Duplex sonography of the brain-supplying arteries

Description

Als schnelles Diagnoseverfahren ist Ultraschall mittlerweile weit verbreitet. Der Band liefert einen Überblick über das gesamte Gebiet der sonographischen Gefäßdiagnostik an den hirnversorgenden Arterien – einschließlich der klinischen Aspekte. Einstiegslektüre und Nachschlagewerk zugleich, bietet der Band leichte Orientierung durch einheitliche Gliederung in Techniken, Krankheitsbilder, Befunde und Fehlerquellen. Fallbeispiele, Lern- und Arbeitsmittel helfen, die Grundlagen zu verstehen und Befunde zu interpretieren. Mit 300 neuen Abbildungen. Preface to the Seventh Edition Notes on the Use of the Book Contents Editors and Authors Part I: Basics 1: Anatomical Basics 1.1 Classification of Supraaortic Arteries 1.2 Aortic Arch Branches 1.2.1 Normal Anatomy Note Practical Tips 1.2.2 Anatomical Variations Note Summary 1.3 Extracranial Course of the Carotid Arteries 1.3.1 Normal Anatomy Practical Tips 1.3.2 Anatomical Variations Bifurcation Variants Variants of the Carotid Bulb Practical Tips Kinkings and Coilings Background Information Practical Tips Additional Carotid Artery Branches Practical Tips Variations of the Vessel Diameter Summary 1.4 Cervical Course of the Vertebral Artery 1.4.1 Normal Anatomy Practical Tips 1.4.2 Anatomical Variations Summary 1.5 Intracranial Course of the Internal Carotid Artery 1.5.1 Normal Anatomy Practical Tips 1.5.2 Anatomical Variations Practical Tips Summary 1.6 Vertebrobasilar Arteries 1.6.1 Normal Anatomy 1.6.2 Anatomical Variations Summary 1.7 Intracerebral Arteries 1.7.1 Normal Anatomy 1.7.2 Anatomical Variations Practical Tips Summary 1.8 Collateral Connections 1.8.1 Extracranial Collaterals to the Anterior Cerebral Circulation Practical Tips Background Information 1.8.2 Extracranial Collaterals to the Posterior Cerebral Circulation Background Information 1.8.3 Intracranial Collateral Connections Practical Tips 1.8.4 Collaterals in Subclavian Artery Occlusions Summary 1.9 Cerebrovascular Territories 1.9.1 Normal Anatomy 1.9.2 Anatomical Variations References 2: Physiological Basics 2.1 Regulation of Arterial Blood Flow 2.1.1 Demand Regulation 2.1.2 Autoregulation Summary 2.2 Cerebral Blood Flow Characteristics 2.2.1 Cerebral Blood Supply Background Information Note 2.2.2 Regulation of Cerebral Blood Flow Background Information Oxygen Extraction Rate Note 2.2.3 Cerebral Perfusion Pressure Summary 2.3 Arterial Flow Summary 2.4 Flow Disturbance 2.4.1 Turbulence Background Information 2.4.2 Flow Separation Practical Tips Summary 2.5 Pulsatile Flow in Arteries Practical Tips Summary Reference 3: Basics of Ultrasound Technology 3.1 Basic Concepts of Diagnostic Ultrasound 3.1.1 Ultrasound Frequencies 3.1.2 Methods of Sound Transmission 3.1.3 Sound Probes Background Information 3.1.4 Ultrasound Investigations Background Information Summary 3.2 Biological Ultrasound Parameters 3.2.1 Reflection 3.2.2 Scattering Practical Tips 3.2.3 Attenuation Note Background Information Summary 3.3 Technical Parameters of Diagnostic Ultrasound 3.3.1 Parameters of the Pulse-Echo Technique 3.3.2 Resolution Practical Tips 3.3.3 Measures to Improve Ultrasound Image Quality Background Information Practical Tips Practical Tips 3.4 Contrast-Assisted Procedures 3.4.1 Signal Amplified Doppler and Duplex Sonography 3.4.2 Contrast Harmonic Imaging 3.4.3 Stimulated Acoustic Emission (SAE) Summary 3.5 Safety Aspects of Ultrasound Diagnostics 3.5.1 Thermal Effects Technical Risk Factors Biologically Induced Risk Factors Practical Tips 3.5.2 Mechanical Effects (Cavitation) Summary References 4: Basics of Sonographic