Cerebral Aneurysms: Imaging and Treatment

Options Jussi Numminen, MD,PhD, neuroradiologist

Helsinki University Central Hospital

10.5.2017

Subarachnoidal Hemorrhage (SAH)

• Blood between arachnoid and the pia: Sulci and cisterns

• Trauma the most common cause

• Nontraumatic SAH • Vasculature imaging mandatory (CTA, DSA) • ~80%: Ruptured intracranial aneurysm • ~20%: ”Nonaneurysmal”

• Perimesencephalic SAH • Convexal SAH

• Venous hemorrhage, trombosis • Vasculitis • Amyloid angiopathy • Reversible Cerebral Vasoconstriction Syndrome (RCVS) • AVM, dAVF • Coagulopathy • PRES etc

Aneurysmal Subaracnoid Hemorrhage

• Sudden onset severe headache (worst in my life)

• 9/100 000/year in Finland

• M/F 1:2, peak age 40-60 years

• 3-5% of all strokes

• 1/3 fatal, 1/3 survive but disabling neurologic deficit, 1/3 survive

• Unfavorable outcome: • Large amount of SAH

• Old age

• Parenchymal hematoma + intraventricular hematoma

Aneurysmal Subarachnoid Hemorrhage

• Without treatment rebleeding rate 20% within first two weeks

• Vasospasm (2/3, 1/3 symptomatic) • Critical period within three first weeks

• Late ischemia and morbidity

• Treatment: Nimodipine + hypertension

• Hydrocephalus • Early (ventriculostomy)

• Late (Shunt)

SAH: Imaging + Diagnosis

• CT • SAH distribution, ICH, IVH, hydrocephalus, late ischemia

• Pseudo SAH: severe cerebral oedema

• MR: • Hyperacute blood is isointense on T1, bright on T2 : difficult to identify

• The best is FLAIR and SWI

• FLAIR subarachnoid hyperintesity can be artefact, meningitis, meningeal metastases, STROKE (slow flow and collaterals), MoyaMoya, RCVS

Perimesencephalic SAH

• Headache

• SAH around pons and midbrain (mesencephalon) and posterior supracellar cistern

• CTA and DSA normal

• CTA control after one week

• Venous bleeding? Perforator rupture?

• Most cases clinically benign, rebleeding rare (<1%)

SAV, CTA negative

Intracranial Aneurysms

• True Saccular Aneurysm • One side of artery focally dilated, have true wall but internal elastic lamina and media may be

missing • Vessel bifurcations

• Pseudoaneurysm • No true arterial wall, cavity within a hematoma clot • Dissection, trauma, infection, neoplasm, iatrogenic • Anywhere in vasculature

• Blood Blister-like Aneurysm • Small broad based dilation of arterial wall • Covered only by fragile thin fibrous tissue • Typically on dorsal supraclinoid ICA

• Fusiform Aneurysm • Whole artery focally dilated • Atherosclerosis

Intracranial Ruptured Aneurysms: Imaging • CTA first option

• Fast and available in an acute setup • 3D data-analysis with MIP or MPR reformats mandatory • Excellent sensitivity and specificity • Calcifications • Artefacts due to previous coiling or clipping or finding needs verification -> DSA

• DSA golden standard • 4-6 vessel selective injections with at least two projections (biplane) • 3D rotational angiography • Invasive • Intervention

• MRA • Suspected dissection: intramural hematoma

CTA Protocol in Helsinki

• Helical whole skull starting C1

• 350 mgI/ml, 70 ml, 5 ml/s

• SmartPrep window C3-4, no delay

• 0.625 mm/0.312 mm slice reconstructions

• 22 mm/3 mm MIP, axial, coronal and sagittal reformats

• 3D analysis programs (GE, Vitrea)

Intracranial Saccular Aneurysm

• Prevalence 2% (Finland), nonruptured and asymptomatic ~10 times more common than ruptured

• Acquired lesions • Smoking, hypertension, alcohol • Abnormal flow (AVM, abnormal anatomy), stress on vessel wall

• Increased risk • Persistent trigeminal artery, fenestration • Vasculopathy (Marfan, Ehlers-Danlos, fibromuscular dysplasia) • Polycystic kidney disease

• Family history • First order relative has SAH due to saccular aneurysm

Intracranial Saccular Aneurysm

• SAH: Intradural (supraclinoid) aneurysms

• Annual rupture rate 1-2%

• Differentiated from infundibular enlargements

• 90% in the anterior circulation (ICA, MCA, ACA) vessel bifurcations • Acomm (~30%), Pcomm (~30%, ”III CN palsy”), MCA bifurcation (~20%) • Oftalmic artery, Anterior choroidal artery, ICA bifurcation, M1 branch, Pericallosa bifurcation

• 10% in the posterior circulation (vertebral and basilar artery) • Basilar tip, PCA-a.cerebelli superior, PICA

• Aneurysm of any size can rupture, larger one more probably

• Aneurysm size in relation to parent vessel may be important

• Aneurysm with secondary lobules may be more prone to rupture

• SAH distribution, parenchymal hematoma close to aneurysm

• Giant aneurysm, size >2,5 cm • Compression symptoms • Trombosis • Tromboembolic event

