This book offers both an outstanding overview of the principles of neurosonology and
a casebook posing interesting angiologic questions. Ultrasound anatomy, technical
aspects of clinical application, and the advantages and limitations of ultrasound are
reviewed with reference to conventional angiography, MR and CT angiography. Thirty
selected cases from the authors’ extensive experience gained at the Department of
Neurology at the Charité University Hospital, Berlin, Germany are then discussed. The
patient history and initial hypothesis are followed by detailed assessment of the extraand intracranial color-coded duplex sonography findings and additional diagnostic
procedures. Videos of the same cases on the DVD provide insight into the diagnostic
method.
Features:
• Complete extra- and intracranial arterial and venous ultrasound examination
• More than 750 high-quality illustrations, including full-color Doppler images
• 30 selected clinical cases graded from easy to difficult in terms of
neurosonologic complexity
• DVD with almost 100 videoclips brings ultrasound anatomy and real cases
right to your screen!
Neurosonology and Neuroimaging of Stroke
Neurosonology is a key modality in diagnosis and management of cerebrovascular
disease and especially of stroke. Now, in this book, this non-invasive, real time
imaging method is placed firmly in the clinical context.
Valdueza/Schreiber
Roehl/Klingebiel
The essentials in
cerebrovascular
disease management
Neurosonology and
Neuroimaging of Stroke
José M. Valdueza
Stephan J. Schreiber
Jens-Eric Roehl
Randolf Klingebiel
Neurosonology and Neuroimaging of Stroke offers neurologists, neuroradiologists,
and all physicians treating patients with cerebrovascular disease an authoritative
guide to this indispensable diagnostic tool.
ISBN 978-3-13-141871-5
MediaCenter.thieme.com
www.thieme.com
Valdueza_Stroke_141871 1
plus e-content online
09.04.2008 10:26:49 Uhr
Neurosonology and
Neuroimaging of Stroke
José M. Valdueza, MD
Professor of Neurology
Director Center of Neurology
Segeberger Clinic Group
Bad Segeberg, Germany
Stephan J. Schreiber, MD
Senior Neurologist
Department of Neurology
Charité University Hospital
Berlin, Germany
Jens-Eric Roehl, MD
Neurologist
Department of Neurology
Charité University Hospital
Berlin, Germany
Randolf Klingebiel, MD
Head of Department of Neuroradiology
Charité University Hospital
Berlin, Germany
766 illustrations
Thieme
Stuttgart · New York
Library of Congress Cataloging-in-Publication Data
Neurosonology and neuroimaging of stroke / José M.
Valdueza ... [et al.].
p. ; cm.
Includes bibliographical references and index.
ISBN 978-3-13-141871-5 (alk. paper)
1. Cerebrovascular disease--Ultrasonic imaging--Atlases. 2. Cerebrovascular disease--Ultrasonic imaging--Case studies. I. Valdueza,
José M.
[DNLM: 1. Cerebrovascular Disorders--radiography--Atlases. 2.
Cerebrovascular Disorders--radiography--Case Reports. 3. Cerebrovascular Disorders--ultrasonography--Atlases. 4. Cerebrovascular
Disorders--ultrasonography--Case Reports. 5. Cerebral Angiography--methods--Atlases. 6. Cerebral Angiography--methods--Case
Reports. 7. Cerebrovascular Circulation--Atlases. 8. Cerebrovascular
Circulation--Case Reports. WL 17 N4935 2008]
RC388.5.N4634 2008
616.8'107543--dc22
2008007225
© 2008 Georg Thieme Verlag,
Rüdigerstrasse 14, 70469 Stuttgart, Germany
http://www.thieme.de
Thieme New York, 333 Seventh Avenue,
New York, NY 10001, USA
http://www.thieme.com
Cover design: Thieme Publishing Group
Typesetting by Primustype Hurler, Notzingen, Germany
Printed by Druckerei Grammlich, Pliezhausen, Germany
ISBN 978-3-13-141871-5
123456
Important note: Medicine is an ever-changing science undergoing
continual development. Research and clinical experience are continually expanding our knowledge, in particular our knowledge of
proper treatment and drug therapy. Insofar as this book mentions
any dosage or application, readers may rest assured that the authors,
editors, and publishers have made every effort to ensure that such
references are in accordance with the state of knowledge at the time
of production of the book.
Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any
dosage instructions and forms of applications stated in the book.
Every user is requested to examine carefully the manufacturers’ leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules
mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such
examination is particularly important with drugs that are either
rarely used or have been newly released on the market. Every dosage
schedule or every form of application used is entirely at the user’s
own risk and responsibility. The authors and publishers request
every user to report to the publishers any discrepancies or inaccuracies noticed. If errors in this work are found after publication, errata
will be posted at www.thieme.com on the product description page.
Some of the product names, patents, and registered designs referred
to in this book are in fact registered trademarks or proprietary names
even though specific reference to this fact is not always made in the
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This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow
limits set by copyright legislation, without the publisher’s consent, is
illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing, preparation of microfilms, and electronic data processing and storage.
V
Foreword
Ultrasound has undoubtedly changed the face of medicine
during the past two decades. Ultrasound testing is safe,
quick, and relatively inexpensive compared with other
imaging modalities. To be able to perform multiple repeat
studies safely has made ultrasound an ideal modality to
monitor various conditions and abnormalities. Echocardiography has revolutionized cardiology, and sonography
of the pregnant uterus has become indispensable for obstetrical care. Compared to ultrasound of the heart and
uterus, ultrasound exploration of the nervous system and
its supply arteries and veins is a relatively new field. The
parts of the nervous system and the cervico-cranial arteries and veins are quite heterogeneous and anatomically
dispersed, making Neurosonology much more complex
and diverse than insonating a single organ. While most
cardiologists and obstetricians have become very familiar
with ultrasound use and images in their specialties,
neurosonology is used extensively by only very few neurologists and neurosurgeons. Cerebrovascular specialists
have become familiar with neck and transcranial ultrasound reports and results, yet very few of these subspecialists actually perform or interpret the examinations. For
these reasons the present monograph fulfills a large void
and will prove extremely useful for neurologists, neurosurgeons, and neuroradiologists and for all physicians caring for patients with cerebrovascular diseases.
This monograph is very systematically organized. The
first part (A) contains the basic principles of neurosonology and of cerebrovascular disease. Ultrasound principles
are described and heavily illustrated with very useful dia-
grams and images. The anatomy, pathology, and pathophysiology of the cervico-cranial arteries are discussed
and illustrated in detail. Other vascular imaging techniques (CT and MR angiography and dye contrast catheter
angiography) are also discussed, compared, and illustrated
in detail in Part A. The quantity, quality, and didactic utility
of the diagrams, cartoons, and illustrations is exceptional
in my experience.