Flow Detection 4.1 Doppler Dependent Procedures 4.1.1 Doppler Effect 4.1.2 Application of the Doppler Effect to Blood Vessels Practical Tips 4.1.3 Doppler Techniques 4.1.4 Acoustic Presentation of Doppler Signals Background Information Summary 4.2 Doppler Independent Techniques 4.2.1 B-Flow Technique 4.2.2 Possible Applications of B-flow Technique Summary 4.3 Diagnostically Relevant Flow Parameters 5: Flow Assessment Using the Doppler Spectrum 5.1 Methodology of Spectrum Analysis 5.1.1 Fast Fourier Transformation (FFT) Summary 5.2 Diagnostic Parameters of the Doppler Spectrum 5.2.1 Detection of Flow Direction Practical Tips 5.2.2 Detection of Flow Velocity Background Information Systolic Maximum Frequency End Diastolic Maximum Frequency Mean Value Systolic Maximum Frequency End Diastolic Maximum Frequency Mean Value Practical Tips 5.2.3 Flow Disturbances Note 5.2.4 Flow Characteristics (Pulsatility) Practical Tips Resistance Index (RI) Pulsatility Index (PI) Diastolic Ratio Practical Tips Practical Tips Summary 5.3 Special Features of Pulsed Doppler Technology 5.3.1 Flow Assessment at Defined Tissue Depths Size of the Sample Volume Practical Tips 3D-Extension of the Sample Volume 5.3.2 Measurement of Flow Velocity Note ``Unfavorable´´ Insonation Angle Vessel Displayed Too ``short´´ Note Poststenotic Flow Disturbances Note Elongations and Kinkings Eccentrically Running Stenoses Practical Tips 5.3.3 Measurement of Flow Volume Background Information Alternative to rCBF Measurements ``Abnormal´´ Vessel Diameters Note Problem of Vascular Pulsations Problem of Vascular Borders Problem of Cross Section Calculation Problem of the Resolution Note Note Practical Tips 5.3.4 Problems with the Aliasing Effect Note Summary References 6: Flow Assessment Using Color Coding 6.1 Technical Principles of Color Coded Imaging 6.1.1 Color Coded Flow Detection 6.1.2 Parameters of the ``color window´´ 6.1.3 Methods of Color Coded Presentation 6.1.4 Resolution of Color Coded Imaging Axial Resolution Lateral Resolution Note 6.1.5 Special Methods of Color Coded Image Processing Summary 6.2 Influencing Variables on Color Coded Flow Imaging 6.2.1 The Insonation Angle 6.2.2 Aliasing Note Practical Tips 6.2.3 Lower Cut-Off Frequency (Wall Filter) 6.2.4 Frame Rate Background Information 6.2.5 Color Gain and Color Balance Summary 6.3 Basic Techniques of Color Coded Duplex Examination 6.3.1 Optimized Vessel Imaging (``Low-flow setting´´) Possibilities for Improving the ``color filling´´ of Vessels (``Low-Flow Setting´´) Practical Tips 6.3.2 Optimized Flow Imaging Summary Part II: Investigation Techniques 7: Extracranial Doppler Sonography 7.1 Indications Indications for CW Doppler Sonography of the Extracranial Arteries Supplying the Brain 7.2 Technical Settings 7.3 Examination of the Periorbital Arteries 7.3.1 Physiological Principles 7.3.2 Examination Procedure Practical Tips Practical Tips 7.3.3 Criteria for the Evaluation of Findings Antegrade Signal with Enddiastolic Flow Antegrade Signal Without Enddiastolic Flow (Approximate) Zero Flow Practical Tips Retrograde Signal Practical Tips Increase in Flow Decrease in Flow Background Information 7.3.4 Possible Errors Summary 7.4 Examination of the Carotid Bifurcation 7.4.1 Sound Distribution Levels 7.4.2 Examination Procedure Practical Tips Location Pulsatility Compression Maneuvers Practical Tips 7.4.3 Diagnostic Criteria 7.4.4 Possible Errors Summary 7.5 Examination of the Vertebral Artery 7.5.1 Examination Procedure 7.5.2 Diagnostic Criteria Summary 7.6 Examination of the Subclavian Artery 7.6.1 Examination Procedure 7.6.2 Diagnostic Criteria 7.6.3 