The North Atlantic Treaty Organization (NATO) has sponsored research and personnel safety standards development for exposure to Radiofrequency Radiation (RFR) for over twenty years. The Aerospace Medical Panel of the Advisory Group For Aerospace Research and Development (AGARD) sponsored Lecture Series No. 78 Radiation Hazards,! in 1975, in the Netherlands, Germany, and Norway, on the subject of Radiation Hazards to provide a review and critical analysis of the available information and concepts. In the same year, Research Study Group 2 on Protection of Personnel Against Non-Ionizing Electromagnetic Radiation (Panel VIIl of AC/243 Defence Research Group, NATO) proposed a revision to Standardization Agreement (STANAG) 2345. The intent of the proposal was to revise the ST ANAG to incorporate frequency-dependent-RFR safety guidelines. These changes are documented in the NATO STANAG 2345 (MED), Control and Recording of Personnel Exposure to Radiofrequency Radiation,2 promulgated in 1979. Research Study Group 2 (RSG2) of NATO Defense Research Group Panel VIII (AC1243) was organized, in 1981, to study and contribute technical information concerning the protection of military personnel from the effects of radiofrequency electromagnetic radiation. A workshop at the Royal Air Force Institute of Aviation Medicine, Royal Aircraft Establishment, Farnborough, U. K. was held to develop and/or compile sufficient knowledge on the long-term effects of pulsed RFR to maintain safe procedures and to minimize unnecessary operational constraints.

To continue the support for the growing trend of chemistry involvement in nuclear medicine, the Division of Nuclear Chemistry and Technology (DNCT) of the American Chemical Society (ACS) planned for a symposium to cover this aspect. This was expressed in arequest to me, as a member of the Program Committee, to organize a symposium on topics related to nuclear and radiochemistry applications to nuclear medicine. Realizing the growing interest in imaging, specially with positron emitting radioisotopes, I invited several colleagues to study with me the idea of imaging centers and the involvement of chemists in their structure and function. The formulated Organizing Committee supported this idea which evolved in proposing an extended international symposium to be held in conjunction with the 206th ACS National meeting in Chicago, Illinois, U. S. A. on August 22-27, 1993. The following are the members of the Organizing Committee: Jorge R. Barrio, Ph. D. Thomas E. Boothe, Ph. D. J. Robert Dahl, Ph. D. Robert F. Dannals, Ph. D. Bruce R. Erdal, Ph. D. Mark M. Goodman, Ph. D. George W. Kabalka, Ph. D. James F. Lamb, Ph. D. Ronald G. Manning, Ph. D. Henry C. Padgett, Ph. D. Roy S. Tilbury, Ph. D. Steven W. Yates, Ph. D. and Ali M. Emran, Ph. D.

"Endourology" provides a summary of the different endourological modalitites, especially the more advanced and controversial techniques, such as the antegrade resection of urethral valves, the transperineal I 125 seed implanations, the spoonloop resectoscope, flexible endoscopy, teflon injection to correct vesicoureteral reflux, stone manipulation in calyceal diverticula, as well as the extraperitoneal pelvioscopy. These techniques are supported by descriptions of the standard endourological procedures.

The philosophy of this NATO Advanced Research Workshop and the monograph it has yielded is that if you put a small number of very talented and creative scientists of different backgrounds and documented accomplishments together in a cloistered place for a few days to consider a very important and timely topic, many new ideas will be generated. The keynote of this conference was the Future. By this we mean the expected future developments of highly reliable sequential quantitative measurements of atherosclerotic plaque size and components in living human subjects. Some of the best minds and the most experienced and talented individuals at the leading edges of imaging of arteries were involved; some of the best scientists and students of the atherosclerotic plaque and its components participated; and some of the leading investigators of the cell biology or, as we call it in the USA, the pathobiology of atherosclerosis, contributed important new information. All of these individuals were actively involved in the conference and each obviously had carefully prepared and was able to communicate effectively.

