Radiology Today 3 presents papers and panel discussions from a multi national faculty at the biannual Salzburg Symposium, which this time covered three important topics: critical diagnostic pathways in gastro" intestinal and genitourinary radiology, interventional radiology of the abdomen, and cost containment in radiology. The choice of these topics illustrates the changing role of the radiolo gist in the practice of medicine today and in the foreseeable future. He will have to serve as a consultant more than ever before, assuming in creasing responsibility for sequencing of imaging procedures and par ticipating more and more in therapeutic intervention. In order to pro vide meaningful assistance, the imaging consultant must be aware of the efficacy and the limitations of every procedure. In this context, cost containment is a worldwide public concern, and the most appropriate procedures must be identified. Radiology Today 3 demonstrates how the radiologist functions as a member of diagnostic and management teams to provide optimal in formation and efficient, low-risk patient care at the lowest possible cost. Martin W. Donner Friedrich H. W. Heuck Contents Critical Diagnostic Pathways Abdomen 3 G. MARCHAL, A L. BAERT, K. GEBOES, E. PONETTE, 1. FEVERY The Diagnosis of Pancreatic Cancer ............ 3 W. REICHARDT Localization Techniques for Hormonally Active Pancreatic Tumors ........... . 7 AR. MARGULIS, S. MCCARTHY Hepatic Mass Lesions .... 12 M. KORMANO, K. PARTANEN, 1. KUIKKA Dynamic Liver CT and New Contrast Agents ....... . 17 W. FROMMHOLD, J. PIRSCHEL 20 Gallbladder Diseases: Imaging Sequences 1.A KIRKPATRICK, Jr."

7 Les Houches The purpose of this workshop was to bring together, for the first time, active scientists from very different fields, such as physics, chemistry, physiology and the behavioural sciences, all having a common interest: The interac tion of static magnetic fields with biological and macromolecular matter. As physicists, biologists and medical scientists naturally have different scientific competences, attitudes and abilities, this appeared to be an enterprise of un certain issue. However, it turned out that all participants tried to find (and many succeeded in reaching) a mutual basis of understanding. Thanks to a fair number of outstanding, comprehensive talks and to very active discus sions, most of us, we believe, have substantially enlarged our insight into the actual hard facts within a research area that was considered for a long time - and still remains in many aspects - somewhat controversial. The perhaps most striking and useful reaction to magnetic fields at the supermolecular level is the alignment of biopolymers, proteins, viruses, large assemblies such as retinal rods and membranes when suspended in a solvent, usually water. The ease of alignment depends on the anisotropy of the dia magnetic susceptibility of the constituent groups and bonds and, in addition, on the extent of their mutual orientational order inside a macromolecular assembly. Here very strong fields above I-lOT appear to be necessary, in general, to achieve measurable alignment."

Owing to the anatomic complexity of the neck and the diver sity of pathologic entities affecting it, the cervical region has long been of great semiological interest. Physical examination is an easy means of evaluating the size and origin of a solitary cervical mass, yet valid interpretation can prove difficult when the normal morphology of the neck has been altered; excellent examples are patients with extensive fibrosis or scarring secondary to previous irradiation or surgery. Like wise, physical examination cannot assess the relations of a pathologic process to adjacent structures - e. g., invasion can not be distinguished from simple displacement -and it is un suitable for monitoring therapeutic efficacy, such as the re sponse of metastatic nodes to medical management. Between physical examination, which remains fundamental, and exploratory surgical procedures, which are often the only means of obtaining indispensable anatomic proof for diagno sis, lie a number of recent imaging techniques including com puted tomography and magnetic resonance imaging using surface coils that provide invaluable information for the in vestigation of cervical pathologies. Real-time ultrasonogra phy occupies a privileged position because of its noninvasive ness, rapidity, and reliability, especially when performed by a specially trained examiner."