Possible Errors Summary 8: Extracranial Duplex Sonography 8.1 Indications Practical Tips Indications for Extracranial Duplex Examination 8.2 Device Settings Practical Tips 8.2.1 Ultrasound Transducers 8.2.2 B-mode Imaging 8.2.3 Color Coded Imaging Note 8.2.4 Doppler Spectrum Practical Tips Practical Tips Practical Tips Recommended ``default settings´´ of the Duplex Device for the Examination of Extracranial brain Arteries 8.3 Examination of the Carotid Bifurcation 8.3.1 Diagnostic Sections 8.3.2 Examination Procedure Practical Tips Unclear Findings in Longitudinal Section Quantification of Stenoses Practical Tips 8.3.3 Diagnostic Criteria Using B-mode Imaging Note Practical Tips 8.3.4 Diagnostic Criteria Using Color Coded Imaging Practical Tips 8.3.5 Diagnostic Criteria Using the Doppler Spectrum Practical Tips Practical Tips Summary 8.4 Examination of the Vertebral Artery 8.4.1 Examination Procedure Practical Tips Practical Tips Prevertebral Course (V1 Segment) Vertebral Origin (V0 Segment) Atlas Loop (V3 Segment) 8.4.2 Diagnostic Criteria Practical Tips Practical Tips Flow Disturbances Practical Tips Summary 8.5 Error Sources 8.5.1 B-mode Imaging Practical Tips 8.5.2 Doppler Spectrum The Most Important Sources of Error When Determining Angle-Corrected Flow Velocity 8.5.3 Color Coded Imaging Summary 9: Transcranial Doppler Sonography 9.1 Indications 9.2 Device Settings 9.2.1 Standard Setting 9.2.2 Insufficient Temporal Bone Window 9.3 Examination Procedure 9.3.1 Transtemporal Access Practical Tips Practical Tips Middle Cerebral Artery Posterior Cerebral Artery 9.3.2 Transorbital Access Practical Tips 9.3.3 Transnuchal Access Summary 9.4 Diagnostic Criteria 9.4.1 Doppler Frequencies Additional Information 9.4.2 Flow Disturbances 9.4.3 Pulsatility Summary Reference 10: Transcranial Duplex Sonography 10.1 Indications 10.2 Device Settings Practical Tips 10.2.1 Transducers 10.2.2 B-mode Imaging 10.2.3 Color Coded Imaging Practical Tips 10.2.4 Doppler Spectrum Practical Tips Practical Tips Recommended ``default settings´´ of the Duplex Device on the Intracranial Arteries Supplying the Brain 10.3 B-mode Sonography of the Brain 10.3.1 Ultrasonic Anatomy of the Brain 10.3.2 Ventricle Width Measurements Summary 10.4 Color Coded Examination Transcranial Duplex Examination in Non-Pathological Cases 10.4.1 Transtemporal Access Practical Tips Carotid T Practical Tips Top of Basilar Artery Practical Tips 10.4.2 Transnuchal Access Practical Tips Curved Vessel Course Vessel Course Outside the Insonation Plane Summary 10.5 Diagnostic Criteria 10.5.1 B-mode Imaging 10.5.2 Color Coded Imaging 10.5.3 Dopppler Spectrum Analysis Practical Tips 10.5.4 MCA/ICA Index (Lindegaard Index) 10.5.5 Asymmetry Index (Zanette Index) 10.5.6 Flow Disturbances Practical Tips 10.5.7 Pulsatility Summary 10.6 Duplex Sonography of the Intracranial Veins References 11: Assessment of Intracranial Collateral Pathways 11.1 Indications Indications for Assessment of Intracranial Collateral Pathways 11.1.1 Assessment of Existing Collateral Channels 11.1.2 Assessment of Future Collateral Pathways 11.2 Examination Procedure and Criteria 11.2.1 Localization of Collateral Vessels Practical Tips 11.2.2 Functional Assessment of Collateral Pathways Practical Tips Summary 11.3 Findings in Different Collateral Pathways 11.3.1 Extra-Intracranial Collaterals 11.3.2 Circle of Willis Note 11.3.3 Leptomeningeal Anastomoses Sonographic Evidence of Collateral Pathways in the Closure of the Extracranial Internal Carotid Artery Summary References 12: Cerebrovascular Reserve Capacity 12.1 Indications Practical Tips 12.2 Examination