The fetal period of human growth and development has become an area of intense study in recent years, due in large part to the development of diagnostic ultrasound. More than 2,000 articles have been published in the last five years describing anatomy and pathology in utero, as reflected in sonographic images. Yet, no stan dard reference exists to correlate these images with fetal gross anatomy and at tempts to draw parallels from adult structure have often led to false assumptions. The dictum "the newborn is not a miniature adult" is all the more valid for the fetus. This text aims to provide a comprehensive reference for normal sectional anat omy correlated with in utero ultrasound images. In addition, magnetic resonance images of therapeutically aborted or stillborn fetuses are paired with similar gross sections to serve as a foundation upon which current in vivo studies may build. Lastly, a miscellaneous section illustrates several anatomic points useful in the understanding of fetal anatomy. These points include the changing anatomy of the fetal brain during gestation and the anatomy of the meninges, the fetal heart, and ductus venosus. It is our hope that this atlas will provide a clear picture of fetal anatomy, rectify some of the confusion which exists in antenatal diagnosis, and stimulate further interest in fetal development."

The investigation of the brain by means of ultrasound has acquired increasing importance in the last years because it permits insight into the spatial relationships within the intact human skull in a short time without endangering the patient. The road from the first ultra sonic investigations on the exposed brain to the detection of intracranial midline shifts on the intact skull, the registration of echo pulsations and recently, to ultrasonotomography has been a long one already. However, this development is by no means at an end. Following the suggestion of numerous colleagues concerned with echo-encephalography in this country and abroad, the Neurosurgical Clinic of the University of Erlangen-Nuremberg organized an "International Symposium on Echo-Encephalography" on April 14th and 15th, 1967. Here there was an open exchange of experience on the results obtained up to the present. The limitations of the method and sources of error as well as the directions of future development of the ultrasonic echo procedure were discussed."

Echo-encephalography, introduced by LEKS ELL in 1955, has gained increasing importance for the early detection of numerous intracranial lesions in the last decade. The main advantage of this diagnostic procedure lies in the fact that it permits a rapid orientation about the spatial relationships within the skull without stressing or endangering the patient. Although this method alone only rarely allows a complete diagnosis, the echo-encephalographic findings always indicate which further diagnostic measures are most suitable for establishing the diagnosis with the greatest accuracy in every case. However, the correct interpretation of an echo-encephalogram is possible only, if the findings which are assumed to be pathological are evaluated in the light of the clinical symptomatology. Since JEPPSSON'S excellent monograph on the origin of the midline echo and its importance for the diagnosis of intracranial expansivities, published in 1961, a great deal of work has gone into the development of echo-encephalography all over the world. For this reason the possibilities of this procedure today go far beyond the mere demonstration of a supratentorial shift. Now we can frequently outline the width of the ventricles exactly and localize tumors or hematomas by means of abnormal reflections. Since a detailed description of the technique, application and present-day diagnostic uses of echo-encephalography has not been available as yet, we undertook to fill this gap in the German literature in 1967 with a monograph summarizing the hitherto existing experience as well as our own extensive case mate rial.

The International Symposium of Acoustical Imaging has been widely recognized as the premier forum for presentations of advanced research results in both theoretical and experimental development. Held regularly since 1968, the symposium brings together th leading international researchers in the area of acoustical imaging. The 24 meeting is the third time Santa Barbara hosted this international conference and it is the first time the meeting was held on the campus of the University of California, Santa Barbara. As many regular participants noticed over the years, this symposium has grown significantly in size due to the quality of the presentations as well as the organization itself. A few years ago multiple and poster sessions were introduced in order to accommodate this growth. In addition, the length of the presentations was shortened so more papers could be included in the sessions. During recent meetings there were discussions regarding the possibility of returning to the wonderful years when the symposium was organized in one single session with sufficient time to allow for in-depth presentation as well as discussions of each paper. And the size of the meeting was small enough that people were able to engage in serious technical interactions and all attendees would fit into one photograph. In light of the constraints of the limited budget with respect to the escalating costs it was not considered feasible.

