Jaap Valk – författare

Our thanks go to our colleagues at the VU Univer- Preface to the Third Edition sity Medical Center and to those in other hospitals Reading through the prefaces of the two previous edi- who referred their patients to us. We are indebted to tions,we can say that much of what was said there still all colleagues who allowed us to use their MR images, holds. At the same time,however,much has changed. published or unpublished,making it possible for us to There has been immense progress in the technical present illustrations of nearly all known white matter possibilities of magnetic resonance and in the know- disorders. Two colleagues were particularly helpful ledge of genetic defects, biochemical abnormalities, and provided us with essential and unpublished f- and cellular processes underlying myelin disorders. ures: our friends Susan Blaser,from the Hospital for This immense progress has prompted us to embark Sick Children in Toronto,and Zoltán Patay,from the upon the enormous task of rewriting the previous King Faisal Hospital in Riyadh. edition and adding 40 chapters. In doing so we have Many people at the VU University Medical Center tried to cover most white matter disorders,hereditary have been of great technical help to us in producing and acquired,and to present a collection of images to high quality images and in providing secretarial illustrate the field to the fullest possible extent. This assistance. The contributions of these people are edition will therefore be more complete than the pre- mentioned separately in the acknowledgements.

Our thanks go to our colleagues at the VU Univer- Preface to the Third Edition sity Medical Center and to those in other hospitals Reading through the prefaces of the two previous edi- who referred their patients to us. We are indebted to tions,we can say that much of what was said there still all colleagues who allowed us to use their MR images, holds. At the same time,however,much has changed. published or unpublished,making it possible for us to There has been immense progress in the technical present illustrations of nearly all known white matter possibilities of magnetic resonance and in the know- disorders. Two colleagues were particularly helpful ledge of genetic defects, biochemical abnormalities, and provided us with essential and unpublished f- and cellular processes underlying myelin disorders. ures: our friends Susan Blaser,from the Hospital for This immense progress has prompted us to embark Sick Children in Toronto,and Zoltán Patay,from the upon the enormous task of rewriting the previous King Faisal Hospital in Riyadh. edition and adding 40 chapters. In doing so we have Many people at the VU University Medical Center tried to cover most white matter disorders,hereditary have been of great technical help to us in producing and acquired,and to present a collection of images to high quality images and in providing secretarial illustrate the field to the fullest possible extent. This assistance. The contributions of these people are edition will therefore be more complete than the pre- mentioned separately in the acknowledgements.

The numerous ways in which man and animals are affected by their physical environment, and the inborn and adaptive responses to change in the "milieu exterieur" have fascinated curious minds since the earliest days of recorded history. Development of the scientific method with its emphasis on evidence obtained through experimentation-perhaps best illustrated in this field by Paul Bert''s encyclopedic work-allowed several generations of our predecessors to establish firmly some facts and reject erroneous beliefs, but it was only during the early 1940s that environmental physiology put on its seven-league boots. In 1941, a young physiologist named Hermann Rahn was recruited by Wallace O. Fenn, then Chairman of the Department of Physiology at the University of Rochester, who was engaged in a study of the effects of altitude on human performance. The years that followed witnessed some of Hermann Rahn''s early achievements not only in the area of altitude, but in other aspects of environmental physiology as well. In particular, he participated in the definitive studies of human adaptive mechanisms in arid climates which formed the basis of Edward Adolph''s classic "Physi­ ology of Man in the Desert" (Wiley/Interscience, NY 1947). During those golden years, environmental physiology flourished, and important dis­ coveries were reported in a seemingly endless stream from many labora­ tories.

Many different opinions exist as to the appropriate diagnostic workup and therapy for spinal tumors. With the advent of new imaging techniques and therapeutic regimens, an up-to-date reference work has become an urgent requirement. This book is designed to meet this need, and is the first of its kind to offer an overview of the opinions of internationally renowned specialists in the field. By addressing in detail all of the relevant topics and areas of contention, it should prove of great value in establishing rational imaging and therapeutic protocols for spinal tumors.