Procedure and Criteria Background Information Practical Tips Practical Tips Hyperventilation-Apnea Test Practical Tips Practical Tips Summary References Part III: Findings in Stenoses and Occlusions 13: Stenoses and Occlusions of the Extracranial Carotid Artery 13.1 Stenoses of the Internal Carotid Artery 13.1.1 Definition of the Degree of Stenosis Note Practical Tips Background Information 13.1.2 Main Criteria for Stenosis Grading Practical Tips Resolution Problems of Color Coding Color Artifacts Practical Tips Background Information Filiform Stenoses Contralateral Carotid Occlusions Short-/Long-Distance Stenoses Tandem Stenoses Narrow Vessels Carotid Dissection Collapsed Vessel Note Expected Poststenotic Velocities Comparison with Intrastotic Flow Velocity 13.1.3 Additional Criteria for Stenosis Grading Note Progress Observations Tandem Stenoses Hyperperfusion Maximum of a Stenosis Not Detected Heavily Curved Vessel Course 13.1.4 Comparison with Other Methods 13.1.5 Follow-up Monitoring 13.1.6 Possible Errors Short-Distance Stenosis Acoustic Shadow Tandem Stenosis Collateralisation Primary Slim Vessel Eccentric Stenosis Incorrect Insonation Angle Overestimating Color Coding Note Summary 13.2 Stenoses of the Internal Carotid Artery Close to the Skull Base Practical Tips 13.2.1 Diagnostic Criteria Prestenotic Flow Velocity Search for Multiple Stenoses Practical Tips 13.2.2 Possible Errors Note 13.3 Occlusions of the Internal Carotid Artery 13.3.1 Main Diagnostic Criteria Practical Tips Background Information 13.3.2 Additional Criteria for Occlusion Diagnosis 13.3.3 Differential Diagnostic Aspects 13.3.4 Possible Errors Summary 13.4 Stenoses and Occlusions of the External Carotid Artery 13.4.1 Diagnostic Criteria in Stenoses Practical Tips 13.4.2 Diagnostic Criteria in Occlusions 13.4.3 Possible Errors Summary 13.5 Stenoses and Occlusions of the Common Carotid Artery 13.5.1 Diagnostic Criteria in Stenoses 13.5.2 Diagnostic Criteria in Occlusions Summary References 14: Stenoses and Occlusions of the Main Cerebral Arteries 14.1 Special Features of Intracranial Vascular Diagnostics 14.1.1 Numerous Causes of Intracranial Occlusions 14.1.2 Limitation to Flow Parameters 14.2 Stenoses of the Intracranial Carotid Artery 14.2.1 Diagnostic Criteria Note Practical Tips Practical Tips 14.2.2 Accuracy and Possibilities of Error Note Degree of Stenosis Extracranial = Intracranial Degree of Stenosis Extracranial Intracranial Degree of Stenosis Extracranial Intracranial Long-Distance Extra-/Intracranial Stenosis (Dissection) Practical Tips Summary 14.3 Stenoses of the Middle Cerebral Artery 14.3.1 Definition of the Degree of Stenosis 14.3.2 Diagnostic Criteria Practical Tips 14.3.3 Differentiating Increased Flow Velocities 14.3.4 Accuracy and Possibilities of Error Summary 14.4 Occlusions of the Intracranial Internal Carotid Artery 14.4.1 Diagnostic Criteria Additional Information 14.4.2 Accuracy and Possibilities of Error Note Occlusion Before the Origin of the Ophthalmic Artery Occlusion Before the Origin of the Posterior Communicating Artery Occlusion After the Origin of the Posterior Communicating Artery Summary 14.5 Occlusions of the Middle Cerebral Artery 14.5.1 Diagnostic Criteria Carotid T-occlusion Proximal Main Stem Obstruction of the Middle Cerebral Artery Practical Tips Distal Main Stem Obstruction of the Middle Cerebral Artery Main Branch Occlusion of the Middle Cerebral Artery Practical Tips Occlusion of a Smaller Branch of the Middle Cerebral Artery 14.5.2 Accuracy and Possibilities of Error Summary 14.6 Stenoses and Occlusions of the Other Cerebral Base Arteries 14.6.1 Stenoses