Mean Hemispheric Cerebral Blood Flow Research Articles

Abstract TMP12: Large Vessel Vasculopathy is Associated With Oxygen Metabolic Stress in Children and Young Adults With Sickle Cell Disease

Background: Large-vessel vasculopathy (LVV), such as moyamoya syndrome, increases stroke risk with sickle cell disease (SCD). We hypothesized that tissue-based cerebral blood flow (CBF) and oxygen extraction fraction (OEF), as indicators of hemodynamic and metabolic stress, would differ in hemispheres with vs. without LVV. Methods: Patients underwent serial brain MRI and time-of-flight MRA to quantify voxel-wise CBF, OEF, and infarcts. LVV was defined as 75-99% stenosis of a major anterior circulation artery. Hemispheres with large vessel occlusion or revascularization surgery were excluded. Infarcted voxels were removed. Mean hemispheric (hemi-) CBF, OEF of the anterior circulation were extracted based on a vascular territory template. Hemi- OEF was normalized to whole brain OEF (nOEF). Hemi- cerebral metabolic rate of oxygen utilization (CMRO 2 ) was calculated from arterial oxygen content, hemi- CBF, and hemi- OEF. Mann-Whitney U was used to compare hemispheres with vs. without LVV. Effects of age, hemoglobin, and repeated MRIs were adjusted for in linear mixed model. Results: Of 158 patients, 221 MRI and MRAs were performed. At baseline, LVV occurred in 5% of hemispheres. Median infarct volume was larger in hemispheres with vs. without LVV (6.5 vs. 0.04 mL, p <0.001). In baseline univariate analysis, hemispheres with LVV had lower CBF (25.8 vs 31.3 mL/100g/min, p =0.04), non-significantly higher nOEF (0.99 vs. 0.96, p =0.067), and lower CMRO 2 (8.1 vs. 12.4 mL/100g/min, p =0.002) vs. without LVV. In mixed model, with all MRIs included, LVV was independently associated with nOEF (β = 0.03, p =0.04) and showed a trend for association with CBF (β = -5.4, p =0.09) and CMRO 2 (β = -35.2, p =0.08). Discussion: In SCD, hemispheric OEF was increased as a compensatory response to flow-limiting stenosis, yet may be inadequate to prevent infarction as CMRO 2 decreased. Hemispheric OEF, as an indicator of increased stroke risk, may guide medical management and surgical intervention.

Whole Brain CT Perfusion Evaluation in Transient Ischaemic Attack: A Cross-sectional Study from a Tertiary Care Centre, New Delhi, India

Introduction: Few studies exist in current literature regarding imaging features in Transient Ischaemic Attack (TIA) and most of the previous studies on Computed Tomography Perfusion (CTP) have used old generation scanners with limited brain coverage. Aim: To study the spectrum of whole brain CTP parameters in patients presenting with TIA using a 256 slice CT scanner. Materials and Methods: This cross -sectional observational study was conducted at tertiary care centre in New Delhi, India over a period of 18 months from October 2017 till March 2019. All patients presenting with the first episode of TIA were evaluated with Non Contrast Computed Tomography (NCCT), Whole brain CTP, and Color doppler of carotid vessels. Quantitative assessment and statistical analysis of the alteration of CT perfusion parameters was done in areas of visualized Focal Perfusion Abnormalities (FPA) and seven predefined locations in bilateral hemispheres on perfusion maps. Results: Five out of 15 patients had FPAs in the colour maps and there was a significant elevation of Cerebral Blood Flow (CBF) and Cerebral Blood Volume (CBV) in the FPA region (p-value= 0.018) suggestive of postischaemic hyperperfusion. The mean hemispheric CBF was increased in the abnormal hemisphere compared to the normal hemisphere (p-value=0.04). Conclusion: CTP parameters are significantly altered in the patients with TIA with predominant increase in CBF and CBV in the patients who have FPA on CTP. CTP shows postischaemic hyperperfusion changes in the form of increased CBF in the hemisphere corresponding to the symptoms.

Carotid stenting for unilateral stenosis can increase contralateral hemispheric cerebral blood flow

BackgroundThe revascularization of carotid stenosis can increase ipsilateral cerebral blood flow (CBF). Occasionally, elevated CBF is also evident on the contralateral side, but this phenomenon is poorly understood.ObjectiveTo analyze retrospectively...

