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Edit Comment Close Premium member Presentation Transcript Slide 1: EVALUATING CEREBRAL VASCULATURE ANATOMICALLY AND FUNCTIONALLY Dr Md Miraj Mondal Chair person Dr. Dipanjan Banerjee Slide 2: Overview of cerebral circulation Evaluation of vessel Status Evaluation of vessel function POINTS TO DISCUSS Arteries to the Brain“Putting it all Together” : Arteries to the Brain“Putting it all Together” CAROTID SYSTEM VERTEBROVASILAR SYSTEM Overview of cerebral circulation : Overview of cerebral circulation CAROTID SYSTEM 70% VERTEBROBASILAR SYSTEM 30% Slide 5: A.O BT RCCA ICA ACA ACoA PCA BA PCoA VA ASA SCA PICA ECA MCA RSCA LSCA VA LCCA AAIC Each artery give rise to two set of branches : Each artery give rise to two set of branches Cortical branches Ramify on the surface of the Cerebral hemisphere and Supply the cortex. Central or perforating branches Pass deep into the substance of the cerebral hemisphere to supply the structure within it. Consist of six main groups. Central or perfortating branches : Central or perfortating branches Six main groups Anteromedial(1) - arises from ACA and ACoA Posteromedial(2) – arises from PCA and PCoA (which are median and unpaired) Right(3) and left(4) anterolateral so called striate arteries – arises mainly from the middle cerebral artey. Right(5) and left (6)posterolateral – arises from the posterior cerebral artery. 1 2 3 4 5 6 R L Deep brain structures : Deep brain structures Arteries of cerebral haemorrhage Overview of cerebral circulation : Overview of cerebral circulation Functional Areas of the Cerebral Cortex : Functional Areas of the Cerebral Cortex Middle Cerebral Artery Supply : Middle Cerebral Artery Supply BA AA WAA MC SC VC Middle Cerebral Artery : Middle Cerebral Artery Arises from the internal carotid Passes laterally under frontal lobe and between the temporal and frontal lobes M1 segment- lentriculostriate arteries supply basal ganglia and most of internal capsule Superior MCA branch- supplies lateral and inferior frontal lobe and anterior parts of parietal lobe Inferior MCA branch-supplies lateral temporal lobe, posterior parietal and lateral occipital lobe Middle Cerebral Artery : Middle Cerebral Artery Key Functional Areas Primary motor cortex for face, arm and leg Primary somatosensory cortex for face, arm, leg Brocas language area (Superior MCA) Wernickes language area (Inferior MCA) Parts of lateral frontal and parietal lobes used in 3D visual-spatial perceptions of own body, outside world and ability to interpret and/or express emotions Anterior Cerebral Artery : Anterior Cerebral Artery Anterior Cerebral Artery : Anterior Cerebral Artery Arises from internal carotid Supplies anterior portion of basal ganglia, corpus callosum, medial and superior portions of frontal lobe and anterior parietal lobe Key Functional Areas: Primary motor cortex for leg and foot areas, urinary bladder Motor planning in medial frontal lobe Middle and anterior corpus callosum- communication between hemispheres Anterior Cerebral Artery Posterior Cerebral Artery : Posterior Cerebral Artery Posterior Cerebral Artery : Posterior Cerebral Artery Blood supply for midbrain, hypothalamus and thalamus, posterior medial parietal lobe, corpus callosum, inferior and medial temporal lobe and inferior occipital lobe Key Functional Areas: Primary visual cortex 3rd nerve in midbrain Sensory control-temperature, pain, sleep, ADH Communication between hemispheres Posterior Cerebral Artery Cerebellar Blood Supply : Cerebellar Blood Supply Blood supply-own arteries from vertebrobasilar Superior cerebellar Anterior Inferior Posterior Inferior Major Functions Control of fine motor movement Coordinates muscle groups Maintains balance, equilibrium Collateral Circulation : Collateral Circulation Not all vessels have