CEREBRAL ANEURYSMS

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CEREBRAL ANEURYSMS

• why do we need
• mathematical models?
• edoardo boccardi
• Neuroradiologia
• Ospedale Niguarda-CaGranda Milano

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the answer is obvious and very simple we
(medical doctors) are very ignorant
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the answer is obvious and very simple we
(medical doctors) are very ignorant we know very
little about vascular diseases and their causes
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the answer is obvious and very simple we
(medical doctors) are very ignorant we know very
little about vascular diseases and their
causes we hope to find answers in modelization
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why cerebral aneurysms? because cerebral
aneurysms represent a possible and not uncommon
cause of death. When they rupture in the brain
they cause a very severe disease subarachnoid
hemorrhage (SAH)
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SAH subarachnoid hemorrhage is a very severe
disease
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• SAH
• subarachnoid hemorrhage is a very severe disease
• one third of patients dies before arriving to
  the hospital

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• SAH
• subarachnoid hemorrhage is a very severe disease
• one third of patients dies before arriving to
  the hospital
• one third of those who are hospitalized will die
  later on

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• SAH
• subarachnoid hemorrhage is a very severe disease
• one third of patients dies before arriving to
  the hospital
• one third of those who are hospitalized will die
  later on
• less than half of the survivors will go back to
  normal (around 20 of the initial population)

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AIMS the goal of modern medicine is to cure in
the best possible way SAH patients, but more than
that it would be better to prevent the
occurence of SAH
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aneurysm localized dilatation of an artery
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aneurysm localized dilatation of an
artery artery blood vessel (tube) where blood
flows in a centrifugal direction (i.e. from the
heart towards the tissues)
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aneurysm localized dilatation of an
artery artery blood vessel (tube) where blood
flows in a centrifugal direction (i.e. from the
heart towards the tissues) the vessels which
bring blood back to the heart are the veins
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arteries
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angiography (arteriography) is the technique
we use in order to visualize cerebral vessels and
to find the aneurysm(s)
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catheter arteriography
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brain arteries
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anterior circulation
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posterior circulation
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when a vessel ruptures there is a
hemorrhage when an artery ruptures the
hemorrhage is more rapid and more intense
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when a vessel ruptures there is a
hemorrhage when an artery ruptures the
hemorrhage is more rapid and more intense a
hemorrhage in the subarachnoid space is a SAH
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subarachnoid space
ventricles
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CT scan of a subarachnoid hemorrhage (SAH)
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a SAH is (almost) always due to the rupture of a
cerebral aneurysm because these arterial
dilatation of the cerebral arteries are usually
to be found in the subarachnoid space
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a person with an acute SAH must be immediately
taken care of to help him/her overcome this
terrible trauma and to avoid possible
complications
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one of the most dreaded complication is a second
rupture of the aneurysm or rebleeding often more
severe than the first, with less chances of
survival to avoid the rebleeding we must
exclude the aneurysm from the circulation. This
is what we call aneurysm treatment
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the aim of the treatment is to prevent a new
rupture of the aneurysm
options surgical clip endovascular coils
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clip open surgery
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where is the aneurysm?
SAH
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where is the aneurysm?
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surgical clip
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before
after
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clips
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coils endovascular treatment
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SAH
rupture of an aneurysm at the tip of the basilar
artery
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before
after
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is it possibile to recognize an aneurysm before
it ruptures?
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is it possibile to recognize an aneurysm before
it ruptures? . symptoms due to compression of
nervous structures
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is it possibile to recognize an aneurysm before
it ruptures? . symptoms due to compression of
nervous structures . incidental finding in
exams for other reasons
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is it possibile to recognize an aneurysm before
it ruptures? . symptoms due to compression of
nervous structures . incidental finding in
exams for other reasons . in cases where a
ruptured aneurysm is also present
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• biology
• unruptured aneurysms
• may not be all the same
• incidental (discovered by chance)
• coincidental (with a ruptured aneurysm)
• large mass effect

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biology not all ruptured aneurysms will
rupture on the contrary, most of them wont
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unruptured aneurysms is it possible to recognize
those that will rupture?
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geometry study of shapes
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geometry study of shapes the human vascular
tree has a reproducible morphology more or less
constant in everybody
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two carotids anteriorly (right and left) two
vertebrals posteriorly (right and left)
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two carotids anteriorly (right and left) two
vertebrals posteriorly (right and left) inside
the head these arteries will divide in a series
of branches
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two carotids anteriorly (right and left) two
vertebrals posteriorly (right and left) inside
the head these arteries will divide in a series
of branches there are many connections between
these branches, for the most part barely visible
and not very effective, except .....
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circle of Willis
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on angiograms the circle of Willis is not
visualized in its whole extension, but only a
segment at a time
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it is not unusual to find aneurysms within an
anomalous (?), unfrequent, original morphology of
the circle of Willis or associated to other
anatomic variants (duplications, fenestrations,
etc.)
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it is not unusual to find aneurysms within an
anomalous (?), unfrequent, original morphology of
the circle of Willis or associated to other
anatomic variants (duplications, fenestrations,
etc.) why? and why not always? is it a direct
relation between shape and shear stress on the
arterial walls or is it something less obvious,
more hidden?
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• what is the origin of an aneurysm?
• congenital
• . already present at birth
• . focal weakness of the wall
• .

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• what is the origin of an aneurysm?
• congenital
• . already present at birth
• . focal weakness of the wall
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• acquired local stress (abuse)
• . progressive
• . acute
• .

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what is the origin of an aneurysm? what is the
cause of the local stress ? .
constitutional factors (wall quality)
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what is the origin of an aneurysm? what is the
cause of the local stress ? .
constitutional factors (wall quality) .
dynamic factors (flow, velocity, pression)
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what is the origin of an aneurysm? what is the
cause of the local stress ? .
constitutional factors (wall quality) .
dynamic factors (flow, velocity, pression) .
morphology (curves, countercurves, bifurcations)
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what is the origin of an aneurysm? what is the
cause of the local stress ? .
constitutional factors (wall quality) .
dynamic factors (flow, velocity, pression) .
morphology (curves, countercurves, bifurcations)
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we hope that the study of shapes and structures
may lead to the understanding of the processes of
aneurysm birth, growth and eventual rupture
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we have many questions and very few answers
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we have many questions and very few answers we
do not know what to tell people who have a
cerebral aneurysm
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we have many questions and very few answers we
do not know what to tell people who have a
cerebral aneurysm with your help we hope to
better understand, because it could mean a major
advance in a fight for life thank you.
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edoardo.boccardi_at_ospedaleniguarda.it
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