Bøger i Radiology serien

I am particularly pleased to be able to write the introduction to this book that resulted from a collaborative effort by the Radiology De­ partment, under the auspices of the Boerhaave Committee for Postgraduate Medical Education of the Faculty of Medicine, at the University of Leiden and the Department of Medical Imaging and Radiological Sciences at Van­ derbilt University. Magnetic resonance imaging affords the opportunity to interrogate organ and system structure and function in a nondestructive manner without se­ rious biological implications. Tissue contrast with this modality is ex­ quisite and inherently superior to that of x-ray computed tomography. The advances to improve signal capture, development of rapid data acquisition techniques, fabrication of more appropriate pulse sequences, and availa­ bility of contrast agents portend increased versatility and specificity of these studies. Despite the proliferation of numerous general and specialized texts, the developments in MRI occur at such a pace that data in these references are necessarily dated. The technical horizon of MRI is vast with almost li­ mitless possibilities of signal generation and plan reconstruction. Tissue contrast is so importantly affected by the coupling of signal generation and capture that collective experience of institutions and investigators is extremely important to the initiate and useful even to those indivi­ duals with the greatest clinical experience.

With the advent of CT we entered a new area of radiological imaging. Structures which rarely if ever were seen became apparent. In no part of the body was the impact of CT as profound as it was in the retroperitoneum. In the pre-CT area this region of the body could not be directly studied and only when gross abnormalities were present could they be appreciated. The best we could do was to try to identify a suspected process by studying its effect on surrounding organs whose position might have been affected by the growth. Urography, barium studies or angiography were employed in the hope that variation in the position of the vessels, ureter or bowel would lead us to the correct diagnosis. With computed tomography all this changed. Modern scanners, available to all today, permit us to appreciate details undreamed of only few years ago. The abundance of fat in this region helps to clearly show even the smallest of structures. We now have the ability to recognize small vessels, lymph nodes and fascial planes. We had a tool which permitted us to study structures which hitherto were only seen by the anatomist or during surgical dissection.

The liver blood flow disorders are usually described under the term 'portal hypertension', which is a well­ known syndrome since it has been widely studied for years from a clinical, radiological and therapeutic point of view. In fact, portal hypertension is only the result of an obstacle to the portal flow, the clinical manifestations of which often occur at a late stage of the disease: bleeding esophageal varices, splenomegaly, ascites. In addition, it is well known that there is not always a precise relationship between the degree of the obstruction, i.e. the decrease of the portal inflow and the level of the portal hypertension. A severe obstruction to the portal flow may therefore sometimes remain clinically inconspicuous for a long time. For this reason improvement of our knowledge of portal hypertension mainly relies on angiographic investigations. Thus, splenoportography permits the discovery of prehepatic obstructions whereas hepa­ tic venography permitted the recognition of two different types of intrahepatic obstruction according to the pre-sinusoidal or post -sinusoidal site of the obstacle. More recently, arterial hepatic changes could be evidenced through arteriography. However, these angiographic investigations have not yet allowed for all the problems about portal hypertension to be clearly identified.

The rapid growth of fibre-optic endoscopy in recent than 7,500 examinations has been accumulated. years has had two consequences for the radiology of In part I of this study the theoretical background the stomach and the duocienum. and the technique of examination proper are de­ scribed. The basic principles of interpretation of DC 1. Radiology has lost its previously rather auton­ studies are stated. omous position in this field. Part II deals with the results. Chapter 5 consists of 2. As a result of the constant feed-back from the general remarks on the results, and on the comple­ endoscopist, which the radiologist can and should mentary role of radiological examination and endos­ have, he is in an excellent position to re-evaluate copy. Chapter 6 deals with a quantative study of and improve his own technique of examination. standard biphasic-contrast examinations in patients The author believes that the radiological exam­ over a period of 3 years. This study was restricted to ination retains its value as a screening technique and malignant lesions, because it is only in this group a complementary method to gastroscopy and biop­ that the definite criterion, a histological diagnosis, is sy. Only a sophisticated radiological technique will obtained. The natural history of malignant lesions fulfil these requirements. In 1973 the author devel­ also makes follow-up studies possible. Results of the oped a standard examination that was called "bi­ diagnosis of Early Gastric Cancer (EGC) are phasic", because it combines the advantages of included.

The purpose of this book is to explain the current state of the art in radiological examination, interpretation, and understanding of colonic disease. The radiologic aspects of colon disease are combined here with clinical information to serve both beginners and advanced students. Major emphasis has been placed on technique for those radiologists, residents, and technologists first undertaking modern gastrointestinal radiographic techniques. The essentials of technique are stressed so that the reader obtains a clear understanding of colon disease based on sound practical information. We believe this book is a thorough and practical text of particular interest to clinical radiologists and gastroenterologists in their everyday practice, and also for teachers, residents and medical students. Digital examination and sigmoidoscopy are the first procedures in examination of the colon. Then, the radiologic examination is the next most important procedure. Endoscopy and biopsy play a compli­ mentary role to the radiological examination. The barium enema reveals quickly and early the overall status of the colon and it can then guide endoscopy and biopsy together with subsequent treatment. Surely, if the lesion is not detected our clinical, radiologic, endoscopic, and therapeutic skills are of no use.