3.2 Technique ............. '. . . . . . . 123 3.3 Drainage Catheters: Materials and Selection . 139 3.4 The Loop Catheter . . . . . . . . . . 141 4 Aspiration of Pancreatic Pseudocysts 145 E. Concluding Remarks 149 151 References " Subject Index . 158 VII List of Contributors BURGER, H. R, Dr. med., Oberarzt, Institut fur Pathologie, Univer sitiit Zurich, SchmelzbergstraBe 12, CH-8091 Zurich EINIGHAMMER, H.J., Dipl. Phys., Dr. rer. nat., Neurologische Uni versitatsklinik, MoorenstraBe 5, 0-4000 Dusseldorf HAUKE, R, Dipl., Phys., Dr. rer. nat., Gesellschaft fur Medizin. Techn. Informationssysteme, MarienstraBe 2,0-7910 Neu-Ulm PEmo, G., Professor Dr. med., Leitender Arzt, Abteilung fUr Zytolo gie, Institut fur Pathologie, Universitatsspital, CH-8091 Zurich " ... so it is not good for men to fear all that is not already known and settled, and thus feel that it is bad and harmful to strive for a greater perfection than already exists." Holderlin to his mother, 16. November 1799 A. Introduction 1 General The modem cross-sectional imaging methods of sonography and computed to mography, developed in the early 1970s, have contributed greatly to noninva sive studies of the parenchymatous organs and permit the evaluation of patho logic changes in areas that were previously accessible only to invasive, indirect, or inadequate examination."

The aim of this book is to expand the clinical information given by computed tomograms (CTs) of cerebral infarcts. Anatomical sections are displayed parallel to the CT correlate in the hope that the interpretation of pathogenesis will provide valuable clinical data at a time when the number of angiographies performed in cerebrovascular cases has diminished rapidly. For better understanding of pathogenesis our concepts concerning the process of infarction have been summarized on the basis of schematic draw ings. K.-J. ZULCH KOln Acknowledgments I am most grateful to Professor Hoeffk: en for permission to use computed tomograms from his institution, to Herr GOldner and Frau Miihlhover for their technical assistance, and to Frau Goldner for help during the editorial work. My particular thanks go to my friend Professor W.S. Fields, Houston, who undertook the great burden of styling the English text. My gratitude is expressed to Dr. Dr. h.c. multo Heinz Gotze and Springer Verlag for the excellent layout and quality of this book."

A thorough knowledge of normal radiological anatomy is necessary for detection and evaluation of pathological changes. In pediatric radiology, normal anatomy and normal proportions of anatomical structures may differ considerably from the adult, and may vary during growth. Therefore, in pediatric radiology there is a multitude of measurements, that in the individual patient is important, but that for the radiologist is not meaningful or even possible to keep in mind. This holds true both for the experienced pediatric radiologist, and for those who practise pediatric radiology only occasionally. This volume is written for both categories. In the literature, normal values are calculated and presented in many different ways, that are not always easy to compare, or easy to use in daily work. Therefore, we have revised and recalculated the data given by authors, in order to present the statistical upper and lower normal limits as between plus and minus two standard deviations (+/- 2SD). This means that about 2% of a normal population will be assessed as abnormally large and around 2% abnormally small with respect to the parameter assessed. In this way, the presentation throughout the book is uniform, and hopefully easy to use. All figures have been redrawn and computed in an attempt to make them as clear as possible.

In this age when we are witnessing a veritable explosion in new modalities in diagnos tic imaging we continue to have a great need for detailed studies of the vascularity of the brain in patients who have all types of cerebral vascular disease. Much of the understanding of cerebral vascular occlusive lesions which we developed in the last two decades was based on our ability to demonstrate the vessels that were affected. Much experimental work in animals had been done where major cerebral vessels were obstructed and the effects of these obstructions on the brain observed pathologically. However, it was not until cerebral angiography could be performed with the detail that became possible in the decades of the '60 's and subsequently that we could begin to understand the relationship of the obstructed vessels observed angiographically to the clinical findings. In addition, much physiologic information was obtained. For instance, the concept ofluxury perfusion which is used to describe non-nutritional flow through the tissues was observed first angiographically although the term was not used until LASSEN described it as a pathophysiological phenomenon observed during cerebral blood flow studies with radioactive isotopes. The concept of embolic occlusions of the cerebral vessels as against thrombosis was clarified and the relative frequency of thrombosis versus embolism was better understood. The concept of collateral circulation of the brain through so-called meningeal end-to end arterial anastomoses was vastly better understood when serial angiography in obstructive cerebral vascular disease was carried out with increasing frequency."

