During the last few years the annual scientific meeting of the American Institute of Ultrasound in Medicine has become one of the largest and most important of the yearly meetings in the field of diagnostic ultrasound. At these meetings papers are presented de­ scribing the latest developments in this field allover the North American continent. The decision of the Executive Board of the American Institute of Ultrasound in Medicine to publish the manu­ scripts presented at its annual scientific meetings will therefore be welcomed both by workers in the field who are unable to attend the meetings, but nevertheless wish to follow the latest develop­ ments in their field of interest, and also by members of the Insti­ tute who will wish to be able to refer later to details in papers of interest. It will be our endeavour to ensure that these Annual Proceedings will be in the hands of subscribers no later than four months after the meeting reported. It is hoped that such prompt publication will further enhance their value to those interested in the field of ultrasound in medicine and biology. The Editor gratefully acknowledges the assistance of his secre­ tary, Mrs. Joan Carson, upon whose shoulders fell the burden of re­ typing all the manuscripts in this volume presented in abstract form and who played an invaluable part in the compilation of all the text for photographic printing. D. N.