1. Imaging of subarachnoid
hemorrhage
Jean-Yves Gauvrit
University hospital of Rennes, Department of
radiology and medical imaging

2. SAH: reminders
Where?
Subarachnoid spaces
Dura mater
Arachnoid
mater
Subarachnoid
spaces
Pia mater
Frequent?
100/1 000 000 inhabitants/year
5% of strokes
Rare before the age of 20 years
Age?
Serious?
Frequent between 40 and 60 years
Mortality rate: ~ 50%
Disabling deficits: 30%

3. SAH: clinical reminders
ANAMNESIS
When?
• Sudden and painful
“thunderclap” headaches
(10% of SAHs)
• Persistent headaches
CLINICAL EXAMINATION
• Meningeal syndrome, neck stiffness
• 2/3 impaired
consciousness (1/2 coma)
• No fever initially
• No prior trauma
III
• Neurological signs
without localizing value VI
with localizing value cranial nerve III paralysis
Nerve compression via carotid siphon aneurysm

4. SAH: reminders
n
Intracranial aneurysm: 80% of cases
PComA
Cause?
20%
40%
AComA
30% MCA
Multiple aneurysms
20%
10%
PCA
BA
PICA
n
n
n
n
n
n
n
Arteriovenous malformations
Intracranial dissections
Angiopathies
Hemopathies
Venous thrombosis
Traumas
Medullary vascular malformations

5. Objectives of imaging
1) Emergency
2) Diagnosis of SAH
Ø Presence of blood in the subarachnoid spaces
Ø Localization of rupture site
Ø Early and late complications
3) Etiologies
a) Aneurysm
Radio-anatomical examination
Ø Aneurysm neck
Ø Dimensions
Ø Aneurysm-carrying artery
b) Others
Therapeutic
decision

6. Confirming SAH
n Brain
¨
scan 95%
Presence of blood
Hyperdensity in the subarachnoid cisterns
and cerebral sulci
¨
Localizing value
Associated signs
Hydrocephalus
Hematoma
¨

7. Confirming SAH

8. HSA : sensibilité du scanner
Confirming SAH
Normal scan 5%
Emergency
brain MRI
Boesiger, B. M.J Emerg Med 2005
FLAIR
T2*
Da Rocha AJ. J Comput Assist Tomogr 2006

9. HSA : sensibilité du scanner
Confirming SAH
Normal scan 5%
Normal MRI
LP
Red, uncoagulated,
xanthochromic
FLAIR
T2*
Mohamed M. AJNR 2004

10. Complications
n Acute hydrocephalus
n Ventricular dilatation
n Obstruction by blood clots
n Intracranial pressure elevation
n Diagnosis with scan or MRI

11. Complications
n Vasospasm
¨ Due to the presence of
blood around the arteries
n
n
maximum from D3 to D12
Artery diameter reduction
¨ Daily
transcranial echo-color
Doppler at patient bedside
n
Narrowing, acceleration of flow
velocities
¨ Asymptomatic
¨ Symptomatic
n Delayed
ischemia
cerebral

12. Complications
MTT
At patient bedside

13. Complications
n Re-bleeding
New rupture of untreated aneurysm
¨ Sudden
¨ 35%
¨ More
and unpredictable
at 1 month
severe than initial SAH
¨ Diagnosis
with scan or MRI

14. Etiological diagnosis of SAH
n Non-invasive
angiography
¨ CT
angiography ++
¨ MR angiography
n Invasive
angiography
¨ Conventional
arteriography
3D

15. Etiological diagnosis of SAH
CT angiography
n
n
n
Acquisition 10 sec
IV inj. of contrast agent
Slices <1mm
n
n
n
Morphology of
aneurysm sac
Sac-to-neck ratio
Aneurysm-carrying
artery
Goddard AJ. Clin Radiol 2005
Therapeutic
decision

