Intracranial Vascular Malformations and Aneurysms From Diagnostic Work-Up to Endovascular Therapy

259 Pages·2005·12.29 MB·English

by  Michael Forsting

Contents I
MEDICAL RADIOLOGY
Diagnostic Imaging
Softcover Edition
Editors:
A. L. Baert, Leuven
K. Sartor, Heidelberg
Contents III
M. Forsting (Ed.)
Intracranial
Vascular
Malformations and
Aneurysms
From Diagnostic Work-Up to Endovascular Therapy
With Contributions by
C. Cognard · A. Dörfl er · M. Forsting · W. Küker · L. Pierot · L. Spelle · I. Szikora
I. Wanke
Foreword by
K. Sartor
With 157 Figures in 587 Separate Illustrations, 16 in Color and 9 Tables
123
IV Contents
Michael Forsting, MD
Professor of Neuroradiology
Institute of Diagnostic and Interventional Radiology
Department of Neuroradiology
University of Essen
Hufelandstrasse 55
45122 Essen
Germany
Medical Radiology · Diagnostic Imaging and Radiation Oncology
Series Editors: A. L. Baert · L. W. Brady · H.-P. Heilmann · M. Molls · K. Sartor
Continuation of Handbuch der medizinischen Radiologie
Encyclopedia of Medical Radiology
ISBN 3-540-26250-4 Springer-Verlag Berlin Heidelberg New York
ISBN 978 3-540-26250-3 Springer-Verlag Berlin Heidelberg New York
Library of Congress Cataloging-in-Publication Data
Intracranial vascular malformations and aneurysms : from diagnostic work-up to
endovascular therapy / M. Forsting (ed.) ; with contributions by C. Cognard ... [et al.] ;
foreword by K. Sartor.
p. ; cm. -- (Medical radiology)
Includes bibliographical references and index.
ISBN 354042430X (hardcover; alk. paper) ISBN 3540262504 (softcover; alk. paper)
1. Intracranial aneurysms. 2. Subarachnoid hemorrhage. 3. Diagnostic Imaging. I.
Forsting, M. (Michael), 1960- II. Cognard, C. (Christophe) III. Series.
[DNLM: 1. Intracranial Arteriovenous Malformations--diagnosis. 2. Diagnostic
Imaging. 3. Intracranial Aneurysms--diagnosis. 4. Intracranial Aneurysm--therapy. 5.
Intracranial Arteriovenous Malformations--therapy. WL 355 I615 2003]
RD594.2 .I586 2003
616.1’33--dc21 2002075766
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Contents V
Foreword
The radiology of vascular malformations and aneurysms is intimately related to the
evolution of magnetic resonance (MR) imaging, digital subtraction angiography (DSA)
and catheter-based endovascular therapy. Prior to the advent of MR imaging radiolo-
gists knew little of so-called venous angiomas (today: developmental venous anoma-
lies), cavernous hemangiomas (cavernomas) or capillary teleangiectasias, as most of
these angiodysplasias could not be diagnosed reliably by computed tomography (CT)
or invasive angiography, let alone the earlier encephalographic techniques with positive
or negative contrast. But only after MR imaging at fi eld strengths of 1 T or higher had
become standard did it become clear how common these aberrations of vascular devel-
opment actually are, in particular cavernomas and developmental venous anomalies.
This surprised even the pathologists and again required the radiologists to learn more
about these anomalies and abnormalities, such as their pathogenesis, histopathology,
epidemiology, genetics, and natural history, including their propensity to bleed. It also
required them to be able to differentiate these angiodysplastic lesions from non-vascular
lesions of potentially graver signifi cance.
Advanced knowledge regarding vascular malformations and aneurysms is now there,
but the interested radiologist is still forced to gather it from multiple sources, mostly
original articles in journals, treatises on specifi c topics, and other publications of a more
or less limited scope. This is why Michael Forsting, a neuroradiological “all-rounder”
with a strong bent towards and considerable experience in minimally invasive endovas-
cular therapy of intracranial vascular abnormalities, has put great effort into producing
a book that condenses the existing information in one handy volume. In doing so he has
been helped by members of his department at University of Essen as well as by friends
and colleagues from leading neuroradiologic institutes in several European countries.