SAH with a Ruptured Aneurysm:Treatment • Treatment of a ruptured aneurysm is to prevent rebleeding

• Highest risk during first two weeks, treatment within 24 hours • Spasm prevention with hypertension after aneurysm closure

• Observation • Severely comatose

• Surgery • Clipping • Trapping • Wrapping • By-pass and vessel closure

• Endovascular treatment • Coiling • Stenting and coiling • Flow diverters • WEB ( intra aneurysmal flow diverter) • Vessel occlusion

• In most centers endovascular > surgery • In Helsinki 2016 110 treated patients: Endovascular 62%, Surgery 38% • Posterior circulation ~100% endovascular, MCA ~100% surgery

Endovascular Treatment

• Suitable for any location, any size, and any form (broad base and narrow neck)

• Any device which remains in the parent vessel needs dual antiplatelet therapy • Klopidogrel 75 mg 1 x 1 + ASA 100 mg 1 x 1

• Stent: 3 months • Flow diverter stent: 6 months • Activity measurement (VerifyNow test)

• Endothelization later, maybe ASA for a longer period

• Acute ruptured aneurysm best treated with coiling or WEB • No need for anticoagulation • Ventriculostomy safe

Endovascular Treatment

• Follow up: • 6 months DSA, 2 years MRA/DSA, 5 years MRA/DSA

• If residive or coil compaction • Flow diverter • Stent assisted coiling • Recoiling • ”Clipping”

• Complications (~6%) • Aneurysm rupture • Dissection • Tromboembolic Event

Endovascular treatment

• General anestesia

• Biplane Neuroangiosuite

• 3D rotational angiogram

• Triaxial-tetraxial system: • Groin puncture, 8 Fr introduser to aorta • 6-8 Fr Guiding catheter to ICA, 6 Fr to vertebral artery • 5 Fr Distal acces catheter to intracranial ICA (Flow diverter, WEB) • 1,7 Fr (~1,7/3 mm = 0,7 mm) Microcatheter to the aneurysm • All continuously flushed with saline

• Heparine with ACT measurements

Ruptured Acomm aneurysm

Primary coiling and 6 months follow up

Aneurysm Coiling Platinum Coil sizes: 1 mm – 24 mm diameter

1 cm – 60 cm lengths

Framing coil: spherical or complex shape

Filling coil: helical

Broad based:

-Baloon assisted coiling

-Comaneci assisted coiling

-Stent assisted coiling

-Pulse Rider bifurcation device assisted coiling

SAH 1981, Acomm aneurysm clipped

SAH 2017, Acomm residive aneurysm and

right MCA bifurcation aneurysm with lobulations

Treatment 3 mm Acomm aneurysm ruptured: ICH at aneurysm site

Stent Neuroform atlas 3 mm x 20 mm

Intraprocedural heparin + ASA 500 mg IV + Plavix loading 300 mg when awake

Nonruptured 3 mm PCA-a.cerebelli superior aneurysm

PulseRider bifurcation device and coiling

6 months follow up

56 y healthy male

Sudden onset headache

CT: Intraventricular hematoma

CTA: MoyMoyA +small aneurysm

in posterior choroidal artery

branch

Treatment with glue and ONYX (Ethylene-Vinyl Alcohol Copolymer)

Aneurysm Treatment with WEB Intra-aneurysmal flow diverter

Broad based aneurysms

No anticoagulation needed: treatment of ruptured aneurysms

Ruptured basilar tip 5 mm x 7 mm aneurysm

Treatment with WEB embolisation device

Aneurysm Treatment with Flow Diverter Dense mesh stent

No need for coils

Perforators remain open: flow demand

Aneurysm tromboses: no flow

Dual antiplatetlet therapy crucial

Acute and late bleeding complications

In acute setup dissecting aneurysms, blister aneurysm, pseudoaneurysms

Later treatment of residives, large and giant aneurysms

30 y female collapsed during horse riding

CT: SAH

CTA: Distal pericallosal dissection/pseudoaneurysm

Treatment Flow diverter: Fred Jr

Intraprocedural heparin, ASA 500 mg IV prior to stent placement, ReoPro bolus + infusion after stent, 600 mg klopidogrel to the nasogastric tube

5 days later Deterioration of clinical condition

CTA: Vasospasm

CT: Ischemia

70 y male Headache

CT: SAH

CTA: dissecting basilar trunk aneurysm

Primary treatment with coiling

6 months follow up Residive

Retreatment with a flow diverter: Surpass

60 y female Abducens paresis

MRI and MRA reveals a large ICA intracavernous aneurysm

Treatment Flow diverter: Surpass 4 mm x 30 mm

Follow up 2 years

Points to remember

• Aneurysmal SAH is a severe disease

• Imaging is simple: CT

• There are good treatment options and the patient should be treated as soon as possible

• In spite of the treatment the course of the disease can be fatal

• Flow diverters are cool!