and Occlusions of the Anterior Cerebral Artery Examination of the Anterior Cerebral Artery Examination of the Anterior Communicating Artery Note 14.6.2 Stenoses and Occlusions of the Posterior Cerebral Artery Normal Posterior Communicating Artery Hypoplastic Posterior Communicating Artery Summary References 15: Stenoses and Occlusions in the Vertebrobasilar System 15.1 Stenoses and Occlusions of the Subclavian Artery 15.1.1 Auscultation and Palpation Practical Tips Practical Tips 15.1.2 Sonographic Findings in the Subclavian Artery Doppler Spectrum Note Color Coded Imaging 15.1.3 Sonographic Findings in the Vertebral Artery Beginning Subclavian Steal Effect Practical Tips Incomplete Subclavian Steal Effect Complete Subclavian Steal Effect Note Summary 15.1.4 Sonographic Findings in the Basilar Artery 15.2 Stenoses and Occlusions of the Brachiocephalic Trunk Note 15.3 Stenoses of the Vertebral and Basilar Artery 15.3.1 Special Features of Vascular Diagnostics in the Vertebral Artery Note 15.3.2 Stenoses at the Origin of the Vertebral artery (V0) 15.3.3 Stenoses in the Prevertebral Course of the Vertebral Artery (V1) 15.3.4 Stenoses in the Intertransversal Course of the Vertebral Artery (V2) Unstenosed Lumen Visible Comparison with the V0/V1 Section Vertebrobasilar Transition 15.3.5 Stenoses in the Area of the Atlas loop (V3) 15.3.6 Stenoses of the Intracranial Vertebral artery (V4) and Basilar Artery Direct Assessment Indirect Assessment Practical Tips Summary 15.4 Occlusions of the Vertebral and Basilar Arteries 15.4.1 Occlusions of the Proximal Vertebral Artery (V0-V1) 15.4.2 Occlusions in the Middle Section of the Vertebral Artery (V2-V3) Practical Tips 15.4.3 Occlusions of the Distal Vertebral Artery (V4) Note Practical Tips 15.4.4 Occlusions of the Basilar Artery Note Summary References Part IV: Findings in Special Questions 16: Arteriosclerotic Vascular Diseases 16.1 Diffuse Arteriopathies 16.1.1 Diffuse Thickening of Vessel Walls Risk Factors Described in the Literature for the Occurrence of Increased IMT in the Common Carotid Artery Note 16.1.2 Dilated Arteriopathies Note Summary 16.2 Circumscribed Arteriopathies 16.2.1 Pathophysiology of Focal Arteriopathies Frequency Distribution of Focally Circumscribed, Arteriosclerotic Vascular stenoses and Occlusions Practical Tips Note 16.2.2 Sonographic Assessment of the Degree of Stenosis 16.2.3 Sonographic Assessment of Plaque Morphology Note Information on Plaque Surface Information on Plaque Structure Information on Acoustic Shadowing 16.2.4 Clinical Significance of Sonographic Plaque Parameters Sonomorphology Versus Surgical Specimen Sonomorphology Versus Spontaneous Course Summary 16.2.5 Ultrasound Parameters for the Indication of Carotid Surgery References 17: Inflammatory Vascular Diseases Causes of Secondary Systemic Vasculitis 17.1 Takayasu Arteritis Early Diagnosis Monitoring of Progress Cerebral Hemodynamics Summary 17.2 Cranial Arteritis 17.2.1 Findings in the Superficial Temporal Artery Halo Sign Absence of Vascular Pulsations Presence of a Vessel Occlusion Reduced Flow Velocity Visible Vessel Wall during Compression Case Study 17.1: Takayasu Arteritis 17.2.2 Findings on the Other Vessels Summary 17.3 Primary Cerebral Vasculitis 17.4 Secondary Cerebral Vasculitis 17.4.1 Vasculitis in Purulent Meningitis 17.4.2 Other (Para)Infectious Vasculitis Summary Case Study 17.2: Cranial Arteritis Case Study 17.3: Primary Cerebral Vasculitis Case Study 17.4: Parainfectious Vasculitis References 18: Arterial Dissections Note Internal Dissection External Dissection Note 18.1 Primary Extracranial Carotid Dissections