The second part of the monograph (Part B) is unique.
Most individuals learn by example, the case method of
teaching, rather than by general principles alone. Part B
contains 30 case scenarios grouped according to the expected difficulty of the neurosonology exploration and
interpretation. The clinical findings are noted and the
imaging results are shown in detail. The discussions are
thorough and most useful in understanding the techniques
and results. Part B helps clinicians and neuroradiologists
put into practical use the principles enunciated in Part A.
Part B also emphasizes potential difficulties and conundrums that are likely to confound even experienced
neurosonologists.
This book will take pride of place on my library shelf and
I anticipate using it often as a reference. It is a superb
addition to the literature on neurosonology and of cerebrovascular diagnosis and management.
Louis R Caplan MD
Professor of Neurology, Harvard University
Boston, Massachusetts, USA
VI
Foreword
Neurovascular disease, in particular stroke, has tremendously contributed to Neurology developing into a therapeutic speciality. Today’s complex treatment strategies of
acute stroke have been established thanks to innumerable
clinical studies. This requires sophisticated pathophysiological and detailed clinical knowledge from the attending
physician, as often the neuroanatomical condition as well
as the functional situation are of therapeutic relevance.
Various diagnostic methods such as magnetic resonance
imaging, computed tomography, angiography as well as
diagnostic ultrasound, which is the only bedside technique, are in continuous development and competition.
This book looks at competing and complementary
methods from the perspective of diagnostic ultrasound.
One of the key issues of this book is the exploration of
the advantages and disadvantages of the diagnostic tools
used in cerebrovascular diagnostics, their specificity and
sensitivity as well as their pitfalls. In the first section, the
reader will find detailed and comprehensive text of the
duplex ultrasound technique, including precise and pragmatic instructions, which will help the reader acquire a
fundamental understanding of Neurosonology.
In the second, more extensive part of the book, the
clinical advantages and disadvantages of various vascular
diagnostic methods are demonstrated in relation to ultrasound, by means of 30 case histories. These have been
carefully selected from the wide field of neurovascular
diseases ranging from acute stroke, arteritis and sinus
venous thrombosis to vascular malformations.
Hereby the book offers beginners as well as experienced
practitioners the opportunity to approach ultrasound diagnostics not only from the perspective of a specialized
diagnostician but also from the perspective of a clinician
who is struggling to gain the relevant information. It therefore closes a gap in the currently available literature about
the use of neurosonological methods and at the same time
offers extensive opportunities to “train” clinical diagnostic
thoughts in cerebrovascular diseases.
I am particularly proud that the work in the Neurological
Department of the Charité University Teaching Hospital in
Berlin, where I have been Director for 15 years, is honored
with this book. I can highly commend the authors of this
book as they have been outstanding colleagues and companions for many years.
I give my best wishes to them and their book with its
original concept, and I hope that it will quickly become a
standard text and reference source for many who work
within the speciality, and beyond.
Prof. Karl M. Einhäupl
Professor and Chairman
Department of Neurology
Charité University Hospital
Berlin, Germany
VII
Table of Contents
Part A
1
2
3
Principles and Rules
Flow and Ultrasound Basics . . . . . . . . . . . . . . . . . .
Flow Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physics of Flow . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flow Pattern and Flow Velocity . . . . . . . . . . . . .
Ultrasound Principles . . . . . . . . . . . . . . . . . . . . . . .
Doppler Effect. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Doppler Shift and Flow Velocity . . . . . . . . . . . .
Ultrasound Systems . . . . . . . . . . . . . . . . . . . . . . . . .
Ultrasound Transducer . . . . . . . . . . . . . . . . . . . .
Imaging Modalities, Parameters, and Settings
Vascular Anatomy and Structure of Ultrasound
Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Arterial Anatomy . . . . . . . . . . . . . . . . . . . .
Extracranial Arterial Anatomy . . . . . . . . . . . . . .
Intracranial Arterial Anatomy . . . . . . . . . . . . . .
General Structure of Arterial Ultrasound
Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Arterial Anatomy
and Ultrasound Anatomy . . . . . . . . . . . . . . . . . . . .
Extracranial Arteries . . . . . . . . . . . . . . . . . . . . . .
Intracranial Arteries . . . . . . . . . . . . . . . . . . . . . .
General Venous Anatomy . . . . . . . . . . . . . . . . . . . .
Intracranial Venous Anatomy. . . . . . . . . . . . . . .
Extracranial Venous Anatomy . . . . . . . . . . . . . .
General Structure of Venous Ultrasound
Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Venous Anatomy and Ultrasound
Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Veins and Sinuses . . . . . . . . . . . . . .
Extracranial Veins . . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Hemodynamics and Functional
Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Autoregulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing of Autoregulation . . . . . . . . . . . . . . . . . .
Neurovascular Coupling . . . . . . . . . . . . . . . . . . . . .
Testing of Neurovascular Coupling . . . . . . . . . .
Metabolic Coupling . . . . . . . . . . . . . . . . . . . . . . . . .
Other Tests to Assess Differences Between the
Right and Left Sides as Markers of Impaired
Collateral Function . . . . . . . . . . . . . . . . . . . . . . . .
2
2
2
2
3
3
4
6
6
7
4
13
13
13
15
17
18
18
24
40
41
42
43
43
43
49
54
55
56
56
57
57
59
5
Parameters of Cerebral Hemodynamics . . . . . . . .
Cerebral Blood Flow Velocity . . . . . . . . . . . . . . .
Resistance Indices . . . . . . . . . . . . . . . . . . . . . . . .
Cerebral Blood Flow . . . . . . . . . . . . . . . . . . . . . .
Cerebral Circulation Time . . . . . . . . . . . . . . . . . .
Cerebral Blood Volume . . . . . . . . . . . . . . . . . . . .
60
60
60
60
61
62
Pathogenesis of Stroke . . . . . . . . . . . . . . . . . . . . . .
Arterial Ischemia . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pathophysiology . . . . . . . . . . . . . . . . . . . . . . . . . .
Classification of Arterial Stroke . . . . . . . . . . . . .
Microembolic Signals . . . . . . . . . . . . . . . . . . . . . . .
Spontaneous Microemboli . . . . . . . . . . . . . . . . .
Detection of Microemboli in Patent Foramen
Ovale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Venous Ischemia . . . . . . . . . . . . . . . . . . . . . . . . . . .
64
64
64
65
72
72
Vascular Pathology . . . . . . . . . . . . . . . . . . . . . . . . .
Vessel Wall Pathology . . . . . . . . . . . . . . . . . . . . . . .
