Arterial and Cerebrovascular Conditions

• Arterial Vasculature supplies the brain

Examples of CVA

• Aneurysm: bulging of blood vessels

• Atherosclerosis: plaque buildup in arteries

• Dissection: tear in the wall of a blood vessel

• Arteriovenous Malformation: abnormal connection between arteries and veins

• Infarction and Ischemia: lack of blood supply to brain tissue

• Venous Vasculature drains blood from the brain

• The presence of a Blood Brain Barrier protects the brain from harmful substances

Arterial Cerebro-Vascular System Main Branches

• Vertebral and Basilar Arteries

• Supply the cerebellar and cerebral regions

• Feed spinal and pontine arteries

• Internal Carotid Arteries

• Supply cerebral arteries

• Circle of Willis: an anastomosis of vessels ensuring continuous blood flow to the brain

Circle of Willis Vertebrobasilar System

• Vertebral Artery and Basilar Artery play a crucial role
• Posterior Cerebral Artery (PCA) is supplied
• Superior Cerebellar Artery (SCA) is supplied
• Anterior Inferior Cerebellar Artery (AICA) is supplied
• Posterior Inferior Cerebellar Artery (PICA) is supplied
• Provides Anterior and Posterior Spinal Arteries

Circle of Willis Internal Carotid System

• Composed of the Internal Carotid Artery
• Posterior Communicating Artery is fed
• Middle Cerebral Artery (MCA) is fed
• Anterior Communicating Artery is fed . Anterior Cerebral Artery (ACA) is fed
• Ophthalmic Artery is fed
• Supplies pontine arteries and internal auditory arteries

Internal Carotid System Component Arteries

• Internal Carotid Artery
• Ophthalmic Artery
• Posterior Communicating Artery
• Anterior Communicating Artery
• Anterior Cerebral Artery (A1, A2)
• Middle Cerebral Artery
• M1 Proximal Branch
• M2 Segments
• Lenticulostriate Arteries
• Anterior Choroidal Arteries

Vertebro-Basilar System Component Arteires

• Vertebral Artery

• Basilar Artery

• Spinal Artery

• Posterior Inferior Cerebellar Artery

• Anterior Inferior Cerebellar Artery

• Superior Cerebellar Artery

• Posterior Cerebral Artery (P1, P2)

• Thalamo-Geniculate Artery also contributes to brain vasculature

• Posterior Choroidal Arteries also contribute to brain vasculature

• Quadrigeminal Artery also contributes to brain vasculature

• Posterior Spinal Artery also contributes to brain vasculature

• Anterior Spinal Artery also contributes to brain vasculature

Latex Filled Vasculature Inferior View

• Anterior Communicating Artery

• A1 Segment of ACA

• M1 Segment of MCA

• Internal Carotid Artery

• Posterior Communicating Artery

• PCA

• Basilar Artery

• Vertebral Artery

• Superior Cerebellar Artery

• AICA

• PICA

• Atherosclerosis occurs at bifurcations of major vessels in the Circle of Willis, affecting collateral blood supply

• Basilar artery involvement results in no collateral perfusion

• Aneurysms are ballonings, with berry aneurysms at the base of the brain (Circle of Willis) and micro-aneurysms intracerebral.

• Dissections involve bleeding within a vessel (internal carotid).

• Arteriovenous Malformation is intracerebral

CVA Risks and Complications

• Atherosclerosis

• Can cause occlusive stroke, infarction or hemorrhage

• Aneurysm and Dissection

• Can cause hemorrhage, infarction (death of tissue)

• Arteriovenous Malformation (AVM): abnormal tangle of blood vessels

Case Study Aneurysm

• Factors: Patient history of smoking, atherosclerosis, coronary artery disease, previous bypass.