capability – lenticulostriate Common sites: External and internal carotid via opthalamic artery Intracranial vessels of the Circle of Willis Small cortical branches of ACA, MCA,PCA and cerebellar arteries Collateral Circulation : Collateral Circulation Effectiveness depends on vessel size Effectiveness depends upon speed of occlusion Atherosclerosis Circle of Willis: vessels are often narrow and cannot adapt for sudden onset of blockage Circle Of Willis : Circle Of Willis Circle of Willis : Circle of Willis Named after Thomas Willis An important anastomosis of arteries around the sella turcica Creates redundancies in cerebral circulation. Equalizes blood pressure in the brain and can provide collateral channels should one vessel become blocked Connects: Anterior-Anterior: Anterior communicating artery. Anterior-Posterior: Posterior communicating artery. Circle of Willis : Circle of Willis Circle of Willis Anterior Cerebral Artery (ACA) Anterior Communicating Artery (ACoA) Middle Cerebral Artery (MCA) Posterior Communicating Artery (PCoA) Posterior Cerebral Artery (PCA) Anterior Circulation Posterior Circulation Circle of Willis normal variant : Circle of Willis normal variant All component present – 20-25% Anomalies of the posterior circulation - 50% of all anatomic specimen. Common normal varient hypoplasia of one or both PCoA - 34% A hypoplasia or absent of A1 ACA & “fetal” origin of the PCA from ICA with hypoplasia or absent of P1 segment - 17% Infundibular dilation at the PCoA origin from the ICA -10% cases Circle of Willis normal variant : Circle of Willis normal variant Vertebrobasilar Circulation : Arise from the subclavian arteries Run alongside the medulla Blood supply for brainstem and cerebellum Key Functional Areas: Spinal cord tracts-pyramidal and spinothalamic Cranial nerves 3-12 Vertebrobasilar Circulation Vertebrobasilar Circulation (Contd.) : Vertebrobasilar Circulation (Contd.) 1- Posterior Cerebral 2- Superior Cerebellar 3- Pontine Branches of Basilar 4- Anterior Inferior Cerebellar 5- Internal Auditory 6- Vertebral 7- Posterior Inferior Cerebellar 8- Anterior Spinal 9- Basilar Portal Circulation in pituitary : Portal Circulation in pituitary Slide 29: VENOUS DRAINAGE Cerebral Veins : Cerebral Veins Drain the cortex and subcortical white matter. Drain the substance of the brain including basal ganglia,and diencephalon. Both superficial and deep veins communicate by anastomotic veins. Superficial veins: Deep veins: Cerebral Veins : Cerebral Veins Superficial veins 1. Superior cerebral veins (8-12 in no.) 2. Superficial middle cerebral vein 3. Inferior cerebral veins Deep veins 1. Internal cerebral veins ( right and left) 2. The paired basal veins (of ROSENTHAL) 3.The great cerebral vein of GALEN Slide 32: Venous drainage at a glance Superficial cerebral veins (lateral view) : Superficial cerebral veins (lateral view) Superior cerebral veins Superficial middle cerebral vein Superior cerebral veins Superficial cerebral veins : Superficial cerebral veins Vein of TROLARD Vein of LABBE Deep cerebral veins (medial view) : Deep cerebral veins (medial view) Internal cerebral vein Great cerebral vein of GALEN Basal vein Dural venous sinuses : Dural venous sinuses Superior sagital sinus Inferior sagital sinus Straight sinus Transverse sinus Cavernosus sinus Sigmoid sinuses Internal jugular vein Dural venous sinuses : Dural venous sinuses Dural venous sinuses : Dural venous sinuses Dural venous sinuses : Dural venous sinuses Functional aspects : Functional aspects Physiological consideration of cerebral circulation : Physiological consideration of cerebral circulation Ever active brain with little metabolic reserve Brain 2% of body wt receive 1/5th of cardiac output and 20% of oxygen Blood flow 750 ml /min Circulation time from ICA to internal jugular vein 7 seconds