Azelnidipine, a long-acting calcium channel blocker, could control hypertension without decreasing cerebral blood flow in post-ischemic stroke patients. A 123I-IMP SPECT follow-up study

Azelnidipine, a long-acting calcium channel blocker, is highly lipid soluble and selective for the vascular wall, and is expected to have an increasing effect on cerebral blood flow (CBF). The aim of this study is to investigate its safety and efficacy in stroke patients in the chronic stage as far as CBF is concerned using N-isopropyl-p-(123)I-iodo amphetamine ((123)I-IMP) single-photon emission computed tomography (SPECT). The patients were orally administered 8 or 16 mg of azelnidipine. Regional CBF was evaluated by (123)I-IMP SPECT using three-dimensional stereotactic region-of-interest (ROI) template (3D-SRT), a technique using anatomical standardization and ROI template consisting of 636 ROIs for the whole brain. Mean hemispheric CBF was defined as the mean value of the corpus callosum, and the precentral, central, parietal, angular and temporal gyri. Mean hemispheric and regional CBF after 1, 3 and 6 months were analyzed using a one-way repeated-measures analysis of variance. Ten post-ischemic stroke patients with hypertension were enrolled between October 2005 and October 2007, and all of them were well controlled with normal blood pressure (before: 172.3+/-16.6/88.4+/-14.0 mm Hg; 6 months: 128.7+/-15.9/70.9+/-10.1 mm Hg). No vascular events were observed during the study period. The mean hemispheric CBF was maintained during the study period (before: 46.0+/-9.7 ml per 100 g per min; 6 months: 49.3+/-11.1 ml per 100 g per min). The regional CBF was also maintained. In the chronic stage of ischemic stroke, azelnidipine could safely decrease systemic blood pressure without decreasing CBF.

Reduced Ipsilateral Hemispheric Cerebral Blood Flow at Admission is Predictive of Vasospasm with Infarction after Aneurysmal Subarachnoid Hemorrhage

Cerebral vasospasm (CV) with infarction causes a significant degree of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). We sought to determine if reduced cerebral blood flow (CBF) on Xenon CT within 48 h of the ictus was predictive of developing CV with infarction. This is a prospective study from 1999 to 2006 of 97 patients with aSAH who underwent Xenon CT within 48 h of their bleed. Demographic, clinical, radiographic, and angiographic parameters were investigated as potential risk factors for the development of CV with infarction. A binary logistic regression analysis was performed to determine the independent predictors of this endpoint. A total of 97 patients with a mean age of 54 +/- 12 years were studied. A total of 78 (80.4%) patients presented with a Fisher grade of 3 and 51 (52.6%) patients with a Hunt Hess score >or=3. CV with infarction was found in 33 (34%) patients. In univariate modeling, younger patients with a Fisher scale of 3 or a reduced ipsilateral mean hemispheric CBF had an association with developing CV with infarction. In binary logistic regression modeling, patients with lower initial hemispheric CBF's were at a significant risk of CV with infarction in the ipsilateral hemisphere. Lower initial CBF at presentation is a risk factor for developing CV with infarction. These findings may help in early prediction of this entity and may have therapeutic implications in the future.

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We performed quantitative measurements of cerebral blood flow (CBF) using 99mTc tracer by the Patlak Plot method with reference to normal aging and cerebrovascular reserve (CVR) capacity and then investigated a new evaluation method of CVR. Aging and decrease of ADL were significantly associated with reduction of the mean hemispheric CBF. In the acetazolamide (ACZ) stress test, these retrospective data showed some overlap in each ischemic grade on the relationship between rCBF and CVR response for the predictability of EC/IC bypass surgery. In these controversial problems, we must reconfirm the principle of cerebral hemodynamic perfusion in SPECT. First, retention tracer is distributed via the microcirculatory system to brain tissue. Second, therefore, we should understand not only the circulation of major vessels, but also the dynamics and rheology in parenchymal microcirculation to determine brain SPECT and CVR capacity. In the next step, we approached the new evaluation method of CVR capacity using 99mTc tracer by a serial dynamic SPECT with a slip-ring rotational gamma camera. These preliminally findings suggest that a serial dynamic SPECT may be more useful for analyzing the pathophysiology on brain circulation and CVR than conventional approaches.

Intra-aortic balloon counterpulsation: augmentation of cerebral blood flow after aneurysmal subarachnoid haemorrhage.

To measure cerebral blood flow before and after intra-aortic balloon counterpulsation (IABC) in patients at high risk of developing delayed cerebral ischaemia after aneurysm surgery following subarachnoid haemorrhage. Six prospectively selected patients at high risk of developing delayed ischaemia had elective IABC after clipping of their cerebral aneurysm(s). The IAB inflates in early diastole and deflates at the end of diastole to increase cardiac perfusion and decrease afterload. This results in enhanced cardiac efficiency. It also augments cerebral blood flow (CBF). We demonstrated a significant increase in the mean hemispheric CBF from the preoperative (preIABC) value of 35.6 mls/100 g/min to 50.9 +/- 12.3 mls/100 g/min (p = 0.0042) as a result of balloon augmentation. Each patient developed a neurological deficit as a result of delayed cerebral ischaemia. These were reversed in 5 patients with increased CBF. There were minimal balloon related complications. IABC consistently enhanced CBF in these patients and resulted in stable cardiovascular parameters. This represents a possible new technique in the management of cerebral ischaemia following subarachnoid haemorrhage and needs further assessment to ascertainlits role.