Elongations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intima-media Thickness . . . . . . . . . . . . . . . . . . .
Atherosclerotic Plaques. . . . . . . . . . . . . . . . . . . .
Dissection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fibromuscular Dysplasia . . . . . . . . . . . . . . . . . . .
Vasculitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stenoses and Occlusions . . . . . . . . . . . . . . . . . . . . .
Ultrasound Criteria of Stenoses . . . . . . . . . . . . .
Ultrasound Criteria of Occlusions . . . . . . . . . . .
Extracranial Pathology . . . . . . . . . . . . . . . . . . . . . .
Extracranial Anterior Circulation. . . . . . . . . . . .
Extracranial Posterior Circulation . . . . . . . . . . .
Intracranial Pathology . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Anterior Circulation . . . . . . . . . . . .
Intracranial Posterior Circulation . . . . . . . . . . .
Collateral Pathways . . . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Collateral Pathways . . . . . . . . . . . .
Intracranial Collateral Pathways in ICA
Occlusive Processes . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Collateral Pathways in VA
Occlusive Processes . . . . . . . . . . . . . . . . . . . . . . .
Extracranial Collateral Pathways . . . . . . . . . . . .
Clinical Relevance of Collateral Pathways . . . .
76
76
76
77
78
80
80
81
81
81
85
86
86
91
94
96
99
101
101
74
74
105
108
108
109
VIII
Table of Contents
6
Angiographic Techniques in Neuroradiology . . . .
Digital Subtraction Angiography. . . . . . . . . . . . . . .
Historical Development . . . . . . . . . . . . . . . . . . . .
Technical Aspects . . . . . . . . . . . . . . . . . . . . . . . . .
Strengths and Disadvantages . . . . . . . . . . . . . . .
Magnetic Resonance Angiography . . . . . . . . . . . . .
Historical Development . . . . . . . . . . . . . . . . . . . .
Technical Aspects . . . . . . . . . . . . . . . . . . . . . . . . .
Strengths and Disadvantages . . . . . . . . . . . . . . .
Computed Tomographic Angiography . . . . . . . . . .
Part B:
111
111
111
112
113
113
113
114
115
116
Historical Development . . . . . . . . . . . . . . . . . . . .
Technical Aspects . . . . . . . . . . . . . . . . . . . . . . . . .
Strengths and Disadvantages . . . . . . . . . . . . . . .
Current Algorithm at the Charité University
Hospital. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intracranial Aneurysm . . . . . . . . . . . . . . . . . . . . .
Vasculitis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cerebral Venous Thrombosis . . . . . . . . . . . . . . . .
Peri-therapeutic Imaging . . . . . . . . . . . . . . . . . . .
116
116
117
119
119
120
121
123
124
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
143
144
144
146
Case 5 M1 Middle Cerebral Artery Stenosis . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Conventional Angiography (Day 2) . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
149
149
149
149
149
149
149
150
151
Case 6 P 2 Posterior Cerebral Artery Stenosis. . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 2) . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
156
156
156
156
156
156
156
157
157
Case 7 Cerebral Circulatory Arrest . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques . .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Cerebral CT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
160
160
160
160
160
160
160
160
160
162
162
Case Histories
Case 1
Extracranial Internal Carotid Artery
Stenosis . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
128
128
128
128
128
128
128
128
130
130
Case 2
Free-floating Thrombus of the
Extracranial Internal Carotid Artery . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques . .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Neurosonologic Findings (Day 20) . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
133
133
133
133
133
133
133
134
134
135
Case 3 Common Carotid Artery Occlusion . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
138
138
138
138
138
138
139
141
142
Case 4 Temporal Arteriovenous Malformation . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
143
143
143
143
143
143
Case 8
Bilateral Intracranial V4 Vertebral
Artery Stenosis . . . . . . . . . . . . . . . . . . . . . . 165
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . . 165
Table of Contents
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Conventional Angiography (Day 1) . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques . .
Initial Neurosonologic Findings (Day 42) . . . . . . .
Neuroradiologic Findings . . . . . . . . . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
165
165
165
165
165
165
166
168
168
168
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
194
194
194
194
194
195
195
196
200
Case 13
Case 9
Moyamoya Disease with Bilateral
Carotid-T Stenosis . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Conventional Angiography (Day 2) . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thrombolysis of M1 Middle Cerebral
Artery Occlusion . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (1 Hour) . . .
Clinical Course (3) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
171
171
171
171
171
171
171
173
173
173
Case 10
Secondary Occlusion in Internal Carotid
Artery Dissection . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Follow-up Neurosonologic Findings (Day 2) . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (Day 7) . . . .
Clinical Course (3) . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (6 Months).
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
176
176
176
176
176
176
176
176
176
177
177
178
Case 11
Case 12
183
183
183
183
183
183
183
184
184
184
184
184
184
185
190
Bilateral Proximal Extracranial Internal
Carotid Artery Occlusion and Highgrade V1 Vertebral Artery Stenosis . . . 194
Internal Carotid Artery Stenosis in
Fibromuscular Dysplasia and
Wegener Granulomatosis . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques . .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Conventional Angiography (Day 5) . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (5 Years) . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
204
204
204
204
204
204
204
205
205
205
206
207
Case 14 Isolated Carotid Siphon Stenosis . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
210
210
210
210
210
210
210
211
213
Case 15
Near Occlusion of the Extracranial
Internal Carotid Artery . . . . . . . . . . . . . . 215
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . 215
Initial Neuroradiologic Findings . . . . . . . . . . . . . . 215
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . 215
Questions to Answer by Ultrasound Techniques . 215
Initial Neurosonologic Findings . . . . . . . . . . . . . . . 215
Conventional Angiography . . . . . . . . . . . . . . . . . . . 216
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Follow-up Neurosonologic Findings (2 Months) . 216
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Follow-up Neurosonologic Findings (5 Months) . 216
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Case 16
Giant-cell Arteritis with Bilateral
Intracranial V4 Vertebral Artery
Stenosis . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
225
225
225
225
225
IX
X
Table of Contents
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (6 weeks) . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ascending Middle Cerebral Artery
Occlusion . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Conventional Angiography (Day 3) . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
225
225
226
226
226
228
Case 17
Bilateral Internal Carotid Artery
Dissection . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (3 Months) .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
231
231
231
231
231
231
231
232
234
235
Case 18
238
238
238
238
238
238
238
239
239
239
239
243
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Case 21 Mid-basilar Artery Occlusion . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neuroradiologic Findings (Day 3) . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 3) . . . . . . . .
