Clinical Neuroscience

[Transcranial doppler of extracranial stenosis in internal carotid artery]

NAGY Valéria1, BEDŐ György1

NOVEMBER 20, 1993

Clinical Neuroscience - 1993;46(11-12)

[Endeavours were made to determine why mean velocity and pulsatility index changes in middle and anterior cerebral artery are caused by the unilateral occlusion of the internal carotid artery or by severe stenosis. The transcranial Doppler method is suitable for judgingre pathologic intracranial blood flow conditions, especially when data are compared to those of healthy conditions.]

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  1. Hajdú-Bihar Megyei Kórház, Idegosztály

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Clinical Neuroscience

[In Memoriam György Bekény]

HORVÁTH Sándor

[After a life of struggle and success, and after a serious illness borne with dignity and discipline, death took him at the age of seventy-eight. Even in the last years of his life, ill but tireless, he served his vocation with his knowledge: healing and teaching; patients and interested students; the Clinic. Shortly before his death, he completed his last scientific work, The History of Hungarian Neurology.]

Clinical Neuroscience

[The illogical therapy]

SZIRMAI Imre, SUREK György, KAMONDI Anita, MAGYAR Hedvig, JUHÁSZ Csaba

[Most of the causative pathological factors in ischemic cerebrovascular events cannot be recognized during the acute stage of the disease partly because of to the complexity of biophysical model of cerebral microcirculation, partly because the causative factors in this model cannot be confidently weighted. Clinical diagnoses on cerebral circulation disorders are based on the fundamental causes of the disorders. Evoking factors are hypotheses, consequently therapies are directed to hypotheses. The mathematical model of cerebral microcircualtion is mondeterministic. The interactions between vascular factors and blood fluidity can be roughly estimated. Judging the therapeutic efficacy is hindered by the nondeterministic disease model, the indefinite clinical clues, their individual variations, heterogenous diagnostic groups, and tendency of spontaneous restoration of symptoms. Non-specific drugs are used to treat cerebral ischemia, and trials making use of monotherapies have failed to change the life expectancy or the clinical course of ischemic patients. The acute stage of the disease cannot be defined and because of the incompleteness of clinical indicators „stroke prevention" appeares to be ambiguious. Therefore, the nature of the treatment of ischemic cerebrovascular disease is at present based on trial and error.]

Clinical Neuroscience

[Molecular characterization of the T cell receptor in experimental allergic encephalomyelitis and multiple sclerosis - new therapeutical approaches]

KÁLMÁN Bernadett, LUBLIN D. Fred

[The authors review here the most recent literature on experimental allergic encephalomyelitis and multiple sclerosis, focusing on the efferent branch of the immune response. They attempt to describe the molecular characteristics of the myelin antigen specific T cell receptors. Identification of the most distinct properties of the disease mediating cells may not only provide clues to the etiology of MS, but also opens new avenues to specific therapeutical approaches.]

Clinical Neuroscience

[Experimential allergic encephalomyelitis multiplex sclerosis!]

KAPÓCS Gábor

[T-lymphocytes and molecular engineering]

Clinical Neuroscience

[Imaging of the lumbar synoval cysts]

PATAY Zoltán, TOURNADE Alain, BALÉRIAUX Danielle, TAJAHMADY Taghy, BERKY Mihály

[Lumbar synovial cysts are infrequent but characteristic manifestations of the commonly encountered but rather complex degenerative disorders affecting the lumbar zygapophyseal joints. The anatomical disposition of the different components of the lumbar motion segment, their sensory innervation and their topographic relationship with the neighbouring nerve structures explain why the neurogical manifestations of these affections, as well as of other articular disorders, cannot always be distinguished from those of discal origin. However, modern imaging methods allow the resolution of the radiological and consequently of the clinical differential diagnostic problems. The systematic use of computed tomography and magnetic resonance imaging in the evaluation of low back pain syndromes has resulted in the recognition and precise description of the practically pathognomonic „radiological syndrome” of the synovial cysts of the lumbar zygapophyseal joints.]

