Computertomographie最新文献

Gallstones extracted by surgery were examined for CT density, which was compared with the x-ray-film, floating performance and chemical analysis of the stones. So far, the water content of the biliary concrements--14% on the average--has not been given much attention. Drying will considerably reduce the density; examination of dried gallstones yields a false picture of direct ray absorption. Pure cholesterol stones do not float in water, and they show positive values on Hounsfield's scale (+30--+60). The article discusses the question whether CT is suitable for effecting a better selection of gallstone patients who can be treated by drug therapy.

Lumbar myelographies were carried out with lopamidol and locarmat of identical concentrations of iodine in 2 groups of 20 patients each. In about one-third of the cases, clinical side effects and EEG changes were found after the examination without difference with the exception of one seizure and one state of confusion which occurred only after locarmat. Resorption of the contrast media was judged by CT examinations of the lumbar spine and the head. There was a more rapid decrease of lumbar contrast density in patients with a narrow lumbar sac which was accompanied by a more rapid intracranial accumulation of the contrast medium. This may be due to a more active transport of cerebrospinal fluid in this group of patients.

In 152 examinations, sonography was found to be a reliable screening method in the follow-up of curative and palliative surgery of carcinoma of the pancreas. By the effected changeover from compound scanning to the high-resolution real-time B-process, it has become possible to recognize at an early date even small locoregional recurring tumours (1.5 cm diameter), metastases of lymph nodes (1-1.5 cm diameter) and hepatic filiae (1.0 cm diameter); it has also been possible to detect typical changes, such as stenoses or thromboses, at the major vessels of the upper abdomen, well in time. If the findings are not clear, CT examination will be mandatory, if necessary in conjunction with bolus injection of a contrast medium. These methods have been able to largely replace the well-known invasive procedures, such as ERCP, angiography and laparoscopy in follow-up controls.

The anatomical relationship between the terminal ureter, the trigone and the vesico-ureteral junction was studied in vivo by ultrasound. In healthy test persons successful visualization and differentiation of the submucosal, transmural and retrovesical segments of the terminal ureter could be obtained. Some potential clinical applications of the method are discussed.

A new imaging method of the prostate is described. After the introduction of a sonographic transducer into the rectum, the prostate, the urinary bladder and the seminal vesicles are scanned. Typical transverse sonograms of benign hypertrophy, abscess, calculous disease and carcinomas are presented. The value of this method and its indications are discussed.

The authors describe a case of lipoma of the lumbosacral region, associated with meningocele in an infant and advocate the utilization of CT scanning in direct coronal mode (DCM) and ultrasound (US) as means of diagnosis of the extension and geography of the lesion and differential diagnosis. The surgical management is also indicated.

By means of suitable hardware and software changes it becomes possible to obtain transmission profiles of high time resolution (up to 50 profiles/sec) with the help of a CT device which is suitable for the recording of digital radiographs, in one transversal body layer. In this manner, it becomes possible to measure changes in the density profile from 6 up to 50 sec and to analyse them. This method called "Chronogram", enables high-resolution recording of density changes, similar to kymography. The possibilities of using contrast media are demonstrated by means of phantom measurements, and initial clinical experiences are outlined on the basis of practical examples.

This paper describes results of measurements characterising the image properties of a CT apparatus triggered by an "R-peak simulator". For this purpose, a phantom was constructed in which--as straightforward simulation of a cardiac wall movement--a plate made of plexiglass of 5 mm wall thickness moves to and fro with a frequency nu (1 s-1 less than or equal to nu less than or equal to 2 s-1) and an amplitude of A = 10 mm. The number of scanning cycles during a measurement could be varied between 2 and 9. It was evident that the measured density values as well as the positions of the plate which could be ascertained from the CT images in the various phases of movement, especially at low frequencies and a large number of cycles, agree well with the real values; however, it was also found that both at the measured density values and the positions of the plate as seen from the CT images, systematic deviations occur, especially at high frequencies and a small number of scanning cycles.