Prospective and retrospective studies of recovery in aphasia. Changes in cerebral blood flow and language functions.

Prospective and retrospective language evaluations and single photon emission computed tomography (SPECT) scans were performed in order to study the relationship between post-stroke recovery from aphasia and changes in cerebral blood flow (CBF) in groups of patients who had made a good recovery and those who had not. For the prospective study, 20 right-handed patients with aphasia secondary to an acute cerebrovascular accident (CVA) in the left middle cerebral artery territory received language evaluations with a Japanese Standard Language Test of Aphasia (SLTA), and SPECT scans performed twice, at a mean of 3.2 and a mean of 9.2 months post-onset. Only one slice of SPECT data was analysed. A significant correlation was observed between the severity of the initial language deficit and initial CBF on the left side, but not the right. Initial CBF was not a predictor for future language recovery in either hemisphere. There was a correlation between the change in the left mean hemispheric CBF (but not the right) and the change in the overall SLTA severity rating from 3 to 9 months post-stroke. In the retrospective study, 16 right-handed patients with residual aphasia secondary to CVA in the left middle cerebral artery territory received SLTA and SPECT at a mean of 82.8 months post-onset. The patients had also received initial language evaluation with SLTA at a mean of 6.5 months post-onset. In contrast to the prospective study, the results demonstrated that the mean left hemispheric CBF at approximately 7 years post-onset did not differ between good and poor recovery groups. However, the mean right hemispheric CBF of the good recovery group was higher than that of the poor recovery group in the frontal and the thalamic regions, and also in the left frontal region. The results of these complementary studies suggest that the initial language recovery within the first year post-onset may be linked primarily to functional recovery in the dominant hemisphere, where an increase in CBF was observed at 9 months post-onset. The increased perfusion adjacent to the lesion may be crucial for early recovery in aphasia. Subsequent language recovery and the long-term recovery in aphasia may be related to slow and gradual compensatory functions in the contralateral hemisphere, specifically in the homotopic frontal and thalamic areas.

Cerebral haemodynamic effects of dihydroergotamine in patients with severe traumatic brain lesions.

Dihydroergotamine (DHE) is used in our recently introduced therapy of post-traumatic brain oedema and is suggested to reduce ICP through reduction in both cerebral blood volume and brain water content. This study aims at increasing our knowledge of the mechanisms behind the ICP reducing effect of DHE by analysing cerebrovascular effects of a bolus dose of DHE in severely head injured patients (GCS < 8). Mean hemispheric cerebral blood flow (CBF) calculated from the clearance of i.v. 133Xenon, ICP, and cerebral arterio-venous difference in oxygen content (AVDO2), were measured before and after hyperventilation and after a bolus dose of DHE (4 micrograms/kg). The patients were divided into two groups, one with preserved and one with impaired cerebrovascular CO2-reactivity to hyperventilation, the latter being predictive of poor outcome. The haemodynamic effects of DHE were compared to those of hyperventilation. Regional CBF and brain volume SPECT measurements were performed in two patients. DHE increased cerebrovascular resistance (CVR) by about 20% and significantly reduced ICP in both groups of patients, resulting in unchanged AVDO2. Hyperventilation with preserved CO2-reactivity caused a similar decrease in ICP as by DHE but with a much larger increase in CVR (by 70%) and a substantial increase in AVDO2. Hyperventilation with impaired CO2-reactivity reduced ICP but otherwise had no significant cerebrovascular effects. The study supports the concept that the ICP reducing effect of DHE results more from constriction of the large veins than from arterial vasoconstriction, also implying a relatively smaller risk of ischaemia with DHE than with hyperventilation.

Regional cerebral hemodynamics in childhood moyamoya disease

Regional cerebral blood flow (rCBF) and its reactivity to acetazolamide were analyzed in a series of 15 cases of childhood moyamoya disease, using the xenon-133 inhalation method and single photon emission CT (SPECT). Most of the patients had normal mean hemispheric cerebral blood flow (mCBF), comparable to that of age-matched healthy children. However, they had abnormal rCBF distribution and disturbed reactivity to acetazolamide in the territory of the internal carotid artery, especially in the frontal lobe. Surgical revascularization for the anterior circulation, which consisted of STA-MCA anastomosis and indirect synangiosis, dramatically improved these cerebral hemodynamics in the anterior circulation, including the frontal lobe, and reactivity to acetazolamide in the whole brain. These results suggest that surgical revascularization for the anterior circulation should be carried out in order to improve cerebral hemodynamics as widely as possible, especially in the frontal lobe, and may improve cerebral perfusion reserve in the posterior circulation.