Conventional Angiography (Day 4) . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
M1 Middle Cerebral Artery Occlusion
with Prominent Early Temporal
Branch . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Neurosonologic Findings (Day 10) . . . . . . . . . . . . .
Neuroradiologic Findings (Day 11) . . . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
261
261
261
261
261
261
261
261
262
262
262
266
Case 22
Case 23
Case 19
Vertebral Artery Dissection with
Distal Occlusion . . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal Carotid Artery Dissection
with Fast Recanalization . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Evaluation of Collateral Function . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (Day 20) . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
245
245
245
245
245
245
245
246
246
248
Case 20
251
251
251
251
251
251
251
252
252
252
253
Takayasu Arteritis with Subclavian
Artery and Vertebral Artery Stenoses . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques
(6 Months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Neurosonologic Findings (6 Months) . . . . . . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques
(8 Months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Neurosonologic Findings (8 Months) . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
269
269
269
269
269
269
269
270
270
270
271
271
275
Dissection of the Extracranial Internal
Carotid Artery and Contralateral M1
Middle Cerebral Artery Stenosis . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . .
279
279
279
279
279
279
279
280
280
280
280
280
280
281
284
Case 24
287
287
287
287
Table of Contents
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
MRI and MR Angiography (10:00 Hours) . . . . . . .
Questions to Answer by Ultrasound Techniques .
Neurosonologic Findings (12:00 Hours) . . . . . . . .
Conventional Angiography (16:00 Hours) . . . . . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Follow-up Neurosonologic Findings (6 Months) .
Clinical Course (3) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Progressive M1 Middle Cerebral
Artery Occlusion . . . . . . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 2) . . . . . . . .
Conventional Angiography (Day 4) . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Clinical Course (2) and Follow-up
Neuroradiologic Findings . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (10 Months)
Clinical Course (3) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
287
287
287
287
288
288
288
288
288
288
294
Case 25
297
297
297
297
297
297
297
298
298
298
298
298
303
Case 26
Extracranial Vertebral Artery
Dissecting Aneurysm following
Basilar Artery Stenting . . . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Cranial CT and CTA (Day 1) . . . . . . . . . . . . . . . . . . .
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
306
306
306
306
306
306
306
306
307
307
307
310
Case 27 Diffuse Cerebral Angiomatosis . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings . . . . . . . . . . . . . . .
Conventional Angiography . . . . . . . . . . . . . . . . . . .
312
312
312
312
312
312
313
Clinical Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
313
313
316
Case 28
Subclavian Steal Phenomenon in
Subclavian Artery and Internal
Carotid Artery Occlusion . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 1) . . . . . . . .
Conventional Angiography (Day 2) . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Follow-up Neurosonologic Findings (4 Weeks) .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
319
319
319
319
319
319
320
320
320
320
320
326
Case 29 Cerebral Venous Thrombosis . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings . . . . . . . . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques
Initial Neurosonologic Findings (Day 1) . . . . . . . .
CT Angiography (CTA) (Day 1) . . . . . . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Question to Answer by Ultrasound Techniques . .
Follow-up Neurosonologic Findings (Day 90) . . .
Question to Answer by Ultrasound Techniques .
Follow-up Neurosonologic Findings (Day 180) . .
Clinical Course (2) . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
331
331
331
331
331
331
331
331
331
331
332
332
332
332
335
Multilocular Extra- and Intracranial
Stenoses and Occlusions . . . . . . . . . . . .
Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . .
Initial Neuroradiologic Findings (Day 1) . . . . . . .
Suspected Diagnosis . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Initial Neurosonologic Findings (Day 20) . . . . . . .
Conventional Angiography (Day 22) . . . . . . . . . . .
Clinical Course (1) . . . . . . . . . . . . . . . . . . . . . . . . . .
Questions to Answer by Ultrasound Techniques .
Follow-up Neurosonologic Findings (Day 29) . . .
Follow-up Neurosonologic Findings (3 Months) .
Final Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
338
338
338
338
338
338
339
339
339
339
340
340
348
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
351
Index
Case 30
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
XI
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XIII
List of Abbreviations
ACA
AChA
ACoA
ACV
ADB
ADC
AICA
ATA
AVM
BA
BIF
BVF
BVR
BZI
CA
CANCA
CBF
CBV
cc
CCA
CCT
CoS
CS
CSF
CT
CTA
CVR
CVT
CW
DMCV
DSA
ECA
EC-IC
EDV
ESR
FLAIR
FMD
FS
FT
FT-PCA
GE
HSV
ICA
ICH
ICP
anterior cerebral artery
anterior choroidal artery
anterior communicating artery
anterior cerebral vein
angiomatosis Divry–Van Bogaert
apparent diffusion coefficient
anterior inferior cerebellar artery
anterior temporal artery
arteriovenous malformation
basilar artery
bifurcation
blood volume flow
basal vein of Rosenthal
border zone infarction
calcarine artery
cytoplasmic antineutrophilic cytoplasmic
antibody
cerebral blood flow
cerebral blood volume
cervico-cranial
common carotid artery
cerebral circulation time; cranial computed
tomography
confluens sinuum
cavernous sinus
cerebrospinal fluid
computed tomograph
computed tomographic angiography
cerebrovascular reactivity
cerebral venous thrombosis
circle of Willis
deep middle cerebral vein
digital subtraction angiography
external carotid artery
extracranial-intracranial
enddiastolic velocity
erythrocyte sedimentation rate
fluid attenuated inversion recovery
fibromuscular dysplasia
fat saturation
fetal type
fetal-type posterior cerebral artery
gradient echo
herpes simplex virus
internal carotid artery
intracranial hemorrhage
intracranial pressure
ICV
IJV
IMT
IPS
ISS
LMC
LSA
MCA
MES
MI
MIP
MRA
MRI
MRV
MSCT
MSCTA
MTT
NIHSS
OA
OccA
OTA
PC
PCA
PCoA
PET
PI
PICA
POA
PRF
PSV
PTA
PTT
rt-PA
SA
SAH
SCA
SCOI
SiS
SPECT
internal cerebral vein
internal jugular vein
intima-media-thickness
inferior petrosal sinus
inferior sagittal sinus
leptomeningeal collateral
lenticulostriate artery
middle cerebral artery
microembolic signal
mechanical index
maximal intensity projection
magnetic resonance angiography
magnetic resonance imaging
magnetic resonance venography
multislice CT
multislice CTA
mean transit time
National Institutes of Health Stroke Scale
ophthalmic artery
occipital artery
occipitotemporal artery
phase-contrast
posterior cerebral artery
posterior communicating artery
positron emission tomography
pulsatility index
posterior inferior cerebellar artery
parietooccipital artery
pulse repetition frequency
peak systolic velocity
percutaneous transfemoral angioplasty
partial thromboplastin time
recombinant tissue plasminogen activator
subclavian artery
subarachnoid hemorrhage
superior cerebellar artery
small centrum ovale infarction
sigmoid sinus
single photon emission computed
tomography
SphS
sphenoparietal sinus
SPS
superior petrosal sinus
SSP
subclavian steal phenomenon
SSS
superior sagittal sinus
STeA
superficial temporal artery
STeA-MCA superficial temporal artery-middle cerebral
artery
XIV
List of Abbreviations
StS
SWS
TAV
TCCS
TCD
TEE
TIA
TIBI
TOF
straight sinus
Sturge–Weber syndrome
time-averaged velocity
transcranial color-coded sonography
transcranial Doppler
transesophageal echocardiography
transient ischemic attack
thrombosis in brain ischemia
time-of-flight
TR
TS
TTE
VA
VG
VV
WG
WMS
repetition time
transverse sinus
transthoracic echocardiography
vertebral artery
vein of Galen
vertebral vein
Wegener granulomatosis
Wyburn–Mason syndrome
XV
Introduction
Stroke is the most common brain disease. In spite of the
often homogeneous clinical picture, there are many different causes of stroke. The institution of tailored, targeted
therapy requires rapid etiological classification and evaluation of the vascular status.