The biennial symposium 'Radiology Today' continues its original mission to bring together European and American radiologists to discuss advances in the field. This volume presents material by well-known experts in cardiovascular and skeletal radiology. Its aim is to provide an overview of each major topic, trends in clinical development, and current interests in research. The future holds much promise for cardiovascular and skeletal radiology, primarily because of new techniques and procedures, but also because of the development of imaginative approaches to clinical problems. Ideas are born on both sides of the Atlantic, and we believe that it is important to ensure a rapid exchange of new information and to determine how it fits into today's medical care, keeping in mind the quality of patients' care, their safety and comfort, as well as cost. The traditional role of radiologists as consultants has increased greatly over time, with new responsibilities being continuously added. We radiologists are challenged to determine the diagnostic pathway appropriate to each patient. To arrive at the diagnosis quickly, safely, and at the lowest possible cost is as important as our participation in determining the patient's management. Some therapeutic procedures are even carried out by diagnostic radiol ogists themselves, employing ultrasound, computed tomography, or fluoroscopy and intracavitary catheters. Abscesses can be drained, and blood vessels dilated or blocked. In diagnosis and therapy, events are moving quickly, and advances are made at a rapid pace."

Just a very few years after Edler and Hertz had described the clinical use of M-mode echocardiographyl Satomura reported the application of Dop 2 pler ultrasound to the study of cardiac function. Yet Doppler ultrasound has been integrated into diagnostic practice in cardiology much more slowly than conventional (M-mode and two-dimensional) echocardiogra phy. Now, however, tremendous growth in the interest of clinicians in the diagnostic use of Doppler ultrasound can be observed and may in fact be due to the recent advent of color flow imaging. The reason for this growth may be that this method makes it possible to directly visualize the blood flow in the cardiovascular system in cross-sectional views. Moreover, the results are reproducible and much easier to understand than the older mapping techniques using a single-gate Doppler. In its short existence many different names have been used to describe this method, for instance, color Doppler, color flow imaging, real-time two-dimen sional Doppler echocardiography, and Doppler flow imaging. This diver sity reflects the large interest that many researchers have shown in this method. The technical development of color blood flow imaging (CBFI) - as this method will be called in this book - has not yet reached a universally accepted standard of performance in cardiology. Despite this state of flux and the uncertainty about future developments, I think it is justified to dedicate an entire book to this fascinating method."

This book is intended as a short guide to the visualization of the anatomy of the normal brain by means of the NMR tomogram. The first section comprises a brief introduction to the physical and technical aspects of NMR. This is followed by the atlas section, which pursues a number of objectives. On the basis of two important NMR imaging techniques, the spin-echo technique and the inversion-recovery technique, those experi enced in CT are given the opportunity to familiarize themselves with the differences in tissue contrast that exist in NMR scans despite their appar ent similarity to conventional CT scans. The mode of action of the two NMR imaging techniques is explained in the technical introduction. An additional innovation is the possibility of producing sections that are not, as in CT scanning, limited by the body of the patient. The sagittal and frontal sections parallel to the plane of the face can show an unfamiliar, but particularly clear, image of the anatomy of the head and brain com pared with conventional horizontal sections. An anatomical description accompanying every section is provided by way of clarification. A particular advantage of NMR imaging, namely, the absence of ionizing radiation and, thus, an injurious effect on biological systems (Budinger 1981), makes it possible to provide a systematic visualization of a healthy human brain in a living person in three planes, arranged at right angles to one another."