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Clinical Neuroscience

The applications of transcranial Doppler in ischemic stroke

FINNSDÓTTIR Herdis, SZEGEDI István, OLÁH László, CSIBA László

Background: This overview provides a summary of the applications of transcranial Doppler (TCD) in ischemic stroke. Results: A fast-track neurovascular ultrasound protocol has been developed for detecting occlusion or stenosis. The technique is more reliable in the carotid area than in the posterior circulation. By monitoring the pulsatility index the in­crea­sed intracranial pressure can be diagnosed. TIBI score was developed for grading residual flow. TCD has been shown to accurately predict complete or any recanalization. Regarding recanalization, TCD has a sensitivity of 92%, a specificity of 88%, a positive predictive value of 96%, a negative predictive value of 78% and an overall accuracy of 91%, respectively. Sonothrombolysis seemed to be a promising application but randomized controlled trials have shown that it does not improve clinical outcome. TCD examination can detect microembolic signals (MES) which are associated with an increased risk of stroke. Micro­em­boli were detected in symptomatic and asymptomatic carotid artery stenosis and during carotid endarterectomy. The number of microemboli can be decreased by antithrombotic therapy. Contrast en­chan­ced examination and Valsalva maneuver with continuous TCD monitoring can accurately screen for right-to-left shunt.

Hungarian Radiology

[Transcranial Doppler monitoring of distal embolism during of carotid stenting]

SZIKRA Péter, VÖRÖS Erika, SZTRIHA László, SZÓLICS Alex

[INTRODUCTION - Reducing the risk of embolisation during endovascular treatment of internal carotid artery stenosis is very important. The rate of embolisation is affected by the different steps of stenting manipulation. Using transcranial Doppler equipment we studied the embolic signals during the different phases of carotid dilatation and stenting. MATERIAL AND METHOD - 50 patients (33 male, 17 female; mean age 64 years) were intraproceduraly monitorized with transcranial Doppler. Predilatation was necessary in nine cases, postdilatation was performed in 39 cases. The number of emboli were measured in seven different steps of endovascular treatment of carotid stenosis. Different type of commercial available endovascular devices were used. RESULTS - Intraprocedural embolisation was observed in every case. In different phases of carotid stenting the rate of embolisation showed marked differences in each phase of carotid stenting. Crossing the stenosis with stent delivery system were accompanied by a low rate of embolism (5.3) compared to the level during stent opening (9.16) and balloon dilatation (9.96). The highest level of embolisation was observed during predilatation (15.9) without the protection of the stent. CONCLUSIONS - We detected embolisation in all of the cases, however the number of embolic signals varied in different phases of carotid artery stenting. Embolisation can be reduced if the most dangerous steps (i.e. pre- and postdilatation) are avoided. Using TCD monitorisation the physician can be informed by the degree of embolisation that may alarm the interventionalist to perform the procedure more carefully, furthermore it can be employed during the training of carotid stenting.]

Clinical Neuroscience

[Effect of mental arithmetic and verbal fluency on the flow velocity in the middle cerebral arteries]

AMREIN Ilona, PÁLVÖLGYI László, DEBRECZENI Róbert, KAMONDI Anita, SZIRMAI Imre

[Introduction - Using transcranial Doppler sonography (TCD), changes in blood flow velocity (BFV) can be measured in the Medial Cerebral Artery (MCA) during cognitive effort. Our goal was to define the time-course and laterality of BFV in healthy vo-lunters during arithmetic and verbal fluency tasks according to handedness. Methods - Twelve subjects (8 right-handed, 4 left-handed) were assessed. The TCD registered BFV in both MCA simultaneously. Heart rate was also recorded using TCD. Finally we included a 16-channel EEG. BFV laterality index (LI) was calculated. Participants were asked to count silently and generate words beginning with a specified letter. To estimate hemispheric differences in BFV, two-tailed Wilcoxon tests were utilized along with correlational analyses. Results - During cognitive effort the BFV changed in a triphasic manner in all participants. A 6-8% elevation of BFV was observed in MCAs without latency at the time of the evoking signal. Laterality of BFV developed after 5-13 seconds during cognitive effort in right-, and several seconds later in left-handed subjects. During tasks the BFV increased in the dominant hemis-phere up to 2.6-4.7% compared to the subdominant one. We also calculated the LI. During the verbal task the LI agreed with the handedness in 9 out of 12 subjects. During the mental arithmetic task, agreement was found in 6 out of 12 subjects. According to LI results we found a discrepancy between verbal and arithmetic tests in 3 out of 12 subjects. Conclusion - Cognitive effort elicites significant bilateral BFV increases in the MCAs, which suggests fast neurogenic regulation. The course of BFV during mental arithmetic proved to be different from course BFV assessed during the word fluency task. Based on the laterality of the BFV, the word-generation task was more sensitive in determining the dominant hemisphere when compared to the mental arithmetic task. The use of LI may help to estimate hemispheric functions even in pathologic circumstances.]