Slide 42: Regional changes in CBF are controlled by Systemic pressure (autoregulation) Response of vessels to metabolites e.g., C02 Innervation of vessels Between a mean systemic blood pressure of about 50 to 170 mmHg cerebral blood flow remains roughly constant : Between a mean systemic blood pressure of about 50 to 170 mmHg cerebral blood flow remains roughly constant Source: BRAIN’S DISEASE OF THE NERVOUS SYSTEM Slide 44: The compensatory mechanisms which maintain cerebral metabolic activity as cerebral perfusion pressure falls CBF=CPP/CVR CPP CBV CMRO2 OEF The threshold of cerebral ischemia at different levels of cerebral blood flow : The threshold of cerebral ischemia at different levels of cerebral blood flow Evaluation : Evaluation Anatomical Evaluation : Anatomical Evaluation 1. CT Angiography 2. MR Angiography 3. Ultrasound Techniques 4. Catheter Angiography Slide 48: • Requires injection of intravenous contrast agent • New generation helical scanners allow rapid evaluation of aortic arch, neck, and intracranial vessels with single injection • 80-100% accuracy compared with catheter angiography • Disadvantages: iodinated contrast agent, radiation exposure CT ANGIOGRAPHY Conventional catheter Angiography : Conventional catheter Angiography Gold standard – atherosclerotic stenosis and identifying and characterizing other pahology Including Aneurysm, Vasospasm, Intraluminal thrombi, Fibromascular dysplasia, AV fistula Vasculitis, and Collateral channels Conventional angiogram showing occlusion of left internal carotid- MCA bifurcation (left) and revascularization of the vessels after successful thrombectomy (right) : Conventional angiogram showing occlusion of left internal carotid- MCA bifurcation (left) and revascularization of the vessels after successful thrombectomy (right) Vasculitis : Vasculitis Beading typical of vasculitis Cerebral angiogram Cerbral Angiogram : Dural AVM : Cerbral Angiogram : Dural AVM Lateral view of the venous phase of a carotid angiogram showing lack of filling of the superior sagittal sinus (arrows). : Lateral view of the venous phase of a carotid angiogram showing lack of filling of the superior sagittal sinus (arrows). MR Angiography : MR Angiography • Noninvasive means to evaluate neck and intracranial vessels • Not reliable in identifying distal or branch intracranial occlusions • Sensitivity and specificity 70-100% compared to catheter angiography • Contrast-enhanced techniques – increased sensitivity • Subject to limitations of standard MRI MR Angiography : MR Angiography MR Venogram Latera Projection : MR Venogram Latera Projection MR Venogram Frontal Projection : MR Venogram Frontal Projection Ultrasound techniques : Ultrasound techniques Identify and quantify stenosis at the origin of the ICA TCD (Trance Cranial Doppler) – assessment of flow in MCA, ACA, PCA and Vertibrobasilar arteries TCD can detect stenotic lesion in the large intra cranial arteries because such lesion increases systolic flow velocity. Slide 61: CLINICAL ASSESSMENT Middle Cerebral Artery : Middle Cerebral Artery Most common stroke syndrome. contralateral weakness face, arm, and hand more than legs contralateral sensory loss face, arm, and hand more than legs visual field cut damage to optic radiations Middle Cerebral Artery (Contd.) : Middle Cerebral Artery (Contd.) Aphasia: language disturbances more likely with L. Hemi. damage especially men Broca's: production Wernicke's: comprehension ~ Middle Cerebral Artery (Contd.) : Middle Cerebral Artery (Contd.) Impaired spatial perception more likely after R. Hemi. damage spatial neglect dressing apraxia constructional apraxia topographagnosia ~ Focal ischemia : Focal ischemia Focal ischemia : Focal ischemia Anterior cerebral artery : Anterior cerebral artery Motor disturbance contra lateral distal leg urinary incontinence