According to Schopenhauer problems are usually passing through three stages: - in the first stage they are ignored or just smiled at, - in the second stage they are fought, and in the third stage they are considered to be self-evident, just taken for granted. Whereas digital subtraction angiography (DSA) has obviously reached stage three of that scale, i.e. routine use in radiology, digital angiocardiography, in particular imaging the heart and coronary circulation, is still on its way to the final goal: the filmless heart catheterization laboratory for all invasive and interventional procedures. A few pioneers have already completely abandoned the conventional cine coronary and angiocardiographic technique, others - as we do -still combine both digital and conventional methods in clinical routine, but most cardiol ogists up till now stay sceptically aside. We hope that at least some of the articles published in this volume may convince more and more cardiologists that digital imaging procedures are the method of choice, in particular if quantitative assessment of the anatomical or functional status of the cardiovascular system is required (pre- and post operations or pre-and post-interventions). Such a critical control of all therapeutic procedures, be it by surgical, catheter-or medical 'interventions', is indeed an urgent and widely under estimated or neglected requirement.

Many noninvasive examination methods of the heart have not held out against the invasive methods, which modern cardiac therapy, surgically or with catheterization, requires. They have disappeared completely or are only used by isolated groups of researchers. However, there is an obvious tendency to apply the invasive procedures as the last diagnostic possibility. In the attempt to select clinically relevant methods, the expert authors of this book demonstrate that echocardiography, expanded with contrast and Doppler, has been developed into one of the most important noninvasive methods. The results with tissue characterization show that the possibilities of this method have not yet been fully explored. Nuclear procedures are widely used, although they should only be applied in direct connection with clinical cardiology. The new lead methods of the ecg, such as ecg-mapping, show that standard electrocardiography of electrical functions is not yet fully exploited. The rapidly developing method of computer tomography is also being applied to cardiology. Since nuclear magnetic resonance requires extensive equipment con struction, its future is as yet unsure. Of course, a book like this does not intend to treat the subject of noninvasive cardiology in extensive detail. Established methods like standard electrocardio graphy, phonocardiography and sphygmography are not discussed. The aim of this book is rather to demonstrate the trend of present developments in the field. LIST OF CONTRIBUTORS Ameling, W., Rogowski-Institut fUr Elektronik, Rheinisch-Westfalische Technische Hochschule, Goethestrasse 27/29, D-5100 Aachen, FRG. Bachmann, K., Medizinische Poliklinik, Universitat Eriangen-NUrnberg, Ostliche Stadtmauerstrasse 29, D-8520 Erlangen, FRG.

In the past few years, the most exciting advances have occured in vascular diagnostics. First of all, well-established techniques like ultrasound have been further refined and developed (intravascular ultrasound). Furthermore, diagnostic investigations could be linked to treatment itself. More and more interventional techniques (the most popular is still percutaneous transluminary angioplasty - PTCA) have been introduced into daily routine. Radiologists and cardiologists are working more and more together, a fact which is reflected by the international group of experts bringing here the knowledge from both fields together for the first time.

Cardiovascular and Neurovascular Imaging: Physics and Technology explains the underlying physical and technical principles behind a range of cardiovascular and neurovascular imaging modalities, including radiography, nuclear medicine, ultrasound, and magnetic resonance imaging (MRI). Examining this interdisciplinary branch of medical imaging from a

There are few techniques that have influenced therapeutic strategies in modem cardiology to a similar extent as coronary arteriography. Bypass surgery as well as transluminal coronary angioplasty would not have been possible without coronary angiography serving as a 'midwife' in their evolu tion. Despite the widespread and long-standing use in clinical practice, however, the interpretation of coronary angiograms has not changed very much since the early days. Most angiogr~s are still reviewed in a visual and semi-quantitative and thus often very subjective way. In the face of an almost exploding field for interventional catheterization including thrombolysis, balloon dilatation, and other rapidly evolving techniques for transluminal revascularization or recanalization, a more detailed and quantitative analysis of coronary arteriograms is urgently required. In addition to the delineation of coronary morphology, we need dynamic and functional information about flow and perfusion to understand the physiological significance of anatomic abnormalities. Coronary arteriography contains and can provide most of this information. With the application of appropriate techniques, it can be made available in the catheterization laboratory even during the patient's investiga tion, thus facilitating and improving clinical decision making. Objective and reproducible analysis will furthermore enhance our understanding about the pathophysiology of coronary disease.

