Cerebrovascular Evaluation PDF
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The University of Lahore
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Summary
This document provides a comprehensive overview of the cerebrovascular system, covering various arteries and their functions. It details the anatomy, characteristics, and clinical significance of each artery, including common carotid, external and internal carotid, vertebral and basilar, as well as the circle of Willis. It also explains the clinical significance of their flow and variations.
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MUHAMMAD YOUSAF SENIOR LECTURER MS MIT (UOL) B.Sc (Hons) MIT (UHS) ARDMS (USA) CEREBROVASCULAR EVALUATION Common Carotid Artery (CCA): Right CCA originates from the innominate artery; Left CCA originates from the aortic arch (second branch from arch) Courses cep...
MUHAMMAD YOUSAF SENIOR LECTURER MS MIT (UOL) B.Sc (Hons) MIT (UHS) ARDMS (USA) CEREBROVASCULAR EVALUATION Common Carotid Artery (CCA): Right CCA originates from the innominate artery; Left CCA originates from the aortic arch (second branch from arch) Courses cephalad on anterolateral neck Distal portion enlarges to form the carotid bulb and then branches into the internal and external carotid arteries Bifurcates at the level of the upper border of the thyroid cartilage Combination of ICA and ECA flow, higher resistance with good diastolic flow Bulb area normally exhibits areas of flow separation on color Doppler and short periods of systolic flow reversal; caused by swirling of the flow as it enters the enlarged segment External Carotid Artery (ECA): Anterior/Medial branch of CCA Smaller diameter than ICA Terminates at the superficial temporal artery Superior Thyroidal Artery-first branch, visible in most patients Other branches include ascending pharyngeal, lingual, facial, maxillary, occipital, posterior auricular and superficial temporal “Some Angry Ladies Fight Off PMS.” Superficial temporal artery used to perform the temporal tap; will demonstrate flow oscillations during diastole ECA branches supply neck, thyroid, face and scalp High resistance, pulsatile flow with minimal antegrade diastolic flow; rapid acceleration and deceleration of flow Internal Carotid Artery (ICA): Posterior/Lateral branch of CCA; courses cephalad to enter the cranium Larger diameter than ECA Siphon Area - distal ICA courses anteriorly then medially, then posteriorly forming an "S“ Siphon reduces flow and has increased risk for flow reducing lesions such as atheroma and thrombus No visible branches extracranially Ophthalmic artery - first branch from siphon area inside the cranium, NOT visible on carotid evaluation; Branches into nasal, frontal & supraorbital arteries Anterior choroidal artery and posterior communicating artery are the other two main intracranial branches of the distal ICA Terminates at the bifurcation into the ACA and MCA once it reaches the circle of willis Supplies 75% of arterial blood to the brain Low resistance flow with increased antegrade diastolic flow; slow acceleration and deceleration of flow Periorbital Arteries: Supraorbital Artery - originates from the ophthalmic artery and joins the superficial temporal artery(branch of ECA) Frontal Artery - originates from ophthalmic artery and joins the superficial temporal artery(branch of ECA); supplies nose Both are potential collateral pathways for ECA to ICA flow Vertebral Arteries (VA): Supplies 10-25% of blood flow to the brain Course within foramina of the pedicles of the vertebra of the C1 through C6, enter the skull through foramen magnum Converge into the basilar artery after entering the posterior skull Left vertebral artery usually larger Branches supply the medulla and inferior cerebellum Right vertebral branches from the proximal right subclavian Left vertebral branches from the proximal left subclavian Flow velocities normally