speech disturbance (may be more of a motor problem) apraxia of arm (sympathetic apraxia) if anterior corpus callosum is affected If bilateral may cause apathy, motor inertia, and muteness ~ Focal ischemia : Focal ischemia Posterior Cerebral Artery : Posterior Cerebral Artery Visual disturbances contralateral homonymous hemianopsia (central vision is often spared) L. Hemi: lesions alexia (with or without agraphia) Bilateral lesions: cortical blindness patients unaware they cannot see (Anton's syndrome) Memory impairment if temporal lobe is affected ~ Posterior Cerebral Artery (Contd.) : Posterior Cerebral Artery (Contd.) Proximal occlusion contralateral hemisensory loss, spontaneous pain and dysesthesia if thalamus affected (thalamic pain syndrome) contralateral severe proximal chorea (hemiballism) ~ Ischemic Stroke: Vertebrobasilar Syndrome : Ischemic Stroke: Vertebrobasilar Syndrome Diplopia Vertigo Coma at onset Crossed sensory loss Bilateral motor signs Isolated field defect Pure motor and sensory deficit Dysarthria Dysphagia Ischemic Stroke: Lacunar Syndromes : Ischemic Stroke: Lacunar Syndromes Makes up 25% of all ischemic strokes Presumed to be occlusion of single small perforating artery Predominantly deep white matter, BG, pons Blood vessel: lenticulostriate branches of the ACA and MCA 30% of patients are left dependant and some long term data suggests up to 25% have a second stroke within 5 years (Wardlaw, 2007) Ischemic Stroke: Lacunar Syndromes : Ischemic Stroke: Lacunar Syndromes Slide 74: Focal ischemia Watershed infarcts Balint´s Syndrome Haemorrhagic stoke - CT Scan : Haemorrhagic stoke - CT Scan Ischemic Stroke – CT scan : Ischemic Stroke – CT scan What about TIA’s? : What about TIA’s? Transient occlusion or reduction in cerebral blood flow Classic definition of TIA - symptoms lasting up to 24 hours Most “true” TIA’s last 2 to 20 minutes with complete symptom resolution - symptoms lasting more than 1 hour is most likely as a result of permanent damage from stroke Serious warning sign of an increased risk for stroke -5% occur within 48 hoursof a TIA. TIA Mechanism : TIA Mechanism Normal Blockage Clot dissolves Perfusion Physiology : Perfusion Physiology Normal blood flow 50 – 60 ml/100 gm/min < 35 ml/100gm/min protein synthesis stops (Tissue survives if no other CBF insult ) < 20 ml/100gm/min loss of neural function, tissue at risk <10ml/100gm/min irreversible cell death. Regional CBV Normal 4 -5 ml/100gm CT Perfusion : CT Perfusion Cerobrovascular physiology in acute stroke patients Irreversibly injured tissue Tissue at risk but potentially viable Option for evaluating physiology (function) PET SPECT XENON CT Perfusion MR Perfusion CT Ischemic Penumbra : Ischemic Penumbra Area around infarct Infarcted brain tissue dies quickly - brain cells within the penumbra remain viable for several hours after stroke Penumbra cells supplied with blood by collateral arteries Reperfusion important as circulation becomes inadequate with time Acute left MCA stroke with right hemiplegia, CT perfusion mean-transit time map showing delayed perfusion of the MCA distribution (blue) : Acute left MCA stroke with right hemiplegia, CT perfusion mean-transit time map showing delayed perfusion of the MCA distribution (blue) Predicted region of infarct (red) and penumbra (green) based on CT perfusion data : Predicted region of infarct (red) and penumbra (green) based on CT perfusion data Diffusion-Weighted Imaging : Diffusion-Weighted Imaging • Ischemia decreases the diffusion of water into neurons • Extracellular water accumulates • On DWI, a hyperintense signal • Present within minutes • Irreversible damage delineated • Non-salvageable tissue?? Perfusion-Weighted Imaging : Perfusion-Weighted Imaging • Tracks a gadolinium bolus into brain parenchyma • PWI detects areas of hypo