Tag Archive | neuroimaging

Lobar haemorrhage – an intracerebral bleed (haemorrhagic stroke)…

Lobar haemorrhage – an intracerebral bleed (haemorrhagic stroke) that occurs superficially within the cerebral lobes. In contrast to hypertensive haemorrhages which occur deep within the brain, primary lobar haemorrhages occur superficially due to cerebral amyloid angiopathy. They typically occur in elderly patients and as with any haemorrhage, it is important to consider the possibility of an underlying tumour or vascular malformation. 

This short video tutorial is courtesy of Dr Frank Gaillard and the Radiology Channel.

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MAGIC DR – a handy mnemonic used to remember…

MAGIC DR – a handy mnemonic used to remember the potential causes of a cerebral ring enhancing lesion.

M – Metastasis

A – Abscess

G – Glioblastoma multiforme

I – Infarct (subacute phase)

C – Contusion

D – Demyelinating disease (eg. tumefactive MS)

R – Radiation necrosis

An alternative is DR MAGIC of course, which is what you may like to call yourself if you can remember the list! Although you can’t possibly know by looking at the single images, for what it is worth, the above cases are; A = metastasis, B = abscess, C = radiation necrosis, D = GBM, E = demyelination, F = contusion.

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Hypertensive haemorrhage – high blood pressure is the most…

Hypertensive haemorrhage – high blood pressure is the most common cause of primary intracerebral haemorrhage (also known as haemorrhagic stroke). Typical locations include:

This short educational video comes to you courtesy of Dr Frank Gaillard and the RadiologyChannel.

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Insular ribbon sign – refers to loss of the normal insular…

Insular ribbon sign – refers to loss of the normal insular cortex grey-white differentiation and is one of the earliest imaging sign of middle cerebral artery territory infarction. The insular cortex is located along the Sylvian fissure overlying the external capsule where a ‘ribbon’ of normal cortex should be appreciable (red arrows). In the setting of MCA infarction, cytotoxic oedema leads to hypoattenuation such that the normal insular ribbon is no longer visible (blue arrows).

Case on the left shows a very early infarct (within the first few hours) while the case on the right shows a more established infarct (greater than 4 hours old).

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Empty delta sign – of dural venous sinus thrombosis within…

Empty delta sign – of dural venous sinus thrombosis within the superior sagittal sinus on contrast enhanced CT. The thrombus creates a filling defect within the sinus outlined by an enhancing triangular rim. Of course calling it the ‘empty triangle sign’ would be too simple and so quite rightly the Greek letter delta (Δ) is used to add an air of mystique. 

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Racing car sign – refers to widely spaced lateral ventricles due…

Racing car sign – refers to widely spaced lateral ventricles due to absence of the corpus callosum with intervening Probst bundles.  Appearances on axial MRI or CT are reminiscent of a formula one car seen from above, with the tires represented by the widely spaced frontal horns and the dilated trigones. This ventricular arrangement may also be referred to as colpocephaly.

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Dural tail sign – thickening of the dura directly adjacent…

Dural tail sign – thickening of the dura directly adjacent to, and seemingly contiguous with, an intracranial mass. Although it may be seen in association with several different pathologies, it is classically described in meningioma being present in around 70% of cases. The tail of thickening was initially thought to result from direct tumour invasion, however it is now thought to be largely reactive in nature.

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Cleft sign – one of the first things to determine when you see…

Cleft sign – one of the first things to determine when you see an intracranial mass is its location: is it within the brain (intra-axial eg. astrocytoma) or outside the brain (extra-axial eg. meningioma)? Extra-axial masses are typically separated from the brain by a thin cleft of signal or density difference. Classically, this cleft was regarded as a rim of CSF however it is now thought that much of the appearance, particularly on MRI, is due to a non-CSF tumour-brain interface phenomenon. Either way, it is an excellent sign to help differentiate an extra-axial mass. Both the above examples are meningiomas. 

from our tumblr blog: http://radiologysigns.tumblr.com/post/25480297279

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Mother in law sign – used to describe lesions that enhance early…

Mother in law sign – used to describe lesions that enhance early during the arterial phase and remain opacified well after the venous phase. The sign is joking named after the uncanny ability of mothers in law to come early and stay late. This matches the classic angiographic enhancement pattern of meningiomas. The above lateral angiogram images from a common carotid artery injection demonstrate a large olfactory groove meningioma.

from our tumblr blog: http://radiologysigns.tumblr.com/post/24372003063

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Infundibulum sign – helpful in distinguishing an empty pituitary…

Infundibulum sign – helpful in distinguishing an empty pituitary sella from a cystic lesion of the pituitary region. In the former, although the sella is enlarged, there is no mass and the pituitary infundibulum continues to traverse the enlarged sella to the residual pituitary at the floor. When a cystic mass is present however the infundibulum is displaced away.

from our tumblr blog: http://radiologysigns.tumblr.com/post/23146212972

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