2. The Natural History of Cerebral Aneurysms
By: Ehsan Mohammad Hosseini Neurosurgery Resident at Isfahan University of Medical Science Advisor: Homayoun Tabesh M.D Assistant Professor of Neurosurgery

4. CEREBRAL ANEURYSMS Prevalence in general population: up to 2%
Prevalence of aneurysmal SAH: 1 in 10000
85% anterior circulation.
Occurs near branching vessels
Can cause compressive cranial neuropathy (P.com aneurysm compressing CN III causing ptosis and pupil dilation)
3 types
Saccular Fusiform Mycotic

6. Natural history is define as outcome of disease without any interventions.
Unruptered Aneurysm & Ruptured Aneurysm

7. Overall mortality at 6 months: 40% - 50%
18% of patients expire before reaching the hospital; 25% within 24 hours.
Only one third of those who survive have functional independent lives.
Rebleed has a catastrophic morbidity : 48% to 78%.

8. Unruptered Aneurysm
Prevalence

10. Rupture Rate of UIA

11. Risks factors for SAH in unruptured aneurysms
Increased aneurysm size on serial imaging
Aneurysm size > 10 mm
Aneurysm between 6-9 mm in middle and young age group
Posterior circulation aneurysms: especially basilar apex
Previous SAH from another aneurysm
Symptomatic aneurysms
Females
Cigarette smoking
Binge alcohol drinking

14. Ruptured Aneurysm
Short term; Hospitalization to 6 months after initial SAH
Long term; After 6 months

15. Subarachnoid Hemorrhage:

26. MCA Larger in 70% ACA Ophthalamic Post communicating
Anterior choroidal
MCA
Larger in 70%
Pierces dura
Hypophysial and meningial
Carotid canal
THE MAJORITY OF THE ANT. CER. ART. LIES WITHIN THE INTERHEMISPHERIC FISSURE AND TNE COLLOSAL CISTERN
THIS SLIDE IS AN ANTERIOR VIEW OF A RIGHT CAROTID ART. ANGIOGRAM
NOTE THE ICA SEGMENTS

27. Common patterns of aneurysms: branches and tortuous turns
ICA system
85% are anterior (ICA) circulating aneurysms
15% are posterior (vertebrobasilar) circulating aneurysms
Acom Artery aneurysms most common (30%)
VB system

30. Intracranial superior view of the right sellar and parasellar region , AC: anterior clinoid process , ICA: internal carotid artery , LT: lamina terminalis , ON: optic nerve , OlN: olfatory nerve , SW: sphenoid wing , TS: tubercullum sellae

31. Frontal view of the anterior (carotid) intracranial circulation
15 A1 segment of anterior cerebral artery
32 lateral lenticulostriate arteries
16 medial lenticulostriate arteries
33 bifurcation/trifurcatio n of middle cerebral artery
1 internal carotid artery - cervical segment
17 recurrent artery of Heubner
2 internal carotid artery - vertical petrous segment
34 anterior temporal lobe branches of middle cerebral
18 A1-A2 junction anterior cerebral artery
3 internal carotid artery – horizontal petrous segment
43 sylvian point
19 anterior communicating artery
44 opercular branches of middle cerebral artery
4 presellar segment (C5) internal carotid artery
20 proximal A2 segment anterior cerebral artery
45 sylvian(insular) branches of middle cerebral artery
9 ophthalmic artery
21 callosomarginal branch of anterior cerebral artery
10 and 11 supraclinoid segment internal carotid artery
28 pericallosal branch of anterior cerebral artery
13 anterior choroidal artery
14 internal carotid artery bifurcation
31 M1 segment of middle cerebral artery

32. -Top down view (superior to inferior) of the skull base
35 orbitofrontal branch of MCA
45 sylvian(insular) branches of MCA
BLACK KEY
RED KEY
5 meningohypophyseal trunk
1 vertebral artery
6 horizontal (C4) intracavernous ICA
2 PICA
7 inferolateral trunk
3 basilar artery
9 ophthalmic artery
4 AICA
12 PCOM
5 superior cerebellar artery
13 anterior choroidal artery
6.1 P1 segment PCA
14 ICA bifurcation
6.2 P2 segment PCA
15 A1 segment of ACA
8 posterior temporal branch of PCA
19 ACOM
9 parieto-occipital branch of PCA
20 proximal A2 segment ACA
10 calcarine branch of PCA
21 callosomarginal branch of ACA
14 vertebral-basilar junction
28 pericallosal branch of anterior cerebral
16 pontine perforators
17 anterior spinal artery
31 M1 segment of MCA
33 bifurcation/trifurcation of MCA
34 anterior temporal lobe branches of MCA

35. -3D frontal view shows lobulated aneurysm arising from the tip of the basilar artery projecting posteriorly into the interpeduncular cistern
1 vertebral artery
2 PICA
3 basilar artery
4 AICA
5 SCA
6.1 P1 segment of (PCA)
6.2 P2 segment of (PCA)
7 PCOM
9 parieto-occipital branch of PCA
10 calcarine branch of PCA
14 vertebral basilar junction

36. Thank You