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Biomedical subjects

H R Müller

Publications and source records attributed to H R Müller.

At least 37 records · Page 2Linked to original sources
PubMed1989

[A probe holder for improving duplex sonography].

To enable mechanical probe fixation for carotid duplex sonography, a hollow cylinder was mounted to the free end of a snake-neck type surgical instrument holder. A second hollow cylinder fitting over the handpiece of the probe is adapted to its bore. This allow turning of the probe from the longitudinal to the axial plane through the examined vessel, the level of the contact surface and its pressure against the tissue remaining unchanged. The use of this device allows better correlation of vessel cross sections to the respective segments of the vessel as imaged in the longitudinal plane. A further advantage of the probe-holder is that once the position of the probe is selected, it leaves both hands of the examiner free for operating the Doppler system. With duplex equipments programmed for volume flow calculation from cross sectional area and time-averaged mean spatial velocity the feasibility of such measurements is considerably improved.

Blood Flow Velocity↗
PubMed1989

[The effect of head and body position on jugular vein blood flow].

The impact of body position on jugular venous flow was studied in 10, and the impact of head position in 33 healthy young volunteers using an ultrasonic Doppler flowmeter. Flow in the right internal jugular vein decreased by 40 +/- 21% with the individuals positioned on their left side. Turning of the head to the contralateral side reduced right internal jugular venous flow by 42 +/- 24% in 18 cases, whereas flow increased by 79 +/- 67% in 15. The respective values for the left internal jugular vein were 35 +/- 26% in 14, and 92 +/- 86% in 18 cases.

Adult↗
PubMed1988

[Doppler sonography findings in arteriitis temporalis].

The results of 145 patients who had been examined by Doppler sonography for suspected giant cell arteritis were analysed. Alternating flow direction, reversed flow direction or "no-flow" in the supratrochlear and/or supraorbital arteries were considered as pathological findings as well as absence of signals from the trunk or branches of one or both superficial temporal arteries. Pathological findings at the periorbital arteries were obtained in 25.9% (n = 7) of the cases with histological proven giant cell arteritis. In a further 29.6% (n = 8) the superficial temporal artery findings were abnormal. Only 13.2% (n = 5) of the patients with normal histological findings and 5.7% (n = 2) of those with degenerative lesions of the temporal arteries had pathological Doppler sonographic findings. Two thirds of the patients with visual impairment showed abnormal findings in the periorbital arteries.

Aged↗
PubMed1987

[Flow index of transcranial Doppler sonography].

A flow index calculated by multiplying mean velocity (v) by signal power is proposed for use in dynamic transcranial Doppler studies. Contrary to velocity this index indicates the relative changes in volume flow even in case of change in diameter of the vessel examined. A CO2 respiration experiment is reported on, in which a simplified flow index (vmax.p) was calculated off-line, and indicated an increase of the caliber of the middle cerebral artery with increased pCO2.

Adult↗
PubMed1986

[Transcranial Doppler sonography in orthostasis].

Middle cerebral artery blood flow velocity was investigated by transcranial Doppler sonography in 20 healthy subjects during a 10 min orthostasis test. Mean maximal velocity proved to be significantly lower in upright compared to horizontal position, its mean amounting to 93 +/- 9% of the latter value over the first two minutes and to 89 +/- 9% during the remaining period of the test. The index of resistance calculated by dividing systolic by enddiastolic maximal velocity was significantly decreased to a mean of 96 +/- 11% and 97 +/- 11% respectively during the two periods of orthostasis, probably due to autoregulation.

Adult↗
PubMed1985

[Quantitative determination of blood flow in the internal jugular vein using ultrasound].

The cross-sectional area of the internal jugular vein was measured in 8 normal healthy subjects and in two patients having AV malformations in the internal carotid circulation using a linear-array scanner with facilities for computerised planimetry. Mean blood flow velocity was measured at the same site of the vessel by means of continuous-wave Doppler flowmeter. The product of the two values was considered to indicate volume flow. The mean value for bilateral flow was 656 +/- 113 ml/min in the normal series. In the two patients the values were 1 331 ml/min and 860 ml/min respectively.

Adult↗
PubMed1985

[Ultrasonic blood flow measurement in stenoses and occlusions of the internal carotid artery].

