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Local CO2 reactivity and autoregulation of cerebral blood flow
ABSTRACTS CEREBRAL BLOOD FLOW AND NEUROPSYCHOLOGICAL TEST RESULTS IN PRIMARY AND VASCULAR TYPE OF DEMENTIA A. Hartmalnn. R.V. Roost. C. Dettm~r~ Neurological University Hospital Bonn, FRG Introduction: In 36 patients with Dementia (Alzheimer's disease/ DAT n=16, dementia of vascular type/DVT n=20) CBF has been measured by the following techniques: Local CBF(LCBF) by the Xenon-CCT, regional CBF(rCBF) by the Xenon inhalation techniques with stationary detectors, rCBF distribution by the SPECT and in 6 cases glucose metabolism by PET. All patients have been tested by neuropsychological testing. Question: 1) Is blood flow distribution similar in all techniques and does it correlate to glucose metabolism? 2) Does s e v e r e n e s s of disease correlate with blood flow data? Results: In patients with OAT codicat flow in Xe-CCT and XerCBF is more depressed than follow of the deeper parts of the brain As compared to 20 normal volunteers). Distribution maps with flow depression affects perietotemporal parts more than frontal parts. In cases with frontal flow depression the white matter was involved also. Glucose metabolism shows similar distribution than flow distribution. Calculation of absolute flow in Xe-CCT resulted in lower flow than in Xe- technique. In patients with DV'F both cortical and white matter flow were involved in the same extent. Frontal flow showed the same extent of reduction than other parts of the brain. Glucose metabolism (n=3) did not correlate to flow distribution. Neuropsychological evaluation showed no correlation to extent of flow reduction except in severely involved cases (MMSE below 16). Conclusion: Absolute flow measurement is important in workup of dementia of different etiology and is not substituted by techniques, which measure only flow distribution. Neuropsychological workup and m e a s u r e m e n t of blood flow do not substitute each other.
XECT CEREBRAL BLOOD FLOW AND THE ENDOVASCULAR MANAGEMENT OF CEREBROVASCULAR DISEASE C. Junnrei~ University of Pittsburgh Medical Center, USA Endovascular therapy in the patient with cerebrovascular disease while frequently quite useful has significant risks and therefore shouJd not be used indiscriminantly, Thus, appropriate patient selection is very impodant. To that end knowledge of the physiologic status of the cerebral circulation is essential, and measurement of the cerebral blood flow (CBF) is a very useful parameter in that regard. Patients with skull base tumors or aneurysms may require vessel sacrifice as part of their treatment. A balloon test occlusion (BTO) has been very reliable in predicting those patients at risk for stroke if an internal carotid artery, for example, were to be sacrificed. In patients who have suffered from an acute subarachnoid hemorrhage (SAH) secondary to a ruptured intracranial aneurysm, delayed neurological deficits caused by vascular spasm of the intracranial arteries remains a dread complication. Management includes pharmacological alterations of systemic b)ood pressure in conjunction with other physiological manipulalions. Endovascular intervention via the transarterial route may be required for intracranial angioplasty and/or papaverine administration. The CBF has been a key to management and patient selection in this context. Patients with atherosclerotic vascular disease (ASVD) may present with an acute stroke and require immediate intervention. If thrombolytic therapy is instituted eady enough tissue can be preserved. However, if large areas of extremely low or no CBF are present, then reperfusion of the cerebral paranchyma may be counter productive and detrimental. In patients with chronic vascular disease a number of subgroups can be delineated by measuring their CBFs. Some of these subgroups appear to benefit from flow augmentation procedures such as angioplasty or bypass surgery. Many procedures and therapeutic inlerventions are available to the vascular patient. Understanding the physiology by measuring the CBF is the key to appropriate selection.