What came out of this joint effort is a well-organized, beautifully illustrated mono-
graph that leaves little to be desired: Whenever one is in need of concise, comprehen-
sive clinical, diagnostic and (endovascular-) therapeutic information on intracranial
vascular malformations and aneurysms – here it is. The book, rich in important facts,
numbers and details, impresses perhaps most by its didactic structure and overall style.
For this reason, I believe, it will quickly fi nd a large readership among radiologists and
neuroclinicians alike. Possibly quite a number of copies will end up on the desks of clini-
cal pathologists who sometimes do envy us for the possibility to visualize and diagnose
most brain lesions in vivo rather than in tabula.
Heidelberg Klaus Sartor
Contents VII
Preface
Why a book about the diagnostic imaging and endovascular therapy of vascular mal-
formations? There is a simple answer: This is a fascinating part of neuroradiology, it has
many interdisciplinary aspects and it has become a large fi eld of my and our professional
life. The book should have been ready at least one year earlier, but there was always
something new that had to be included. Still, I am sure, each reader will miss something
he or she has just heard at a meeting or read in the current issue of a journal. On the
other hand, there is already a wealth of established basic knowledge about diagnostic
imaging and endovascular therapy that will not change fast and justifi es writing a book
instead of a review paper.
There are a lot of basics one should know about vascular malformations of the brain,
and during our daily practice my colleagues and I see a lot of images and patients that
do not have a proper diagnosis or have had a lengthy odyssey before fi nding an expert.
We all hope that our book will fi nd readers who are willing to go into this important
aspect of radiology and will enable them to care for their patients in a professional way.
And it is not only written for interventional neuroradiologists: it should be of interest
for everybody working in “neuro-disciplines”.
Although we belong to the younger generation of European neuroradiologists – we
know that age is a moving target, but never mind – we chose not to write a modern
book with colored “memory boxes” or other such aids, but an old-fashioned textbook.
It is something to read at leisure – perhaps on a pleasant evening with a glass of red
wine beside you - and memory will be supported by some redundancies and repetitions.
Anyone in a hurry can run through the book just looking at the many images.
We invite all readers to help us improve the next edition. If something is good, let us
know! More importantly, if something is not good or even wrong, please give us a call or
send us an e-mail!
It was tough work, but fi nally we enjoyed it. We owe a debt of thanks to Ursula Davis
of Springer-Verlag, who continuously pushed us to fi nalize it, always friendly and always
stimulating.
Last but not least, a lot of people contributed substantially to this book without writ-
ing a chapter by themselves. They include my academic teachers Hermann Zeumer
(Hamburg), Armin Thron (Aachen) and Klaus Sartor (Heidelberg), who gave the fi rst
impulse to write this book. I would like to thank them for supporting me during my
whole professional career and for numerous stimulating discussions on vascular prob-
lems of the brain.
Essen Michael Forsting
Contents IX
Contents
1 Developmental Venous Anomalies
M. Forsting and I. Wanke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Diagnostic Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4 Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2 Cavernomas and Capillary Telangiectasias
W. Küker and M. Forsting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1 Cavernomas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2 Capillary Telangiectasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3 Pial Arteriovenous Malformations
C. Cognard, L. Spelle, and L. Pierot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.2 Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.3 Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.4 Diagnostic Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.5 Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4 Dural Arteriovenous Malformations
I. Szikora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
4.1 Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
4.2 Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
4.3 Diagnostic Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
4.4 Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
5 Intracranial Aneurysms
I. Wanke, A. Dörfl er and M. Forsting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
5.1 Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
5.2 Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
5.3 Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.4 Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
List of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Developmental Venous Anomalies 1
1 Developmental Venous Anomalies
M. Forsting and I. Wanke
CONTENTS 1.1
Pathology
1.1 Pathology 1
1.2 Clinical Presentation 2 The pathogenesis of a DVA is still unknown. Saito
1.3 Imaging 9
1.4 Therapy 11 and Kobayashi et al. (1981) hypothesized that an
References 12 intrauterine event during formation of the medul-
lary veins or tributaries induces the formation of col-
In a typical neurovascular working day, developmen- lateral venous drainage pathways. This hypothesis is
tal venous anomalies (DVAs) are causing a lot of con- supported by the absence of normal draining veins in
fusion. In part, this confusion is related to the term the region of the large draining collector vein.