perfusion –Infarct core (DWI area) AND –Ischemic penumbra DWI/PWI Mismatch : DWI/PWI Mismatch • Subtract DWI signal (infarct core) from the PWI signal (infarct core and ischemic penumbra) • DWI/PWI mismatch is the hypoperfused area that may still be viable (ischemic penumbra) DWI/PWI Mismatch : DWI/PWI Mismatch • Important clinical implications • May identify the ischemic penumbra • If there is a large mismatch, then reperfusion may be of benefit, even beyond the three hour tPA window • If there is no mismatch, there may be little benefit to thrombolytic therapy, even within the three hour window PWI hypoperfusion area DWI infarct core DWI/PWI Mismatch : DWI/PWI Mismatch DWI/PWI Mismatch : DWI/PWI Mismatch Diffusion Weighted Images : Diffusion Weighted Images MRI DWI Diffusion Weighted Images : Diffusion Weighted Images MRI DWI Diffusion Weighted Images : Diffusion Weighted Images MRI DWI Brain aneurysm common location : Brain aneurysm common location Aneurysm Symptoms : Symptoms Sudden headaches (most severe headache ever!) • Stiff neck, vomiting, nausea, vision or speech impairment, weakness in any part of the body, seizure, increased sensitivity to light, and loss of consciousness • Sudden death Aneurysm Diagnosis : Aneurysm Diagnosis CT Scans of the brain • Cerebral Catheter Angiography (“4-vessel” angiogram essential) • CT Angiography • MRI / MRA Slide 96: Rupture of an aneurysm at the tip of the basilar artery SAH Aneurysm at left MCA – CT Angiography : Aneurysm at left MCA – CT Angiography Future directions : Future directions Comprehensive Stroke Centre: Using angiography and endovascular technique 1. Intraarterial delivery of thrombolytic agents 2. Inserting stent within delicate intrcranial vessels 3.Balloon angioplasty of stenotic vessels 4.Intracranial aneurysm embolization 5.Mechanical thrombectomy to open occluded vessels Blood Oxygen Level Dependent fMRI (BOLD) : Blood Oxygen Level Dependent fMRI (BOLD) Signal increase Signal decrease Functional MRI – used to investigate brain function. Enables watching brain activity in vivo. Measures haemodynamic response. Changes in oxygen content of the blood occur as the result of neuronal activity. Summary : Summary Brain gets blood supply from two arterial system Carotid (70%) and Vertebrobasilar (30%) Venous drainage through superficial and deep vein and via dural sinuses Powerful cerebral auto regulation through wide range of mean arterial pressure. CT, CTA, MRI, MRA are the main imaging modalities to anatomical evaluation Perfusion scan, DWI helpful for recognition of diminished flow and delineating ischemic penembra Slide 101: WAITING FOR THE MOON EID MUBARAK Slide 102: EXTRA SLIDES Medial medullary syndrome : Medial medullary syndrome (occlusion of vertebral artery or of branch of vertebral or lower basilar artery) Signs and symptoms:Structures involved On side of lesion Paralysis with atrophy of half the tongue: Ipsilateral twelfth nerve On side opposite lesion Paralysis of arm and leg, sparing face; impaired tactile and proprioceptive sense over half the body: Contralateral pyramidal tract and medial lemniscus Lateral medullary syndrome : Lateral medullary syndrome (occlusion of any of five vessels may be responsible—vertebral, posterior inferior cerebellar, superior, middle, or inferior lateral medullary arteries) On side of lesion Pain, numbness, impaired sensation over half the face: Descending tract and nucleus fifth nerve Ataxia of limbs, falling to side of lesion: Uncertain—restiform body, cerebellar hemisphere, cerebellar fibers, spinocerebellar tract (?) Nystagmus, diplopia, oscillopsia, vertigo, nausea, vomiting: Vestibular nucleus Horner's syndrome (miosis, ptosis, decreased sweating): Descending sympathetic tract Dysphagia, hoarseness, paralysis of palate, paralysis of vocal cord, diminished gag reflex: