1	Control #: 845 eSE #: Paper 39 Location of Focal Ischemic Changes, Perfusion Abnormalities and Angiographic Findings as Predictors of the Etiology of Acute Ischemic Stroke: A Pictorial Display
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3	INTRODUCTION You can view this presentation as a review of the subject, illustrated with cases, or view the cases as unknowns first and then follow the review. Click on the buttons on the left side of the screen to go to the part of the presentation you have selected and use the arrows to navigate. A list of abbreviations is available at the end of the presentation
4	STROKE ETIOLOGY The assessment of the ischemic stroke subtype is important, to define prognosis, risk of recurrence and choices for management. TOAST Diagnostic Classification: 1 Large artery atherosclerosis (embolus/thrombosis) 2 Cardioembolic 3 Lacunar, probable 4 Other determined etiology 5 Undetermined etiology Diagnoses are based on clinical features, brain imaging, cardiac imaging, duplex imaging of the extracranial vessels, arteriography, and laboratory assessments for a prothrombotic state. (TOAST = Trial of Org 10172 in Acute Stroke Treatment)
5	1. LARGE ARTERY ATHEROSCLEROSIS Clinical signs of cortical impairment, brainstem or cerebellar dysfunction. History of intermittent claudication, TIA in the same vascular territory, carotid bruit or diminished pulses. Significant (>50%) stenosis or occlusion of a major brain artery or branch cortical artery presumably due to atherosclerosis, no cardiac source of emboli. Cortical or cerebellar lesions, or brainstem or subcortical infarcts greater than 1.5 cm in diameter.
6	Case 10 - New onset aphasia and right hemiparesis
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9	2. CARDIOEMBOLISM Arterial occlusion presumably due to an embolus arising in the heart. At least one source of cardiac embolus. Evidence of prior stroke or TIA in more than one vascular territory. No large artery atherosclerotic sources of thrombosis or embolism. Cortical or cerebellar lesions, or brainstem or subcortical infarcts greater than 1.5 cm in diameter.
10	Case 2 – Aphasia and left leg weakness
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13	Case 3 – Transient left hand paresis
14	"DWI demonstrates a single tiny..." DWI demonstrates a single tiny focus of restricted diffusion in the right centrum semiovale FLAIR images show a few other punctate foci of high signal in the deep white matter MRA of the brain is unremarkable
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16	Dissection Common locations: Cervical ICA 2–3 cm distal to the carotid bulb Vertebral artery at the level of the first and second cervical vertebrae Multiple-vessel disease Angiography: Double lumen and intimal flap. Arterial stenosis. tapered end, string sign or flame shape , aneurysm formation and arterial occlusion. Appearance evolves with time. MRI: Narrowed eccentric flow void, surrounded by a crescent shaped, hyperintense area expanding the vessel diameter T1 hyperintense signal form mural hematoma
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20	Vasculitis Heterogeneous group of CNS disorders Inflammation and necrosis of the blood vessels. Infectious, non infectious, primary, and secondary types. Stroke in multiple territories. Variable angiographic findings including stenosis of small or large vessels and aneurysm formation.
21	Case 8 – Left sided weakness and visual changes
22	"DWI demonstrates areas of acute..." DWI demonstrates areas of acute infarct with magnetic susceptibility indicative of hemorrhage, in the right parietal and occipital lobes. FLAIR image also multiple ischemic lesions of different ages in both cerebral hemispheres. Perfusion (mean time to enhance) is abnormal in the same area of restricted diffusion. MRA shows occlusive changes in the right MCA branches. The left MCA has multiple stenosis with a beaded appearance.
23	Moyamoya Progressive occlusion of branches of the circle of Willis. Collateral network results in "puff of smoke“ appearance in angiograms Children in the first decade or adults in the third or fourth decade.
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25	"DWI demonstrates multiple small foci..." DWI demonstrates multiple small foci of restricted diffusion in the left MCA territory. There is encephalomalacia in the right frontal lobe. MRA shows occlusive changes in the MCA and in the proximal ACA branches, Hypertrophied lenticulostriate arteries (arrows) and PCA branches provide collateralization.
