intracranial aneurysm is a good topic covered with theory and some images regarding aneurysm with refrence taken from Osborn book of radiology

1. INTRACRANIAL
ANEURYSMS
BY:- DR AVINASH DAHATRE
RADIOLOGY DEPARTMENT

2. HISTOLOGICAL ARTERIAL ANATOMY

3. INTRACRANIAL
ANEURYSM
SACCULAR FUSIFORM DISSECTING

5. SACCULAR ANEURYSM
 Rounded berry like
 Arise from arterial bifurcation
 Dilatation of vascular lumen due to weakness in vessel wall.
 Absent or reduced internal elastic membrane.
 T. adventitia may be infilterated by Lymphocyte and phagocyte.

6. SACCULAR ANEURYSM
MRA

7. CAUSES:-
1. Developmental/ degenerative aneurysm
2. Traumatic aneurysm
3. Mycotic aneurysm
4. Oncotic aneurysm
5. Flow related aneurysm

8. DEVELOPMENTAL/
DEGENERATIVE ANEURYSM
 In past few yrs intracranial aneurysm thought to
be congenital origin occuring due to focal defect in
T. media
 Most common intracranial aneurysm occurs as
hemodynamically induced vascular origin.
 Abnormal hemodynamic shear stress on wall of
larger cerebral arteries particularly at bifurcation
point.
 Change in flow direction occurring during systole
and diastole cause damage to T. intima.

9. Less common causes are:-
TRAUMA
INFECTION
TUMOR
DRUG ABUSE
HIGH FLOW STATES

10. INCIDENCE:-
Incidence is unknown.
In patient undergoing coronary angio incidental
Intracranial aneurysm were found in 5.6 % in cases.
1% of patient undergoing four vessel cerebral angio for
indications other than SAH.
Familial incidence have been reported.

11. Increase in incidence of ICA seen in
 Anamolous vessel
 Arterial coarctation
 Fibromuscular dysplasia
 MARFANs syndrome
 Ehlers danlos synd.
 High flow states (Fistula, vascular malformations)

12.  40-60yrs.
 In children they are post traumatic or mycotic.
 Aneurysm in children are larger than adult.(>17mm)
LOCATION:-
At bifurcation of larger arteries.
Most common MCA bifurcation.
90% of aneurysm arise in anterior circulation.
30-35% occurs in A.com and P.com
20% in MCA

13.  GRADE I
 GRADE II
 GRADE III
 GRADE IV
 GRADE V
 Asymptomatic patient or have mild
headache
 Moderate to severe headache with 3rd nerve
palsy
 Confusion and drowsy
 Hemiparesis
 Comatose or moribound.

14. B. T1WI MRI
Aneurysm appears
as iso to
hyperdense mass
with loss of signal
intensity.
C. DSA image
Aneurysm in
internal carotid
artery near
ophthalmic division
A.NCCT axial section
of brain showing well
delineated mass
located in suprasellar
cistern.

15. Fig. Coronal section
post contrast T1WI of
brain showing
partially thrombosed
vessel with intensly
enhanced lumen and
outer wall
enhancement.

16. Fig. non-contrast
CT image
showing slightly
hyperdense, well-
defined round
extra-axial
masses may
demonstrate a
peripheral
calcified rim

17. TRAUMATIC ANEURYSM
PENETRATING TRAUMA
 Due to high velocity missile
head wound.
 Meningeal vessels are
common site.
 Post traumatic aneurysm
may be over looked on Ct
because of the lesion is often
obscured by hemorrhage.
NON PENETRATING
TRAUMA
 Due to skull trauma or skull
fracture
 Frontolateral impact
produces shearing force
between inferior margins of
falx cerebri and distal
anterior cerebral artery and
juxta falcine hematoma is
seen.

18. PENETRATING TRAUMA ANEURYSM
Fig. A 40-year-old pedestrian man was involved in a motor vehicle
accident, his initial Glasgow Coma Scale (GCS) was 3. On day one,
cerebral angiography revealed a right internal carotid artery
paraophthalmic aneurysm measuring 4mm x 4 mm.