A concise introduction to the principles and practice of point-of-care echocardiography for neonatologists Practical Neonatal Echocardiography is based on an acclaimed course that the authors havetaught for the past 15 years at USC training neonatologists in cardiac ultrasound ofneonatal patients for on-the-spot examination and diagnosis. Drs. Siassiand Noori have trained hundreds of physicians to use ultrasound equipment toexamine neonatal cardiac function at the first sign of distress, leading to fasterdiagnosis and referral to pediatric cardiologists for treatment. This book is designed to helpreaders develop the skills necessary to perform a high quality neonatalechocardiographic examination, evaluate cardiac function, and recognizeabnormalities and defects. Practical Neonatal Echocardiography begins with an introduction to the basic principles of echocardiography and the ultrasound scanners commonly used at pediatric cardiac centers. Neonatal cardiac anatomy is clearly described through the use of 2-dimensional images andvideo clips. Subsequent chapters teach the assessment of cardiac function, bloodflow, shunts, physical defects, and abnormalities that may exist in the absence of adefect. Myocardial dysfunction, heart failure, shock, hypertension, cardiomyopathy,cyanosis, and more are discussed in detail with multiple illustrative cases. *Integrated throughout the chapters are 110 video clips, which when looped, will display a beating heart. These real-life cases will help readers hone their skills in recognizing defects in cardiac function and growth.*Covers essential principles of echocardiography with clear descriptions and illustrations*Describes common features of ultrasound scanners and how to use them

The first of a two volume set, Volume 12 provides a long-awaited compilation of NMR theory to paramagnetic molecules. International experts report the latest developments in NMR methodology as applied to strongly relaxed and shifted resonances, detail the theoretical aspects of paramagnetic shift and relaxation, and discuss the interpretive bases of these molecular properties in relation to the structure and function of various paramagnetic molecules.

Alfons Staudach has been a long-time member of the Anatomic Institute of Karl Franzens University in Graz, where he has devoted particular atten tion to the deeper understanding, appreciation and visualizion of gross ana tomic details. In this work the author has achieved correspondence between sonograms and anatomic sections with a consistency and persuasiveness unequaled in all the previous literature on diagnostic ultrasound. The various planes of section andtheir characteristic features, and indeed the entire format of the text, are designed to provide even the less experienced sonographer with a valuable basis for conducting his examinations. The more experienced reader will find essential information on topographic relations and organ development that is not available in any other work dealing with fetal ana to y. I am certain that my high estimation of this volume will prove justified, and that it will provice its readers with a useful and stimulating resource. Univ. -Prof. Dr. Walter Thiel (Chairman of the Anatomic Institute of the University of Graz) Foreword Anyone setting this book down after an initial perusal must wonder why such a reference was not available ten years ago. The meticulous and fas cinating juxtaposition of gross anatomic sections with sonograms, together with explanatory drawings and many practical guidelines, should enable even the novice accurately to identify details and interpret sonographic findings with precision."

Published as a companion to Volume 12, the current volume presents the latest advances in electron paramagnetic resonance of iron proteins, metalloproteins, and free radicals. The book features a diskette containing programs for iron ERP spectral simulation and ENDOR analyses.

It is now more than 40 years since Drs. Wild and Reid published their first experience with rectal ultrasonography from the Surgery Department at the University of Minnesota. Professor Owen H. Wangen steen, in whose laboratory the studies were carried out, recognized at that time the need for early detection in the treatment of cancer. Technical improvements over the past 20 years have made endoscopy the procedure of choice for examination of the hollow organs of the genital, urinary and gastrointestinal tracts. The simultaneous development of endosonography has had an equally dramatic impact on the practice of medicine and surgery. The technology has been demonstrated to be helpful in both benign and malignant conditions. One of the so-called benign conditions of the anorectum is fistula-in-ano. Fistula surgery has always relied on excellent anatomic delineation of the intramuscular tracts. There is hope that adaptation of ultrasonographic technology will aid in the surgical management of this malady. Clearly, rectal ultrasonography has considerable potential in the management of rectal carcinoma. Accuracy rates in the range of 90% for the depth of neoplastic invasion have been reported. This ability for accurate assessment will undoubtedly lead to a better definition of the population of patients that can be managed by local therapeutic means.

'Morphological imaging' and 'functional imaging' are current mainstays for the diagnosis, successful treatment and accurate follow-up of patients with endocrine disorders. Functional and Morphological Imaging of the Endocrine System provides the reader with comprehensive but concise insights in the application of cutting edge imaging techniques and updated imaging protocols for the diagnosis and treatment of hypersecretory hormonal syndromes and functional endocrine masses.

