Imaging of subarachnoid hemorrhage

Jean-Yves Gauvrit University hospital of Rennes, Department of radiology and medical imaging

SAH: reminders

Frequent?

Age?

Serious?

100/1 000 000 inhabitants/year

5% of strokes

Rare before the age of 20 years Frequent between 40 and 60 years

Mortality rate: ~ 50% Disabling deficits: 30%

Where? Subarachnoid spaces

Arachnoid mater

Subarachnoid spaces

Dura mater

Pia mater

SAH: clinical reminders

•  Sudden and painful “thunderclap” headaches

(10% of SAHs)

• Persistent headaches

•  No prior trauma

ANAMNESIS

When?

III

•  Meningeal syndrome, neck stiffness

•  No fever initially •  Neurological signs without localizing value VI with localizing value cranial nerve III paralysis Nerve compression via carotid siphon aneurysm

CLINICAL EXAMINATION

•  2/3 impaired consciousness (1/2 coma)

SAH: reminders n  Intracranial aneurysm: 80% of cases

n  Arteriovenous malformations n  Intracranial dissections n  Angiopathies n  Hemopathies n  Venous thrombosis n  Traumas n  Medullary vascular malformations

Multiple aneurysms 20%

Cause? PComA

MCA

PCA BA

PICA

AComA

30% 20%

10%

40%

Objectives of imaging

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

1) Emergency

Confirming SAH

n Brain scan 95% ¨  Presence of blood

Hyperdensity in the subarachnoid cisterns and cerebral sulci

¨  Localizing value

¨  Associated signs Hydrocephalus Hematoma

Confirming SAH

HSA : sensibilité du scanner

Normal scan 5%

FLAIR

Confirming SAH

T2*

Emergency brain MRI

Da Rocha AJ. J Comput Assist Tomogr 2006

Boesiger, B. M.J Emerg Med 2005

HSA : sensibilité du scanner

Normal scan 5%

FLAIR

LP Red, uncoagulated, xanthochromic

Confirming SAH

T2*

Normal MRI

Mohamed M. AJNR 2004

Complications n Acute hydrocephalus

n  Ventricular dilatation n  Obstruction by blood clots n  Intracranial pressure elevation n  Diagnosis with scan or MRI

n Vasospasm ¨  Due to the presence of

blood around the arteries n  maximum from D3 to D12 n  Artery diameter reduction

¨ Daily transcranial echo-color Doppler at patient bedside

n  Narrowing, acceleration of flow velocities

¨ Asymptomatic ¨ Symptomatic

n  Delayed cerebral ischemia

Complications

Complications

At patient bedside

MTT

Complications

n Re-bleeding New rupture of untreated aneurysm

¨ Sudden and unpredictable

¨ 35% at 1 month

¨ More severe than initial SAH ¨ Diagnosis with scan or MRI

Etiological diagnosis of SAH

3D

n Non-invasive angiography

¨ CT angiography ++ ¨ MR angiography

n  Invasive angiography ¨ Conventional arteriography

Etiological diagnosis of SAH

CT angiography n  Acquisition 10 sec n  IV inj. of contrast agent n  Slices <1mm

n  Morphology of aneurysm sac

n  Sac-to-neck ratio n  Aneurysm-carrying

artery Goddard AJ. Clin Radiol 2005

Therapeutic decision

Etiological diagnosis of SAH

CT angiography

Angiography

VRT

MIP

Aneurysm of the right PICA

Etiological diagnosis of SAH CT angiography

Dissection Dural fistula

Etiological diagnosis of SAH

CT angiography

TOF T2

VRT

False positive: normal vein

CT angiography

MR angiography ¨ Acquisition 3 min ¨ Without injection, TOF ¨ Slices 1mm

Etiological diagnosis of SAH

n  Morphology of aneurysm sac

n  Sac-to-neck ratio n  Aneurysm-carrying

artery

3D

2D

MR angiography

Etiological diagnosis of SAH MR angiography

TOF

VRT

MIP

FLAIR

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  Morphology of aneurysm sac n  Sac-to-neck ratio n  Adjacent branches

Van Rooij WJ. AJNR Am 2008

Diffuse SAH without aneurysm ¬  Technical

¬  Thrombosis ¬  Vasospasm ¬  Compression ¬  Anatomy-localization

10-15% of aneurysms visible with 2nd angiography Bradac et al. Neuroradiology 1997

Causes?

Scan-CT angiography

Angiography (2)

-

Angiography (1)

-

Perimesencephalic SAH

FLAIR

Scan

Ø  Preserved general state

Ø  Limited SAH

Ø  Normal angiography

Ø  Hypothesis: vein rupture?

Ø  No usual complications (vasospasm)

Ø  No recurrence

Perimesencephalic SAH

Scan-CT angiography

MRI-MR angiography Angiography

Ruigrok YM, Stroke 2000 Greebe P, Stroke 2007

Cortical SAH

Angiitis FLAIR

Diffusion

Cortical SAH

Venous thrombosis

E Aufray-Calvier

T2* T2*

DP

Oppenheim, C.AJNR 2005

Cortical SAH

Scan-CT angiography

MRI-MR angiography

Angiography

Ø Anamnesis, clinical examination Ø Causes

Ø Venous thrombosis Ø Angiitis Ø Trauma Ø Remote ruptured aneurysm Ø Malformations…

-

Bonneville F AJNR 2010 Geraldes R J Stroke Cerebrovasc Dis 2013

Vascular malformations Reversible cerebral vasoconstriction syndrome

Vasculitis Septic aneurysm

Cerebral venous thrombosis

PRES Neoplasia Abscess

Endocarditis

Cerebral venous thrombosis

Amyloid angiopathy Cavernoma

-

AngioCTA

Angio CTV

FLAIR DWI

T2* SWI

T1+Gd

MRVein

MRA

DSA

Bonneville F AJNR 2010

Vascular malformations Reversible cerebral vasoconstriction

syndrome Vasculitis

Septic aneurysm

Cerebral venous thrombosis

PRES Neoplasia Abscess

Endocarditis

Cerebral venous thrombosis

Amyloid angiopathy Cavernoma

Cortical SAH

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

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