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Biomedical subjects

H K Beyer

Publications and source records attributed to H K Beyer.

At least 73 records · Page 4Linked to original sources
PubMed1986

[Chronic ethmoid and sphenoid sinusitis as an incidental finding in computerized tomography of the skull].

From 373 patients examined by cranial CT 60 had as accidental findings chronic ethmoidal and/or sphenoidal sinusitis. From 234 patients with pathologic brain CT findings 33 had chronic sinusitis (14%). By comparison 27 from 139 patients without pathologic brain CT had findings like sinusitis (19.4%). We suppose that often chronic sinusitis ethmoidalis and/or sphenoidalis suspense signs lead to cranial CT, although sinusitis was the only pathologic cause.

Brain Diseases↗
PubMed1986

[Disk hernia of the lumbar spine. Radiologic study with special reference to the technic and value of nuclear magnetic resonance tomography].

Degenerations of the spinal disc especially in the lumbar region are the most frequent degenerative diseases in orthopedics. As diagnostic proceedings to discover disc herniation myelography and computerized tomography have been proven to be very usefull. Each of those methods show a high sensitivity and accuracy. Computerized tomography seems to be the first procedure because of the lac of any risk. Myelography has been reserved for the second approach, if there is any doupt in diagnosis. This paper will especially discuss advantages and disadvantages of MRI-tomography for the diagnosis of disc herniation. In MRI-tomography we have no radiation, there is no risk for the patient and we have the possibility of slices in different orientations with the sagittal orientation having priority in diagnosis of disc herniation. A more pronounced contrast in MRI relatively to the computerized tomography with nearly the same spatial resolution is an other important fact in favour for MRI. The value of MRI diagnosis of the spine depends however mainly on the use of special surface coils and on the use of high magnetic fields which provides a good signal to noise relation and which would permit us to use a thin-slice technique.

Humans↗
PubMed1985

[Initial experiences with MR in liver tumors].

We examined 21 patients with focal lesions of the liver. Routinely we used T1 weighted, proton weighted and T2 weighted measurement modes, mainly with repetition times of 1.6 sec and echo delay times of 35 or 120 msec. Using these parameters we can see characteristic changes of the signals of the liver tumours. Cystic lesions usually show a strong decrease of the signal in the T1 weighted images in comparison with the normal liver pattern, in the proton weighted images a weak decrease but also in some cases a weak increase of the signal; in the T2 weighted images they show signals of very great intensity. We can differentiate haemangioma of cystic lesions because of the very strong signal in the proton weighted images in comparison with the normal liver pattern, which we could not see in any other focal liver disease. Metastases and hepatoma produced low signal intensity in the T1 weighted image. The proton weighted and the T2 weighted images show signals with a slightly greater intensity compared with the normal pattern, i.e. a very good possibility to distinguish hepatoma and metastases from cystic lesions or haemangioma. The differentiation from hepatoma and metastases cannot be made with NMR up to now. We are also not able to differentiate the focal nodular hyperplasia (FNH) from metastases. We used a 0.35 T supraconductive magnetic system.

Cysts↗
PubMed1985

[Nuclear spin tomography in brain tumors. Evaluation of 40 confirmed cases].

Forty histologically confirmed primary and secondary cerebral tumours are described. These contained fifteen primary tumours, five adenomas of the hypophysis, four hamartomas or lipomas and craniopharyngiomas, three meningiomas and three vascular malformations. One malignant lymphoma, one chordoma and eight cerebral metastases were also included. In our series, the accuracy of CT and MR were the same, particularly since most patients coming for MR had abnormal CT findings. MR was superior in demonstrating vascular malformations and sometimes in the differential diagnosis of tumour versus infarct. MR is also more accurate in demonstrating the extent of a tumour and of infiltration, since it is possible to obtain images in several planes. Disadvantages of MR are related to the characterisation of primary brain tumours, since the signals from these tumours failed to show characteristic differences. Calcification cannot be recognised. In sixteen out of 36 patients, MR proved superior, whereas CT was superior in five. Tumour-related oedema was present in 18 cases and demonstrated by MR in seventeen. CT failed to differentiate tumour from oedema on one patient.

Adult↗
PubMed1985

[Value of nuclear magnetic resonance tomography in lung tumors].

A total of 93 patients with pulmonary diseases were examined by means of magnetic resonance tomography. Of these, 39 had a bronchial neoplasm of varying histological structure and varying hilar and mediastinal extension. Compared with other imaging methods, magnetic resonance tomography offers advantages in the imaging of a malignant process and accurate definition of its spatial extension. MR and CT seem to be essentially of equal value in respect of the diagnostic problem of deciding whether lymph node metastases are present in the mediastinum and in the hilus. On the other hand, CT is presently still superior to MR with regard to verifying small-scale processes which are in the process of undergoing endobronchial growth, since CT provides better spatial resolution. Hence, in our opinion the special value of magnetic resonance tomography is the exact definition of the extension of an already identified neoplastic process. This method can supply accurate pointers towards the operability of a bronchial neoplasm. In this regard it is an ideal complement to mediastinoscopy. However, MR will not be an important tool--even in the foreseeable future--for effecting early diagnosis of a neoplasm. The value of diagnostic information supplied by this method may improve by the future use of breath triggering, and additional diagnostic advantages are envisaged by the use of contrast media and the future possibility of producing thinner layers. That is why the catalogue of indications prepared at this time should be seen as a kind of momentary snapshot which may have to be supplemented or extended after the prevailing technical and equipment parameters have undergone further optimisation.