26	Venous infarct Associated conditions: pregnancy/puerperium, infection, dehydration, oral contraceptive use Imaging findings: Parenchymal changes: Multiple ischemic or edematous lesions adjacent to the affected sinuses or veins. Associated hemorrhage in the early stages Replacement of the vascular flow void of the sinus with the signal of the thrombus
27	Case 1 – Mental status changes
28	"DWI demonstrated bilateral areas of..." DWI demonstrated bilateral areas of restricted diffusion in the centrum semiovale, with multiple foci magnetic susceptibility Gradient-echo images confirm multiple bilateral small hemorrhages MRV shows occlusion of the sagittal sinus
29	Fibromuscular dysplasia Nonatherosclerotic, noninflammatory arterial disease. Most commonly involves the renal and carotid arteries. Angiographic classification includes the multifocal type, with multiple stenoses and the 'string-of-beads' appearance that is related to medial FMD, and tubular and focal types. Cervicocranial FMD can be complicated by dissection or can be associated with intracerebral aneurysms.
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34	STROKE IN SPECIFIC ARTERIAL TERRITORIES
35	INTERNAL CAROTID ARTERY Branches: Anterior choroidal artery, ACA and MCA Collaterals: Ophthalmic artery Contralateral ICA Posterior cerebral artery Infarcts may involve variable extents of the MCA, one or both ACA and occasionally the PCA depending on the configuration of the circle of Willis.
36	Case 9 – Right hemiparesis and aphasia
37	"DWI shows multiple foci of..." DWI shows multiple foci of acute ischemia in the left MCA territory. There is a diffusion-perfusion mismatch, with two concentric penumbras in the left ICA territory (lines). MRA shows occlusion at the origin of the left ICA (arrow). DSA reveals acute occlusion of the left ICA with an irregular end. Ophthalmic collaterals (small arrows) reconstitute the supraclinoid ICA, which is re-occluded.
38	ANTERIOR CEREBRAL ARTERY Branches: A1: Medial lenticulostriate A2: Recurrent artery of Heubner, Orbito-frontal, Fronto-polar artery, Callosomarginal artery, Pericallosal artery, Anterior communicating artery Anatomic variants: Azygos anterior cerebral artery Absent A1 segment Collaterals: Contralateral ACA, PCA splenial branches
39	Case 5 - Acute onset bilateral leg weakness.
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41	MIDDLE CEREBRAL ARTERY Branches: M1:Lateral lenticulostriate arteries, Temporopolar, Orbitofrontal, Anterior temporal. M2, M3 and M4: Operculofrontal, Central sulcus arteries, Anterior parietal artery, Posterior parietal artery, Angular artery: superior temporal gyrus, Middle temporal artery, Posterior temporal artery branches Distal to the origin of the anterior temporal branch, two main trunks are identified: anterior and posterior division. Collaterals: lenticulostriate perforators, leptomeningeal arteries
42	Case 11 - Acute right hemiparesis and aphasia
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44	POSTERIOR CEREBRAL ARTERY Branches: P1: Mesencephalic, Thalamic perforators P2: Medial and lateral posterior choroidal branches P3: Parietooccipital, Calcarine, Posterior pericallosal, Anterior temporal, Posterior temporal Anatomic variants: Fetal origin from ICA via posterior communicating artery Collaterals: Perisplenial ACA branches Temporal MCA branches
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47	VERTEBROBASILAR SYSTEM Branches: Posterior inferior cerebellar artery (PICA) Basilar artery Anterior inferior cerebellar artery (AICA) Superior cerebellar artery (SCA) Collaterals: Internal carotid artery via posterior communicating artery, cervical muscular branches to vertebral arteries
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50	PEARLS
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52	PEARLS
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54	PEARLS A few named small vessels result in lacunar infarcts with a classic appearance. Left to right: Recurrent artery of Heubner, Artery of Percheron, Anterior choroidal artery.
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56	Case 1 – Mental status changes
57	"DWI demonstrated bilateral areas of..." DWI demonstrated bilateral areas of restricted diffusion in the centrum semiovale, with multiple foci magnetic susceptibility Gradient-echo images confirm multiple bilateral small hemorrhages DSA shows occlusion of the sagittal sinus
58	Case 2 – Aphasia and left leg weakness
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60	Case 3 – Transient left hand paresis
61	"DWI demonstrates a single tiny..." DWI demonstrates a single tiny focus of restricted diffusion in the right centrum semiovale FLAIR images show a few other punctate foci of high signal in the deep white matter MRA of the brain is unremarkable
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65	Case 5 - Acute onset bilateral leg weakness.