Only a few years ago, most treatises on sonography covered all the diagnostic applications of ultrasound, de scribing organs from the brain down to the placenta. Dr. Bruneton and his associates must be thanked for pre senting this book devoted to the spleen. It probably offers the most complete presentation of details and the richest images available in its field. This book will thus become the ultimate reference in most libraries of books on son ography. March 1988 F. Weill The authors wish to thank Christine Rostagni, Fran ise Fein, and Bernard Fontaine for their assistance in the preparation of this book. Contents 1 Sonographic Anatomy of the Normal Spleen, Normal Anatomic Variants, and Pitfalls B. Senecail . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 Anatomy of the Spleen. . . . . . . . . . . . . . . . 1 1. 1. 1 Morphology and Structure . . . . . . . . . . . . . 1 1. 1. 2 Location and Relations of the Spleen. . . . . . . . 3 1. 1. 3 Average Dimensions of the Cadaver Spleen . . . . 5 1. 1. 4 Congenital Anomalies and Normal Variants. . . . 5 1. 1. 4. 1 Fissured Spleen. . . . . . . . . . . . . . . . . . . . 5 1. 1. 4. 2 Lobulated Spleen. . . . . . . . . . . . . . . . . . . 5 1. 1. 4. 3 Spleen with Two Hili. . . . . . . . . . . . . . . . . 5 1. 1. 4. 4 Wandering or Ectopic Spleen . . . . . . . . . . . . 6 1. 1. 4. 5 Numeric Anomalies . . . . . . . . . . . . . . . . . 6 Ultrasonography of the Spleen . . . . . . . . . . . 1. 2 6 1. 2. 1 Equipment . . . . . . . . . . . . . . . . . . . . . . 6 1. 2. 2 Patient Examination . . . . . . . . . . . . . . . . . 7 1. 2. 3 Scanning Technique . . . . . . . . . . . . . . . . . 7 1. 3 Sonographic Features of the Normal Spleen. . . . 7 1. 3. 1 Splenic Contour . . . . . . . . . . . . . . . . . . . 7 1. 3. 2 Echo Pattern of the Splenic Parenchyma. . . . . ."

Congenital hip dysplasia and dislocation are common diseases of newborns and small infants, with frequently severe consequences if orthopaedic therapy is not initiated at an early stage. Therefore many clinicians have been looking for a simple method for the investigation of the hip joint in the early neonatal period. Up to 1980 the diagnosis of hip dysplasia could usually not be made before the 3rd month of life, by means of pelvic roentgenography. Only incomplete or complete unilateral dislocations were diagnosed in the neonatal age group. In 1980, however, Graf, an Austrian orthopaedic surgeon, began using ultrasound investigation ofthe hip joint in newborns and small infants in order to make an early diagnosis and to avoid radiation exposure. The intention of the present study was to compare ultrasound of the hip joint with other established diagnostic procedures and to establish whether it is suitable as a screening procedure in newborns. 2 Incidence of Congenital Hip Dysplasia and Dislocation In 1972 Barlow reported that 90 % of hips which are unstable at birth develop to normal joints spontaneously without any therapy. Visser (1984) thus suggested determining the percentage of hip dislocations after the 2nd - 3rd month of life so that children with spontaneous stabilisation would be excluded.

Vascular diagnostics traditionally rely on x-ray angiography. This approach remains even today essential in the clinical work-up of patients with vascular pathology. Recently, however, newer imaging modalities have been intro duced to assess vascular disease. Among these the color Doppler flow and magnetic resonance imaging appear the most promising. Due to their noninva sive character both methods are ideally suited for screening as well as serial follow-up of vascular patients. The emergence of color Doppler flow and magnetic resonance vascular imaging coincides with new concepts in vascular medicine. Today, vascular prevention and percutaneous interventions are becoming the leading compo nents in modern vascular care. It is in this new and exciting environment of novel vascular concepts where the demand for reliable noninvasive vascular imaging is becoming a high priority. Color Doppler flow and magnetic reso nance vascular imaging are well on the way to satisfy this demand. This textbook provides the long awaited information on vascular imaging by color Doppler flow and magnetic resonance. The text covers the essentials of vascular anatomy, physiology and noninvasive imaging technology before providing a state-of-the-art review of their current clinical applications. All chapters are written by competent scientists and clinicians in a clear, conscise and yet thorough and exhaustive manner. The coherent and didactic composi tion of the textbook allows the reader an easy access to the elementary as well as the advanced principals and clinical applications of the modern noninvasive vascular imaging.