Issuing fibers ninth and tenth nerves Loss of taste: Nucleus and tractus solitarius Numbness of ipsilateral arm, trunk, or leg: Cuneate and gracile nuclei Weakness of lower face: Genuflected upper motor neuron fibers to ipsilateral facial nucleus On side opposite lesion Impaired pain and thermal sense over half the body, sometimes face: Spinothalamic tract Slide 105: Total unilateral medullary syndrome (occlusion of vertebral artery): Combination of medial and lateral syndromes Lateral pontomedullary syndrome (occlusion of vertebral artery): Combination of lateral medullary and lateral inferior pontine syndrome Basilar artery syndrome (the syndrome of the lone vertebral artery is equivalent): A combination of the various brainstem syndromes plus those arising in the posterior cerebral artery distribution. Medial inferior pontine syndrome : Medial inferior pontine syndrome (occlusion of paramedian branch of basilar artery) On side of lesion Paralysis of conjugate gaze to side of lesion (preservation of convergence): Center for conjugate lateral gaze Nystagmus: Vestibular nucleus Ataxia of limbs and gait: Likely middle cerebellar peduncle Diplopia on lateral gaze: Abducens nerve On side opposite lesion Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract in lower pons Impaired tactile and proprioceptive sense over half of the body: Medial lemniscus Lateral inferior pontine syndrome : Lateral inferior pontine syndrome (occlusion of anterior inferior cerebellar artery) On side of lesion Horizontal and vertical nystagmus, vertigo, nausea, vomiting, oscillopia: Vestibular nerve or nucleus Facial paralysis: Seventh nerve Paralysis of conjugate gaze to side of lesion: Center for conjugate lateral gaze Deafness, tinnitus: Auditory nerve or cochlear nucleus Ataxia: Middle cerebellar peduncle and cerebellar hemisphere Impaired sensation over face: Descending tract and nucleus fifth nerve On side opposite lesion Impaired pain and thermal sense over half the body (may include face): Spinothalamic tract Medial midpontine syndrome : Medial midpontine syndrome (paramedian branch of midbasilar artery) On side of lesion Ataxia of limbs and gait (more prominent in bilateral involvement): Pontine nuclei On side opposite lesion Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract Variable impaired touch and proprioception when lesion extends posteriorly: Medial lemniscus Lateral midpontine syndrome : Lateral midpontine syndrome (short circumferential artery) On side of lesion Ataxia of limbs: Middle cerebellar peduncle Paralysis of muscles of mastication: Motor fibers or nucleus of fifth nerve Impaired sensation over side of face: Sensory fibers or nucleus of fifth nerve On side opposite lesion Impaired pain and thermal sense on limbs and trunk: Spinothalamic tract Medial superior pontine syndrome : Medial superior pontine syndrome (paramedian branches of upper basilar artery) On side of lesion Cerebellar ataxia (probably): Superior and/or middle cerebellar peduncle Internuclear ophthalmoplegia: Medial longitudinal fasciculus Myoclonic syndrome, palate, pharynx, vocal cords, respiratory apparatus, face, oculomotor apparatus, etc.: Localization uncertain—central tegmental bundle, dentate projection, inferior olivary nucleus On side opposite lesion Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract Rarely touch, vibration, and position are affected: Medial lemniscus Lateral superior pontine syndrome : Lateral superior pontine syndrome (syndrome of superior cerebellar artery) On side of lesion Ataxia of limbs and gait, falling to side of lesion: Middle and superior cerebellar peduncles, superior surface of cerebellum, dentate nucleus Dizziness, nausea, vomiting; horizontal nystagmus: Vestibular nucleus Paresis of conjugate gaze (ipsilateral): Pontine contralateral gaze Skew deviation: Uncertain Miosis, ptosis, decreased sweating over face (Horner's syndrome): Descending sympathetic fibers Tremor: Localization unclear—Dentate nucleus, superior cerebellar peduncle On side opposite lesion Impaired pain and thermal sense on face, limbs, and trunk: Spinothalamic tract Impaired touch, vibration, and position sense, more in leg than arm (there is a tendency to incongruity of pain and touch deficits): Medial lemniscus (lateral portion) Medial midbrain syndrome : Medial midbrain syndrome (paramedian branches of upper basilar and proximal posterior cerebral arteries) On side of lesion Eye "down and out" secondary to unopposed action of fourth and sixth cranial nerves, with dilated and unresponsive pupil: Third nerve fibers On side opposite lesion Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract descending in crus cerebri Lateral midbrain syndrome : Lateral midbrain syndrome (syndrome of small penetrating arteries arising from posterior cerebral artery) On side of lesion Eye "down and out" secondary to unopposed action of fourth and sixth cranial nerves, with dilated and unresponsive pupil: Third nerve fibers and/or third nerve nucleus On side opposite lesion Hemiataxia, hyperkinesias, tremor: Red nucleus, dentatorubrothalamic pathway Balint's syndrome : Balint's syndrome Bilateral visual association area lesions may result in Balint's syndrome, a disorder of the orderly visual scanning of the environment usually resulting from infarctions secondary to low flow in the "watershed" between the distal PCA and MCA territories, as occurs after cardiac arrest. Patients may experience persistence of a visual image for several minutes despite gazing at another scene (palinopia) or an inability to synthesize the whole of an image (asimultanagnosia). Embolic occlusion of the top of the basilar artery can produce any or all of the central or peripheral territory symptoms. The hallmark is the sudden onset of bilateral signs, including ptosis, pupillary asymmetry or lack of reaction to light, and somnolence. Ischemic Stroke: Vertebrobasilar Syndrome : Ischemic Stroke: Vertebrobasilar Syndrome Diplopia Vertigo Coma at onset Crossed sensory loss Bilateral motor signs Isolated field defect Pure motor and sensory deficit Dysarthria Dysphagia SPECT Cerebral Perfusion Imaging : SPECT Cerebral Perfusion Imaging Acute Stroke • Transient Ischemic Attacks • Differentiation of Recurr. tumor from Rad. Nec. • Refractory Complex Partial Seizure Disorder • Dementias, especially Alzheimer's disease • Diagnosis of Brain death Clinical Applications : Clinical Applications Normal Distribution: heterogeneous uptake, less uptake in the white matter vs gray matter, highest in the visual cortex and cerebellum, followed by the temporal, parietal, and frontal lobes and the basal ganglia Cerebral Infarction: more sensitive than CT and MRI in detecting cerebral ischemia during the first hours of stroke. Small infarcts, particularly those in the white matter (lacunar infarcts), may not be detected with SPECT or PET, Cannot distinguish between hemorrhagic and ischemic infarction. Acute phase: reduction of blood flow; subacute phase: luxury perfusion; Chronic phase: perfusion deficits Middle Cerebral Artery Supply : Middle Cerebral Artery Supply Slide 119: BOTTOM VIEW OF BRAIN Slide 121: Mechanisms of autoregulation Lacunar stroke : Lacunar stroke Thrombosis of small, deep penetrating arteries causing a small lake or cavity Seen with chronic hypertension Only minor deficits seen Necrotic brain cells reabsorbed with time, leaving a very small cavity or lacune MRI showing venous thrombosis of the sagittal sinus (arrows). : MRI showing venous thrombosis of the sagittal sinus (arrows). Hypertensive Encephalopathy, Vasogenic theory : Hypertensive Encephalopathy, Vasogenic theory MIDDLE CEREBRAL ARTERY DEEP