Intramural Bleeding Detection of a ``False Lumen´´ Intimal Flap Detection Short-Distance, ``Pointy´´ Stenoses (So-Called Bishop´s Mitre) 18.2 Primary Intracranial Carotid Dissections Case Study 18.1: Aortic Arch Dissection Short-Distance Dissection Close to the Skull Base Case Study 18.2: Traumatic Dissection of the Common Carotid Artery Note Long-Distance, Proximally Extending Dissection Case Study 18.3: Traumatic Dissection of the Extracranial Internal Carotid Artery Case Study 18.4: Carotid and Vertebral Dissection After Marathon Run Note Vascular Occlusion Due to Dissection Dissection in the Intracranial Carotid T-Area Note Case Study 18.5: Incorrect Findings of a Carotid Dissection with Anatomical Variant 18.3 Dissections of the Vertebral Artery Case Study 18.6: Vertebral Artery Dissection After Chiropractic Treatment Case Study 18.7: Spontaneous Vertebral Artery Dissection in the Distal V3 Segment Note Practical Tips Summary References 19: Other Vascular Diseases 19.1 Fibromuscular Dysplasia (FMD) Additional information Note Practical Tips Case Study 19.1: Fibromuscular Dysplasia of the Internal Carotid Artery Summary 19.2 Moya Moya Disease Case Study 19.2: Moya Moya Syndrome on Both Sides Case Study 19.3: Moya Moya Syndrome with Bilateral Extra-intracranial Bypass Case Study 19.4 Long-term Moya Moya Syndrome Summary 19.3 Aneurysms 19.3.1 Extracranial Aneurysms Secondary Aneurysm Pseudoaneurysm ``False´´ Aneurysm (Aneurysm Spurium) Carotid Bulb Other Vessel Course 19.3.2 Intracranial Aneurysms Summary 19.4 Carotidodynia 19.5 Reversible Cerebral Vasoconstriction Syndrome References 20: Vascular Anomalies and Malformations 20.1 Kinkings and Coilings 20.1.1 Sonographic Assessment Problem of Cranial Localization Practical Tips Problem of Angle Correction 20.1.2 Clinical Significance Summary 20.2 Hypoplasia of the Carotid Artery 20.2.1 Sonographic Assessment Differential Diagnostic Considerations for Suspected ``Hypoplasia´´ of the Internal Carotid Artery 20.2.2 Clinical Significance Summary 20.3 Hypoplasia of the Vertebral Artery 20.3.1 Sonographic Assessment Note Note Practical Tips 20.3.2 Clinical Significance Indications of an Intermittent Compression Syndrome of the Vertebral Artery Case Study 20.1: Head Rotation-dependent Compression of the Vertebral Artery Case Study 20.2: ``Vertebrobasilar Insufficiency´´ in Severe Vertebral Hypoplasia Note Summary 20.4 Arteriovenous Malformations and Fistulas 20.4.1 Sonographic Assessment Sonographic Findings in the Feeder Vessels of Arteriovenous Fistulas and Angiomas 20.4.2 Clinical Significance Frequent Causes of Pulse Synchronous Ear Noises Local Findings Findings in Feeding Vessels Case Study 20.3: Retroauricular AV Fistula Intracranial Local Findings Findings in the Periorbital Arteries Extracranial Duplex Findings Summary References 21: Ultrasound Diagnostics in Acute Stroke 21.1 Emergency Diagnostics 21.1.1 Special Features of Emergency Diagnostics Note Practical Tips 21.1.2 Selection of the Sonographic Method 21.1.3 Localization Diagnostics Occlusion of the Proximal Internal Carotid Artery Occlusion of the Distal Internal Carotid Artery Carotid T-occlusion Practical Tips Main Stem Occlusion of the Middle Cerebral Artery Distal Main Stem Occlusion or Multiple Branch Occlusions of the Middle Cerebral Artery Occlusion of the Proximal Vertebral Artery (V1/2 Segment) Occlusion of the Distal Vertebral Artery (V3/4 Segment) Basilar Artery Occlusion 21.1.4 Clinical Significance Summary 21.2 Monitoring 21.2.1 Recanalization of Vascular Occlusions Additional Information 21.2.2 Hyperperfusion Use of the MCA/ICA Index Summary 21.3 