Computertomographie最新文献

A retrospective study of 65 histologically proven lymphoma patients evaluated the staging capabilities of CT in Hodgkin's disease. Nodal and extranodal tumor manifestations were detected in the mediastinum (89%), thoracic bones (23%), pleura (26%), periphery of the lung, and in 14% as an infiltrating thoracic well lesion. Advantages and disadvantages of the method are discussed.

Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data. Starting with a review of the principles of nuclear magnetic resonance it is explained how the measured signal can be associated with an image point; it is also explained what type of apparatus is necessary and what the physical limitations are. Possible risks the patient may be exposed to in an examination using nuclear magnetic resonance are discussed. The present state of the technical development enables the production of whole-body sectional images of a living person within about one minute. By means of some typical examples the nature and properties of these images are explained. Although extensive clinical studies will be necessary before a more general assessment can be made of this method, an outlook is provided on expected further developments and possible future fields of application.

Ultrasonic devices with rapid image build-up and high power of resolution enable detailed assessment of the vascular and biliary structures. Visualisation of the biliary tract of normal lumen in the extrahepatic region enables identification of a biliary obstruction at a time where dilatation of the intrahepatic biliary tract has not yet taken place. The identification of small visceral branches of the aorta abdominalis as well as of portal and systemic veins yields sonographically reliable vascular points of reference which enable, apart from the exact localisation of the biliary tract and of the pancreas, accurate topographic identification of abdominal mass lesions.

For diagnosis of adenomas in primary aldosteronism CT proved to be helpful. Although microadenomas have to be ruled out by selective venous sampling from both adrenal glands adenomas down to 8 mm in diameter can be visualized. Scintigraphy does not always permit reliable differentiation of unilateral adenoma from bilateral hyperplasia. -- in endogenous Cushing's syndrome adrenal carcinomas are underlying etiologically in about 10% of the cases. Since carcinomas are detected easily by CT it should be performed in the first place. Whereas adenomas and hyperplasia are easily diagnosed by scintigraphy carcinomas may escape scintigraphy. -- Pheochromocytomas, if situated in the vicinity of the kidneys, can be localized safely by CT. Contrary to adenomas, carcinoma and pheochromocytomas may be detected by CT without difficulty because of their size.

The diagnostic ranking and importance of computerised tomography was examined in 116 patients with abnormal findings in the mediastinal region, and was compared with conventional, non-invasive x-ray examinations. This method also yielded significant CT-specific additional information in the anterior mediastinum in 74.4% of the cases, in the mesomediastinum in 69.1%, in the posterior mediastinum in 79.2% in the upper thoracic aperture in 94.4% and in the paracardial region in 100% of the cases. The hilar region is an exception; in 68.8% of the cases, both methods were rated equal, whereas in 28.1% of the cases assessment via the CT method was even inferior. The specific additional information furnished by the CT method justifies a wider application of CT in solving the following problems concerning the mediastinum. -- clarification of a suspected but not yet established space-occupying growth in the mediastinum, before using invasive diagnostic methods such as mediastinoscopy and angiography; -- staging of an already identified primary mediastinal tumor of malignant lymphoma; -- in case of suspected changes in the large mediastinal vessels before employing angiography; -- on-target in the following diseases: bronchogenic carcinoma (because of improved pretherapeutic staging according to the TNM system), myasthenia gravis and identification of thymoma, hyperparathyroidism with suspected dystopic parathyroid glands.

The sonographic morphology of adenomas is studied on the basis of 7 sonographically identified and surgically confirmed adenomas of the parathyroid gland, taking the available literature into consideration. Information is given on differential diagnosis against normal anatomical structures and pathological processes. A correlation is established between sonomorphological and pathologico-anatomical findings.

In contrast to conventional methods of x-ray diagnosis, recurrence of a rectum carcinoma may be visualized directly by means of computerized tomography. CT criteria of a tumor relapse are discussed. Based on own cases, it is shown that the method is usually employed too late. CT as follow-up examination should be used as a routine procedure in order to establish an early diagnosis of tumor recurrence.