[Lymph node metastasis-recurrence following head and neck tumors: computed tomography].
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Adolescent↗
Biomedical subjects
W Bautz
Publications and source records attributed to W Bautz.
[Local recurrence in head and neck tumors: computed tomography].
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Adolescent↗
[Computed tomography of the head and neck region following therapy: post-therapy normal findings, inflammation, scars].
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Adolescent↗
[Lung changes caused by Mycobacterium xenopi infection in a patient with bone marrow transplantation: problems in differential diagnosis].
Pulmonary affections caused by atypical mycobacteria are an increasingly common problem particularly in patients with immune deficiency disorders. We here report a case of pulmonary infiltrates due to Mycobacterium xenopi in a patient after allogeneic bone marrow transplantation for acute myeloid leukemia in first complete remission and under immunosuppressive treatment with prednisolone and Cyclosporin A. While sputum cultures, serology as well as bronchial lavage and transbronchial biopsy remained inconclusive, diagnosis could only be established by open lung biopsy. We suggest that particularly in immunocompromised patients unclear pulmonary infiltrates require rapid and possibly invasive diagnostic procedures.
Adult↗
[Angiodynography of circumscribed thyroid changes].
Conventional methods of thyroid diagnosis, such as scintigraphy, differentiate between hot and cold areas, but within cold areas no distinction between malignant and benign changes is possible. Angiodynography provides a new method which gives the usual sonographic information and also indicated variations in blood-flow in the organ. Various diagnostic methods--thyroid scintigraphy, conventional sonography, fine-needle biopsy and angiodynography--have been compared in patients with focal thyroid disease. It has been shown that it is possible to differentiate between malignant and benign lesions on the basis of their vascularisation.
Adult↗
[Angiodynography: initial experiences with a new sonographic method].
Angiodynography is a further development of Duplex sonography and a new, non-invasive imaging method that places no stress on the patient and enables simultaneous sonomorphological diagnosis of the organs and soft parts as well as their blood supply. Experience to date has shown that the angiodynographic vascularisation pattern is a diagnostic criterion in the clarification of circumscribed thyroid changes. If thyroid findings appear to be unclear, e.g. in case of scintigraphic cold nodes, angiodynography can be used with success as a complementary method. It can also help to classify findings in focal lesions of the liver. Information on functional parameters are supplied for differentiating arterial and venous vascular processes. They are easier to apply, more rapid and more accurate than with Duplex sonography. A drawback is the limited depth of penetration (5 MHz transducer). Angiodynography can be appreciated quickly and easily. It appears to be not only a complement to conventional examination methods but may even replace established diagnostic methods in solving certain problems.
Color↗
[Clinical results of dual-energy radiography in thoracic studies].
Dual energy methods permit the reconstruction of either soft tissue or calcium density structures. The value of the technique is demonstrated in 220 patients. Demonstration of the thoracic organs without superimposition of the skeleton improves the recognition of pulmonary lesions. Opacities related to ribs no longer simulate pulmonary lesions. The mediastinal borders are demonstrated more clearly by double spectrum radiography than by any other radiographic method. Soft tissue calcification can be shown with a high degree of sensitivity. Skeletal changes which may be obscured by overlapping soft tissue shadows on conventional radiography can also be diagnosed by this technique.
Humans↗
[Material selective imaging and determination of density using the dual energy method. II. Clinical use of dual energy radiography].
The use of dual energy methods in digital radiography allows selective imaging of soft tissues or calcified structures and contrast media. The value of this method is demonstrated on the basis of 400 patient examinations. The isolated imaging of soft tissues without skeletal superposition gives particular advantages in diagnosis of the chest and the cranio-cervical region. Soft tissue calcifications and calcium-containing concrements in the bile ducts and in the urinary tract are well demonstrated without soft tissue superposition. The disadvantages and the limits of the method are discussed, its potential and possible future developments are shown.