In the 1970s, conventional invasive angiography was
practically the only method for visualizing the arteries
supplying the brain. In the 1980s, magnetic resonance
imaging (MRI) and MR angiography (MRA) were developed, and since the end of the 1990s, computed tomography (CT) has metamorphosed from simple penchymal to
angiologic imaging. The latter two techniques are now
well established, though they do have limitations: MRI
requires compliance and may not be used in patients
with a pacemaker, whereas CT angiography (CTA) involves
radiation exposure and the administration of a contrast
agent.
Diagnostic ultrasound is a noninvasive technique. It was
introduced in the early 1970s and became a reliable
method for neurovascular imaging in the 1980s with the
use of extracranial color-coded duplex sonography and
transcranial Doppler (TCD) techniques. The development
of transcranial color-coded sonography (TCCS) in the early
1990s was another milestone for the technique. TCCS
greatly facilitated vessel identification because of the additional spatial information derived from B-mode and colormode images. In the late 1990s, TCCS reached a diagnostic
sensitivity equal to TCD. Compared with the current generation of TCCS ultrasound systems, TCD is no longer an
acceptable alternative, particularly because of the inherent
problem of precise vascular identification and considerable operator dependency. The combination of extra- and
intracranial duplex ultrasound permits an almost complete assessment of all brain-supplying vessels with a
single bedside device. For comparison, in myocardial infarctions, the target vessels can be assessed only with
invasive or CT angiography. In our opinion the TCD technique, which is currently still widely used, will lose its
importance in vascular diagnostics because of the abovementioned limitations and the developments in TCCS, MR
and CT imaging. However, TCD is likely to remain, and may
even gain importance, as a method for functional assessments in stroke diagnostics. This is because of its ability to
detect microemboli and assess cerebrovascular reactivity,
for example, and because it allows continuous bilateral
monitoring. Until now, conventional digital subtraction
angiography (DSA) has been the gold standard in diagnos-
tics of the brain-supplying arteries purely because of its
sensitivity. It is used in primary stroke diagnostics in many
countries. At the beginning of this decade, DSA was a
frequent part of the routine diagnostic algorithm in our
hospital, too. However, in recent years MRA, CTA, and
ultrasound have increasingly come to the fore. Thus it
seems that DSA will lose its significance in acute stroke—except for the therapeutic option of intraarterial
thrombolysis—in favor of less invasive diagnostic methods.
But which method is the best for acute diagnosis as well
as chronic phases of brain ischemia? In contrast with
cardiology, doctors treating stroke patients have several
angiologic methods—partly competing, partly complementary—at their disposal. A rapid and valid assessment
of extra- and intracranial vascular pathology is essential,
particularly for thrombolysis outside the classic 3-hour
timeframe. MRA, CTA, and ultrasound can be equally important here. However, each of these methods has its
strengths and weaknesses. Examples of limitations include
availability of equipment and/or trained staff, patient restrictions (such as avoiding MRI in patients with pacemakers or contrast imaging in patients with relevant allergies), restrictions due to the inability to identify certain
vessel segments, and the associated cost implications. Our
book describes the use of these methods. However, the
focus of our presentations is the neurosonologic examination, as we want to emphasize the ultrasound techniques
and compare them in a sensible context with the other
available angiologic methods.
The concept of this book is based on the authors’ (J.M.
Valdueza, S.J. Schreiber, J.E. Roehl) teaching experiences in
ultrasound courses over the past 8 years. We realized that
the presentation of real-life cases induced the greatest
interest among our course participants, subsequently
leading to lasting learning. The book is divided into two
parts. Part A outlines the necessary basic principles, with a
particular focus on the precise description of ultrasound
anatomy and the related examination techniques. The
enclosed DVD contains video sequences of a complete
extra- and intracranial arterial and venous duplex examination. Part A describes and explains technical and devicerelated aspects that are necessary to know for clinical
application of the techniques. This section also includes a
discussion of the basic principles of cerebral hemodynamics and the typical constellations of pathologic findings.
The principal aspects of stroke from a clinico-radiological
XVI
Introduction
point of view are presented in a separate chapter. Part A
ends with an overview of the current available radiologic
techniques: DSA, MRA, and CTA (R. Klingebiel).
In Part B, we present 30 case histories of selected patients managed in the Department of Neurology of the
University Charité Hospital of the Humboldt University
Berlin (Germany) between the years 2000 and 2005.
Each case is divided into two sections: the case report
and a discussion. The case reports, their diagnostic algorithm, and the therapeutic strategy are presented in chronologic order. Each case report begins with a short history
of the presenting complaint and a description of the initial
radiologic findings. On these grounds, we have formulated
a hypothesis and angiologic questions to be answered by
ultrasound. The findings of extra- and intracranial colorcoded duplex sonography are controlled for plausibility
and the postulated hypothesis is confirmed or rejected. A
final diagnosis is then made on the basis of the findings of
all the diagnostic procedures, including the parenchymal
and vascular imaging. In more than 20 of the cases, additional video sequences of the ultrasound studies are provided on the DVD accompanying this book to give a better
impression of the real examination situation and also to
emphasize the advantages of the ultrasound technique as
the single noninvasive real-time imaging method. In cases
with a complex hemodynamic constellation, we have provided additional schematic drawings that illustrate the
occlusive process and collateral situation. The case discussion is divided into a clinical and an angiologic-anatomic
part. The former gives a short overview of the diagnosed
disease as well as specific diagnostic and therapeutic aspects of the case. The latter focuses on ultrasound-related
or general angiologic questions arising from the individual
case.