19. Fig. Axial NCCT showing hyperdense
subdural hemorrhage along left side of
anterior falx cerebri
NON PENETRATING TRAUMA

20. MYCOTIC ANEURYSM
 mycotic aneurysm is a dilation of an artery due to
damage of the vessel wall by an infection.
 “mycotic” referring to fungal is a misnomer as various
organisms including predominantly bacterial can cause
the aneurysm.
 most common organisms are:-
 Staphylococcus aureus
 Salmonella spp.
 There is disruption of muscular layer and adventitia of
vessel wall causing aneurysmal dilatation.
 Thoracic aorta is most common site and intra cranial is
less common.

21. MYCOTIC ABDOMINAL AORTIC ANEURYSM
Contrast CT Abdomen Axial and Coronal section showing Mycotic
aneurysm.

22. ONCOTIC ANEURYSM
 Neoplastic aneurysm result from direct vascular invasion by tumor
or implant.
 Forms pseudoaneurysm.
 Eg. Squamous cell carcinoma and severe epistaxis.

23. Fig.3D MRA showing pseudoaneurysms of
Internal carotid artery.

24. FLOW RELATED
ANEURYSM
 Occur along proximal and distal feeding vessels.
 Proximal lesion- arises in circle of willis related to increased
hemodynamic stress.
 Distal flow related aneurysm located within AVM nidus.

25. Fig. Digital substraction angiogram showing abnormal blood
vessels (nidus)

26. 1. SLE
2. TAKAYASU ARTERITIS
3. FIBROMUSCULAR DYSPLASIA
4. DRUG ABUSE –COCAINE
-HEROINE
-Methamphetamine

27. Fig. T2WI Subcortical and
periventricular hyperintense
Fig. FLAIR axial image
showing periventricular
hyperintensities.
Autoimmune disease causing small vessel dementia a/k/a Binswanger
disease.

28.  granulomatous large vessel vasculitis that
predominantly affects the aorta and its major
branches.
USG showing smooth, homogeneous and moderately
echogenic circumferential thickening of the arterial wall. this
finding is termed as the 'macaroni sign' and is highly specific
for Takayasu arteritis.

29. Contrast CT image showing aortic wall thickness
of takayasu arteritis.

30.  characterized by an idiopathic, non-inflammatory, and
non-atherosclerotic angiopathy of small and medium-
sized arteries.
 Most commonly seen in renal arteries then ICA and
vertebral arteries.
Fig. CECT axial image showing
alternating stenoses and
dilatations, causing a string of
beads Appearence

31. FUSIFORM ANEURYSM
 Occurs due to damage to tunica media layer.
 Vertebrobasilar system is commonly affected.
 Intraluminal clots are more common.
 Produces brain stem infract and compresses adjacent brain.
 Causes cranial nerve palsies.

32. Fig. CT and MRI revealed bilateral giant fusiform aneurysms of
the petrous portion of the internal carotid artery

33. Fig. DSA showing fusiform dilatation of petrous part of ICA

34. DISSECTING ANEURYSM
 Blood accumulates in the vessel wall through a tear in
the Intima and internal elastic lamina.
 If intra luminal hematoma extend to sub adventitial
plane sac like out pouching is formed called as false
saccular aneurysm or dissecting aneurysm.

35. Fig. CT AXIAL section showing aneurysmal dilatation
of the ascending aorta.

37. INTRACRANIAL
ANEURYSMS
SACCULAR
Dilatation of vascular
lumen due to weakness
in vessel wall.
Absent or reduced
internal elastic
membrane.
FUSIFORM
Occurs due to
damage to tunica
media layer.
DISSECTING
Blood accumulates
in the vessel wall
through a tear in
the Intima and
internal elastic
lamina.
SUMMARY POINTS:-

38.  Osborn diagnostic neuroradiology.