Intracranial

Question 1

Which intra-cranial lesions are associated with marked surrounding oedema?

Answer 1

Metastasis Abscess Glioblastoma multiforme Radiation necrosis Hematoma (mild)

Question 2

What is the DDx for a haemorrhagic tumour?

Answer 2

Glioblastoma multiforme: most common overall Metastasis: second most common overall Renal cell carcinoma Thyroid carcinoma Choriocarcinoma Melanoma Oligodendroglioma: second most common primary tumor

Question 3

DDx for a calcified glial tumour?

Answer 3

Oligodendroglioma: 75% are Ca++ Ependymoma Astrocytoma (commonest cause, but purely because it is the commonest glial tumour) Glioblastoma multiforme

Question 4

What primary tumours are associated with a solitary brain met.

Answer 4

1: melanoma 2: lung ca 3: breast ca

Question 5

DDx for posterior fossa tumour in a child includes?

Answer 5

1: Medulloblastoma 2: Cerebellar astrocytoma 3: Ependymoma 4: Brain stem glioma NB: Haemangioblastoma is the commonest lesion in adults

Question 6

1: Where do Medulloblastoma’s arise from? 2: How can they be differentiated from an astrocytoma?

Answer 6

1: the Cerebellar vermis 2: They are HYPERdense on an unenhanced CT cf pilocytic astrocytoma which are hypo

Question 7

What is the management of Medulloblastoma?

Answer 7

1. Neurosurgery,
2. Chemo and radiotherapy
3. MRI of the spine for drop mets.
4. ? MR Spectroscopy looking for:

• Elevated choline,
• Reduced NAA,
• Reduced creatine
• Occasionally elevated lipid and lactic acid peaks.

Question 8

What is the commonest tumour in NF1?

Answer 8

Pilocytic astrocytoma is the most common tumor seen in neurofibromatosis type 1 (NF1) and is present in 15% to 21%.

Question 9

What is the key imaging fx of a pilocytic astrocytoma?

Answer 9

About 66% are cystlike with an enhancing mural nodule.

Question 10

DDx for hydrocephalus

Answer 10

DDx Hydrocephalus

Non-Communicating - Think

• Intraventricular tumours - Ependymoma
• Extraventricular tumours - e.g. colloid cyst, craniopharyngioma; medulloblastoma; haemangioblastoma
• Ventriculitis - leads to encysted CSF collections
• Haemorrhage - clots; delayed adhesive arachnoiditis

Location:

• Foramen of Monro:
  
  • colloid cyst;
  • subependymal giant cell astrocytoma
• 3rd ventricle:
  
  • pituitary adenoma;
  • craniopharyngioma;
  • arachnoid cyst
• Cerebral aqueduct:
  
  • congenital aqueduct stenosis (only 4th vntricle is not dilated - see image);
  • pineal tumours
• 4th Ventricle:
  
  • Ependymoma;
  • Medulloblastoma
  • Metastasis
  • Haemangioblastoma
  • SAH

Communicating / Extraventricular obstruction

1. SAH
2. Meningitis
   
   1. Malignant - lung, breast
   2. Infectious
   3. Granulomatous: TB; Sarcoidosis
3. Overproduction of CSF - Choroid plexus papilloma
   4.

Question 11

Which Tumours May Have Ca++?

Answer 11

Tumours with Ca++

• Oligodenroglioma - usu in frontal lobe
• Dysembroplastic neuroepithelial tumour (DNT)
• Meningioma
• Dermoid - may rupture causing chemical meningitis; look for fat droplets
• Central neurocytoma - septum pellucidum
• Mets - adenocarcinoma - breast; gi
• Pineal tumours - germinoma; teratoma
• Choroid plexus papilloma
• Craniopharyngioma

Remember infections:

• TORCH
• Cysticercosis
• TB

Question 12

Where is the aneurysm likely to be in this patient?

Answer 12

The location of the haemorrhage can help localise the site of the ruptured aneurysm.

Anterior Comm Artery Aneurysm:

• Interhemispheric fissure
• Lateral ventricle

MCA aneurysm: (previous case)

• Sylvian fissure

PCA aneurysm (see below)

• 4th ventricle