Any book with the words percutaneous and interventional is immediately identified as one that brings to its readers a distillation of a number of new and exciting techniques. Percutaneous is not exactly a new word but it has come to take on an entirely new meaning in recent years. Interventional is a recent acquisition to medical language indicating an entirely new approach to many aspects of medical management. Exactly when is the right time to make a distillation of new thoughts and expertise requires something of the art of a master brewer. First the ingredients must be prepared, the recipe must be just right, there must be excellent quality control as well as the master brewer's touch to produce the product when the time is right. Dr. Lang has assembled just the right ingredients in the form of a very impressive team of experts in these new fields of uroradiology and urological management. Ventures into percutaneous urology may date back 30 years but the main growth in the range of procedures and the development of the technology has occurred only in the last 10 years. Relieving upper tract obstruction seemed a natural sequel to renal biopsy but the imagination to develop an effective treatment for stones was an impressive extension of the concept of minimally invasive surgery.

The quantitative analysis of blood flow within central and peripheral blood vessels has attracted more and more interest, for with the rapid developments in vascular surgery and the introduction of percutaneous transluminal angioplasty, it is becom ing increasingly important to be able to measure regional blood flow in man. In clinical radiology, angiography has been used predominantly from the point of view of its morphological applications. However, theoretically angiography may also be regarded as a specific application of indicator-dilution measurements of blood flow. The indicator is contrast medium (CM), the changing concentration of which is re corded by cinematography or video-electronic systems at sites downstream from the point of injection. The curves of density thus obtained correspond to indicator-di lution curves. The blood flow can be calculated from the concentration-time curves ofCM in much the same way as it is estimated from other indicator-dilution curves. In our early work with clinical application of videodensitometric measurement of blood flow in the iliac artery, we found that this method did not offer as high a degree of accuracy as one would have expected from investigations by other authors. We saw that we needed to examine the following problems: 1. We had to investigate whether our conventional X-ray equipment and video densitometer could be viewed as a linear measuring system. To what extent do unavoidable nonlinear changes in the measuring signals influence the blood flow values? 2."

In thc space of ooly a few years, reconstructive surgery of the skeleton of the hand has become a foeus of attention. Thc reason for this has been the advent of principles and techniques of stable internal fixation, tbc unparaJleled advantages of which are particularly evident in the treatment of the complex, multi- structural lesions so typical of injuries of the hand, and also in procedures such as replantation or revascularisatioss. What a striking contrast on the other hand is to be seen in the slow and painful progress made in Dur understanding of the biomechanics of the radiocarpal joint! This is most elo- quently ilIustrated by the embryonie state of prosthetic surgery of the wrist, compared with the sophisticatcd advances made in hip and knee surgery. Yet it is undeniable that painful condi- tions involving dysfunctions of the wrist are increasing in number and affect young people in particular; this should spur us on to seek more effective therapeutic solutions.

There are two important reasons for commencing this new series of publi cations entitled "Advances and Technical Standards in Neurosurgery": 1. the lack of any organized common European postgraduate training system for young neurosurgeons and 2. the language barriers, which impede the exchange of neuro surgical findings in Europe more than in other parts of the world. The fact that the English language is well on the way to becoming the international medium at European scientific conferences is a great asset in terms of mutual understanding. Therefore the Editors have decided to publish all contributions in English, regardless of the native language of the authors. All contributions are submitted to the entire editorial board before publi cation of any volume. Our series is not intended to compete with the publications of original scientific papers in other neurosurgical journals. Our intention is, rather, to present fields of neurosurgery and related areas in which important recent advances have been made. The contributions will be written by specialists in the given fields and will constitute the first part of each volume."

