PubMed Health⌕ Search

Biomedical subjects

F Brassel

Publications and source records attributed to F Brassel.

31 records · Page 2Linked to original sources
PubMed1989

[Depth EEG and evoked potentials using an intravascular catheter electrode in the baboon].

Obtaining an intracranial EEG, as well as a depth recording of the somatosensory evoked potentials, via a vascular approach are described. Experimentally, a directable microcatheter was placed in the middle cerebral artery of baboons. Using the catheter guide wire as electrode, intracranial electrical activity was recorded from within the cerebral vessels. Significantly, depth recordings of the SEP showed waves of thalamic origin not present in surface recordings. Advantages of this method over surface recordings are the greater gain of information possible and, over other techniques of depth recording, the comparibly lesser invasiveness.

Animals↗
PubMed1988

An unusual congenital arteriovenous fistula of the vertebral artery and its embolization by a detachable balloon catheter.

This report concerns a 4-year-old boy with a pulsating tumor on the left side of the neck. Angiography revealed a congenital arteriovenous fistula of the vertebral artery at C2 level being fed by a left ascending cervical artery. The shunting vessel was cut off by a detachable balloon catheter via the vertebral artery so that the physiological blood supply could be restored.

Child, Preschool↗
PubMed1988

[Preoperative diagnosis: the Wada test with SPECT control for localizing brain function in therapy-refractory epilepsy].

Extensive diagnostic measures are necessary to clarify the indication for surgery in patients suffering from epilepsy that is refractory to treatment. Within the overall framework of neuropsychological diagnosis we conducted the Wada test, injecting 200 mg (or 3 mg/kg body weight) of sodium amytal on different days, in each case into the left or right internal carotid artery. This results in a 3-5 minute anaesthesia of the relevant hemisphere. By means of a neuropsychological short test it is possible to determine the performance of the non-blocked hemisphere. The extent of the blocking is also determined by simultaneous i.v. injection of HM-PAO (hexamethyl propylene amine oxime) labelled with 99m Tc, the uptake of which by various cerebral regions is visualised via SPECT. The Wada test supplies information on the lateralisation of cognitive functions (speech, memory etc.) whereas the SPECT examination enables additional determinations not only of processes that must be characterised as diaschisis, but also on the extent of blocking of a hemisphere. The results supply clues to expected postoperative cognitive deficits and thus enable a differentiated assessment of the indication for surgery. This is discussed on the basis of two clinical cases.

Adult↗
PubMed1987

[Intracranial and intraspinal hemorrhages in treatment with coumarin derivatives. Catamnesis of 63 cases between 1978 and 1986].

From 1978-1986, 63 patients (48-79 years) under coumarin derivatives had to be hospitalized neurosurgically because of intracranial or intraspinal bleedings. This corresponds to a twelvefold increased risk compared to the untreated people. The male/female ratio was 1.5. At the time of the bleeding there was no true indication for anticoagulation in at least 60% of the patients. 80% with coma on admission died. Only for 2/7 with an intraspinal hemorrhage the outcome was better than paraplegic. Women proved to have a better chance of survival. There is a need for more concise indications for chronic anticoagulation.

Acenocoumarol↗
PubMed1987

Three trigeminal neurinomas of different location and extension.

Three cases of trigeminal neurinoma, which vary widely in their clinical features, location, and extension of the tumor are presented. Symptoms and radiological findings are described and supported by typical radiographs. Operation was carried out in all cases and the diagnosis of a neurinoma histologically confirmed.

Adult↗
PubMed1987

Technetium-99m HM-PAO brain SPECT in epileptic patients before and during unilateral hemispheric anesthesia (Wada test): report of three cases.