The numerous ways in which man and animals are affected by their physical environment, and the inborn and adaptive responses to change in the "milieu exterieur" have fascinated curious minds since the earliest days of recorded history. Development of the scientific method with its emphasis on evidence obtained through experimentation-perhaps best illustrated in this field by Paul Bert's encyclopedic work-allowed several generations of our predecessors to establish firmly some facts and reject erroneous beliefs, but it was only during the early 1940s that environmental physiology put on its seven-league boots. In 1941, a young physiologist named Hermann Rahn was recruited by Wallace O. Fenn, then Chairman of the Department of Physiology at the University of Rochester, who was engaged in a study of the effects of altitude on human performance. The years that followed witnessed some of Hermann Rahn's early achievements not only in the area of altitude, but in other aspects of environmental physiology as well. In particular, he participated in the definitive studies of human adaptive mechanisms in arid climates which formed the basis of Edward Adolph's classic "Physi­ ology of Man in the Desert" (Wiley/Interscience, NY 1947). During those golden years, environmental physiology flourished, and important dis­ coveries were reported in a seemingly endless stream from many labora­ tories.

Many different opinions exist as to the appropriate diagnostic workup and therapy for spinal tumors. With the advent of new imaging techniques and therapeutic regimens, an up-to-date reference work has become an urgent requirement. This book is designed to meet this need, and is the first of its kind to offer an overview of the opinions of internationally renowned specialists in the field. By addressing in detail all of the relevant topics and areas of contention, it should prove of great value in establishing rational imaging and therapeutic protocols for spinal tumors.

With the growing number of MR installations, clinicians and radiologist are being confronted more and more with visual information they do not feel as confident with as with the more ''mono-form'' infor­ mation of conventional radiographs, CT and US. The freedom of parameter choice ofthe MR operator allows the same object to be depicted in various ways and the contrast in the images to be changed and inverted at will. For those not experienced in interpreting MR images, this may cause confusion and uncertainty about their diagnostic content. This will sometimes lead to an unnecessary retreat to other diagnostic modalities. The purpose of this book is to help close the gap between MR operators and readers and clinicians. A variety of cases is presented, together with the MRI considerations. In nearly all these cases, confirma­ tion of diagnosis was obtained by histological examination. Quite deliberately, this book only includes the occasional CT scan or angiography for comparison, to avoid the temptation of falling back on other modalities and of escaping from the often more difficult to interpret, but in the end more rewarding MR images. All the MR images in this book were made with a ''first-generation'', unsophisticated Teslacon I, 0.6 T, superconducting magnet system. Hopefully, they will reflect the quality of the machine. Some people will agree with me that it is sad that investments in expensive health care systems are subject to the whims of those who are mainly interested in satisfying their stockholders.

MRI is assuming a dominant role in imaging of the larynx. Its superior soft tissue contrast resolution makes it ideal for differentiating invasion of tumors of the larynx from normal or more sharply circumscribed configuration of most of the benign lesions. Over ten years ago CT made a major impact on laryngeal examination because it was the first time that Radiologists were beginning to look at submucosal disease. All of the previous examinations duplicated the infor­ mation that was available to the clinician via direct and in-direct laryngo­ scopy. With the advent of rigid and flexible endoscopes, clinical examination became sufficiently precise that there was little need to perform studies such as laryngography which merely showed surface anatomy. The status of deep structures by these techniques was implied based on function. Fortunately laryngography is now behind us together with all of the gagging and contrast reactions which we would all like to forget. CT is still an excellent method of examining the larynx but it is unfortunately limited to the axial plane. With presently available CT techniques motion deteriorates any reformatting in sagittal or coronal projections. The latter two planes are extremely helpful in delineating the vertical extent of submucosal spreads. MRI has proven extremely valuable by producing all three basic projections, plus superior soft tissue contrast. Although motion artifacts still degrade the images in some patients, newer pulsing sequences that permit faster scanning are elimi­ nating most of these problems.