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Biomedical subjects

G M von Reutern

Publications and source records attributed to G M von Reutern.

At least 37 records · Page 2Linked to original sources
PubMed1986

Transcranial Doppler sonography. Examination technique and normal reference values.

The main application of ultrasound in neurology is the examination of extracranial arteries. Recently the Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Doppler frequencies in systole and diastole were recorded in 51 healthy subjects at 0.5 cm steps along the middle (MCA), anterior (ACA) and posterior cerebral artery (PCA) as well as the basilar artery (BA). The averaged Doppler shift in the MCA was 2.3 +/- 0.4 kHz in systole and 1.15 +/- 0.25 kHz in diastole, in the ACA 1.8 +/- 0.35 kHz and 0.85 +/- 0.22 kHz, in the PCA 1.5 +/- 0.29 kHz and 0.74 +/- 0.18 kHz, in the BA 1.45 +/- 0.31 kHz and 0.72 +/- 0.22 kHz. Separation in four age groups showed a decrease of Doppler shift in the MCA of 20% from a mean age of 17 to 67 years. Static and dynamic compression tests were evaluated to assign transcranial Doppler signals to the MCA, ACA and PCA. No compression test was necessary for the identification of the BA insonated through the occipital foramen.

Adolescent↗
PubMed1986

[Morphologic and Doppler sonographic criteria for determining the degree of stenosis of the internal carotid artery].

There is no standard classification for quantifying the degree of internal carotid artery stenoses by means of Doppler sonography. Above all this requires a clear concept of how to define the degree of stenosis morphologically, which can be described as the local lumen narrowing or the residual lumen compared with the distal internal carotid artery. Because two different physical principles are applied, the correlation between morphologic findings and hemodynamic criteria assessed by Doppler sonography can be only rough. A classification into 5 categories is presented that is practicable also with Duplex scanning and which also takes Doppler frequency analysis into account.

Carotid Artery Diseases↗
PubMed1985

[Quality assurance of Doppler sonographic procedures].

For new diagnostic procedures, such as Doppler sonography, measures for quality assessment are of particular importance. Certificates are required by the professional authorities attesting adequate training and practical experience. In addition, minimum technical requirements for the equipment are laid down. The scientific associations may give advice in the preparation of training programme. They can also propose suitable trainers and training centres. For the doctor, Doppler sonography is only one link in the chain of the diagnostic procedures for vascular disease. It should only be employed when the investigation is clearly directed and if the user is familiar with the methods concerned. The decision to undertake further diagnostic examinations, which frequently involve risks, and the therapeutic consequences demand clinical experience and the cooperation of the individual clinical disciplines involved.

Curriculum↗
PubMed1985

Cystic adventitial degeneration as a cause of dynamic stenosis of the popliteal artery: a case report.

Cystic adventitial degeneration, which is generally localized in the popliteal artery, leads to a dynamic, exercise-dependent flow inhibition. The cysts of the adventitia, which increase in size with exercise, cause an increasing degree of stenosis which can be completely reversed after a longer period if rest. Angiographic presentation may therefore be misleading. Functional examination with Doppler sonography is able to identify the obstruction in such cases. Resection of the involved vessel and restoration of flow by interposition of a vein graft is the therapy of first choice.

Arterial Occlusive Diseases↗
PubMed1984

[Simulation of arterial pulse curves in elastic tubes and a carotid preparation].

Results of Doppler sonographic examination of the arteries in the neck are not completely comparable to angiographical findings, because the application of the Doppler probe is not standardised and angiography does not demonstrate the exact vascular morphology. To experimentally correlate the Doppler-findings with morphology, a flow rig was constructed that generated within elastic tubes as well as human carotid artery specimens all types of human arterial pulse curves (e.g. subclavian or internal carotid artery). This was achieved by taking into account the principles of pulse wave propagation and reflection in vivo. A degassed aqueous suspension of amylum maidis was used as circulating medium. This flow rig allows the evaluation of the diagnostic criteria of Doppler spectrum analysis, such as peak frequencies and spectral broadening. Testing the characteristics of Doppler equipment is another useful application.