Clinical Neuroscience

[Transcranial Doppler assessment of cerebral vasomotor reactivity in evaluating effects of vinpocetine in cerebral small vessel disease: a pilot study]

JOVANOVIC B. Zagorka, PAVLOVIC M. Aleksandra, PEKMEZOVIC Tatjana, MIJAJLOVIC Milija, NADEŽDA Šternić Čovičković

[Background - There are still dilemmas about the vasodilating effect of vinpocetine, a synthetic ethyl alkaloid vincamine. The method of measuring cerebral vasomotor reactivity (VMR) by transcranial Doppler (TCD) technique before and after administration of the medication was used to estimate the degree of arterioles vasodilatation. The aim of this study was to test of the vasodilating effect of vinpocetine in patients with cerebral small vessel disease (SVD) by measuring cerebral VMR. Material and methods - Thirty patients with SVD were on 3-month-long oral treatment with 15 mg vinpocetine daily. Cerebral VMR was determined by breath holding test. The breath holding index (BHI) was calculated in standard manner and values >0.69 were considered normal. At the baseline, before treatment (I), BHI, modified Rankin scale (mRS) score, Mini Mental State Examination (MMSE) score were determined. One month later (II) BHI was assessed again, while after 3 months of treatment (III) we analyzed BHI, mRS score and MMSE score. Results - The average age of patients was 61.4±11.5 years (range 40 to 77 years), 18 (60%) female and 12 (40%) males. Values of BHIs were increased during treatment at the right MCA (I) 1.18±0.53, (II) 1.26±0.54, (III) 1.37±0.41, with statistical significance between I and III measurement (p<0.05). An increase was noted on the left MCA (I) 1.25±0.53, (II) 1.31±0.55 and (III) 1.32±0.42, but it did not reach statistical significance (p>0.05). Mean MMSE score significantly increased from baseline 27.4±2.3 to 28.5±2.0 after three months of treatment (p<0.001). Functional status showed a statistically significant improvement with mRS score increasing from 2.1±1.0 to 1.1±0.6 (p<0.001). Conclusion - This pilot study showed that 3-month-long oral treatment with vinpocetine 15 mg daily had tendency to increase BHI, indicating improvement of cerebral VMR. It is possible that higher doses of vinpocetine are needed to achieve substantial increase of VMR.]

Clinical Neuroscience

[Vasoreactivity changes of healthy volunteers investigated by transcranial doppler]

VALIKOVICS Atilla, OLÁH László, FÜLESDI Béla, MUNKÁCSY Csaba, CSIBA László

[Transcranial Doppler (TCD) was used to measure the effect of 1 g acetazolamide (Diamox, Lederle) on blood flow velocity in the middle cerebral artery of 50 healthy volunteers (aged 20-70 years). Parameters of blood flow, blood pressure, heart rate and blood gas values were determined before and after intravenous administration of Diamox. The reserve capacity was expressed as a percentage change of baseline values. The acetazolamide did not result in significant blood pressure and blood gas changes. The mean velocity of blood flow before Diamox administration was 59.8+14.4 cm/s. The velocity of flow significantly increased after acetazolamide, peaking after 10 minutes. The extent of reserve capacity was the greatest in the age group of 31-40 years and the smallest in the 61-70 years group. The reaction was longer lasting in age groups over 50 years. Significantly higher flow parameters and greater reserve capacity was found in women than in men at each measuring time point. The reserve capacity depended on age and gender.]