In 1932 there appeared the work of SCHMORL and JUNGHANNS, Die gesunde und kranke Wirbelsiiule im Rontgenbild, which laid the foundations of diagnostic radiology of the spine. Since that time the discipline has been extended and refined in a systematic manner and our knowledge has been greatly enriched by the large number of monographs in which leading experts have assembled additional data. An encyclopedic treatment of all that is currently known requires not only that reference be made to all work published since 1932 in order to reveal the problems that remain but also that a serious attempt be made to contribute to the solution of such problems. For this reason, Professor TONDURY and Professor THEILER of Zurich, who know more than anyone else about the ontogeny of the spine, have been invited to display their erudition in this field. Should contra dictions or divergent opinions on certain points be revealed through this confrontation with radiologically obtained findings, so much the better; the effect of this could only be to spur workers in both disciplines on to more advanced research. We have only to recall how in Goethe's time the premaxilla was still the subject of controversy, yet this great man pursuing his studies in comparative anatomy and anthropology was able to prove its existence beyond all doubt. Mainz, May 1974 L. DIETHELM Inhaltsverzeichnis - Contents A. Die normale Wirbelsliule . . . . . . . . . . . . . . . . . . . . 1 1 I. Phylogenetische Entwicklung des Achsenskelets. Von K. THEILER 1 1. Die Bogenelemente. . . . . . . . . . . . . . . 2. Die Chorda dorsalis . . . . . . . . . . . . . ."

by Dr. Jan. J. Smulewicz Ultrasound imaging has reached a stage of sophistication where by diagnostic information can be gained without discomfort to the patient and with complete absence of morbidity and mortality. The procedure is quick, safe, noninvasive and in many instances can supersede and obviate more time-consuming procedures requiring catheterization, injection of a contrast material, and radiographic imaging. In obstetrical problems the danger of ionizing radiation to the fetus is eliminated. In debilitated and very ill patients this simple and painless method becomes the procedure of choice. Unique features of ultrasound equipment allow for pinpoint local ization oflesions and direct visual guidance of percutaneous puncture techniques for aspiration and biopsy. The accuracy of ultrasound guided punctures and the absence of side effects make this modality far superior to percutaneous invasive techniques performed with other imaging systems. Renal cyst puncture and amniocentesis are but two of the procedures in which ultrasonic guidance is the method of choice. v Dr. Hassani has throughly explained and carefully explored the wide variety of exam inations available with ultrasound. The large volume of material and the clear interpre- tion makes this book of great interest to all of the medical profession. In addition to the existing methods available for diagnostic in terpretations, this method of noninvasive diagnosis should find its way into every hospital or center where good medical care is provided. JanJ. Smulewicz, M.D."

This book has been written for radiologists, ophthalmologists, neurologists, neurosur geons, plastic surgeons, and others interested in the evaluation of disorders with ophthalmologic signs and symptoms. It is designed to provide recent knowledge in this area derived from ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). In the past decade, the advent of ultrasonography, computed tomography, and more recently magnetic resonance imaging has provided diagnostic images of the eye, orbit, and brain in a fashion that had been a dream of many prior to the develop ment of these techniques. These newer modes of diagnosis have replaced some previous techniques, such as nuclear medicine imaging and, to some degree, vascular studies and orbitography. There are three sections to this book. The first section is a discussion of the imaging techniques. The second is devoted to the role of these imaging methods in the evaluation of ophthalmic disorders. The last section, dealing with radiotherapy for ophthalmologic tumors, is included because the current imaging techniques are needed for treatment planning. We wish to thank the many people who have assisted us in preparing this manuscript. Among these are many librarians, secretaries, trainees, and photographers. Weare especially indebted to artist Peter Clark for his illustrations and to Mr. Martin Leibo vici, Associate Curator of New York University Medical School and Director of Health Sciences Library of Goldwater Memorial Hospital, New York City. Also, we wish to thank our families for their help and patience."

During the past decade there has been a burgeoning of interest in arthritis and related rheumatic diseases. The spe ciality of rheumatology, once regarded as a "Cinderella" speciality, is now one of the leading specialties in internal medicine. Indeed, just as infant mortality is a good index of the general health of a community, so a University Med ical School can be similarly judged by the quality of its Department of Rheumatology. Perhaps no other specialty has helped to advance knowledge in medicine as has rheu matology One might have thought that little could be added to the clinical and radiologic description of one of the most studied diseases in rheumatology rheumatoid arthritis. There are several excellent large radiology textbooks on bones and joints, and it is surprising that yet another book has been published. However, the reader will soon appreciate on reading this superb radiologic text on rheumatoid arthritis that here is something new and quite different from what has been published in the past. The combination of clinician and radiologist has produced a textbook which will become a standard reference on the subject. The authors are both well known in their respective fields and they have concentrated on the early changes in the disease-not only those in the articular surfaces but also those in the soft tissues. In 1948 the late Dr Philip Ellman coined the term "rheumatoid disease," to indicate the systemic nature of rheumatoid arthritis."

