Brain Contrast Gadolinium MRA severe stenosis & aneurysm
MRV venous sinuses

8 MRI Brain It is more often possible to make a specific diagnosis with MRI than CT. Demyelinating plaques of MS AVM

9 Neurosonography Hydrocephalus Hemorrhage Congenital abnormalities.

10 Brain Tumors Glioma Solitary irregular mass surrounded by edema
may compress or displace ventricle. usually hypodense may be hyper or mixed. may calcify most show partial enhancement. may be ring enhancement. Low in T1 , high in T2

11 Metastases may be of high or low density. surrounded by edema typically multiple a solitary metast. could not be diff. from a primary neither by CT nor by MRI

12 Meningioma arise from meninges of the vault, falx & tentorium. commonest sites are parasagittal region over the cerebral convexities & sphenoid ridge. Slightly hyperdense on native CT marked enhancement Acoustic neuroma; in the CPA near IAM.

13 Pit. Tumors: microadenoma < 10mm macroadenoma.> 10mm MRI

14 Cerebral infarction & hemorrhage
Clinically similar CT is the initial exam. Hge….high density surrounded by edema. May be SAH or intraventricular. In Infarction ….CT normal initially. MRI diffusion Weighted Images.

15 SAH usually due to rupture aneurysm.
CT is the best initial exam. The large aneurysms are seen by CT. MRA can show smaller aneurysms. Arteriography is the best. AVM may present with Hge….CT can show the AVM esp. with contrast. But MRI is better even without contrast.

16 Abscess Low density with ring enhancement

17 Head Injury: Fractures # more translucent # may branch abruptly Suture in known anatomical positions. Depressed #....dense. EDH can result from # through MMA groove.

18 CT in head injury CT should be done when there is:
-deterioration in the conscious level. -worsening of neurological deficits. Extracerebral lesions -EDH.. biconvex. Associated with # High density for 2Wks. After 3-4Wks…..hypodense Isodense in between. -SDH…….concavoconvex

19 Fractures of the base & vault are easily
seen in bone window Intracerbral lesions: -Edema- homogenous low density. -Contusions- patchy low density areas -Intracerebral hematoma Severe head injury can exist with no abnormal CT

20 Cerebral infarction with mass effect

21 Intracerebral hemorrhage (hyperdense lesion in CT scan)

22 Acute epidural hematoma (lenticular shaped clot)

23 Subarachnoid hemorrhage (hyperdensity in Sylvain fissures and interhemispheric fissures in CT scan)

24 Subdural hematoma (crescentic collection over the convexity of the hemisphere)

25 MCA aneurysm

26 Meningioma

27 Brain abscess

28 Meningioma

29 Pituitary adenoma

30 Multiple osteolytic lesions (multiple myeloma)

31 Multiple brain secondaries

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