Clinical Neuroscience

[Measurements of regional cerebral blood flow and blood flow velocity in experimental intracarnial hypertension: infusion via the cisterna magna in rabbits]

BARZÓ Pál1, DÓCZI Tamás2, CSETE Klára1, BUZA Zoltán3, BODOSI Mihály4

MARCH 20, 1993

Clinical Neuroscience - 1993;46(03-04)

[The cerebral blood flow velocity (CBFV), as measured by transcranial Doppler sonography (TCD) via the transorbital route in the intracranial segment of internal carotid artery (ICA), and the regional cerebral blood (volume) flow (rCBF) in the corresponding cortical areas, as measured by the hydrogen clearance technique, were determined in 8 New Zealand White rabbits undergoing cisterna magna infusion for elevation of the intracranial pressure (ICP). In the lower range of autoregulation, i. e. at perfusion pressures (PP) between 80 and 40 mm of mercury and even below this, the changes in (CBFV) and CBF showed a strong correlation (0,86) under conditions with standard PCO2 (PaCO2)=35+2 mm of mercury). Autoregulation was exhausted at 40 mm of mercury and the cerebrovascular resistance (CVR) was minimal. Below this PP, the CBF and CBV dropped sharply, whereas CVR, gradually increased, indicating that, despite the maximally dilated resistance vessels, the intracranial hypertension causes the vascular resistance to increase, possibly via blocking of the venous outflow. Our results confirmed that non-invasive and easily (even at the bedside) applicable measurements of CBFV changes could substitute the cumbersome and expensive isotope measurements of CBF in intracranial hypertension.]

AFFILIATIONS

  1. Szent-Györgyi Albert Orvostudományi Egyetem Idegsebészeti Klinika
  2. Pécsi Orvostudományi Egyetem Idegsebészeti Klinika
  3. Bács-Kiskun megyei Önkormányzat Hollós József Kórház-Rendelőintézet Idegggyógyászati Osztály
  4. Gyógyszertani Intézet

COMMENTS

0 comments

Further articles in this publication

Clinical Neuroscience

[Post-stroke depression]

ASZALÓS Zsuzsa, PATAKY Ilona, SIMON Andrea, NAGY Zoltán

[The pathogenesis of depression following cerebrovascular accident (post-stroke depression) is poorly understood. Thirty seven (28%) out of 134 patients from the „Budapest Stroke Data Bank" were found to be depressed. Thirty two patients (86%) in this group were affected by depression within three months or the stroke. Diagnosis of depression was bades on CES-D, Ham-D and Zung scales, and a word fluency test was performed with 11 depressed and 11 non-depressed patients. Comparing the frequency of post-stroke depression in groups with ischemic damage of the carotid versus the vertebrobasilar system, as well as the left versus right middle cerebral artery, no significant differences were found. Depression reduced the activities of daily living (score: 7.8) compared to the activities of non-depressed patients (score: 3.8) at the same score of stroke – severity (4.7 versus 4.1). These observations suggest that post-stroke depression influences the rehabilitation of stroke patients, therefore the diagnosis and treatment of post-stroke depression may increase the efficacy of stroke rehabilitation.]

Clinical Neuroscience

[The role of brainstem auditory evoked potentials in the diagnosis of vertebrobasilar insufficiency]

MOGYORÓS Ilona

[The diagnostic usefulness of brainstem auditory evoked potentials was compared with other diagnostic possibilities. Brainstem auditory evoked potential was examined in patients with vertebrobasilar insufficiency. Based on the duration of clinical symptoms, patients were divided into three groups: 85 patients with transient ischaemic attack (TIA), 31 patients with prolonged ischaemic symptoms, and 35 patients with chronic symptoms were examined. The latency and interpeak latency of the auditory evoked potentials increased in 49,3 per cent. A subgroup within the TIA group was specially tested. The patients belonging to this group were admitted to the clinic soon after the onset of TIA. Acoustic evoked potentials showed increased latencies and interpeak latencies in 45,8 per cent of this group. The increasing latencies of the waves I. and III. and the interpeak latancies of I-II. and I-V. waves were the most frequent differences. Otoneurology demonstrated more frequent functional disturbances in brainstem than in acoustic evoked potentials in the second and third group. Computerized tomography is a really helpful only in examining chronic cases, while the CT reports 3,6 per cent hypodensities in the first group and 17,3 per cent in the third group. Brainstem auditory evoked potential testing is the most sensitive diagnostic method in the diagnosis of transient ischaemic attack.]

Clinical Neuroscience

[Spontaneous intracerebral haematomas in children]

VELKEY Imre, DOBAI József, GYARMATI János

[The authors report two cases of spontaneous intracerebral haematomas in children. Both children presented with serious symptoms of acute intracerebral haemorrhage. Investigations do not reveal the cause of the haemorrhage in either of the cases and angiography detected no arteriovenous malformation. The term ,,occult” is reserved for these cases, as spontaneous intracerebral haematomas do not result in space-occupying process or CSF passage blockage and may be treated medically.]