Blood Pressure↗
PubMed1982

[Thoughts on training in ultrasound diagnosis of brain-supplying arteries].

Training programmes for the ultrasonic investigation of the arteries supplying the brain should be primarily oriented towards exercise and acquirement of skill in handling the probe. This is true for both Doppler sonography and real time B-mode scanning. Postexamination reading of the stripcard recordings is not sufficient, and even with a more sophisticated data recording system, including frequency analysis and flow-imaging, the need for practical exercise remains, and the training period cannot be shortened. About 1000 examinations are required for sufficient training. Ultrasonic examinations of the carotid and vertebral arteries should be performed by neurologists or angiologists who are familiar with cerebral vascular disease. Only careful clinical evaluation assures the appropriate interpretation of Doppler findings.

Brain↗
PubMed1979

[Noninvasive screening of cerebral death by Doppler sonography (author's transl)].

Directional Doppler sonography of the supratrochlear and extracranial cerebral arteries was performed on 16 patients without any cerebral flow, as confirmed angiographically. The findings were inconsistent for the supratrochlear artery, but the internal carotid and vertebral arteries had characteristic changes in the Doppler curve with clearly diminished systolic flow velocity and flow reversal during diastole. These results were never seen in arteriosclerotic occlusion, hypoxaemic or toxic cerebral oedema. Doppler sonography thus helps to formulate indications for early cerebral angiography.

Adolescent↗
PubMed1979

Progressive myoclonus epilepsy. A variant with probable X-linked inheritance.

The syndrome of myoclonus, epilepsy, and mental deficiency is observed in a number of distinct nosologic entities differing with respect to clinical course, (--) pathologic, and biochemical findings. Genetically, the heterogeneity within this group of disorders is shown by the occurrence of autosomal recessive and dominant forms with incomplete penetrance. In this paper we report on a sibship with at least four affected males suffering from progressive myoclonus epilepsy, ataxia, and mental deterioration. The syndrome is probably X-linked, as suggested by the maternal transmission and mild, variable symptoms in some female carriers. In a survey of the literature we have found another pedigree suggesting X-linked inheritance of this variant of progressive myoclonus epilepsy.

Adult↗
PubMed1978

[Doppler-sonographic control of a carotid-cavernous fistula occluded by balloon catheter (author's transl)].

Angiographic and Doppler-sonographic findings from a patient suffering from a traumatic carotid-cavernous fistula are presented. Data were obtained before, during, and after occlusion of the fistula by means of a balloon catheter. Doppler examination of the periorbital vessels and the carotid arteries in the neck region (selective for the common, internal, and external carotid arteries) allows a reliable and atraumatic evaluation of the carotid circulation and the pathologic venous drainage of the fistula by the orbital veins. The proper positioning of the balloon therefore is facilitated by simultaneous Doppler recording of the pathologic venous flow. The balloon-catheter technique described by Prolo et al. (1971) was modified and lead to a complete occlusion of the fistula without causing a carotid thrombosis.

Adult↗
PubMed1977

[Doppler findings in intracranial vascular disorders. Differential diagnosis of extracranial and intracranial vascular occlusions (author's transl)].

Directional Doppler sonography of the carotid arteries in the neck (selective for the common carotid artery, external and internal carotid arteries) and of the supratrochlear artery permits reliable diagnoses and localizations of extracranial stenoses and occlusions of these arteries. In addition, severe intracranial vascular disorders may also be detected by these methods. Characteristic combinations of Doppler results are described in occlusions of the trunk of the middle cerebral artery, cerebral circulatory breakdown, large arteriovenous angiomas of one hemisphere and carotidcavernous fistulas, and are compared with angiographic findings. The knowledge of these Doppler findings is indispensable for the differential critical evaluation of such disorders found at the level of the neck arteries and at the fronto-orbital terminal branches of the ophthalmic artery.

Adult↗