Biomedical subjects
Publications and source records attributed to J Freyschmidt.
Multicentric reticulohistiocytosis is a granulomatous systemic disease of histiocytic cells, involving mainly the skin and synovial tissue of joints with secondary bone destructions. The clinical, histological and radiological findings of a typical case are described and the histological and radiological differential diagnosis are briefly discussed.
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The paper is concerned with the use of rare-earth intensifying screens in order to overcome some of the exposure problems during magnification techniques using very small focal spots. Theoretical experiments and tests with biological objects indicate that the use of high intensifying screens under these circumstances is acceptable and useful. A comparison has been carried out between the results of conventional techniques without magnification and magnification techniques using very small focal spots and rare-earth intensifying screens.
Using a procedure which resembles actual practice, it has been shown that an increase in kV. results in a reduction of radiation dose similar to that obtained by using the new high intensity rare earth screens while maintaining similar detail. In practical terms this means that there is only limited usefulness for the new rare earth screens. An exception to this is the screen which reduces dose while producing similar, or better, detail than a standard screen. We could demonstrate this for the film-screen combination Trimax alpha4XD.
Multicentric reticulohistiocytosis is a special form of an erosive, destructive arthropathy. It can be distinguished from other forms of erosive polyarthropathies by the characteristic x-ray appearances, although the final proof of the diagnosis is histological in association with the clinical features and the presence of nodular skin lesions. A case of multicentric reticulohistiocytosis is described. The typical radiological appearances are discussed and the differential diagnosis from other forms of chronic polyarthritis, such as gout, psoariatic arthropathy, Reiter's disease and erosive osteoarthritis is considered.
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The case of a 45-year old female patient with primary hyperparathyroidism is described to show that this disease can occur under the principal sign of a destruction of the cervical vertebral column. The roentgenological changes associated with primary hyperparathyroidism are discussed and their differential diagnostic significance is emphasised. The radially located subperiostal absorptions are the first roentgenological changes seen in PHPT and represent signs which make it highly probably that this disease is present.
The future of epi- and metaphyseal fractures depends on exact radiologic diagnosis. This will always have to show whether the growthzone has been damaged. This can be clearly indicated by classification of slipped epiphyses and fractures (Aitken I-III). The pathophysiology of epiphyseal injuries, possible classifications and general and special radiology of these injuries are discussed.
Method of direct geometrical X-ray magnification technique are discussed in the light of new technical possibilities,--fine-focus, high speed screen--and- the value in surgical X-ray diagnosis for the fine bone structure changes is demonstrated using practical examples. Also mentioned are other methods for a quirering a better form of diagnosis--such as for example the harmonising method.
The degree of intensification and resolution was compared using rare-earth-screens and conventional calcium tungstate screens. -In order to approximate usual phantom (DIN 6, 815) was equipped with a lead grid at a depth of 6 cm. Nine screen-film combinations were exposed at 70 to 80 kv., using a 12-pulse generator and Bucky grid till blackening of S = 1 was obtained. -Resolution depends substantially on the inherent noise of the system and improves from 0.6 Lp/mm. for the most sensitive combinations (intensitification factor 8.0) to 1.15 Lp/mm (intensification factor 1.7). Compared with the standard combination with a resolution of about 0.9 Lp/mm., dose was reduced by more than 40% with an increase in resolution of 45% (combination 3M-Trimax A4/XD).
In more than 1,000 radiological and endoscopic examinations of the smooth muscle hollow organs of the upper intestinal tract, crysalline glucagon (0.2 to 0.5 mg., average dose 1 u/kg. body weight given at a single intravenous injection) resulted in a significant relaxation and reduction of peristalsis. This effect was less marked in the colon and recto-sigmoid. In five patients with colonic diverticulosis it had no effect. In 150 patients it was found that the onset of hypotonia after injection of glucagon increases from proximal to distal, the duration of maximal reduction in peristalsis decreasing distally. Glucagon is indicated for reducing the tone of smooth muscle hollow organs in order to judge their elasticity and to distinguish between functional and organic causes of a stenosis or increased size of folds. The rapid onset of peristaltic inhibition makes various diagnostic and therapeutic endoscopic procedures simpler or even possible. Compared with the usual atropin-like antispasmodics, glucagon has the advantage of being free from side effects apart from transient hyperglycaemia. Diabetes mellitus requiring insulin is a (relative) contra-indication to the use of glucagon.
A clinically applicable procedure for testing new intensifying rare earth screens, as well as the special Siemens' screen is described. The results are related to universal screens. The film-screen combination alpha 4XD (gadolinium oxysulphide with normal, green sensitive film) results in a reduction of radiation dose to half with detail comparable with universal screens. The Siemens' special screen has similar advantages. Screens with a higher intensification factor and reduction of the mAs to one sixth results in loss of detail. This does not necessarily reduce their clinical use if they are used for appropriate purposes. The results of this clinically orientated technique agreed well with physically objective methods using lead grids. The advantages of the new screens are discussed in terms of their practical application.
Tests show that the usual definition of cut-density is not applicable to angiotomography. New appropriate data for definition should take account of the relation between vessel and direction of cut and between timing of cut and contrast. These data cannot be obtained by examination in vivo. The concept of cut-density should be abandoned for inear angiotomography and replaced by that of layer of definition.
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On the basis of the physical and clinical findings of this investigation, the characteristics of new screens made of rare earths were described. The possibilities of application for pediatric radiology and those advantages which can be achieved with the new screens were discussed. Possible technical difficulties were mentioned.
A comparative investigation on the resolution of angio-tomography and cut-film changer technique, standard views and direct geometrical radiographic magnification were carried out, using a phantom. Catheters of varying calibre and contrast were tested. The most significant result was the finding that lower concentrations of contrast were necessary to demonstrate small vessels or catheters when using angio-tomography or magnification, than with conventional techniques. It was also shown that angio-tomography and a magnification technique are able to show smaller and less contrasty vessels.
Experiments with models and post mortem angiograms have shown that the supposed advantages of angiotomography, such as determination of the depth of vessels, cannot be achieved with accuracy if there is repeated change in direction of the vessels. Blurring of superimposed vessels depends not only on their contrast and calibre, but also on their alignment in relationship to the direction of blurring. Vessels running in the direction of blurring produce undesirable shadows through a considerable depth, whereas vessels running across the direction of blurring are rapidly blurred if not in the selected plane. The demonstration of vessels running at right angles to the direction of blurring may at times be very difficult with simultaneous tomography. The clinical significance of this finding is pointed out.