Stroke: Lobar haemorrhage - radiology video tutorial (MRI, CT)


Uploaded by RadiologyChannel on 14.01.2013

Transcript:
Hi, this is Frank Gaillard from Radiopaedia.org and today we will be looking at lobar haemorrhages.
As we saw in our previous
video on hypertensive hemorrhages, intracranial hemorrhages are typically
divided it into primary and secondary according to whether or not there is an
underlying lesion.
primary hemorrhages are further subdivided into hypotensive and lobar haemorrhages,
although these two have underlying specific pathologies;
in the case of lobar haemorrhage, it's cerebral amyloid angiopathy.
hemorrhages can also be divided according to their location as lobar,
basal ganglia, pontine and cerebellar.
the last three tend to be seen in patients with poorly-controlled
hypertension.
Lobar haemorrhages tend to be large, located superficially within the
cerebral hemispheres and are more commonly seen in elderly patients.
Their superficial location makes them prone to extend into the subdural space,
although given their size they also can extend into the intraventricular system
although this is not as common as with hypertensive hemorrhages.
the distribution of lobar haemorrhages
is due to the distribution of the underlying pathology, namely that of
cerebral amyloid angiopathy.
this is seen on T2* or susceptibility weighted
MRI images as multiple foci of signal loss
scattered peripherally through the cerebral hemispheres.
this is in contrast to chronic hypertensive microhemorrhages which are
clustered in the basal ganglia, pons and cerebral hemispheres matching the
distribution of hypertensive hemorrhages.
A differential for these regions of signal loss is multiple
cavernous malformations seen either as an autosomal dominant condition
or in patients who have received previous cranial irradiation.
cerebral amyloid angiopathy is the underlying pathology seen in patients who
develop lobar haemorrhages. It is also known as congophilic angiopathy
on account of the appearance all the amyloid deposits within the walls of the
vessels
seen on congo red stain.
cerebral amyloid angiopathy should not be confused with systemic amyloidosis
and this histological change is seen only within the brian.
When evaluating patients with a large superficial hemorrhage
it's important to keep in mind the possibility of underlying lesions, this is
especially the case in young patients
an underlying tumour,
an underlying vascular malformation such as an arteriovenous malformation or a cavernous
malformation
, as well as venous infarcts should be considered.
The later typically has a very heterogeneous or gyriform appearance to
the blood and is located in parts of the brain drained by adjacent dural venous
sinuses.
in this case
the sigmoid sinus can be seen containing a filling defect.
you can read more about lobar haemorrhages and other forms of intracranial haemorrhage
on Radiopaedia.org.
In the next episode we'll be covering hyperacute signs of ischaemic
infarction on CT. See you then.