The management of ankle injuries has long been a stumbling block for orthopae dists in training. As a first year resident, I was fortunate to encounter the series of articles by N. Lauge-Hansen and T. Baek Kristensen that classified ankle injuries according to their mechanism. I found this information quite helpful throughout my residency and early years of practice. Several years ago, an attempt was made to summarize this material for the benefit of the orthopaedic house staff of Thomas Jefferson University. It quickly become obvious that such a "manual" would require a great deal of professional illustration and editorial assistance in order to be effective. Almost simulta neously, a fortuitous encounter with Ms. Marie Low (at that time Medical Editor of Springer-Verlag New York Incorporated) provided both the stimulus and the means to present this information in the manner and detail which it deserved. Contributors were carefully selected for their knowledge and experience in particular areas and for their willingness to cooperate in providing a smooth flowing manuscript. This text contains little new material. Rather, it represents an attempt to bring together, under one cover, the wealth of extant information on this subject. Wherever a consensus could not be perceived, conflicting views have been sum marized as objectively as possible. Unfortunately, there are still many aspects of ankle injury for which we have more questions than answers."

The Information Processing in Medical Imaging Conference is a biennial conference, held alternatively in Europe and in the United States of America. The subject of the conference is the use of computers and mathematics in medical imaging, the evaluation of new imaging techniques, image processing, image analysis, diagnostic decision making and related fields. The conference brings together the top specialists in the field (both scientists and medical doctors) and other participants doing active research on the subject of the conference. The success of a meeting primarily depends on the enthusiasm of the participants. It also greatly depends on the financial support as well as on the personal efforts of the technical staff and collaborators of the organizers. To all who made this conference a success, the members of the organizing committee want to express their sineere thanks. In particular, the organizers want to acknowledge the help received from: De Vice-Voorzitter van de Vlaamse Executieve De Minister van Onderwijs Het Nationaal Fonds voor Wetenschappelijk Onderzoek De Vrije Universiteit Brussel Adac Agfa-Gevaert Bruker Spectrospin Byk Belga Elseint Instituut voor Radioelementen, IRE Nucleobel Solco Sonotron VII TABLE OF CONTENTS Foreword. v A. VENOT, J.L. GOLMARD, J.F. LEBRUCHEC, L. PRONZATO, E. WALTER, G. FRIJA and J.C. ROUCAYROL: "Digital Methods for Change Detection in Medical lmages."

During recent decades there has been a revolutionary change in the life expectancy and quality of life of the hemophiliac. This has been achieved by hematologic and c1inical research, and the future for the hemophiliac depends upon further medical knowledge and research. In spite of the dramatically improved life situation of hemophiliacs, hemorrhagic complications remain a threat. The hemorrhagic disorder may influence and/or aggravate the course of trauma or other diseases in these patients. Hemophiliacs suffering from hemorrhagic complications or eligible for elective surgery should be referred to Hemophilia Treatment and Training Centers, where evaluation and examination are performed by a multidisciplinary team with experience and interest in the disease. The radio10gist is an important member ofthis team. In the past diagnostic imaging has been based mainly on conventional radiography, and this is still very important for the diagnosis ofhemophilic complications, but the diagnostic imaging of today offers a wide range of modalities-conventional radiography, computed tomography, sonography, radionuc1ide imaging, and, in its infancy, magnetic resonance imaging. Thus there is a need for a thorough description of the potential and limitations ofthese modern diagnostic techniques.