The lipophilic brain SPECT agent [99mTc]hexamethyl propylene amine oxime (HM-PAO) was used in three cases before and during unilateral anesthesia of one hemisphere for lateralization of speech dominance (Wada test). This procedure led to a decrease of regional cerebral blood flow (rCBF) in each of the hemispheres to 55 and 90%, respectively. Diminution of rCBF was significantly more pronounced in the dominant hemisphere. A second phenomenon observed during the Wada test was crossed cerebellar diaschisis. These findings support the assumption that HM-PAO allows monitoring of brain perfusion, as rapid changes of rCBF due to decreased neuronal activity cause respective alterations of cerebral and cerebellar uptake of this new brain agent.

Adolescent↗
PubMedDate not supplied

Color and conventional image-directed Doppler ultrasonography: accuracy and sources of error in quantitative blood flow measurements.

Accuracy of two systems--conventional (DRF 400, Diasonics) and color-coded (Angiodynograph, Quantum/Phillips) image-directed Doppler ultrasonography--was investigated using an in vitro model that generated both monophasic and triphasic pulsatile flow patterns. Estimated and actual blood volume flow rates showed good correlations, but the sampling with a hand-held transducer led to wide variations in measurement error for the conventional (-69.2% to 50%) and the color-coded (-79.3% to 265.7%) systems. By performing multiple measurements, one could improve accuracy considering only the maximal values of a series instead of the mean values. Accuracy was impaired by interposed muscular or fatty tissue due to false low time-average velocity measurements caused by a loss of Doppler signal. Comparison of both systems revealed significant differences between pulsatility index values (p less than 0.001), blood flow velocities (p less than 0.001), and blood volume flow rates (p less than 0.05 for program flow, p less than 0.001 for manual and automatic flow program of the color-coded system).

Blood Flow Velocity↗
PubMedDate not supplied

Carotid artery stenting in patients at surgical high risk: clinical and ultrasound findings.

Angioplasty and stenting (A/S) provide an alternative for patients with simultaneous severe cardiac and cerebrovascular disease, or with medical illnesses which carry a high perioperative risk. We conducted A/S in 20 high-risk patients (15 males, 5 females, mean age = 64.5 years, range = 49-83 years) with symptomatic (n = 16) and asymptomatic (n = 4) high-grade stenosis (>70%, NASCET criterion) of the internal carotid artery. Patients had neurological examinations before, during and after the procedure. Color-coded duplex sonography was performed before and 24 h and every 3 months after the procedure; the 3-month examination also included cerebral angiography. The mean degree of stenosis was reduced from 85.75 +/- 7.47 to 8.0 +/- 22.09% in angiography. In an 18-month follow-up with color-coded duplex sonography the effects of the A/S could be visualized effectively: 2 with local, transient vasospasms, 1 with asymptomatic occlusion, 2 carotid arteries with remaining stenosis of 50% and 2 with minimal hyperplasia within the stent. In conclusion, in patients with a high perioperative risk, A/S is a therapeutic alternative to surgery.

Aged↗
PubMedDate not supplied

[Possibilities and limits of local intra-arterial fibrinolysis in thromboembolic vascular occlusions of the central nervous system].

It is now possible with the help of microcatheters to superselectivity catheterize the cerebral vessels right up to the point of thromboembolic vascular occlusion. Short acting fibrinolytic agents such as urokinase and rt-PA are ideally suited for local intraarterial fibrinolysis (LIF) of thromboembolism in cerebral arteries. Despite high dosages (1,000,000-2,000,000 I.U. urokinase/hr), the risk of symptomatic haemorrhage is relatively low if therapy is started within 4-5 hours of the onset of symptoms and is administered only for a short time (1-2 hrs). To reduce the high mortality rate in patients with thromboembolic occlusion in the vertebrobasilar territory, LIF is the treatment of choice. If therapy is promptly started within 4-5 hours of the clinical onset of symptoms, a favourable clinical course may result even in patients with internal carotid artery or middle cerebral artery occlusions. However, further studies are required to optimize the treatment strategy in the latter group of patients. Results of studies to date have shown that the immediate intraarterial fibrinolysis of the acutely occluded central retinal artery is by far superior to conservative therapy.

Cerebral Angiography↗