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