According to the complexity of the ultrasound examination, the presented cases are categorized into three levels
of difficulty: low, medium, and high (10 cases in each
category). This allows readers to use the book according
to their level of expertise. Beginners can start by reading
the general part and progressively approach more complex questions. Experienced examiners may focus on the
case reports and only consult the general part if necessary.
What will be the gold standard of neuro-angiologic
diagnostics in 10 years’ time? MRA, CTA, and ultrasound
are currently undergoing rapid and successful develop-
ments. Methods that were thought to be out of date are
suddenly surprising the experts with new approaches and
perspectives. The basic anatomy will not change, but the
expectation of more and more accurate anatomic vascular
classification is increasing. This particularly applies to the
diagnosis of intracranial stenoses as they are probably
underestimated as a cause of cerebral ischemia. Consequently, complete imaging is required not only of the
extracranial brain-supplying arteries but also of the more
distal segments of the major intracranial vessels.
We believe that the clinical attending physician as well
as the radiologist should know the methodologic principles of the available angiologic techniques and that they
should be aware of the particular strengths and weaknesses of these methods so that they can offer the patient
the best diagnosis, using the most economically viable
techniques. Our particular interest is to promote the duplex ultrasound technique while giving the user a better
understanding of the technique’s potential within the clinical context. In our opinion, color-coded duplex sonography has a good chance to sustain or even further improve
its position in the field of diagnostics because of its wide
availability, low cost, and noninvasive character.
The book is aimed at all doctors, in particular neurologists, neurosurgeons, internists, angiologists, and (neuro-)
radiologists, who treat neurologic or neurosurgical patients with vascular diseases.
We would like to thank all those who directly or indirectly contributed to this book. We especially want to
express our profound gratitude to our wives and partners
for their constant support and understanding. We thank
Dr. Florian Doepp for his contribution to the topic of embolus detection and Juliane Gruß for her patience while
taking the images to demonstrate the exact placement of
the ultrasound probe. Our particular thanks go to Dr.
Niksha Ranpura who contributed to the linguistic improvement of this project. And finally, we also want to
thank Dr. Cliff Bergman, Rachel Swift, and Elisabeth Kurz
from Thieme Publishers for their quick and reliable support in all developmental phases of this book.
José M. Valdueza
Stephan J. Schreiber
Jens-Eric Roehl
Randolf Klingebiel
Part A
Principles and Rules
1 Flow and Ultrasound Basics . . . . . . . . . . . . . . . . . . .
2
2 Vascular Anatomy and Structure
of Ultrasound Examination . . . . . . . . . . . . . . . . . . .
13
3 Intracranial Hemodynamics and Functional
Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
4 Pathogenesis of Stroke. . . . . . . . . . . . . . . . . . . . . . .
64
5 Vascular Pathology . . . . . . . . . . . . . . . . . . . . . . . . . .
76
6 Angiographic Techniques in Neuroradiology. . . . . 111
2
1
Flow and Ultrasound Basics
Flow Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physics of Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flow Pattern and Flow Velocity . . . . . . . . . . . . . . . . . . .
Ultrasound Principles . . . . . . . . . . . . . . . . . . . . . . . . . . .
Doppler Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2
2
3
3
Doppler Shift and Flow Velocity . . . . . . . . . . . . . . . . . . .
Ultrasound Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ultrasound Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . .
Imaging Modalities, Parameters, and Settings . . . . . . .
4
6
6
7
Flow Pattern and Flow Velocity
Flow Dynamics
Physics of Flow
The flow of a liquid substance in a tubular system can be
described by the following physical rules. According to
Hagen–Poiseuille’s law, flow velocity in a straight tube
depends on the pressure gradient (Dp), the vessel diameter
(r) and the vessel length (l) (Fig. A1.1). This function, in
general, also applies to the human vascular system in
which pressure is generated by the pump function of the
heart. However, the pressure gradient is difficult to assess
accurately because the diameter of the blood vessels in the
system varies and vessels rarely follow a straight path. This
restricts the direct application of the Hagen–Poiseuille law
in clinical practice.
Flow in a vessel system can be linear or turbulent depending on the vessel size and flow velocity (Figs A1.2–A1.4).
Our example in Figure A1.2 shows the water flow in a
segment of the Colorado River as it flows through the
Grand Canyon (Colorado, USA). The width of the river
changes from relatively wide with calm flow to narrow,
and cataracts can be seen in this segment. The river then
widens again and the flow becomes calmer. Within the
calm areas the water flow is steady but flow velocity
increases distinctly within the narrowing, i. e., within the
stenosis (Fig. A1.3). While flow in the wider segments of
the river is laminar, it changes to turbulent within the
narrowed areas (Fig. A1.4). Applying this phenomenon to
the human vasculature, flow velocity increase occurs in
I
V
P
P*
r
V = ∆ P · r 2 /8 · η · I
P – P*= V · 8 · η · I / π · r 4
Fig. A1.1 Hagen–Poiseuille’s law. V = mean velocity; P–P*= pressure
gradient; l = vessel length; r = vessel radius, h: dynamic fluid viscosity.
Fig. A1.2 The pattern of flow of water in the Colorado River as it
flows through the Grand Canyon (Colorado, USA). Note the normal,
calm flow in the wider segments of the river and the increase in flow
and turbulence in the narrow segment. (Reproduced from Google
Earth, Mount View, USA.)
Ultrasound Principles
Turbulence
Laminar flow
Flow velocity
Laminar flow
Vessel narrowing
= stenosis
Fig. A1.3 Schematic drawing of the changes in flow velocity around
and within a vessel narrowing: Normal initial flow velocity, increased
velocity within the stenosis and normalized flow afterward.
Vessel narrowing
= stenosis
Fig. A1.4 Schematic drawing of the flow pattern around and within
a vessel narrowing: Initial laminar flow changing to turbulent flow
within the stenosis, with the normal laminar flow pattern resuming
after the stenosis.
any case of vessel narrowing. In addition, this phenomenon can be observed in vessel segments with a raised
pressure gradient, i. e., hyperperfusion within a normalsized vessel. If flow velocity reaches a certain magnitude, it
changes from laminar to turbulent. This is why turbulent
flow is always looked for in vessel stenosis. Turbulence can
also be seen in regions with vessel elongation, kinking, or
hyperperfusion, which sometimes limits its diagnostic
value.