“venous angioma”, which is used in many institu- Another assumption is that an in-utero acquired
tions as a synonym for DVA! But, “venous angioma” is venous occlusion maintains the intrinsic venous
clearly a misnomer, because the term “angioma” usu- anastomoses within the white matter. The DVA then
ally suggests a severe disease with a substantial risk expresses an early collateral adaptation, but devel-
of bleeding. In contrast, DVAs must be considered as ops on a preexisting venous system that has been
unusual, but nonpathological, venous drainage and transformed. However, the majority of DVAs are not
an embryologically determined variant of venous associated with any sort of neural tissue damage or
drainage. On the other hand: DVAs are considered dysfunction. Lasjaunias (1997) commented on this
to be the most common form of cerebral vascular theory that it can hardly be imagined that a signifi -
malformations, occurring in up to 4% of the popula- cant venous disorder (such as thrombosis) at an early
tion (Garner et al. 1991; Ostertun and Solymosi stage of development would not be associated with
1993; Truwit 1992). This high incidence is a good some tissue abnormality. Furthermore, the fact that
reason to familiarize oneself with these lesions and DVAs do not exist in the diencephalon, brain stem, or
keep abreast of new fi ndings in this area. spinal cord and are only encountered where tectum
In my experience, another factor contributing to derivates exist, excludes DVAs from the group of
the DVA-related confusion is that many radiologists pathological malformations (Lasjaunias 1997).
and clinicians just see abnormal vessels on magnetic The association of venous malformations with
resonance imaging (MRI) scans, immediately tell the other vascular malformations gave further room for
patient something about a vascular malformation, speculation. Mullan et al. (1996) hypothesized that
and refer the patient for neurosurgical extirpation true arteriovenous (AV) malformations may be fi stu-
of the lesion. lized venous malformations and that both vascular
To avoid too much irritation, specifi cally within anomalies may be related to a developmental failure
the group of referring doctors, the term “venous of the cortical venous system. However, these are nice
angioma” should be avoided and DVA should be theories, but do not have any impact on diagnostic
used. However, if you are reporting about a DVA, it is work-up or patient management, nor are they sup-
usually necessary to explain what this is. And this is a ported by any study. Kilic et al. (2000) looked for
good reason to read the upcoming chapter. expression of structural proteins and angiogenic fac-
tors in cerebrovascular anomalies. Whereas AVM and
cavernomas had expression of vascular endothelial
growth factor, DVAs did not express any of the stud-
M. Forsting, MD, PhD; I. Wanke, MD
ied growth factors and mainly consisted of structural
Institute of Diagnostic and Interventional Radiology,
proteins of angiogenically mature tissue. This fi nd-
Department of Neuroradiology, University of Essen,
Hufelandstrasse 55, 45147 Essen, Germany ing strongly supports the idea of a simple variation of
2 M. Forsting and I. Wanke
the venous drainage instead of being a true vascular Developmental venous anomalies represent the
malformation. most common vascular variant, accounting for 63%
In contrast, the relationship of DVAs with cav- of intracranial vascular malformations in one large
ernous hemangiomas has been well documented autopsy study, with an overall incidence of 2%–4%
(Abe et al. 1990; Comey et al. 1997; Goulao et al. (Sarwar and McCormick 1978). The lesion consists
1990; Rigamonti and Spetzler 1988; Wilms et al. of a tuft of abnormally enlarged medullary venous
1994). There are also reports about de novo forma- channels that are radially arranged around, and drain
tion of cavernous hemangiomas in the vicinity of into a central venous trunk. The common trunk drains
DVAs (Ciricillo et al. 1994). The close relationship intracerebrally into the deep or superfi cial venous
of mixed malformations may be related to venous system (Lasjaunias 1997). It is important to bear in
hypertension within the regional microenvironment mind that the vein’s course is not normal; however,
with erythrocyte diapedesis and angiogenic growth it does drain normal functioning brain tissue. This
factor release (Cirillo et al. 1994; Robinson et al. should be of particular interest when surgery has to be
1995). Another interesting fi nding is that in families performed around the draining vein, e.g., if the DVA is
affected with cavernomas – an autosomal dominant associated with a cavernoma. In these patients, it is of
inheritance has been established in these families the utmost importance to preserve the draining vein
– none of the patients described to date with the and to remove only the cavernoma (see Fig. 1.7).