Blood flow in the common carotid artery as measured by means of the QFM system of Furuhata in 100 patients with angiographically proven obstructive or occlusive lesions of the internal carotid or middle cerebral artery, was compared with the normal blood flow range in healthy persons of 41 to 70 years of age. Findings were considered to be pathological in 72% of the patient pool. This figure was based on one or more of the standard-value criteria, namely, unilateral flow, bilateral flow, and percentage of the difference between both sides. Pathological findings were thus obtained in 100 per cent of the bilateral and in 90 per cent of the unilateral occlusions, in 53 per cent of the bilateral and in 52 per cent of the unilateral stenoses of the internal carotid artery. In occlusions of the internal carotid artery, no significant correlation between blood flow in the common carotid artery and the presence of an ophthalmic collateral extending beyond the carotid siphon could be established. However, there was a correlation with the diameter of the external carotid artery as well as to the sum total of the cross-sectional areas of its main branches. There was no significant correlation between common carotid blood flow and linear luminar narrowing in stenoses of the internal carotid artery if contralateral pathology was disregarded. Compared with normal flow (7,6 +/- 1,4 ml/sec), the mean flow was reduced in all unilateral stenoses of more than 30 per cent, whereas it was increased in stenoses of less than 30 per cent associated with a contralateral stenosis, and in stenoses of less than 70 per cent associated with a contralateral occlusion of the internal carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Arterial occlusive diseases of the eye. Diagnostic contribution of Doppler sonography].

In a retrospective study, patients with 125 ocular arterial occlusions (71 men, 54 women) observed between 1978 and 1981 were analyzed with regard to etiology, therapy, and course of disease. Particular attention was given to information obtained by means of Doppler sonography. Among our patients the most common condition was occlusion of either the central retinal artery or its branches (62 cases), as opposed to 30 patients with apoplexia papillae, 6 with chronic ocular ischemia (or ischemic ophthalmopathy), and 4 with less common types of occlusion. In the patient collective as a whole, the causes in those over 50 years of age are predominantly hypertony, arteriosclerosis, and emboli, as well as other causes which cannot be determined with certainty. If occlusions of the central artery and its branches and amaurosis fugax are considered alone, emboli are by far the most common cause. According to the findings with Doppler sonography, the most frequent source of emboli appears to be the bifurcation of the carotid artery. A chronic ocular ischemia (also known as ischemic ophthalmopathy) is always indicative of obstruction of the carotid artery. The situation is completely different in apoplexia papillae, which is, as a rule, either secondary to an affection of the smaller vessels, hypertonically arteriosclerotic, or caused by inflammation, as is the case in temporal arteriitis. Doppler sonography is of paramount importance as a simple, non-invasive method for determining the pathogenesis of ocular arterial occlusion. It also provides pointers to further clarifications which could lead to bypass surgery being indicated. In those patients in whom such examinations were possible, the findings were pathologic in all cases of chronic ocular ischemia (6 out of 6), in 84% of the cases of amaurosis fugax, in 62.5% of the cases of occlusion of the central artery or its branches, but only in 23% of the cases of apoplexia papillae, which further distinguishes this later condition from the other forms of occlusion. Frequently suggested therapies, for example RheomacrodexR, failed to produce any convincing results in our patient collective - not only those with central arterial thrombosis but also those with apoplexia papillae. In a statistical comparison, no significant difference could be demonstrated between our treatment of apoplexia papillae without corticosteroids (as long as arteriitis temporalis was not involved) and that of Hayreh, who administered corticosteroid treatment not only for apoplexia papillae but also for arteriosclerotic conditions of the optic disk induced by hypertension.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1983

[Results of the first hundred cerebral bypass operations in Basel].

This is a report on clinical findings after 100 extra-intracranial bypass procedures for cerebral ischemia. The patients presented with transient ischemic attacks, prolonged ischemic neurological deficits, completed strokes, low perfusion syndromes and ischemic ocular diseases. The microvascular anastomosis is performed between a branch of the external carotid artery and a cortical branch of the middle cerebral artery. In 10 patients we performed a bilateral bypass. We had no mortality. The morbidity was 5%, the patency rate 96%. The effect of the microvascular procedure can be determined by comparing the postoperative follow-up (averaging 22 months) and the natural course of cerebrovascular disease. Clinical benefit is gained in the elimination of transient ischemic attacks. Patients considered candidates for diagnostic studies are those presenting with completed strokes. Finally in patients with large aneurysms extra-intracranial bypass procedures may prove to be of value, when carried out in a combined approach.

Adult↗