Much confusion exists in the accurate identification and classification of the many disorders in infancy which affect the skeleton by producing sclerosing lesions throughout the entire skeleton or in selected areas. A scholarly effort to bring order into this confusing field must be welcomed. Professors Beighton and Cremin have skillfully defined the problem and concisely yet thoroughly have identified the various sclerosing dysplasias. They bring to this task a wealth of clinical experience in their many years in the Departments of Radiology at the University of Cape Town Medical School and the Groote Schuur and Red Cross Children's Hospitals in Cape Town, South Africa. The authors also have had available data from the University of Cape Town Skeletal Dysplasia Registry. Professors Beighton and Cremin have used as a basis for their treatise the Paris Nomenclature (the modified version of 1977). This monograph is a felicitous combination of a working atlas and a scholarly exposition of the various sclerosing bone dysplasias, considering in detail eighteen major entities adopted from the Paris classification. Other disorders which present with osteosclerosis are also described. These include Caffey disease, oculodento-osseous dysplasia, central osteosclerosis with bamboo hair, fluorosis, osteosclerosis associated with renal disease and mastocytosis.

The purpose of this series of volumes is to present a comprehensive view of the complications that result from the use of acceptable diagnostic and therapeutic procedures. Individual volumes will deal with iatrogenic complications involving (1) the alimentary system, (2) the urinary system, (3) the respiratory and cardiac systems, (4) the skeletal system and (5) the pediatric patient. The term iatrogenic, derived from two Greek words, means physician-induced. Originally, it applied only to psychiatric disorders generated in the patient by autosuggestion, based on misinterpretation of the doctor's attitude and com ments. As clinically used, it now pertains to the inadvertent side-effects and com plications created in the course of diagnosis and treatment. The classic categories of disease have included: (1) congenital and developmental, (2) traumatic, (3) infectious and inflammatory, (4) metabolic, (5) neoplastic, and (6) degenerative. To these must be added, however, iatrogenic disorders-a major, although gen erally unacknowledged, source of illness. While great advances in medical care in both diagnosis and therapy have been accomplished in the past few decades, many are at times associated with certain side-effects and risks which may result in distress equal to or greater than the basic condition. Iatrogenic complications, which may be referred to as "diseases of medical progress," have become a new dimension in the causation of human disease."

As an addition to the European postgraduate training system for young neurosurgeons we began to publish in 1974 this series devoted to Advances and Technical Standards in Neurosurgery which was later sponsored by the European Association of Neurosurgical Societies. The fact that the English language is well on the way to becoming the international medium at European scientific conferences is a great asset in terms of mutual understanding. Therefore we have decided to publish all contributions in English, regardless of the native language of the authors. All contributions are submitted to the entire editorial board before publication of any volume. Our series is not intended to compete with the puhlicationR of original scientific papers in other neurosurgical journals. Our intention is, rather, to present fields of neurosurgery and related areas in which important recent advances have been made. The contributions are written by specialists in the given fields and constitute the first part of each volume. In the second part of each volume, we publish detailed descriptions of standard operative procedures, furnished by experienced clinicians; in these articles the authors describe the techniques they employ and explain the advantages, difficulties and risks involved in the various procedures. This part is intended primarily to assist young neurosurgeons in their postgraduate training. However, we are convinced that it will also be useful to experienced, fully trained neurosurgeons.

There are two important reasons for publishing this new series entitled "Advances and Technical Standards in Neurosurgery" 1. the lack of anyor ganized common European postgraduate training system for young neurosurgeons and 2. the language barriers, which impede the exchange of neurosurgical findings in Europe more than in other parts of the world. The fact that the English language is well on the way to becoming the international medium at European scientific conferences is a great asset in terms of mutual understanding. Therefore the Editors have decided to publish all contributions in English, regardless of the native language of the authors. All contributions are submitted to the entire editorial board before publi cation of any volume. Our series is not intended to compete with the publications of original scientific papers in other neurosurgical journals. Our intention is, rather, to present fields of neurosurgery and related areas in which important recent advances have been made. The contributions are written by specialists in the given fields and constitute the first part of each volume. In the second part of each volume, we publish detailed descriptions of standard operative procedures, furnished by experienced clinicians; in these articles the authors describe the techniques they employ and explain the advantages, difficulties and risks involved in the various procedures. This part is intended primarily to assist young neurosurgeons in their postgraduate train ing. However, we are convinced that it will also be useful to experienced, fully trained neurosurgeons."