LOCAL C02 REACTIVtTY AND AUTOREGULATION OF CERE6RAL BLOOD FLOW Y ShinoharaDept. of Neurology+Tokai UniversitySchoolof Medicine, Isehara, Kanagawa,JAPAN The responsesofcerebral vesselsand cerebralblood flow to changes in arterialcarbon dioxide tension (C02 reactivity) and perfusion pressure {autoregulation)are well known and have been confirmed by numerous experiments and clinical observations over many years. However, there is controversyas tO whetherCO2 reactivityand autoFeguiatoPj abilityare uniform throughoutthe centralnervoussystem. The. purpose of my talk is to discuss wheter there is inhomogeneity in regional cerebral C02 vasoreactivityand autoreguMtooj ability based on published data and our own observations. C02 reactivity: A few reports on regional C02 reactivity in man measuredby using positronemission tomographyor the cold xenon method indicate that regional C02 reactivity in various parts of the brain may be different, but a study in cats show that the larger recjulatoo/responses to C02 may be related to higiler levelsof resting CBF. Our study, which was pen'ormedin monkeys by using the cold xenon method, indicated that C02 responseswere gooclin the basalganglia, frontal cortexand so on. but iow in white matter. The values of CBF increase per lmmli dse in PaC02 divided by the resting CBF value (C02 reactivity/resting CBF) were similar throughout the vadous parts of the brain, suggesting that apparent variation in CO2 reactivity is only related to the differences in microvasculardensity in the brain's various pates. This finding indicates that there is essentially no regional differencein C02 responsein the brain. Autoregulation: It is known that global CBF values are well maintained in the MARP range from 60 to 140 mmllg. provided artedal C02 tension is stable. Our results also showed that a normal autoregulatory ability in various regions of the brain, especiallyin high-blood-flowareasat an MABP of 60 to 80 mmllg was observedin the mdibrain and hypocampus. This "predysautoregulaiotyovershootof CBF" was also observed in rate. This may be a kind of defense mechanism against brain tissue hypoxia, particularly in the Iower-pedusionareas.
The Cilinieal CT Study of Astrocytnma l-l! Treated with f/DR Ir-192
Inter~tiliM Brachytherapy -,li~F'anli, l'ianjin Medical U.i,.,~rshy. P.R.Ch,na.
Sittce Jan 1990, 3O patients with a.lmx;Ttoma I-ll went treated by HDR It'- 192 RemoteAfledoading lntorsdlial Brachytherap.v. The 30 cases(mute 16. tumale14) or ccrehronta were taken the biopsy ~41l,J~Jia,gnosed as astrocytnma I-IL 1he av,:rage age was 46 yeats. The location of them wore showed by c r as. frontal pro1 12. leJnpl9 l0 and paricto 8. PHItlKEy 18 and recurrem i2.
All patients wen: implanted the plastic tube with the diameter of 2ram. provided with the microsr HDR tr-f92 to the center of itttcrsdda] of tumor by thme-dimentional posiooner Ta*~r was along the long axis of iL There were interstitial impJmtlation of 2U0-4t~OCGY a day wah a total duse of 000-3000 CGY. lltc mdiotheraW lasted for 3-7 days. ReferenCe point distance was 5-2thorn whtcJl was selected based on the tumors size and shape,
According to check C r (potenthdi,~atiun) show: within I month after tNatnxenL tumor completely disapf~ar I [ c&9.,~, part t)f disappear t9 cases. No one of them recurred after 20-72 weeks follow-up study, NO patient has demonstrated neurological dysfunctions ~.au.~-.d by irrsdiatinn. Regular does uea~.'d by HDR 1r-192 interstitial b~chythcmpy of astrocytoma l-It was discussed, and long time w_.aultwas following up..
XECT CEREBRAL BLOOD FLOW AND THE ENDOVASCULAR MANAGEMENT OF CEREBROVASCULAR DISEASE C. Junnrei~ University of Pittsburgh Medical Center, USA Endovascular therapy in the patient with cerebrovascular disease while frequently quite useful has significant risks and therefore shouJd not be used indiscriminantly, Thus, appropriate patient selection is very impodant. To that end knowledge of the physiologic status of the cerebral circulation is essential, and measurement of the cerebral blood flow (CBF) is a very useful parameter in that regard. Patients with skull base tumors or aneurysms may require vessel sacrifice as part of their treatment. A balloon test occlusion (BTO) has been very reliable in predicting those patients at risk for stroke if an internal carotid artery, for example, were to be sacrificed. In patients who have suffered from an acute subarachnoid hemorrhage (SAH) secondary to a ruptured intracranial aneurysm, delayed neurological deficits caused by vascular spasm of the intracranial arteries remains a dread complication. Management includes pharmacological alterations of systemic b)ood pressure in conjunction with other physiological manipulalions. Endovascular intervention via the transarterial route may be required for intracranial angioplasty and/or papaverine administration. The CBF has been a key to management and patient selection in this context. Patients with atherosclerotic vascular disease (ASVD) may present with an acute stroke and require immediate intervention. If thrombolytic therapy is instituted eady enough tissue can be preserved. However, if large areas of extremely low or no CBF are present, then reperfusion of the cerebral paranchyma may be counter productive and detrimental. In patients with chronic vascular disease a number of subgroups can be delineated by measuring their CBFs. Some of these subgroups appear to benefit from flow augmentation procedures such as angioplasty or bypass surgery. Many procedures and therapeutic inlerventions are available to the vascular patient. Understanding the physiology by measuring the CBF is the key to appropriate selection.