Etiologic Assessment 21.3.1 Differential Diagnosis of Stroke Etiology 21.3.2 Hemodynamic Assessment Summary References 22: Cerebral Vasospasms 22.1 Spontaneous Vasospasms Case Study 22.1 (After Arning et al. 1998) Summary 22.2 Vasospasms in Subarachnoid Hemorrhages 22.2.1 Basic Methodological Problems Underestimation of Vasospasms Overestimation of Vasospasms Only Direct Assessment Reliable Considering Angle Dependence Consideration of Collateral Supply 22.2.2 Sonographic Assessment Summary 22.3 Vasospasms in Inflammatory Brain Diseases References 23: Diagnostics for Increased Cerebral Pressure and Cerebral Circulatory Arrest 23.1 Assessment of Elevated Cerebral Pressure 23.1.1 Doppler Sonographic Findings Note 23.1.2 Influence of Disrupting Factors 23.2 Cerebral Circulatory Arrest 23.2.1 Doppler Sonography Versus Other Procedures 23.2.2 Doppler and Duplex Sonographic Findings Practical Tips Practical Tips 23.2.3 Examination Procedure Practical Tips Practical Tips 23.2.4 Problems of Transtemporal Assessment Tachycardia Arteriovenous Fistulas Prolonged Brain Death Open Fontanel Large Open Skull Injuries 23.2.5 Requirements for the Examiner 23.2.6 Requirements for the Status Report Summary References 24: Ultrasound in Revascularization Procedures 24.1 Revascularizing Interventions of the Carotid Artery 24.1.1 Intraoperative Monitoring in Carotid Surgery 24.1.2 Postoperative Findings Practical Tips Practical Tips Additional Information Proximal Border of Resection Practical Tips Suture Area External Carotid Artery Distal End of the Resection Secondary Aneurysm Real Aneurysm False Aneurysm Infected Patch Kinking Formations Additional Information 24.1.3 Carotid Stenting Additional Information Stent Dislocation Stent Fracture Kinking at the Distal Stent End 24.1.4 Hyperperfusion Syndrome Summary 24.2 Supraaortic Bypass Operations Summary 24.3 Extra-intracranial Bypass Surgery 24.3.1 Preoperative Diagnostics Evidence of Hemodynamic Failure Evidence of an Intact External Carotid Artery Evidence of a Large Caliber Superficial Temporal Artery 24.3.2 Postoperative Findings Assessment of Pulsatility Measurement of Flow Volume Assessment of the Intracranial ``Watershed´´ Note Summary References 25: Cardiac Right-Left Shunt 25.1 Anatomy and Pathophysiology 25.2 Clinical Significance 25.3 Detection by Echocardiography 25.4 Detection by Transcranial Doppler sonography (PFO Test) 25.4.1 Ultrasonic Contrast Medium Practical Tips 25.4.2 Doppler Sonographic Settings 25.4.3 Performing the PFO Test Additional Information Practical Tips Procedure of the Transcranial PFO Test Additional Information Practical Tips 25.4.4 Doppler Sonographic Findings 25.4.5 Side Effects Summary References 26: Transorbital Sonography 26.1 Examination Procedure Note 26.1.1 B-Scan of the Optic Nerve and Optic Sheath 26.1.2 Imaging of the Central Artery 26.2 Increased Intracranial Pressure 26.3 CSF Hypotension 26.4 Central Retinal Artery Occlusion Note Summary References Part V: Glossary and Standard Values 27: Glossary of Sonographic Terms 28: Standard Values 28.1 Extracranial Duplex Sonography 28.1.1 Common Carotid Artery 28.1.2 Internal Carotid Artery 28.1.3 External Carotid Artery 28.1.4 Vertebral Artery 28.2 Transcranial Doppler Sonography 28.2.1 Middle Cerebral Artery 28.2.2 Anterior Cerebral Artery 28.2.3 A Cerebri Posterior 28.2.4 Basilar Artery 28.3 Transcranial Color Coded Duplex Sonography 28.3.1 Middle Cerebral Artery (M1 Segment) 28.3.2 Anterior Cerebral Artery (A1 Segment) 28.3.3 (P1 Segment) 28.3.4 Vertebral Artery (V4 Segment) 28.3.5 Basilar Artery 28.4 Summary of Important Standard Values References Index