Since the pioneering work of Donald and his first Lancet paper in 1958, the use of ultrasound in obstetrics and gynaecology has evolved rap idly. The introduction of grey scale techniques enhanced our ability to identify different tissues on the basis of their texture. However, it was the introduction of the linear array real-time scanner in the mid seven ties that changed ultrasound from being an "eccentric art form" to a readily available and usable technique. This led to the first reports of the diagnosis of neural tube defects using ultrasound by Campbell, as well as the establishment of fetal biometry. In the midst of this activity the parallel development of the transvaginal probe by Kratochwill went almost unnoticed by most gynaecologists. Yet the application of this technique has since had a major impact on many areas of gyna ecological practice, and on infertility in particular. Since the demon stration of transvaginal follicle aspiration, the vaginal route has become standard for most invasive ultrasound guided gynaecological procedures. The relatively new technical advance of transvaginal colour Doppler may potentially have just as great an impact. The introduction and use of transvaginal colour flow imaging has facili tated the study of vascular changes within the pelvis.

It will be a long time before the quality of this profusely illustrated book is overtaken and the present spate of books on the subject of obstetric ultrasound may, as a result, suffer a numerical set-back - especially with translation into English which will "deliver the milk on everyone's doorstep". Two of the authors studied in our department in Glasgow and worked like If there are any rewards for teaching, then we humble Scots who demons. have had the privilege have had more than our share as a result of the pride with which we regard our pupils. In my own old age and looking back over the last thirty years, the innumer able difficulties, set-backs and disappointments have been more than compen sated for by those who have turned the subject from a laughable eccentricity (as I have at one time experienced) into a science of increasing exactitude. This transformation has come about, not by any efforts of mine, but by the enthusiasm and ingenuity of those who would probably have achieved as much on their own if given the encouragement which I ultimately received in Glasgow University life. Limbo must be the expected lot of most of us ordinary mortals but the work lives on. And so, in this reminiscent and philosophical mood I beg leave to quote a little poem which I wrote at an age when young men do that sort of thing.

Dr. Jean Lintermans came to Seattle in 1962 from his general pediatric residency at the University of Iowa. He worked with us in clinical pediatric cardiology and in our animal physiology laboratory for the next three years. He was the most productive individual in the history of our training program, publishing seven papers in those three years, four clinical papers and three involving pulsed ultrasonic flowmeters and implanted ultrasonic displacement devices in animals. The work, from laboratory to publication, was always done with the utmost attention to accuracy, and was well developed conceptually. Although English was not his native language, Jean's mastery of English was not only excellent, I felt that he actually communicated better than many of our native physicians. During the past year, I was delighted to learn that Jean was preparing a textbook on pediatric echocardiography with Dr. van Dorp, and was even more pleased to be asked to write a foreword .. However, the greatest pleasure came from actually reading this book, and finding that it does indeed have a unique approach, and with the additional genuine benefit to the reader of a thorough, consistent, segmental approach to the diagnosis of congenital heart disease.