Ultrasound Principles
Doppler Effect
Diagnostic ultrasound enables visualization and measurement of the phenomenon of flow dynamics. Ultrasound is
generated by oscillating piezoelectric elements, emitting
frequencies in the nonaudible range between 20 kHz and
1 GHz (Hz = Hertz = number of oscillations per second).
This frequency travels through the human body tissues in
the form of a wave. While traveling through tissue at a
speed of approximately 1500 m/s, the wave is reflected by
various structures which may be resting (tissue) or moving
(blood corpuscles, mainly erythrocytes). The reflected
wave is then analyzed. When there is a frequency shift
between the emitted and received frequency, a “Doppler
effect” has occurred, named after the physicist Christian A.
Doppler (Fig. A1.5).
The Doppler effect can easily be explained using audible
sound. Consider a chamber tone “A” tuning fork emitting
sound with a frequency of 440 Hz (Fig. A1.6). This frequency travels with the speed of sound (330 m/s) toward
an observer, who can hear exactly the same frequency of
440 Hz. However, if the observer rides a bicycle at a speed
of 18 km/h (5 m/s) towards the tuning fork his speed would
lead to the subjective registration of a higher frequency,
i. e., 447 Hz in our example.
Fig. A1.5 Christian A. Doppler (1803–1853).
The human auditory system (Fig. A1.7) is able to recognize a Doppler frequency shift of the audible sound. An
ambulance with sirens moving toward or away from us
will lead to characteristic changes in the received sound
pitch. All ultrasound systems are constructed in a pattern
which resembles the human hearing system (Fig. A1.8).
The difference between emitted and received frequencies
(Doppler shift) is caused by the reflection of ultrasound by
various moving reflectors—the corpuscular blood components.
The received frequency is amplified (corresponding to
the function of the tympanic membrane and ossicles). A
demodulator subtracts the received from the emitted frequency (f*– f) which is then directly sent to a speaker, as
the Doppler shift is within the audible kHz range of the
human ear. In addition, flow direction is determined, depending on whether f*– f is positive or negative. Finally,
the received frequency spectrum is processed by a Fourier
3
4
1 Flow and Ultrasound Basics
(Frequency)
440 Hz
440 Hz
330 m/s
Tenor
447 Hz?
Baritone
330 m/s
Bass
1
2
3 (Time)
5 m/s
Loud
Fig. A1.6 Example of the Doppler effect occurring within the range
of the audible sound. An observer evaluates the sound emitted by a
tuning fork. Top: The observer stands still. The emitted frequency is
identical to the received frequency. Bottom: The observer is moving
toward the acoustic source, therefore passing more quickly through
the sound waves resulting in a subjectively higher received frequency.
Acoustic Doppler shift analysis
Moving
acoustic
source
Tympanic
membrane
Middle ear
Inner ear and central
nervous system
Fig. A1.7 Schematic drawing of the human auditory apparatus and
its ability to detect a frequency shift of a moving acoustic source.
Ultrasound Doppler shift analysis
Emitter (f)
Amplifier
Receiver (f*)
Demodulator
(f*– f)
Low
Fig. A1.9 Explanation of Fourier analysis with the example of a choir.
A frequency analysis is performed over time. At defined timepoints
the song is analyzed and documented in colored boxes according to
the active singers (= frequencies) and to the strength at which they
sing, i. e., point 1 depicts the moment when the tenor is loudest, the
baritone sings at moderate volume and the bass has the weakest
sound.
analysis. This calculation can be explained by the following
example: An observer is asked to analyze the male voices
of a choir. At timepoints 1, 2, and 3 seconds, he is asked to
mark on a diagram how loud he can hear the tenor, baritone, and bass. At time points 1 and 2, the tenor is the
loudest, the baritone is moderately loud, and the bass is
the quietest. At time point 3, the tenor is silent while the
bass is loudest (Fig. A1.9). Applying this to Doppler frequencies, a large Doppler shift translates into high flow
velocity and a small Doppler shift translates into a low flow
velocity, while the volume depends on the number of
reflectors, moving with a given flow velocity. In our example (Fig. A1.10), most erythrocytes are flowing fast, a moderate number are slower, and a small number are very
slow, which is usually the case in regions with a laminar
flow pattern.
Extension of frequency step numbers of timepoints per
second leads to a typical Doppler spectrum (Fig. A1.11).
The exact number of frequency steps varies from 64 to 256
depending on the Doppler or duplex ultrasound system
being used.
Doppler Shift and Flow Velocity
Discriminator
of flow direction
Frequency analysis
Fourier analysis
Medium
Speaker
Fig. A1.8 Schematic drawing demonstrating the analogy of a diagnostic ultrasound machine to the human auditory system.
To transfer the Doppler shift (= a frequency in kHz) into
flow velocities (cm/s or m/s) the Doppler formula needs to
be applied (Equation A1.1). As the formula includes the
cosine of the insonation angle, exact flow velocity can only
be calculated if the ultrasound beam is directly in line with
the direction of blood flow in the vessel segment being
analyzed (cosine of 0° insonation angle = 1). Therefore,
Ultrasound Principles
(Velocity = frequency)
Fast
Medium
Slow
1
2
3 (Time)
Number of reflectors:
many
medium
few
Fig. A1.10 Fourier analysis of ultrasound-generated Doppler signals: Transferring the example of the choir to blood flow analysis.
The detected frequencies now resemble the detected Doppler shift,
the loudness results from the number of reflectors generating an
equal Doppler shift.
Angle
Doppler shift
(%)
0
100
0
10
98
2
20
94
6
Fig. A1.11 The Doppler spectrum of a transcranial (TCD) ultrasound
system. Note the “systolic window,” i. e., in laminar flow most erythrocytes are fast flowing, therefore the highest intensities (orange
colored) are close to the highest flow velocities. Intensity near the
zero line is low as only few erythrocytes are slow.
Error
(%)
30
87
13
45
71
29
v=
α < 20°
v=
90
0
c (f* - f )
2f cos a
c (f* - f )
2f
100
v
c
= Flow velocity
= Velocity of sound
within the tissue
f
= Emitted frequency
f* = Received frequency
f – f* = Doppler shift
α
= Insonation angle
cos = Cosine
Fig. A1.12 Relation of insonation angle and error in Doppler shift
determination.
Equation A1.1
whenever the angle is greater than 0° the calculated velocity will be “false low.” As blood vessels hardly ever point
directly toward the ultrasound transducer, an acceptable
flow velocity can only be calculated if the insonation angle
is less than 30° (error from real Doppler shift is ≥ 13 %) or
the insonation angle is known and corrected for
(Fig. A1.12).