LOCAL C02 REACTIVtTY AND AUTOREGULATION OF CERE6RAL BLOOD FLOW Y ShinoharaDept. of Neurology+Tokai UniversitySchoolof Medicine, Isehara, Kanagawa,JAPAN The responsesofcerebral vesselsand cerebralblood flow to changes in arterialcarbon dioxide tension (C02 reactivity) and perfusion pressure {autoregulation)are well known and have been confirmed by numerous experiments and clinical observations over many years. However, there is controversyas tO whetherCO2 reactivityand autoFeguiatoPj abilityare uniform throughoutthe centralnervoussystem. The. purpose of my talk is to discuss wheter there is inhomogeneity in regional cerebral C02 vasoreactivityand autoreguMtooj ability based on published data and our own observations. C02 reactivity: A few reports on regional C02 reactivity in man measuredby using positronemission tomographyor the cold xenon method indicate that regional C02 reactivity in various parts of the brain may be different, but a study in cats show that the larger recjulatoo/responses to C02 may be related to higiler levelsof resting CBF. Our study, which was pen'ormedin monkeys by using the cold xenon method, indicated that C02 responseswere gooclin the basalganglia, frontal cortexand so on. but iow in white matter. The values of CBF increase per lmmli dse in PaC02 divided by the resting CBF value (C02 reactivity/resting CBF) were similar throughout the vadous parts of the brain, suggesting that apparent variation in CO2 reactivity is only related to the differences in microvasculardensity in the brain's various pates. This finding indicates that there is essentially no regional differencein C02 responsein the brain. Autoregulation: It is known that global CBF values are well maintained in the MARP range from 60 to 140 mmllg. provided artedal C02 tension is stable. Our results also showed that a normal autoregulatory ability in various regions of the brain, especiallyin high-blood-flowareasat an MABP of 60 to 80 mmllg was observedin the mdibrain and hypocampus. This "predysautoregulaiotyovershootof CBF" was also observed in rate. This may be a kind of defense mechanism against brain tissue hypoxia, particularly in the Iower-pedusionareas.
The Cilinieal CT Study of Astrocytnma l-l! Treated with f/DR Ir-192
Inter~tiliM Brachytherapy -,li~F'anli, l'ianjin Medical U.i,.,~rshy. P.R.Ch,na.
Sittce Jan 1990, 3O patients with a.lmx;Ttoma I-ll went treated by HDR It'- 192 RemoteAfledoading lntorsdlial Brachytherap.v. The 30 cases(mute 16. tumale14) or ccrehronta were taken the biopsy ~41l,J~Jia,gnosed as astrocytnma I-IL 1he av,:rage age was 46 yeats. The location of them wore showed by c r as. frontal pro1 12. leJnpl9 l0 and paricto 8. PHItlKEy 18 and recurrem i2.
All patients wen: implanted the plastic tube with the diameter of 2ram. provided with the microsr HDR tr-f92 to the center of itttcrsdda] of tumor by thme-dimentional posiooner Ta*~r was along the long axis of iL There were interstitial impJmtlation of 2U0-4t~OCGY a day wah a total duse of 000-3000 CGY. lltc mdiotheraW lasted for 3-7 days. ReferenCe point distance was 5-2thorn whtcJl was selected based on the tumors size and shape,
According to check C r (potenthdi,~atiun) show: within I month after tNatnxenL tumor completely disapf~ar I [ c&9.,~, part t)f disappear t9 cases. No one of them recurred after 20-72 weeks follow-up study, NO patient has demonstrated neurological dysfunctions ~.au.~-.d by irrsdiatinn. Regular does uea~.'d by HDR 1r-192 interstitial b~chythcmpy of astrocytoma l-It was discussed, and long time w_.aultwas following up..