• Symptoms: Sudden headache, common aneurysm, bi-frontal headache / mild nuchal rigidity

• Diagnosis: diffuse subarachnoid haemorrhage, hydrocephalus

• Angiogram reveals saccular berry aneurysm in anterior communicating artery

• Sclerotic plaques weaken vessel wall, predisposing to aneurysms

• Internal Carotid vascular supply feeds anterior choroidal and Lenticulostriate arteries

• Basilar Artery Vascular Supply is supported by PCA, Thalamoperforator/Thalamogeniculate/Posterior Choroidal

Internal Vascular Supply:

• The Internal Carotid supplies:
• Anterior Choroidal artery, basal ganglia, hippocampus, and the posterior limb of the internal capsule
• The M1 proximal branch of the MCA supplies lenticulostriate arteries, the basal ganglia, and the posterior limb of the internal capsule
• The Proximal ACA supplies penetrating branches, the recurrent artery of Heubner, basal ganglia, limbic structures, and the anterior limb of internal capsule
• The Basilar Artery:
• PCA supplies thalamoperforator, thalamogeniculate and posterior choroidal

Ischemia vs Hypoxia vs Infarction

• Ischemia: Lack of blood flow

• Hypoxia: lack of oxygen

• Infarction: Cell Death due to circulation failure

• Occlusive Stroke: Closure of vessel

• Hemorrhagic stroke: Rupture of vessels

• Global cerebral ischemia: includes a diffuse hypoxic / ischemic encephalopathy, cardiac arrest, shock etc

• Focal cerebral ischemia: related to embolism, thrombus, and vasculitis

• Intra-cerebral hemorrhage: caused by lacunar infarction, Charcot-Bouchard micro-aneurysms

• Penetrating arteries to thalamus/basal ganglia/internal capsule are END ARTERIES which causes no collateral perfusion

• Pallidal hemorrhage: affects the posterior limb internal capsule, resulting in hemi-paresis (motor loss)

• Thalamic hemorrhage: affects the ventral posterior nucleus of thalamus, resulting in hemi-sensory loss

• Etat lacunaire: progressive dementia, cranial nerve, dysarthria, dysphagia, gag reflex, emotional imbalance

Case Study Stroke

• Indications: diabetes, hypertension, slurred speech (dysarthria), right-sided/facial weakness, hemiparesis
• Diagnosis: occlusion of lenticulate-striate branches off left M1 segment into internal capsule (left internal capsule infarct)

Cortical Supply:

• Midline Cortical Supply:
• ACA: calloso-marginal, peri-callosal artery
• PCA: medial temporal, occipital
• External Cortical Supply:
• ACA: anterior-medial frontal lobe
• MCA: M3 (superior - lateral frontal, parietal, temporal lobe), M4 (inferior - parietal, inferior temporal, occipital)

Case Studies Cerebral Arteries

• Case #1: Indicates mild leg/arm weakness, Babinski's sign, poor motor control is related to right anterior cerebral artery (ACA)

• Case #2: Indicates blurry vision and it's related to left posterior cerebral artery (PCA)

• Watershed Infarction: related to hypo perfusion, proximal limb weakness ( ACA/MCA) or aphasia (PCA/MCA)

Cerebral Veins

• Important Veins: Superior Sagittal Sinus, Inferior Sagittal Sinus, Straight Sinus, Transverse and Cavernous Sinus

• Superficial Veins: superior sagittal sinus and cavernous sinus

• Deep Vein: Includes Great Vein of Galen

• Internal cerebral veins, basal veins of Rosenthal, & great cerebral vein drain into the internal jugular vein.

• Other venous drainage includes inferior sagittal sinus, superior/inferior anastomotic, and turca

• Venous drainage thrombosis results in negative delta sign

• The blood brain barrier features astrocytes that induce endothelial tight junctions/BBB, is maintained by pericytes, contains a metabolic barrier - MAO

Interfacing blood to CSF

• Factors include lipid, receptor, and ion exchange
• Functions include shock absorber and metabolite extraction
• CSF Barrier is composed of capillary filtration and epithial transport
• CSF exhibits low protein and is low ionic
• CSF has increased risk of protein because of meningitis and red blood cells

Doping Brain

• Oral L-DOPA is permenant
• Carbidopa is used to decease metabolism
• After those two steps are addressed, L-DOPA Converts to Dopamine inside the brain

Test your knowledge of arterial conditions, including aneurysms, atherosclerosis, and arterial dissection. Understand the causes, risks, and potential cerebrovascular events associated with these conditions. Review the impact of arterial issues on blood flow and brain structures.