Clinical Neuroscience

[The effect of cerebrospinal fluid drainage on middle cerebral artery blood flow velocity in conditions with raised intracarnial pressure]

BARZÓ Pál, DÓCZI Tamás, KOPNICZKY Zsolt, ROTYIS Mária, BODOSI Mihály

[Middle cerebral artery (MCA) blood flow velocity and intracranial pressure (ICP) were recorded in 42 patients suffering from raised ICP. A major (ICP25 mmHg) or moderate (251CP15 mmHg) degree of intracranial hypertension was reduced by means of either continuous or intermittent CSF drainage. Measurements of MCA blood flow velocity were carried out with transcranial Doppler sonography (TCD). Three types of reactions were observed with regard to cerebral blood flow velocity (CBFV) changes in response to CSF drainage. Patients in Group 1 demonstrated pressure passive CBFV changes throughout the observed cerebral perfusion pressure (PP) range. In Group 2, cerebrospinal fluid (CSF) drainage brought about a transitory increase in CBFV for a few minutes. In Group 3, the reduction of ICP to the normal level did not influence CBFV at all. The pulsatility index (PI) of the cerebrovascular reserve capacity (CVR), which was highest in Group 1, changed in contrast with the CBFV changes in Groups 1 and 2. The pressure-passive velocity pattern (in Group 1) suggests that the blood vessels were at nearly maximum dilatation and were perhaps failing to constrict properly in response to increased PP. As recovery proceeded (Group 2), the mechanism became effective, thereby reestablishing autoregulation. Whereas clinical signs and computed tomography reveal only the trend of the ICP, TCD provides the possibility of a semi-quantitative evaluation of ICP changes and seems especially promising in the rapid assessment of the efficacy of treatment aimed at ICP reduction.]

Clinical Neuroscience

[Benign focal amyotrophy]

DIÓSZEGHY Péter, MOLNÁR Mária, MOLNÁR Tibor, MECHLER Ferenc

[A 36 year old female is presented with focal segmental atrophy and weakness of the right lower limb affecting predominantly the lower leg. The slight asymmetry presentsince in her childhood started to progress at the beginning of the fourth decade. The EMG and the muscle histology revealed chronic neurogenic changes, which were consistent with spinal motoneuron lesions. The electrophysiological investigations verified the focal segmental localisation of the involvement. The benign course and the good prognosis of this clinical syndrome point out the importance of its recognition and separation from other motoneuron diseases. The cause of this disorder is unknown; probably, it has heterogeneous etiology.]

All articles in the issue

Related contents

Clinical Neuroscience

[The effect of cerebrospinal fluid drainage on middle cerebral artery blood flow velocity in conditions with raised intracarnial pressure]

BARZÓ Pál, DÓCZI Tamás, KOPNICZKY Zsolt, ROTYIS Mária, BODOSI Mihály

[Middle cerebral artery (MCA) blood flow velocity and intracranial pressure (ICP) were recorded in 42 patients suffering from raised ICP. A major (ICP25 mmHg) or moderate (251CP15 mmHg) degree of intracranial hypertension was reduced by means of either continuous or intermittent CSF drainage. Measurements of MCA blood flow velocity were carried out with transcranial Doppler sonography (TCD). Three types of reactions were observed with regard to cerebral blood flow velocity (CBFV) changes in response to CSF drainage. Patients in Group 1 demonstrated pressure passive CBFV changes throughout the observed cerebral perfusion pressure (PP) range. In Group 2, cerebrospinal fluid (CSF) drainage brought about a transitory increase in CBFV for a few minutes. In Group 3, the reduction of ICP to the normal level did not influence CBFV at all. The pulsatility index (PI) of the cerebrovascular reserve capacity (CVR), which was highest in Group 1, changed in contrast with the CBFV changes in Groups 1 and 2. The pressure-passive velocity pattern (in Group 1) suggests that the blood vessels were at nearly maximum dilatation and were perhaps failing to constrict properly in response to increased PP. As recovery proceeded (Group 2), the mechanism became effective, thereby reestablishing autoregulation. Whereas clinical signs and computed tomography reveal only the trend of the ICP, TCD provides the possibility of a semi-quantitative evaluation of ICP changes and seems especially promising in the rapid assessment of the efficacy of treatment aimed at ICP reduction.]

Clinical Neuroscience

[Comparative human immunohistochemical investigations of peptidergic innervation of embryonal and adult cerebral blood vessels]

BÜKI András, DÓCZI Tamás, HORVÁTH Zoltán, FÜRTÖS András

[Peptidergic fibres innervating human embryonic and adult cerebral blood vessels were screened for calcitonine gene-related peptide, neuropeptide-Y and substance-P immunopositive fibres, the mediaadventitia border displayed a network-like fibre arrange ment. There was no significant difference either in the distribution of the individual peptidergic fibres or in the age-dependent appearance of peptidergic networks. On the basis of these results it seems to be unlikely that the different clinical course of juvenile and adult subarachnoid haemorrhages could be the result of an age specific difference of peptidergic fibre distribution influencing the neurogenic mecha nisms of cerebral autoregulation.]