combination of cavernoma and DVA has a positive
familial history, nor has any genotypic classifi cation
been found. However, we have to accept the coinci-
dence between DVAs and cavernomas, but have to 1.2
admit that we do not have any substantial hypothesis Clinical Presentation
what the pathogenetic origin of this coincidence is.
The histologic examination does not reveal any Hemodynamically, DVAs represent low-fl ow, low-
vessel abnormality. The vessel wall is completely resistance lesions that are less likely to bleed. Garner
normal in DVAs. The anomaly in DVAs is the course et al. (1991) calculated the hemorrhage rate to be
of the draining vein. There is no arterial component in 0.22% per year; McLaughlin et al. (1998) found
this entity. Intervening brain tissue is present between a symptomatic hemorrhage rate of 0.34% per year.
the veins compromising the lesion, and this brain This range of hemorrhage risk is within the range we
tissue is usually normal without evidence of hemosid- expect from cavernous hemangiomas alone. Based
erin staining or gliosis. On MRI, there is sometimes a on these data and on hemodynamics, one might
high T2-signal visible around the draining vein. How- already conclude that hemorrhages in the presence
ever, this should not be interpreted as gliosis, but can of a DVA are not related to the DVA itself, but in
be explained by dilated perivascular and cerebrospinal nearly all patients related to an associated cavernous
fl uid (CSF)-containing space (see Fig. 1.4). angioma! My opinion is that the risk of hemorrhage
a b
Fig. 1.1. a Axial nonen-
hanced computed tomog-
raphy scan reveals a hyper-
dense dot within the right
frontal lobe representing
the transcerebral drain-
ing collector vein. b The
contrast-enhanced scan
with a 4-mm slice thickness
[explaining the decreased
signal-to-noise ratio com-
pared to (a)] shows the
marked enhancement of the
vein and confi rms the diag-
nosis of a developmental
venous anomaly
Developmental Venous Anomalies 3
a b
Fig. 1.2a, b. Axial (a) and sagittal (b) contrast-enhanced T1-weighted magnetic resonance imaging with a typical right fron-
tal developmental venous anomaly. Conspicuous on both views is the transcerebral draining vein. A second look reveals the
“Medusa head”, small venules radially arranged around and draining into the transcerebral collector vein
in a pure DVA is around zero! I did not fi nd a single A major problem of most studies reporting hemor-
case report with a well documented intracerebral rhages due to a DVA is how they ruled out an associ-
hemorrhage (ICH) due to a pure DVA. However, this ated cavernoma. It is clearly not enough just to perform
is not evidence-based, just a simple clinical impres- T2-weighted images in patients with DVAs. All these
sion gained over the years. In all cases mentioning a patients need an imaging work-up with T2*-weighted
pure DVA as the cause of an ICH, imaging was not MRI sequences to exclude or to visualize associated
optimal and did not rule out the more common con- cavernomas with the highest sensitivity.
stellation with an associated cavernoma. Beside the risk and discussion of hemorrhagic
The coincidence of DVAs and cavernomas, how- complications, DVAs have been associated with vague
ever, is evidence-based and therefore has to be taken neurological symptoms, such as nonspecifi c head-
into consideration whenever facing a cavernoma or aches and dizziness, or with more specifi c symptoms
a DVA. Up to one third of DVAs are associated with and/or signs like seizures (McLaughlin et al. 1998).
cavernomas (see Figs. 6–9). However, having in mind the association of caver-
a b
Fig. 1.3a, b. Axial
contrast-enhanced
T1-weighted magnetic
resonance imaging
with a developmen-
tal venous anomaly
located in the left
cerebellar hemisphere.
Again, the transpar-
enchymal draining
vein is the most strik-
ing sign. On (b), the
Medusa head is clearly
visible. There is no
need for an additional
digital subtraction
angiography