Bone Diseases↗
[Material-selective imaging and density measurement using the dual-energy method. I. Principles and methodology].
The principles of the Dual Energy method are discussed from two perspectives: a clear illustration of the method and an exact presentation of the principles involved. The principles apply to both radiography and computed tomography. The method was implemented on a CT scanner (SOMATOM DR, Siemens AG). Dual Energy images enable highly selective imaging based on the determination of density values for calcified and soft tissue. Images may also be reconstructed that are based on other parameters such as electron density and effective atomic number. The degree to which selective imaging is possible is discussed. Examples of Dual Energy clinical applications for radiography and computed tomography are presented. More detailed information will be available in future contributions.
Humans↗
[Computed tomographic diagnosis of malignant lymphoma of the thorax].
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Breast Neoplasms↗
[Is the PACS feasible for a large radiological department? Reflections on the image data volume of the Medical Radiation Institute of the University of Tübingen in 1983. Picture Archiving and Communication System].
Picture Archiving and Communication Systems (PACS) are getting more and more important for departments of radiology with the increasing spread of digital imaging methods. To determine the demands made on such systems, we calculated the digital image data volume for all examinations carried out in 1983 at the Department of Medical Radiology of the University of Tübingen. 20.37% of all examinations were performed with digitalised equipment. Plain radiography takes the lion's share among the total number of image data. If digitalisation is based on a spatial resolution of 8 Lp/mm, the share is 98.4% of the total image data volume of 7 123 GByte. This figure is far in excess of the estimates stated in literature. The possibilities of image data reduction and feasibility of a major PACS are discussed.
Academic Medical Centers↗
Human pattern recognition: individually different strategies in analyzing complex stimuli.
Multidimensional scaling experiments were performed with "size" and "brightness" as parameters. Subjects (ss) had to rate the dissimilarity of pairs of discs differing in size or in brightness only, or in both parameters. It was then attempted to find a rule, by which the dissimilarity judgements of two-dimensional differences can be predicted from judgements given for the one-dimensional components. Minkowski-metrics were chosen as models, since for most of the ss the prerequisites for applying these metrics seem to be fulfilled. A simple procedure is described by which the one metric out of all Minkowski-metrics can be found which gives the best description for the data of a subject (Fig. 4). Although the task and the parameters used were the same for all ss, individually best metrics differed considerably, indicating individually different modes of perceptual analysis: Most ss adhered, roughly, to either the City-block or the Euclidean metric (cf. Fig. 10). (Only City-block metric was to be expected, since "size" and "brightness" are generally thought to be "separable" parameters.) In addition, there were three ss with metrics clearly different from both the City-block and the Euclidean metric (best exponents around 1.4). In view of those substantial differences between individuals one has to be cautious against the practice of averaging data from different ss.
Cybernetics↗
[Circumscribed and diffuse skin thickening (peau d'orange) of the female breast].
Skin thickening of the breast observed by mammography should always alert the radiologist to suggest the possibility of carcinoma. The roentgenographic appearance of skin thickening, however, is nonspecific and identical in each disorder, and provides no clue to its benign or malignant origin. It is therefore important to the radiologist to be familiar with the possible etiologies, which can often be simply evaluated by obtaining an appropriate medical history, clinical inspection or a thorough physical examination of the breast. A review of the mammary skin thickening is given, and the differential diagnosis is discussed with reference to the literature.
Adenocarcinoma, Scirrhous↗
[Value of MR tomography vs. CT in the diagnosis of rectal carcinoma and its recurrence].