Clinical Neuroscience

[Transcranial doppler detection of cerebral vasospasm following aneurysmal subarachnoid haemorrhage]

BARZÓ Pál, BORDA Lóránt, VÖRÖS Erika, KISS Mariann, BODOSI Mihály, DÓCZI Tamás

[In 22 patients with subarachnoid hemorrhage secondary to ruptured intracranial aneurysms serial neurological evaluations, transcranial Doppler examinations and computer tomographic scans were performed. Transcranial Doppler flow velocities were significantly elevated for the group with vasospasm on posthemorrhage day 2. The maximum blood flow velocities were recorded between days 9 and 18, with normalization occurring within the following 3 weeks. Increase in velocity preceded clinical symptoms and could therefore be used as a prognostic factor for the management of patients with subarachnoid hemorrhage. The data also indicated that the extent and location of blood in the subarachnoid space determine the severity and location of vasospasm.]

Clinical Neuroscience

[Increasing cerebral perfusion pressure in serious cranial injury - contradictory effects of dopamine]

BARZÓ Pál, CZIGNER Andrea, ANTHONY Marmarou, ANDREW Beaumont, DEÁK Gábor, PANOS Fatouros, FRANK Corwin

[Background - Management of cerebral perfusion pressure is an important element of the treatment of traumatic brain injury. Vasopressors are accepted as a method of choice to increase mean arterial blood pressure and thus cerebral perfusion pressure in the face of rising intracranial pressure. There are, however, some unresolved issues and potential risks to this therapy. Matherial and methods - This study therefore examines the effects of dopamine on physiological changes as well as on brain edema and water content that can be readily assessed by MRI/MRS in 1. a rodent model of rapidly rising intracranial pressure, caused by diffuse injury with secondary insult and 2. a model of cortical contusion. Results - Dopamine was capable of restoring cerebral perfusion pressure in the model of rapidly rising intracranial pressure. However, this was associated with only a partial restoration of cerebral blood flow. In the brain tissue two profiles of change in the apparent diffusion coefficient of water (ADCw) were seen; one in which ADCw recovered to baseline, and one in which ADCw remained persistently low. Despite that dopamine did not alter these profiles, MRI-assessed tissue water content was increased four hours after injury and dopamine increased cerebral water content in both subgroups of injury, especially in the subgroup with a persistently low ADCw (p<0,01). In the contusion group dopamine significantly worsened the edema both in the injured and in the contralateral area of hippocampus and temporal cortex even though the ADCw values did not change, except for the contralateral hippocampus, where both water content and ADCw values rose with treatment, suggesting extracellular accumulation of water. Conclusion - The results suggest that dopamine has a double effect - while it temporarily and partially restores cerebral blood perfusion, at the same time it induces an increase in brain swelling and thus an increase in intracranial pressure in some cases. It is possible that in a subgroup of patients vasopressor treatment leads to an opposite effect several hours later. Vasopressor therapy in the clinical setting therefore should be cautiously applied.]

Clinical Neuroscience

[Investigation of cerebral autoregulation in Parkinson’s disease]

DEBRECZENI Róbert, AMREIN Ilona, KOLLAI Márk, LÉNÁRD Zsuzsanna, PÁLVÖLGYI László, TAKÁTS Annamária, GERTRÚD Tamás, SZIRMAI Imre

[Background and purpose - The frequent orthostatic intolerance in Parkinson’s disease could be the consequence of cardiovascular autonomic failure and/or a damaged cerebral autoregulation (AR). To clarify this question the regulation of cerebral circulation was investigated by polygraphic method. Methods - On a tilt table simultaneous and continuous registrations were made of MCA velocity (VMCA) by transcranial Doppler, arterial blood pressure by non-invasive method, and end-tidal CO2, in supine and in tilted positions of 10°, 30°, 70° grades. The cerebral autoregulation was characterized by the slope of the curve of the arterial blood pressure at the level of the Willis-circle (BPW, as MCA perfusion pressure) plotted against the MCA velocity, achieved by linear regression (y=ax+b function, a=AR, or index of autoregulation). Patients - The data of 17 parkinsonian patients (PP) and eight age-matched controls (C) were analyzed. Results - The decrease of blood pressure in parkinsonian patients was significantly lower than in the controls when supine position was restored from 70° (ΔABP 70°-0°PP= -3.1±7.5 Hgmm; ΔABP 70°-0C°=-11.1±7.3 Hgmm; p<0.05), which suggests a damage to the sympathetic cardiovascular system. A disturbance of the cerebral autoregulation in patients was suggested by a progressively decreasing MCA average velocity (VMCA) during graded tilt, which was significiant at 70° (ΔVACM=9.8±8.82% cms-1; pCPP <0,05), and by a higher slope of pressure-velocity curve (ARC=0.143±0.125% cms-1/Hgmm; ARPP=0.38±0.25% cms-1/Hgmm; pC-PP<0.05). Conclusions - The results show that the cerebral blood flow of patients is more dependent on perfusion pressure compared to healthy controls. The disturbance of the sympathetic cardiovascular system and of cerebral autoregulation could be the consequence of a damage to the postganglionic structures in Parkinson’s disease. These results could explain the frequent orthostatic intolerance of patients even with normal blood pressure.]