In the past, coronary arteriography was the only modality available to provide high quality images of the coronary anatomy. Quantitative coronary arteriography (QCA) was developed, implemented, validated and extensively applied to obtain accurate and reproducible data about coronary morphology and the functional significance of coronary obstructions. Over the last few years extensive basic technological research supported by clinical investigations has created competing modalities to visualize coronary morphology and the associated perfusion of the myocardial muscle. Currently, the following modalities are available: X-ray coronary arteriography, intracoronary ultrasound, contrast- and stress-echocardiography, angioscopy, nuclear cardiology, magnetic resonance imaging, and cine and spiral CT imaging. For all these imaging modalities, the application of dedicated quantitative analytical software packages enables the evaluation of the imaging studies in a more accurate, reliable, and reproducible manner. These extensions and achievements have resulted in improved diagnostics and subsequently in improved patient care. Particularly in patients with ischaemic heart disease, major progress has been made to detect coronary artery disease in an early phase of the disease process, to follow the atherosclerotic changes in the coronary arteries, to establish the functional and metabolic consequences of the luminal obstructions, and accurately to assess the results of interventional therapy. Aside from all these high-tech developments in cardiac imaging techniques, the transition from the analogue to the digital world has been going on for some time now. For the future, it has been predicted that the CD-R will be the exchange medium for cardiac images and DICOM-3 the standard file format. This has been a major achievement in the field of standardization activities. Since these developments will have a major impact on the way images will be stored, reviewed and exchanged in the near future, an important part of this book has been dedicated to DICOM and the filmless catheterization laboratory. Cardiovascular Imaging will assist cardiologists, radiologists, nuclear medicine physicians, image processing specialists, physicists, basic scientists, and fellows in training for these specialties to understand the most recent achievements in cardiac imaging techniques and their impact on cardiovascular medicine.

In this fourth book in the series on quantitative coronary arteriography (QCA) with the earlier three volumes published in 1986, 1988 and 1991, the latest developments in this exciting field are covered. Both the methodolog ical and clinical application aspects of these advances are presented in a comprehensive manner in a total of 37 chapters by world renowned experts. The book is subdivided into a total of eight parts, beginning with the more methodological issues, such as QCA and other modalities (3 chapters), cine film versus digital arteriography (3 chapters), quality control in QCA (4 chapters), and coronary blood flow and flow reserve (3 chapters). Since QCA has been well established as the technique for the assessment of regression and progression in atherosclerotic disease, and of restenosis after recanaliz ation procedures, major clinical trials in both groups are described extensively by their principal investigators in a total of 11 chapters. In addition, the QCA results after the application of various recanalization techniques are presented in another eight chapters. In the last part the experiences with various intracoronary prostheses with the emphasis on QCA are discussed in five chapters. This large increase in application oriented chapters means that QCA is well alive and gaining momentum. Although the accuracy and precision of the analytical methods steadily improve with the increasing complexity of the algorithms, there is still always the human factor involved in these processes in terms of frame selection, segment definition, etc.

This volume brings together the results of research into the methodology and applications of pattern recognition, with particular emphasis given to the incorporation of artificial intelligence methodologies into pattern recognition systems.The first part of this volume covers image analysis and processing software, systems and algorithms. Pattern analysis and classifier design are dealt with in part two, while the last part deals with model based and expert systems, including uncertainty calculus methods in pattern analysis and object recognition. A number of specific application areas are considered, including such diverse topics as fingerprinting, astronomy, molecular biology and pathology.

In June 1989, a third conference concentrating on the progress in quantita tive coronary angiography and related techniques was held in Rotterdam, again very successful as the two preceding events in 1985 and 1987. Tech nical as well as clinical aspects of digital and digitized coronarography, morphometry, parametric imaging and functional quantification of the human coronary circulation were presented and discussed by prominent exponents of those groups who have been active in this particular field for many years. This book contains the chapters representing the lectures held by leading experts during the symposium that update the knowledge currently available, including most recent aspects in angioscopy and intravascular ultrasound imaging. It also includes a historical review on the development of angiogra phic techniques from the very early days on to our times given by one of the pioneers in heart catheterization and angiography, Dr. Kurt Amplatz. Those who had the chance to listen to his talk, will surely remember his impressive, humorous lecture as one of the highlights of this meeting.