Medical applications of ultrasound range from therapy, foetal monitoring, diagnostic imaging and blood flow measurement, to surgery and lithotripsy. Ever since the earliest developments of medical ultrasound there has been an interest in the measurement and characterisation of the ultrasonic fields generated in these applications, either for assessment of performance of equipment or for safety. Until recently, procedures for acoustic output measurements were ill-defined, but standards are now being developed internationally by the International Electrotechnical Commission (1EC) and reliable commercial measuring equipment is becoming more widely available. The aim of this book is to introduce acoustic output measurement techniques and to provide an insight into the measurement methods. The material presented is based on a course originally run during November 1989 at the National Physical Laboratory. In addition to the lectures, the course consisted of a series of practicals to allow participants to gain experience of making measurements. Teddington, UK Roy C. Preston February 1991 Contents List of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii List of Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Safety of Diagnostic Ultrasonic Equipment: The Relevance of Acoustic Output Information to the Clinical User R. C. Preston 1. 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 2 The Relevance of Acoustic Output Information. . . . . . . . . . . . . 6 1. 2. 1 What Is Acoustic Output Information? . . . . . . . . . . . . . . . . . . . 6 1. 2. 2 What Is Acoustic Output Information Used For? . . . . . . . 6 1. 2. 3 Why Should You Know the Acoustic Output Levels of Your Equipment? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. 2. 4 Are Acoustic Output Levels Really that Important? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technical improvements over the past twenty years have made endos copy the procedure of choice for examination of the hollow organs of the genitourinary and gastrointestinal tracts. The development of electro surgical techniques, laser technology, injection therapy, and a wide variety of other modalities now allow the endoscopist to treat many problems that in the past required open surgery. The simultaneous development of transcutaneous abdominal sonography has had an equally dramatic impact on the practice of gastrointestinal and geni tourinary surgery. The marriage of these proven technologies, known as endoscopic sonography, provides an exciting new modality that promises to further revolutionize the diagnosis and management of many intraabdominal diseases. Endoscopic sonography opens new frontiers by overcoming the primary limitations of its parent technologies. Fiberoptic endoscopy is limited by the inability to see beyond the luminal surface, this is particularly important when considering neoplastic disease because depth of wall invasion is a key factor in determining treatment. The limiting factor in transcutaneous sonography is the distance between the transducer and the target organ. With endoscopic sonography, the transducer is placed in close proximity to the target organ. This allows the use of high frequency waves (greater than 5 MHz), which provide better tissue resolution and eliminates the image distortion caused by overlying structures.

The acute abdomen is one of the most frequent, most dangerous and most difficult problems that the diagnostic radiologist has to deal with. This comprehensive manual presents a clinico-radiologic approach to the use of diagnostic imaging techniques for acute abdominal conditions. Imaging techniques, radiologic symptoms and clinical conditions are treated separately. This lucid format, together with a detailed subject index, offer the reader a quick and reliable reference aid in daily practice. The text is clearly structured and concise in style, and provides helpful practical hints, including discussion of diagnostic pitfalls. It is supported by a wealth of illustrations covering native diagnosis, ultrasonography, computer tomography and angiography.

Since the beginnings of diagnostic ultrasound in the 1950s, each decade has seen significant advances in this technology. Commer cialization of ultrasound occurred during the 1960s with the introduction of many of the clinical uses that are in existence today. The 1970s showed the most dramatic changes with the commercial introduction of gray-scale and real-time ultrasound. In the 1980s many new advances were introduced, including color Doppler, as well as a wide variety of endoluminal approaches, including endorectal, endovaginal and transesophageal. The decade of the 1990s promises even more significant advances with further transducer miniaturization, three-dimensional ultra sound, and the introduction of a variety of ultrasound contrast agents. With such rapid changes occurring, it becomes important to disseminate knowledge in as rapid a fashion as possible, thus it was quite appropriate that a meeting such as this be held to provide an in-depth review of the many new areas of ultrasound imaging that show promise for the future. Emphasis was on the new uses of ultrasound in gastrointestinal diseases. Many of these advances will, of course, also have applications in many other areas of the body. It is hoped that those in attendance will acquire a much broader understanding of where ultrasound is now and where it is headed in the not too distant future.

Over a mere 5 years, neonatal cranial sonography has evolved from an obscure and largely experimental imaging possibility to the modality of preference in the examination of the young brain. The almost immediate acceptance of the ultrasound examination of the neonatal brain was based on a number of coinci dent factors, the most important of which was the emergence of a burgeoning population of premature neonates who were, for the first time, surviving be yond infancy. These delicate patients were beginning to withstand the rigors of extrauterine life when not fully prepared for it; pulmonary, cardiac, and infec tious diseases no longer claimed most of them. With survival, a new specter reared its head: Would the eventual mental and neurologic status of these same children be worth the expense and time needed to bring them through their first months? This issue became increasingly pressing as evidence mounted through the 1970s that very premature neonates were at a high risk for intracranial hemor rhage and posthemorrhagic complications. An imaging modality that could evaluate the premature brain was sorely needed. The CT scanner with its proven ability to diagnose intracranial hemorrhage was of little value in this regard. So too were static gray-scale or waterpath ultrasound units. These modalities all had the same limitation, lack of portability. As neonatal intensive care units proliferated, so did the technology that would soon allow cribside neonatal neuroimaging, the real-time sector scanner."