Computertomographie最新文献

In 47 patients the authors calculated the volume at the end of a diastole according to both the cardiac catheter ventriculogram and the CT ventriculogram, comparing the results obtained with each of these methods. A linear regression was found. The correlation coefficient was approximately r = 0,96; n = 47. Cardiological examination revealed that of the examined patients (including the cardiac catheter finding) 18 patients had coronary heart disease, whereas 9 had cardiomyopathy, 6 arterial hypertension, 9 had various cardiac abnormalities and 5 did not show any organically manifest heart disease. The article discusses CT determination of the volume at the end of the ventricular diastole, and discusses the results.

Following an analysis of the most important metabolic disturbances and other diseases associated with fatty degeneration of the liver, it is shown, basing on a previous study, by means of examples, that subtle diagnosis of changes of the fatty content of the liver can be achieved via CT density measurement. Lipolysis in alcoholic fatty liver is quantified during abstention from alcohol, and a lipolysis factor of 1% fatty decomposition per day is determined from the measurements. Observations in pancreatitis with liver lipid storage during the course of the disease, point to an enzymatic weakness in lipid metabolism. Case histories show fatty degeneration associated with an enhanced cortisone serum level (in adrenal adenoma and cortisone therapy) and in poorly stabilized diabetes mellitus. It is concluded from the studies that determination of the relative fatty content by CT densitometry should be conducted as a routine procedure and that pathological lipid content should stimulate subtle diagnosis of the pancreas and the adrenals. In addition, examinations repeated during the course of the disease with assessment of change in fatty content, will be useful for assessing the value of the therapy employed.

The diagnostic significance of computerized tomography in the diagnosis of destructive and deforming processes of the sacrum is demonstrated by means of 69 examinations of 55 patients. The results are compared with those obtained by means of conventional roentgenography, including tomography and bone scintigraphy. It is confirmed that recent CT scanners are the most sensitive instruments in existence for the visualization of affections of the sacrum in respect to identification and extension.

The CT criteria of the Sturge-Weber syndrome are described on the basis of 5 cases observed by the authors. Computerized tomography makes it possible to identify earlier - and in some cases more clearly - than by conventional roentgenography, the classical signs of the disease (calcification of the cerebral cortex, unilateral shrinking of the skullcap, distension of the frontal and sphenoidal sinus, thickening of the skullcap as a whole). Anomalies of vascularization, which had so far been demonstrable only by invasive methods, can also be demonstrated direct by means of computerized tomography.

The present article reports on the effects of weakening and hardening of radiation on CT values in the environment of highly absorptive materials, using phantoms for carrying out these measurements. First of all, it was found with the help of geometrically simple phantoms (discs, circular rings), that the measured CT value of each volume element depends on the density distribution in the environment and that the CT values of homogeneous object layer are not uniform, but clearly dependent on the location at which measurement is effected. The standard deviation of the CT values of a homogeneous part of an object layer was also found to depend on the environment. Finally, using anatomically relevant phantoms, it was found that density value changes from max. +20 HU to -65 HU occur in the region of the cranium, whereas in the environment of the lumbar vertebra the density varies between max. +20 HU and -10 HU; in the pleural region, the maximum density variations are +/- 10 HU.

The article reports on 78 CT scans of surgically verified diseases of the pancreas, namely, 30 cases of chronic pancreatitis, 12 cases of haemorrhagic-necrotizing pancreatitis, and 36 cases of carcinoma of the pancreas. 12 of these cases were operable, whereas 234 were inoperable. The operable carcinomas were so small that proper diagnosis was effected in 50% only, whereas the inoperable carcinomas eluded CT identification in 17% of the cases only. The most important signs of an operable carcinoma of the pancreas are a well-defined enlargement and inhomogeneity of the parenchyma with reduced contrast, especially on bolus injection, as well as dilatation of the bile duct system. The most essential criteria for inoperability are absence of boundaries, especially towards the dorsal side, with infiltration of the retroperitoneal fatty tissue, and lack of delineation of the large vessels. According to the present state of the art, CT does not supply definite criteria for differentiating between an operable carcinoma of the pancreas and chronic fibrotic pancreatitis. Overstepping of the marginal contours is a reliably distinctive feature between carcinoma and pancreatitis, but it also points to the inoperable nature of the disease. Haemorrhagic-necrotizing pancreatitis is characterized by definite CT criteria, so that diagnosis is easy.

In 30 patients with decompensated autonomous adenoma of the thyroid gland, the possibility was investigated whether sonography of the thyroid gland could replace the thyroid stimulation scintigram or a diagnostically insufficient, saturated scintigram. It was found that the thyroid sonogram--which has a lower specificity--has a markedly higher sensitivity than the saturated scintigram of the thyroid gland.

In addition to computed tomography which presents actually the most important processing and transfer procedure of digital X-ray images, application of real time addition and subtraction of X-ray images in a digital mode has found considerable interest. An estimation of the information contents of both digital and analog images is made in close relation to applications. As example of an image processing system on digital base a recently developed system for intravenous arteriography is described: the Philips-DVI.

A phantom is described which has been developed for investigating factors depending on the scanner itself and on the scanned object which potentially influence the kind and the extent of motion artefacts on the CT-image. Additionally, the phantom may be applied to qualify assurance measurements in computer tomography. A cylindrical insert mounted on a motor driven axis is fitted centrally in a cylindrical block machined from lucite. Two interchangeable inserts are available, one containing test objects made of various materials, and another one containing small vessels which can be filled with test solutions. The insert positioned in the phantom can rotate either continuously or with the direction of motion being altered periodically. Speed, frequency and arc can be varied within wide limits. Examples demonstrating the static and the dynamic mode of the phantom are shown. By means of the dynamic phantom it is quite easy to directly determine the scan-time of a Computer tomograph.

The article reports on a 56-year old patient with the very rare preoperative diagnosis of a cyst wall hypernephroma. This diagnosis was confirmed both surgically and histopathologically. Diagnosis with the help of roentgenography showed that the diagnosis which had been suspected on the basis of selective arteriography, received a high measure of certainty by the additional use of non-invasive sonography and computerized tomography, thus finally justifying surgical approach to lay open the kidney.