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Biomedical subjects

C Zwicker

Publications and source records attributed to C Zwicker.

At least 73 records · Page 4Linked to original sources

[Experimental ultrasonic study of imaging of vascular implants].

An experimental in vitro study was performed, evaluating 13 bypasses and eight patches of different materials. Sonography was unsuccessful due to a total reflection of the ultrasound for the PTFE-Vitagraft, the Impra, and the Microvel Haemashield bypasses. All other studied bypass types were successfully evaluated by ultrasound. All studied patch materials did not interfere with the ultrasound examination of the vascular structures.

Blood Vessel Prosthesis↗

[Sonographic assessment of vascular bypasses in vitro].

13 bypasses and 8 patches were examined by ultrasound in vitro with a 3.5 MHz and a 10 MHz probe. Whereas only 6 bypasses were assessable by sonography, all patches could be demonstrated in vitro. In these cases, sonography could be accomplished with either of the two frequencies used. The 10 MHz probe was superior for imaging structural details. Immediate postoperative sonography of such grafts, which cannot be demonstrated accurately in vitro, is not reliable.

Blood Vessel Prosthesis↗

[Nuclear magnetic resonance tomography study in orbital diseases with surface coils].

MRI of the orbit with surface coils was performed in 40 patients. In 35 cases the findings were pathologic. The most frequent (n = 9) were malignant melanomas of the choroid, which were distinguishable from hemorrhages (n = 2) by the characteristic signal intensity pattern. MRI only offered advantages over CT in lesions of the orbital apex, the upper part of the orbit, and in the diagnosis of inflammatory processes. In most of the cases of orbital tumors, and particularly where there was involvement of bony structures, CT was equal to or better than MRI.

Adenoma↗

[Ultrasound findings in patients with AIDS].

The ultrasonographic findings of 43 patients with AIDS and ARC were analyzed. In 63% an enlarged liver, in 66% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical parenchymal lesions of the kidney (focal segmental glomerulosclerosis) were not observed. Abdominal ultrasound is the first diagnostic procedure to perform in patients with AIDS and ARC with the suspicion of abdominal pathology. With additional thin needle puncture of the lesions a histological verification of the pathologic findings is possible.

AIDS-Related Complex↗

[Scrotal changes in the 3.5 MHz ultrasound image].

Sonography enables sensitive detection of pathological changes in the scrotum, since the planes of intersection can be selected as may be required, and since local resolution is excellent. However, sonographic criteria alone do not permit differential diagnosis of malignomas against benign changes. Anamnesis and clinical examination are of equal importance as sonography. Diagnostic conclusions are possible only if all the findings based on all the diagnostic approaches are combined in synopsis. Although reports published in recent years postulated transducer either of a frequency higher than 3.5 mHz (1, 5, 11, 12, 13, 14, 17, 20, 21, 24, 25, 27) or low-frequency transducers associated with immersion technique (7, 23), in our patients the use of a 3.5 mHz convex scanner with water forerun resulted always in confirming the diagnosis (in conjunction with anamnesis and clinical findings). In our experience a transducer of this frequency (3.5 mHz) with water forerun appears to be suitable for routine diagnosis of changes in the scrotum. This is an important aspect in general practice, where ultrasound equipment is often fitted with 3.5 mHz transducers.

Diagnosis, Differential↗

[Digital radiographic image enhancement in bone diagnosis--initial clinical results].

34 patients with skeletal alterations mostly in the periphery were investigated by digital image intensifier radiography (DIIR). A high resolution image-intensifier system (1024 x 1024 matrix, 40 cm, 28 cm, 14 cm image intensifier, maximal spatial resolution: 3.6 lp/mm) was available. The image quality was diagnostic sufficient in 76% using DIIR. A good or very good image quality of fine-structures was obtained only in 41%. The quality deficits in comparison to conventional radiograms were particularly obvious in investigation of the phalangeals. Logarithmic amplification and software upgrading lead after these first clinical investigations to a better image quality.

Adult↗

[Long-term follow-up of a choledochal cyst in childhood].

Report on a woman patient with an idiopathic hepatic duct cyst, who had been followed up by us over a period of 12 years and who was a laparotomy case for 4 times. On the basis of intraoperative results and the course of the disease we were able to collect information on the growth and involution of the cyst, as well as on the influence exercised on the clinical picture. If resection of a cyst with drainage of the gall passages to the jejunum by means of Roux sling proves too dangerous, it would be better to choose a simple drainage operation; in this regard we prefer a transduodenal interior connection to an exterior one.

Abdomen, Acute↗

[Combined use of duplex sonography and CW Doppler in diseases of the carotid arteries].

740 patients with findings of cerebrovascular insufficiency were investigated by duplex sonography and frequency-analysing cw doppler. In 620 pathological arteries not stenosing lesions of the carotid bifurcation were found most frequently (93%). In 35% moderate-severe stenoses of the a. carotis interna were diagnosed. The advantage of duplex sonography and cw doppler in combination is the addition of both methods, so that a very reliable diagnosis of the extracranial carotis is possible.

Blood Flow Velocity↗

[Nuclear magnetic resonance tomography studies of orbital space occupying lesions].

A comparative study of MRI, CT and ultrasound of orbital tumors revealed that only for malignant melanomas and orbital pseudotumors MRI had the most diagnostic relevance. Malignant melanomas could be differentiated from a haematoma due to their characteristic T1 and T2 signal intensity. MRI is impaired by its long examination time and the danger of quality reduction caused by motion artifacts.

Diagnosis, Differential↗

[Digital subtraction angiography of cancerous changes in the ear, nose and throat area].

Intravenous and intra-arterial digital subtraction angiography is able to demonstrate hypervascular tumours in the ear, nose and throat territory. Direct puncture of a venous bypass used for intra-arterial chemotherapy, within the external carotid artery territory, is devoid of risk and can be used for assessing the accessibility of the tumour. Lesions of low vascularity can only be recognised by DSA on the basis of vessel displacement. These lesions are not a primary indication for examination by digital angiography.

Adult↗

[Indications for venous digital subtraction angiography in otorhinolaryngologic diseases].

Intravenous DSA was performed on 45 patients for diagnosis of otorhinolaryngologic diseases. Hypervascular glomus tumours can be accurately diagnosed. Furthermore, vascular architecture and topography can be analysed to allow the planning of tumour embolization or surgery. Hypovascular tumours are inadequately demonstrated by intravenous DSA. A specific and detailed analysis of thin vessel architecture in malignant tumours is impossible by intravenous DSA.

Adult↗

[Angiomorphology of arteriosclerotic changes in the area of the carotid bifurcation].

100 intravenous digital subtraction angiograms of bifurcations were compared to one hundred plain film arteriograms. Both types of examinations were of excellent image quality. Arteriosclerotic lesions in the posterior circumference of the internal carotid artery were found in 55% plain film angiograms and in 49% of intravenous DSA examinations. Plain film angiography was significantly more accurate in the evaluation of arteriosclerotic ulcerations than i.v. DSA. The total amounts of arteriosclerotic stenoses with a smooth or rough surface were equal with both methods. The interindividual comparative study demonstrated that in respect of diagnosis of ulcerative lesions, i.v.. DSA is inferior to plain film angiography, even if an excellent image quality for all projections is achieved in i.v. DSA.

Aged↗