Transcranial Doppler Sonography

Every few years a dissertation comes to the area of clinical application of medical technology which carries us forward as on a magic carpet into new regions of understanding and patient care. This book is such a magic carpet. It brings together, in a clear and incisive fashion, important hemodynamic principles with a simple noninvasive method of application to a part of the cerebral vasculature which has been relatively inaccessible. To the lucky and perceptive person who reads this book, a feeling of excitement and hope for progress is engendered. The diligent application of the potentials of transcranial Doppler ultrasound brings new power to our efforts in understanding the cerebral circulation and the causes, treatment and prevention of cerebrovascular disorders. Merrill P. Spencer, M. D. Director Institute of Applied Physiology and Medicine Seattle, Wash. , July 1986 Acknowledgements I am greatly indebted to Prof. He1ge Nornes, Oslo, who introduced me to the fascinating study of cerebral hemodynamics in the early 1970's and since then continually encouraged my interest in this field. It was through his pioneering work on the cerebral circulation-using peroperative electromagnetic flowmetry and Doppler techniques-that the basis was laid for the noninvasive trans cranial approach to the circle of Willis described in this book. I also gratefully acknowledge the stimulating case discussions with Prof. Peter Huber, Berne, at the very early introduction of trans cranial Doppler, the inspiring exchange of ideas with Dr. Merrill P.

The measurement of the cerebral circulation in children, particularly in newborns and young infants, has for a long time been high on the list of needs in clinical and scientific pediatrics. The methods available to date have either been too unreliable or unsuitable for use on children. In the course of a research project at the Department of Pediatrics of the Uni versity of Freiburg, Dr. Harald Bode has made the first systematic ex amination of the cerebral circulation of children using transcranial Doppler sonography. Over 500 children with ages between 0 and 18 years were included in this exhaustive study, documenting Doppler measurements in about 3,000 basal cerebral arteries. Basic reference values were obtained which involved adapting the methodology and available equipment to the special re quirements of the pediatrician. Moreover, the influence of biological and physiological factors on these Doppler values has also been considered in addition to those of disease and therapy. The result is an impressive record of the many applications of trans cranial Doppler sonography during childhood. It is not difficult to predict that this methodology will be of lasting value and capable of further de velopment. I hope this book receives the attention it undoubtedly deserves and that the author is able to continue in realizing his fruitful scientific ideas in clinical pediatric practice.

The Second Edition of this highly regarded text provides a current reference source on the clinical and research applications of Transcranial Doppler (TCD) ultrasonography. All of the chapters have been updated to reflect the rapid evolution that has taken place in the field. New information has been included on the increased use of TCD in the operating room, the introduction of contrast media, and the development of new softwares that permit the detection of microemboli.

Transcranial Doppler (TCD) ultrasound, first introduced more than a decade ago, has steadily evolved into a dynamic, reliable, reproducible, and practical diagnostic tool. Clinical neuroscientists have found TCD to be an indispensable technique in the management of many types of patients. This book is designed to provide basic instruction in the perfor mance and interpretation of transcranial Doppler ultrasonography for technologists, nurses, and physicians. The information included in the text is critical for the development of a strong knowledge base. It is not intended to be all inclusive, and the TCD novice is likely to use it as the platform upon which to build his/her experience in the application of TCD. This book is organized as a step-guided approach for the performance of TCD, and it includes specific guidelines for interpretation of the TCD save forms. We hope that the reader finds it useful during what we think is the most difficult phase of this technique-the learning curve. John P. McCartney, R.V.T. Kathleen M. Thomas-Lukes, R.N., M.N.

This book clearly explains the basics of cranial ultrasonography in the neonate, from patient preparation through to screening strategies and the classification of abnormalities. The aim is to enable the reader consistently to obtain images of the highest quality and to interpret them correctly. Essential information is provided both on the procedure itself and on the normal ultrasound anatomy. The standard technique is described and illustrated, and emphasis is placed on the value of supplementary acoustic windows. Attention is also drawn to maturational changes in the neonatal brain and to the limitations of cranial ultrasonography. Frequently occurring abnormalities are described and classifications for these abnormalities are provided. A new classification for neonatal cerebellar hemorrhages is introduced. In this third edition, all ultrasound images have beena replaced, reflecting the improvements in image quality. An entirely new chapter is devoted to Doppler ultrasonography. The illustrations have been improved and new illustrations were added. The reader will have access to highly informative videos on the cranial ultrasound procedure, available online via SpringerLink. The compact design of the book makes it an ideal and handy reference that will guide the novice in understanding the essentials of the technique while also providing useful information for the more experienced practitioner.

In 1981, the Norwegian physiologist and cyberneticist, Rune Aaslid, developed a device which made it possible to apply the transcranial Doppler sonographic technique in man. In 1983, Dr. Albrecht Harders took on the project of working out a clinically practicable method that would allow atraumatic measurements to be made of the blood flow velocity in the large branches ofthe circle of Willis. The technique has now become a competitor of the conventional methods of measuring the intracranial hemodynamics, including angiography and the xenon method of cerebral blood flow measurement. Harders proceeded from the assumption that the measurement of the blood flow velocity is more relevant for clinical diagnoses than the usual volume flow measurements. He stresses the very valuable application of the technique in detecting cerebral vasospasm before and after aneurysm surgery. The changes in the blood flow velocities measured by transcranial Doppler sonography in the individual vessel segments of the circle of Willis are interpreted with respect to the various factors that can effect such changes (collateral circulation in the circle of Willis, diameter of the vessel, vascular resistance, the general cardiovascular situation, arterial partial CO pressure, autoregulatory factors, position of body). The rate of 2 complications associated with angiography has thus been reduced, since the best time both for angiography and for surgery can be determined, and continuous TCD examinations show when the patient is out of a critical phase of cerebral vasospasm.

Neurovascular ultrasound increases the reliability of assessing occlusive cerebrovascular disease, including the detection of instable carotid plaques, the delineation of cerebral perfusion and therapeutic options such as ultrasound-enhanced sonothrombolysis. Written by international experts, this publication provides the reader with the present knowledge and future research directions of diagnostic and therapeutic neurovascular ultrasound. The first chapters deal with physical and technical principles of ultrasound, arterial wall imaging, endothelial function testing and modern assessment of atherosclerotic obstruction of the carotid and vertebro-basilar systems. Subsequently, typical ultrasound findings in cervical artery dissection, dural fistula, glomus tumor and vasculitis are reported. The book concludes with the description of diagnostic and therapeutic transcranial ultrasound and clinical applications of transcranial Doppler monitoring as well as the presentation of future developments. Neurologists, angiologists and radiologists will find a valuable source of up-to-date information on this fascinating, essentially non-invasive technique, which allows real-time assessment of the human cerebral vessels.