BRANCHES : MIDDLE CEREBRAL ARTERY DEEP BRANCHES Magnetic Resonance Imaging : Magnetic Resonance Imaging Excellent for clearly visualizing structures in soft tissues, such as the brain. Very commonly used in: Diagnosis Image-guided surgery and therapy By adjusting scanning settings, specific features can be detected. MRI images are 2D slices through the body at a specific location. Picture of endovascular coiling procedure : Picture of endovascular coiling procedure Types of Neuroimaging : Types of Neuroimaging Structural Magnetic resonance imaging Computed tomography Ultrasound Functional Functional MRI Positron emission tomography Single photon emission computed tomography fMRI : fMRI Functional MRI – used to investigate brain function. Enables watching brain activity in vivo. Measures haemodynamic response. Changes in oxygen content of the blood occur as the result of neuronal activity. Blood Oxygen Level Dependent fMRI (BOLD) : Blood Oxygen Level Dependent fMRI (BOLD) Signal increase Signal decrease SAH : SAH Diseases/conditions affecting blood flow : Diseases/conditions affecting blood flow Atherosclerosis Hypertension (acute and chronic) Inflammatory diseases Aneurysms Arteriovenous malformations Cerebral amyloidosis Miscellaneous diseases CADASIL Moyamoya Diseases/conditions affecting blood vessels : Diseases/conditions affecting blood vessels Saccular 2-5% of cases Increases with age (mostly after 5th decade) In older patients, females>males In younger patients, males>females 40-70% rupture before death Occurs at bifurcations Degenerative lesions + hemodynamic stress Aneurysms (arterial dilatations) Diseases/conditions affecting blood vessels : Diseases/conditions affecting blood vessels Fusiform Commonly in basilar artery Elongation and tortuosity Advanced athersclerosis Aneurysms (arterial dilatations Slide 155: Watershed infarcts Hemorrhage : Hemorrhage Sudden onset of “the worst headache of my life” Mild nuchal rigidity Hemorrhage : Hemorrhage (Venous thrombosis) Common Effects by Hemisphere : Common Effects by Hemisphere Cerebral Malformations : Cerebral Malformations Cerebral Arteriovenous Malformation Cerebral Cavernous Malformation Cerebral Venous Malformation Capillary Malformation Anterior CirculationCommon Carotid Artery : Anterior CirculationCommon Carotid Artery Derived from Greek word “Karotis” = “To plunge into a deep sleep” Travels in the carotid sheath Common Carotid artery Internal Jugular vein Vagus nerve Frontal (Townes View) : Frontal (Townes View) Lateral View : Lateral View Lateral View : Lateral View Posterior Circulation : Posterior Circulation Vertebral-Basilar System Vertebral Arteries: From Latin word “verte” = “to turn / hinge”. Right Vertebral artery: distal to r. common carotid. Left Vertebral artery: first superior branch from left subclavian artery. Vertebral Arteries : Vertebral Arteries Vertebral Foramen : Vertebral Foramen Basilar Artery : Basilar Artery Basilar Artery (Waters View) : Basilar Artery (Waters View) Persistent Fetal Origin of PCA : Persistent Fetal Origin of PCA Persistent Fetal Origin of PCA : Persistent Fetal Origin of PCA Circle of Willis : Circle of Willis Angiographic Views : Angiographic Views Four Basic Views: AP View: Townes View: AP with slight cranial angulation Lateral View Waters View: AP with caudal angulation Slide 173: AP LATERAL WATERS TOWNES Extracranial Carotid : Extracranial Carotid Intracranial Anterior Circulation : Intracranial Anterior Circulation TOWNES LATERAL Posterior Circulation : Posterior Circulation WATER TOWNES “The Tree in the Head” : “The Tree in the Head” IMPORTANT RELATION IN CAVERNOUS SINUS : IMPORTANT RELATION IN CAVERNOUS SINUS SUPERFICIAL ARTERIES : SUPERFICIAL ARTERIES You do not have the permission to view this presentation. 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