Acute Stroke Imaging

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Morgan Horton
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1 Acute Stroke Imaging Goals: Determine stroke subtype Understand mechanism Institute treatment Radoslav Raychev, MD

2 Acute Stroke Facts Leading cause of disability 4 rd leading cause of death in USA 2 nd leading cause of death worldwide >5 million stroke survivors $40 to $50 billion per year in the US 1 in 6 Americans will be affected 90% of those who survive will have deficits 30% of strokes can be reversed 80 % of strokes can be prevented

3 Stroke: Definition Permanent injury to the brain or spinal cord of vascular origin (reduced blood flow or bleeding into or around the brain or spinal cord)

4 Stroke imaging objectives Brain tissue Brain vessels

6 Brain Tissue Imaging - Non Contrast Head CT Stroke Suspected ISCHEMIC HEMORRHAGIC

7 Hemorrhagic stroke imaging Non-traumatic Intracerebral hemorrhage (ICH) = Intraparenchymal hemorrhage» 70% of intracranial hemorrhage Subarachnoid hemorrhage» 30% of intracranial hemorrhage

8 Head CT Advantages:» Quick» Best for bony anatomy» Excellent for blood» Widely available Disadvantages:» Radiation» Limited detail

9 MRI for ICH Blood dark on GRE weighted sequence AVM nidus Large draining vein

10 Gradient Echo Imaging best for blood FLAIR GRE: Multiple microbleeds, not visible on other sequences

12 Traumatic ICH» Epidural» Subdural» Intraprenchymal» Subarachnoid Mostly in the convexities

13 All Traumatic hemorrhages at once

14 Intraparenchymal Hemorrhage Cortical (lobar) Deep (basal ganglia)

15 Basal ganglia hemorrhage

16 Basal ganglia = small vessel rupture usually due to chronic HTN

17 Lobar hemorrhage - multiple etiologies

18 Lobar hemorrhage = r/o vascular lesion VASCULAR LESIONS CAUSING ICH AVM DURAL AV FISTULA CAVERNOUS MALFORMATION VENOUS SINUS THROMBOSIS ANEURYSM Mycotic Blister Dissecting VASCULITIS

19 VASCULAR IMAGING CTA Advantages» Great spacial resolution Aneurysms Dissections Stenosis» Quick» Readily available Disadvantages» Radiation» Contrast MRA Advantages» No contrast» No radiation» Special sequencing for arterial wall Dissection Intraluminal clot Disadvantages» Less optimal spacial resolution» Prolonged acquisition» Motion artifact» Contraindicated in some implants

20 Good for LARGE lesions CTA MRA

21 Patient with posterior fossa ICH

22 CTA - negative

23 Angiogram The gold standard vascular imaging Most detailed Dynamic Invasive (0.5% risk of stroke) Therapeutic» The most advanced way to treat stroke

24 AVM Tiny residual post embolization Complete treatment with surgical resection

25 Vascular lesions requiring catheter angiogram AVM Dural AV Fistula Small (mycotic and blister ) aneurysms Vasculitis

26 Dural AV Fistula 15 % of all cerebral vascular malformation» Direct high-flow communication between dural veins and arteries» No intervening nidus (as opposed to AVM) Often missed on CTA or MRA Leading to hemorrhage due to high venous pressure Completely curable endovascularly Artery Vein

27 Patient with ICH and SAH CTA negative

28 Cervical Dural AV fistula No residual fistula after embolization with Onyx Microcatheter in the fistula

29 Aneurysmal subarachnoid hemorrhage - facts 10-15% of patients die before reaching the hospital 30-60% in-hospital mortality Lower at facilities with Interventional Neuroradiology Johnston S et al. Stroke. Jan % of survivors will have deficits Better outcome with dedicated Neuro ICU team Samuels et al, Neurocritcal Care 2001

30 Common location of cerebral aneurysms surrounding the circle of Willis. A, Middle cerebral (proximal to bifurcation, bifurcation, distal to bifurcation); (B) carotid terminus; (C) anterior choroidal; (D) superior hypophyseal; (E) anterior communicating (proximal to communicating artery, at communicating artery); (F) posterior communicating; (G) ophthalmic; (H) basilar artery (terminus, trunk); (I) superior cerebellar; (J) V4 segment, vertebral; (K) posterior inferior cerebellar; (L) pericallosal artery. Meyers P M et al. Stroke 2009;40:e366-e379 Copyright American Heart Association

31 Aneurysmal subarachnoid hemorrhage - imaging Blood is mostly in the cisterns and fissures, often accompanied by Intraventricular Hemorrhage (IVH) Hydrocephalus Cerebral edema Intraparechymal hemorrhage (IPH) Frontal lobe (A-comm) Temporal lobe (MCA)

32 SAH FIISHER GRADING SCALE 1 - No hemorrhage evident. 2 - SAH < 1mm thick 3 - SAH > 1mm thick 4 - SAH of any thickness with intra-ventricular hemorrhage (IVH) or parenchymal extension

