lecture 13 - neuroimaging Flashcards
What are the signs of brain ischaemia on CT?
Hypo attenuated (hypodense/dark) brain tissue, lentiform nucleus obscuration, insular ribbon sign, sulcal effacement
How does oedema appear on MRI
As a hyperdense area
How does iscahaemia appear on MRI?
As a hyperdense area
What are the types of intracranial space occupying lesions?
Tumors, abscesses, hematomas
What is the gross appearance of a brain with raised ICP due to a intracranial space occupying lesion?
Widened, flattened gyri with narrowed sulci
What are the general sign/symptoms of intracranial space occupying lesions?
Headache, nausea, vomiting, reduced consciousness, dilated fixed pupils, seizure
What is the most common type of brain tumour?
Glioma (tumor of glial cells) - then the most common of this subgroup is astrocytoma
What are the 2 major categories of astrocytoma, and what are their characteristics?
Infiltrating - poorly defined lesions that can expand and distort the brain without forming a discrete mass
non-infiltrating - form a discrete mass
What is the term for a grade IV infiltrating astrocytoma?
Glioblastoma
What is the gross appearance of a glioblastoma?
A discrete mass with areas of haemorrhage and necrosis
What is the appearance of a glioblastoma on CT/MRI with contrast?
Lesion with ring-like contrast enhancement due to abundant tumour vascularisation
What is the appearance of a glioblastoma on CT/MRI with contrast?
Lesion with ring-like contrast enhancement due to abundant tumour vascularisation
What are the histological findings in a glioblastoma?
Cellular changes: High cellularity, pleomorphism, visible mitoses
Pallisading Necrosis: areas of necrosis surrounded by viable tumour cells with microvascular proliferation
What is an extra-axial brain tumour?
A tumour of the meninges/skull that is inside the cranium but not made of brain tissue
What is the gross morphology of a meningioma?
Tumor is adherent to the dura, has round well-circmusscribed margins and presses on the underlying brain