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68	"DWI demonstrates multiple small foci..." DWI demonstrates multiple small foci of restricted diffusion in the left MCA territory. There is encephalomalacia in the right frontal lobe. MRA shows occlusive changes in the MCA and in the proximal ACA branches, Hypertrophied lenticulostriate arteries (arrows) and PCA branches provide collateralization.
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71	Case 8 – Left sided weakness and visual changes
72	"DWI demonstrates areas of acute..." DWI demonstrates areas of acute infarct with magnetic susceptibility indicative of hemorrhage, in the right parietal and occipital lobes. FLAIR image also multiple ischemic lesions of different ages in both cerebral hemispheres. Perfusion (mean time to enhance) is abnormal in the same area of restricted diffusion. MRA shows occlusive changes in the right MCA branches. The left MCA has multiple stenosis with a beaded appearance.
73	Case 9 – Right hemiparesis and aphasia
74	"DWI shows multiple foci of..." DWI shows multiple foci of acute ischemia in the left MCA territory. There is a diffusion-perfusion mismatch, with two concentric penumbras in the left ICA territory (lines). MRA shows occlusion at the origin of the left ICA (arrow). DSA reveals acute occlusion of the left ICA with an irregular end. Ophthalmic collaterals (small arrows) reconstitute the supraclinoid ICA, which is re-occluded.
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78	Case 11 - Acute right hemiparesis and aphasia
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85	ABBREVIATIONS ACA anterior cerebral artery AICA anterior inferior cerebellar artery CABG coronary artery bypass grafting CNS central nervous system CT computed tomography CTA computed tomography angiography DSA digital subtraction angiography DWI diffusion weighted images FLAIR fluid-attenuated inversion recovery FMD fibromuscular dysplasia ICA internal carotid artery MCA middle cerebral artery MIP maximum intensity projection MR magnetic resonance MRA magnetic resonance angiography MRI magnetic resonance imaging MRV magnetic resonance venography PCA posterior cerebral artery PICA posterior inferior cerebellar artery SCA superior cerebellar artery TIA transient ischemic attack TOF time of flight tPA tissue plasminogen activator
86	REFERENCES Adams HP, Bendixen BH, Kappelle LJ, et al. Classification of Subtype of Acute Ischemic Stroke. Definitions for Use in a Multicenter Clinical Trial. Stroke 1993;24:35-41 Flis CM, Jäger HR, Sidhu PS. Carotid and vertebral artery dissections: clinical aspects, imaging features and endovascular treatment. Eur Radiol. 2007;17:820-34 Goldstein LB, Jones MR, Matchar DB, et al. Improving the Reliability of Stroke Subgroup Classification.Using the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) Criteria. Stroke 2001;32:1091-1097 Hoffman HJ. Moyamoya disease and syndrome. Clin Neurol Neurosurg. 1997;99 Suppl 2:S39-44 Hupperts RM, Lodder J, Heuts-van Raak EP, et al. Infarcts in the anterior choroidal artery territory. Anatomical distribution, clinical syndromes, presumed pathogenesis and early outcome. Brain 1994;117:825- 834 Lee LJ, Kidwell CS, Alger J, et al. Impact on Stroke Subtype Diagnosis of Early Diffusion-Weighted Magnetic Resonance Imaging and Magnetic Resonance Angiography. Stroke 2000;31:1081-1089 Lell M, Fellner C, Baum U. Evaluation of Carotid Artery Stenosis with Multisection CT and MR Imaging: Influence of Imaging Modality and Postprocessing. AJNR Am J Neuroradiol. 2007,28:104-110 Matheus MG, Castillo M. Imaging of Acute Bilateral Paramedian Thalamic and Mesencephalic Infarcts. AJNR Am J Neuroradiol. 2003, 24:2005–2008 Momjian-Mayor I, Baron JC. The pathophysiology of watershed infarction in internal carotid artery disease: review of cerebral perfusion studies. Stroke 2005, 36:567-577 Plouin PF, Perdu J, La Batide-Alanore A, et al. Fibromuscular dysplasia. Orphanet J Rare Dis. 2007; 2: 28