1. Differential Diagnosis of Hydrocephalus By: Nour-Eldin Mohammed Ref : Radiological Differential Diagnosis : Stephen Chapman,2003

2. The Normal CSF Flow

3. Hydrocephalus Abnormal dilatation of the cerebral ventricular system Hydrocephalus should be differentiated from disorders producing ventricular enlargement secondary to cerebral atrophy. Classified into : 1. Communicating Hydrocephalus 2. Non communicating Hydrocephalus

4. Characterisics of Hydrocephalus Ventricular enlargement disproportionate to the degree of sulcal widening Enlagement of temporal horne Periventricular fluid 2ry to transependymal CSF permeation Enlarged 3 rd ventricle with large suprapineal and chiasmatic receses In children < 2 years the head circumference is often the best distinguishing feature between hydrocephalus and atrophy.

5. Normal CT Brain Hydrocephalic Brain

6. Subependymal CSF permeation

7. Non-Communicating Hydrocephalus (Intraventricular obstruction) Ventricular dilatation caused by intraventricular obstruction at or above the the outlet foramina of the 4 th ventricle Causes: 1. Lateral ventricle 2. Foramen of Monro 3. 3 rd ventricle 4. Aqueduct of sylvius 5. 4 th ventricle

8. Lateral Ventriclar causes: 1. Intrinsic tumor: ependymoma 2. Ventriculitis: due to intraventricular adhesions 3. Extraventricular Tumour: mass effect from large parenchymal mass

9. Ventriculitis case 1Ventriculitis case 2

10. Neuroepithelial Cyst

11. Obstruction of Foramen of Monro: 1. Tumour : colloid cyst, subependymal giant cell astrocytoma 2. Ventriculitis 3. Haemorrhage : fresh clot, or adhesive arachnoiditis 4. Cerebral swelling with subfalcine herniation

12. Subependymal Giant cell astrocytoma

13. Subependymal giant cell astrocytoma

14. Central Neuocytoma

15. Colloid cyst

17. Subfalcine Herniation :

19. Causes of Thid Ventricle Obstruction: 1. Intraventricular Tumor 2. Extraventricular tumour : Pituitary adenoma, craniopharyngioma, arachnoid cyst.

20. Pituitary Adenoma

21. Craniopharyngioma :

22. Causes of Cerebral Aqueduct of Sylvius Obstruction: 1. Developmental aqueduct stenosis 2. Intraventricular tumour: epndymal seedling 3. Extraventricular Tumour : Pineal Body tumour 4. Ventriculitis 5. Haemorrhage

23. Aqueduct Stenosis

24. Pineal Body Tumours:

25. Pineal Body Tumour:

26. 4 th Ventricle obstruction : 1. Intraventricular Tumour: Ependymoma, metastases 2. Extraventricular Tumours: medulloblastoma, haemangioblastoma, cerebellopontine angle tumours (acoutic neuroma), meningioma 3. Outflow obstrction: infection (TB), SAH, leptomeningeal malignancy

27. Ependymoma

28. Medulloblastoma :

29. Cerebellar Haemangioblastoma

30. Intraventricular Haemorrhage:

31. Acoustic Neuroma:

32. Communicating Hydrocephalus: There is free flow throughout the ventricular system. Impaired CSF resorption by the arachnoid granulation accounts for majority of cases 1. SAH 2. Infectious meningitis 3. Malignant meningitis 4. Granulomatous mningitis : TB, sarcoidosis 5. Altered venous Dynamics : Vein of Galen malformation, venous obstruction

33. TB Meningitis :

34. Vein of Galen :

35. Vein of Galen

36. Thank you