33 ACA SAH pattern Blood in the interhemispheric fissure Hematoma in the corpus callosum IVH with hydrocephalus

34 Pericallosal Artery Aneurysm CTA

35 ANGIO with coiling

36 Vasospasm after SAH Diagnostic» TCD great screening and diagnostic tool» CTA or MRA may be used for confirmation of suspected vasospasm Diagnostic and therapeutic» Angiogram

37 Vasospasm after SAH

38 Vasospasm after SAH

39 Ischemic Stroke Imaging

40 The Ischemic Penumbra Core Infarct Ischemic Penumbra: zone of salvageable tissue surrounding core infarct

41 In a typical acute ischemic stroke, every minute the brain loses 1.9 million neurons 14 billion synapses 7.5 miles myelinated fibers -- Saver, Stroke 2006

42 Strategies in Acute Ischemic Stroke Therapy Proven» Recanalization» Supportive Care» Early Implementation of Secondary Prevention Experimental» Neuroprotection» Reperfusion via Collateral Enhancement

43 NINDS tpa Stroke Trials 1 and 2 p <.001 Hemorrhage tpa Placebo tpa Placebo Excellent Recovery (mrs 0-1) Death

44 Absolute imaging contraindication for IV TPA:»Evidence of intracranial hemorrhage In the first 3 hours virtually every patient has potentially salvageable tissue

45 Impact of Acute Ischemic Stroke Treatments NNT Benefit per 100 pts TPA 1-3h 3 32 Thrombectomy (ICA/M1) 5 20 TPA 3-4.5h 6 16 IA Lytics 7 14 Stroke Unit Aspirin 77 1

46 Ticking Clock Tissue Clock

47 Tissue Status Perfusion Status Vessel Status CBV CT PCT CTA Multimodal CT Multimodal MRI DWI PWI MRA Bioenergetic Compromise Hemodynamic Compromise Occlusions or Stenoses

48 Non contrast head CT Hyperdense vessel No Evidence of early ischemic changes in the territory

49 Early ischemic changes Effacement of the sulci Obscuration between the gray/white matter junction

50 Completed infarct frank hypodensity

51 CT Perfusion Imaging Cerebral blood volume - for core Time to peak - for tissue at risk Mismatch (penumbra) = Core / Tissue at risk

52 Vessel status CTA Collateral filling in the L MCA No visible contrast in the L ICA

53 MRI best for acute stroke Diffusion weighted imaging (DWI) Bright area = completed infarction Identifies infarcted tissue within minutes of onset The gold standard for visualization of core

54 Multimodal MRI DWI: Very tiny area of completed infarction GRE: No hemorrhage FLAIR: L ICA hyperintensity PERFUSION: Large area of tissue at risk MRA: No flow in the L ICA

55 FLAIR or T2 best for subacute and old strokes DWI FLAIR

56 MRI for acute stroke Advantages: Most accurate evaluation of stroke size and location Detailed brain tissue evaluation Potential pitfalls: Time consuming Cost Contraindicated for some patients

57 Case # 1 65 y/o male with acute global aphasia and right sided hemiplegia (NIHSS 20) Presented to ED within 1 hour of onset On full dose anticoagulation (contraindication for IV TPA)

58 Hyperdense L MCA No early ischemic changes

59 CTA Head L M1 occlusion

60 CTA Neck: - Severe R ICA stensosis - Complete L ICA occlusion

62 Tiny channel within the occluded L ICA Catheter passed through the channel in the L ICA terminus Injection through the catheter confirmed L MCA occlusion

63 Complete reperfusion after one pass with the Solitaire Device

64 L ICA remained occluded at the neck, but the L MCA was getting flow form the R ICA across the A-comm Final Angiogram MRA the following day

65 Patient was walking and talking in full sentences within 24h (NIHSS = 2) DWI sequence: Small area of infarcted tissue in the L frontal operculum

66 R ICA stenosis Ulcerated plaque causing 80% stenosis

67 Successful CEA 2 weeks later

68 Case 2 50 y/o male with acute aphasia and R hemiplegia (NIHSS 22) Witnessed onset at work 911 called EMS transported the patient to primary stroke center within 15 min (Riverside county)

69 Non contrast head CT

70 Patient received IV TPA No improvement noted Transferred to UCI Arrived at UCI 4.5 hours after onset Repeat exam showed persistent global aphasia and R sided hemiplegia NIHSS 22

71 Occluded L ICA Large Mismatch

72 INR suite» within 60 minutes of CT completion

73 Solitaire FR

75 Follow up Substantial improvement within 24 hours:» Patient is moving the right side against gravity, comprehends and utters simple words = NIHSS 10

76 CT CBV CTA Day 0 NIHSS 22 MRI FLAIR MRA Day 5 NIHSS 10

77 Acute Ischemic Stroke Care in the 21 st Century Symptoms Call EMS Primary Stroke Center Imaging Multimodal Imaging Comprehensive Stroke Center EMS IV Lytic Telemedicine INR Cath Lab Angiogram IA Mechanical or Lytic Stroke Unit

Imaging of Acute Stroke. Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group

Imaging of Acute Stroke. Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group Imaging of Acute Stroke Noam Eshkar, M.D New Jersey Neuroscience Institute JFK Medical Center Edison Radiology Group Modalities Non Contrast CT (NCCT) Contrast CT Angiography MRI MR Angiography Perfusion