16. CT angiography
Etiological diagnosis of SAH
VRT
MIP
Angiography
Aneurysm of the right PICA

17. CT angiography
Etiological diagnosis of SAH
Dissection
Dural fistula

18. CT angiography
Etiological diagnosis of SAH
VRT
False positive: normal vein
TOF
T2
CT
angiography

19. MR angiography
Etiological diagnosis of SAH
MR angiography
¨ Acquisition
3 min
¨ Without injection, TOF
¨ Slices 1mm
2D
n
n
n
Morphology of
aneurysm sac
Sac-to-neck ratio
Aneurysm-carrying
artery
3D

20. MR angiography
Etiological diagnosis of SAH
VRT
TOF
FLAIR
MIP

21. Etiological diagnosis of SAH
n Cerebral
angiography
¨ 40
minutes
¨ IA injection of contrast agent
¨ Slices <0.5mm
¨ 3D reconstructions
n 78%
patients with negative arteriography had an
aneurysm (<2 mm) visible with 3D angiography
n
n
n
Morphology of aneurysm sac
Sac-to-neck ratio
Adjacent branches
Van Rooij WJ. AJNR Am 2008

22. Diffuse SAH without aneurysm
¬ Technical
Scan-CT angiography
Causes?
Angiography (1)
¬ Thrombosis
¬ Vasospasm
¬ Compression
¬ Anatomy-localization
Angiography (2)
10-15% of aneurysms visible with 2nd angiography
Bradac et al. Neuroradiology 1997

23. Perimesencephalic SAH
Scan
FLAIR

24. Perimesencephalic SAH
Ø Preserved general state
Ø Limited SAH
Scan-CT angiography
Ø Normal angiography
Ø Hypothesis: vein rupture?
Ø No usual complications
(vasospasm)
Ø No recurrence
Ruigrok YM, Stroke 2000
Greebe P, Stroke 2007
Angiography
MRI-MR angiography

25. Cortical SAH
FLAIR
Diffusion
Angiitis

26. Cortical SAH
DP
Venous
thrombosis
T2*
Oppenheim, C.AJNR 2005
T2*
E Aufray-Calvier

27. Cortical SAH
Ø Anamnesis, clinical
examination
Vascular malformations
Reversible cerebral vasoconstriction syndrome
Vasculitis
Septic aneurysm
Scan-CT angiography
Ø Causes
Ø Venous thrombosis
Ø Angiitis
Ø Trauma
Ø Remote ruptured
aneurysm
Ø Malformations…
-
Cerebral venous
thrombosis
PRES
Neoplasia
Abscess
Endocarditis
MRI-MR angiography
-
Cerebral venous
thrombosis
Amyloid angiopathy
Cavernoma
Angiography
Bonneville F AJNR 2010
Geraldes R J Stroke Cerebrovasc Dis 2013

28. Cortical SAH
AngioCTA
Angio CTV
FLAIR
DWI
T2*
SWI
Vascular malformations
Reversible cerebral vasoconstriction
syndrome
Vasculitis
Septic aneurysm
Cerebral venous thrombosis
PRES
Neoplasia
Abscess
Endocarditis
Cerebral venous
thrombosis
Amyloid angiopathy
Cavernoma
T1+Gd
MRVein
MRA
DSA
Bonneville F AJNR 2010

29. Fortuitously discovered aneurysm: risk factors for
hemorrhage
INDEPENDENT
- SIZE >7mm
- LOBULATION, GIRLS
- LOCALIZATION: anterior and posterior communicating
arteries
- WOMEN, AHT (p ∼0.05)
Multiple aneurysms: no increased risk/aneurysm, but cumulated risk of
different locations
Calcified or thrombosed aneurysm: trend to increased hemorrhagic risk
29

30. Subarachnoid hemorrhage
Emergency imaging
Aneurysm 80%
Triple diagnosis:
• Positive
• Etiologies
• Complications
Scan-CT angiography in 1st intention
MRI-MR angiography: localized SAH
Angiography: alternative examination option