The value of NMR tomography for the diagnosis of carcinoma of the rectum and of recurrences has been studied, using a 1.5 Tesla NMR apparatus and comparing the results with high resolution CT. There were five patients with a histologically proven primary tumour, eighteen patients with a recurrence and five patients who had had a rectal carcinoma removed, where there was no evidence of recurrence. By obtaining images in three planes, NMR showed the true tumour extent in all cases and was superior to CT in the diagnosis of the primary tumour (in four patients out of five) and in showing recurrences (in five out of eighteen patients). NMR also had advantages in demonstrating lymph node enlargement in the pelvis, where difficulties are often encountered using CT. Early experience with tissue characterisation indicates that it is possible to diagnose rectal tumours confined to that organ. These are usually missed by CT. CT is superior to NMR in demonstrating destructive lesions in bone. Early clinical experience suggests that NMR is a further advance in the early diagnosis of carcinoma of the rectum and of recurrences.
Aged↗
[Nuclear spin tomography of the male pelvis. Methods, anatomy and initial clinical results].
A pilot study of MRI was carried out on three normal male volunteers and 15 patients with tumours in the prostate or bladder. One advantage of the method is the ability to obtain images in three planes, without moving the patient. It is therefore possible for the first time to demonstrate lesions in the base of the bladder in their cranio-caudal extent. Tissue contrast of MRI, using long sequences with suitable proton or T2-weighted images is better than with CT and provides more accurate diagnosis. Even non-expansive tumours within the gland can be differentiated from normal glandular tissue. It has been noted that carcinoma of the prostate in the T2-mode provides an increased signal, whereas tumours of the bladder look dark. Up to a point, tissue characterisation may be possible.
Aged↗
[Representation of tumor and organ contours by projection radiography--an important supplement to radiotherapeutic treatment planning].
A special program developed in collaboration with the manufacturer ot the computer tomograph Somatom DR3 allows to transfer organ or tumor shapes from the transverse computed tomography scan to the localization radiograph (projection radiography). Some typical examples are presented in order to describe the possibilities offered for radiotherapy planning by this method. The procedure may be applied in all cases where neoplasms have to be irradiated or to spared and where this is of a decisive importance for simulator planning.
Female↗
[Anaerobic serum ultrafiltration--a new method for determination of protein-binding rates of drugs under physiological conditions (author's transl)].
Only the free and not the protein-bound fraction of a drug shows pharmacologic activity. Therefore the rates of drug-binding to serum proteins are of great importance for clinical and pharmacological purposes. A basis prerequisite for accurate measurements are experimental designs giving the possibility of keeping the most important factors influencing the protein-binding rate within physiological ranges. In vivo these factors are, among others, the concentration of albumin, the absorption of different exogenous and endogenous substances to albumin, the type and the amount of ions present, the total ionic strength, the pH-value and hence the pCO2 as well as the temperature. An experimental set-up was described giving the possibility of keeping all these factors absolutely constant under in vivo conditions by means of a newly developed and simply to handle ultrafiltration device. From withdrawing the blood sample from the vein to the complete separation of the protein-bound fraction the blood sample can be processed under strictly anaerobic conditions (to prevent loss of CO2!). Compared to common methods generally used for the determination of protein-binding rates, such as equilibrium dialysis, column chromatography and ultracentrifugation, this new procedure saves a considerable amount of time. Within 1 h up to 8 samples can be processed in a single device. Besides short filtration times there is no need for any additional sample preparation such as buffering or adding antibacterial substances, etc.
Blood Proteins↗
Semiautomatic evaluation procedures for quantitative CT of the lung.
Accuracy, reproducibility, and objectivity are important in quantitative assessment of lung density and structure by CT, and the measurement has to be carried out under tightly controlled conditions. We therefore employ respiratory gating at defined levels of inspiration for CT scanning. In the evaluation process, we found operator-induced errors of 2-6 HU standard deviation for the relatively simple task of global lung density estimates; in regional evaluations, they frequently exceeded 10 HU. We therefore developed semi-automated evaluation algorithms that isolate lung parenchyma by fast contour tracking and define subregions by shrinking, radial segmenting, and anteroposterior subdividing of the left and the right lung. Global and regional mean density values and histogram parameters were extracted. Based on our clinical studies, we estimate that an overall precision of better than 5% can be achieved in quantitative CT of the lung with cooperative patients.
Algorithms↗