The reflected ultrasound waves contain a spectrum of
frequencies. From these, several diagnostically relevant
hemodynamic parameters are generally automatically
calculated by modern ultrasound machines, provided
that a correct envelope curve has been fitted (Fig. A1.13)
(for further details about hemodynamic parameters, see
also Chapter 3, “Parameters of Cerebral Hemodynamics,”
p. 60).
5
6
1 Flow and Ultrasound Basics
settings can be adjusted in a similar manner. The basic
structure of every ultrasound system has been described
in “Ultrasound Principles” (p. 3).
Ultrasound Transducer
Fig. A1.13 Hemodynamic parameters derived from Doppler spectrum analysis. Top: TCD system; bottom: Duplex ultrasound system.
PSV = peak systolic velocity; EDV = end diastolic velocity; Vmean =
intensity weighted mean velocity.
Fig. A1.14 Examples of the three transducer types and frequencies
often used for insonation of the vessels supplying the brain. A linear
transducer, frequency range: 5–15 MHz for extracranial insonation,
B sector transducer, frequency range: 4–8 MHz for extracranial insonation, C trapezoid transducer: 1–3 MHz for transcranial insonation.
Ultrasound Systems
This section will focus on characteristics and function of
duplex ultrasound systems. The use of these systems for
routine vascular diagnostics, particularly for determination of stenoses and occlusion, is increasingly becoming
the current standard, whereas pure Doppler ultrasound is
being modified to perform functional tests or assessments
of patients in intensive care units. The majority of ultrasound diagnostics in the cases presented in this book are
derived from duplex ultrasound. If data are derived from
Doppler systems, the particular specifications are discussed therein. In general, the same basic principles are
being applied in Doppler and duplex systems, and system
The transducer combines the emission of ultrasound
waves into the tissue and the simultaneous registration
of reflected ultrasound in quick succession of the emitted
impulse. Duplex ultrasound transducers contain a series of
simultaneously working piezoelectric elements. These
crystals, which if exposed to an alternating voltage, start
to vibrate and therefore emit mechanical waves into the
surrounding tissues. This also works in reverse order, enabling the detection of mechanical—i. e., ultrasound—
waves, and the conversion into electrical current. More
than 500 piezoelectrical elements may be integrated into
current modern transducers. Their configuration on the
probe varies and determines the appearance of the image.
Three main types of transducer configuration are usually
used for insonation of the brain-supplying arteries and
veins (Fig. A1.14). For extracranial insonation, high-frequency transducers with a frequency range between
5 MHz and 15 MHz and a linear or sector ultrasound
beam configuration are used. The linear transducer has
the advantage of providing undistorted images with high
spatial resolution, but it requires a large contact surface.
For extracranial insonation however, this is generally not a
problem, so that the linear probe is most frequently used.
The high-frequency sector transducer has the advantage to
provide images from a wider fan-shaped range but delivers distorted images. For transcranial insonation, lower
frequencies in the range of 1–3 MHz are required to permit
transmission and reception of sound through the skull
bone. However, this is limited to regions of the skull where
the bone is naturally thin, i. e. a “bone window” is present
(for further details, see also Chapter 2, “General Structure
of Arterial Ultrasound Examination,” p. 17, and Fig. A2.26).
The use of a linear transducer for transcranial insonation
would, if applied result in small, narrow images, whereas
the application of the trapezoid-shaped ultrasound field
allows insonation with maximum image information even
through a small bone window (Fig. A1.14). The ultrasound
fields of all transducer types are focused by either the
spatial arrangement of the piezoelectrical elements on
the surface of the transducer, by electronic control, or
both. The ultrasound field can be divided into a near field
and a far field. The transitional area between both is the
focus zone with the best lateral spatial image resolution
(Fig. A1.15). The localization of the focus zone can be adjusted in all duplex ultrasound systems and should always
be optimized according to the insonated region of interest.
The axial resolution along the ultrasound beam depends
on the insonation frequency used. The higher the frequency, the higher the axial resolution. The mode in which
the piezoelectrical element operates in all duplex transducers is a pulsed emission of waves (pulsed-wave), which
Ultrasound Systems
Fo
F
N
Fo
F
N
Depth
Fig. A1.15 Schematic drawing of a focused ultrasound field with
near field (N), far field (F) and the focus zone (Fo). For image
optimization, the focus can be adjusted in most duplex ultrasound
systems. Top: Focus set for small insonation depth. Bottom: Focus
set for high insonation depth.
Fig. A1.16 B-mode imaging: Transcranial insonation. The image is
derived from the analysis of the echo reflection pattern along several
ultrasound beams, allocated to the corresponding insonation depth.
The brightness within the image corresponds to the strength of the
received echo, hence the name: brightness-mode.
enables the system to determine the insonation depth
from which the signal is being reflected. Pure Doppler
ultrasound systems may alternatively be switched to the
continuous-wave mode, where a minimum of two piezoelectric elements simultaneously work. One of these constantly emits ultrasound while the other constantly receives the reflected waves. The disadvantage of the continuous-wave mode is the lack of information regarding
the depth from which a signal derives. In duplex ultrasound systems, this simple mode is not used.
Imaging Modalities, Parameters, and Settings
Image Modalities
Brightness-mode Imaging
The brightness-mode (B-mode) permits two-dimensional
visualization of tissue and is based on ultrasound signals
being reflected from the insonated structures. The resulting image is a compound of information from the parallel
connected piezoelectric elements of the ultrasound transducer. The reflected amplitudes along each single ultrasound beam (A-mode data) are gray-scale coded, and
within the image, arranged according to their reflection
depth (Fig. A1.16). The sum of all side-by-side ultrasound
beams add up to the final B-mode image.
Color-mode Imaging
While B-mode images are focussing on tissue properties,
the color-mode analyses blood flow. Based on the Doppler
shift principle, regions with a detectable blood flow are
color-coded within the complete or part of the B-mode
image (Fig. A1.17A). In the velocity mode, the direction
Fig. A1.17 TCCS, transtemporal bone window, axial midbrain plane.
A Color-mode imaging of the middle cerebral artery and anterior
cerebral artery. B Power-mode image of the same region. C Combined color- and power-mode. D Doppler spectrum analysis of the
blood flow in the middle cerebral artery.
toward or away from the probe is coded with a color.
The brightness of the color increases or the color changes
with increasing flow velocity. Further information that
may be gained from the color-mode signal is the recognition of turbulences— routinely looked for during extracranial insonation. All ultrasound images of extracranial
blood vessels in this book have been obtained using this
insonation mode.
Power-mode Imaging
Power-mode imaging is another option to visualize blood
flow. Here, the signal is not derived from the Doppler
frequency but only from the changes in Doppler amplitude, i. e., intensity of the reflected signal. This results in an
angle-independent registration of flow while the flow
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