Adenocarcinoma↗
PubMed1985

[Immediate effect of x-ray contrast media on thyroid hormone parameters].

Immediately after application of various contrast media a number of functional parameters of thyroid function were determined. Especially after application of Biliscopin which is strongly bound to plasma proteins, a significant rise of the free thyroid hormone fractions, a significant increase in the binding capacity of specific transport proteins and a decrease of the total concentration of thyroid hormones was noticed. It is therefore recommended that neither in the early phase within the first hour, nor in the late phase within 10 days after application of contrast media, blood for determination of parameters of thyroid function should be collected, since otherwise misleading results may be obtained.

Blood Proteins↗
PubMed1985

[NMR tomography in confirmed multiple sclerosis. An assessment of 21 cases].

The authors report on 21 cases of confirmed multiple sclerosis examined by both CT and magnetic resonance tomography. To safeguard the results, strict criteria were applied in accordance with the suggestions made by neurological work teams. Pathological lesions were seen in 20 patients; the MR image did not reveal anything abnormal in one case. On the average, 10.3 lesions were seen in the MR tomogram, whereas CT images showed on the average only 2.1 foci. The size and number of lesions in the MR tomogram were independent of the duration of the disease, the presented clinical symptoms, or the type of treatment at the time of examination. Evidently the sensitivity of MR tomography is very high in MS patients, but it has not yet been clarified to what extent this applies also to the specificity. Further research is mandatory. First experiences made by us show that lesions of a similar kind can also occur in diseases such as malignant lymphoma involving the brain, in vitamin B 12 deficiency syndrome, or encephalitis, and can become manifest in the MR tomogram.

Adult↗
PubMed1985

[Nuclear magnetic resonance tomography and computed tomography of the brain for detection of Wilson's disease].

The authors report on two woman patients with confirmed Wilson's disease (hepatolenticular degeneration) who had neurological deficits and showed typical changes evident from laboratory data. Both computed tomography and magnetic resonance tomography revealed degenerative changes in the basal ganglia, especially of the lenticular nucleus, MR showing these defects more clearly than CT. There was a noticeable symmetrical enhancement of signals in the lenticular nucleus which was particularly evident on the image basing on the T2 (spin-spin relaxation time constant) values. MR could be superior to CT with regard to showing up pathological changes in the basal ganglia. The future indication of MR could be the establishment of an exact correlation between clinical signs and symptoms on the one hand, and morphological findings on the other. Over and above this, it should be explored to what extent MR can already detect degenerative changes in the brain in primarily hepatic types of the disease even without prior neurological examination.

Adult↗
PubMed1985

[Value of nuclear magnetic resonance tomography in the diagnosis and stage determination of urinary bladder neoplasms].

We arrived at the following conclusions in our study on the ranking of magnetic resonance tomography in diagnosis and staging of urinary bladder neoplasms: MR tomography possesses high sensitivity but only low specificity in diagnosing the local spread of the tumour. Sensitivity of MR seems to be better in respect of determining the paravesical tumorous spread, than that of other methods. However, it is not possible to determine the tumour status of a space-occupying growth. No advantages of MR over other methods, especially computed tomography, were seen in the examination of lymph node metastases in the minor pelvis.

Humans↗
PubMed1984

[Exposure technics for computed scintigrams].

The technique of making copies on radiographic films or on multiformat cameras from computer scintigrams, computer tomograms, digital radiographs or other similar digital images should be carefully studied in order to make the best use of the characteristics of the film. Contrast transfer was studied using a nuclear medicine camera computer system with registration on radiographic film. Possible difficulties in obtaining copies and a simple software arrangement are described, which would influence contrast transmission.

Absorptiometry, Photon↗
PubMed1984

[Varying results of different procedures for determining the FT4 concentration in serum before and after heparin administration].

After application of heparin FT4 was determined by various methods in patients undergoing hemodialysis, and the results were compared with those obtained before application of heparin. Using ultrafiltration (Amicon) and the Dow-Lepetit test a significant increase in FT4 concentration could be registered at all times after heparin application. By use of the Corning test a non-significant increase in FT4 concentration was found one hour after heparin application. When the Amerlex method was employed no change in FT4 concentrations was detectable. Most probably, the observed increase in FT4 concentration after heparin application does, in fact, occur.

Heparin↗
PubMed1984

[Varying results of different procedures for determining the FT4 concentration before and after the administration of contrast media].

After application of contrast media a rise in FT4 concentration was detected by use of the ultrafiltration method (Amicon) and the Dow-Lepetit method, especially after injection of Biliscopin, whereas the determination of FT4 concentration with the Amerlex method revealed a significant drop in FT4 concentration after contrast medium application. The results obtained with the Dow-Lepetit test have to be regarded as correct. The decrease detected by the Amerlex test is probably the result of a changed affinity of albumin to the labeled T4. Within 1 hr after application of contrast media blood for the determination of FT4 should not be collected.

Contrast Media↗