Postsurgical observations of mean hemispheric cerebral blood flow with patients receiving high-flow EC-IC bypass using a radial artery graft: (preliminary report, one-year observation of 10 hemispheres)

BACKGROUND When we encounter an inaccessible internal carotid artery lesion, we sacrifice the inaccessible internal carotid artery and, at the same time, establish a high-flow extracranial-to-intracranial arterial bypass (EC-IC bypass). Questions and concerns remain, however, about the dynamics of the patient's cerebral blood flow postoperatively. METHOD Ten hemispheres from 9 patients had received radial artery grafting as an EC-IC bypass with the simultaneous obstruction of the internal carotid artery. Their mean hemispheric cerebral blood flow (mCBF) was measured longitudinally during 1 year after surgery by single photon emission computed tomography (SPECT) and a 133Xenon-inhalation method. RESULTS The serial mCBF values of the five hemispheres with giant aneurysm or paracavernous meningioma were attenuated during the postoperative 3-month period and then returned to the normal range. In only one case did the postoperative reduction of mCBF fail to return to normal; in addition there was a memory disturbance that had developed and progressed. Five hemispheres with the ICA stenosis did not present reduction in mCBF. In three out of five hemispheres, transient elevation of mCBF at 1 month after surgery was observed. CONCLUSIONS We conclude from our study that the internal carotid artery can be safely substituted by the radial artery graft from the view point of cerebral blood flow.

Unaltered cerebral blood flow during hypoglycemic activation of the sympathochromaffin system in humans

To determine if increases in plasma epinephrine and norepinephrine caused by hypoglycemia are associated with increments in cerebral blood flow (CBF), we measured CBF with positron emission tomography in normal humans at ambient fasting arterial plasma glucose levels and at clamped plasma glucose levels of 5.3, 3.5, and 2.8 mmol/l using the hyperinsulinemic, stepped hypoglycemic clamp technique. Despite significant increases in plasma epinephrine to 7,340 +/- 350 (SE) pmol/l and in plasma norepinephrine to 3.32 +/- 0.35 nmol/l, mean hemispheric CBF (41 +/- 1, 49 +/- 1, 48 +/- 2, and 51 +/- 3 ml x 100 g-1 x min-1) remained constant at the ambient (5.2), 5.3, 3.5, and 2.8 mmol/l glycemic levels, respectively. Furthermore, there was no correlation between CBF and either plasma epinephrine levels ranging from 160 to 10,580 pmol/l or plasma norepinephrine levels ranging from 0.56 to 5.10 nmol/l. Failure to demonstrate any dose-response relationship between plasma catecholamine levels and CBF argues against their primary role in cerebrovascular control during hypoglycemia.

A porcine model for sequential assessments of cerebral haemodynamics and metabolism.

We present a physiologically stable porcine model designed for sequential assessments of pharmacological effects on mean hemispheric cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) at sustained normocapnia. The dynamic influence of continuously administered fentanyl (0.040 mg.kg-1.h-1 i.v.), nitrous oxide (70%) and pancuronium (0.30 mg.kg-1.h-1 i.v.) on these variables was studied in eight normoventilated pigs. CBF was reliably assessable at 10-min intervals by clearance of intra-arterially injected 133Xe, monitored by an extracranial scintillation detector. CMRO2 was calculated from CBF and the simultaneously measured cerebral arteriovenous difference in blood oxygen content. The intracerebral distribution of a contrast medium injected into the external and internal carotid arteries was studied by angiography, and the cerebral venous outflow was investigated by measurements of the distribution of an intra-arterially administered non-diffusible tracer, [99mTc]pertechnetate, to the internal and external jugular veins. After a 3-h equilibration period, CBF and CMRO2 were determined on six occasions over a study period lasting 1 h 40 min. The mean ranges of these variables were 56-60 and 1.9-2.0 ml.100 g-1.min-1, respectively. We conclude that the model enables repeated assessments of CBF and CMRO2 under stable physiological background conditions and thus valid cerebral pharmacodynamic investigations of drugs given for anaesthesia.

Cerebral blood flow autoregulation in experimental subarachnoid haemorrhage in rat.

Haemodynamic instability is of great importance in clinical management of patients with subarachnoid haemorrhage (SAH). The significance of angiographically demonstrable vasospasm for disturbances of cerebral blood flow (CBF) and cerebral autoregulation has not yet been clarified. The present study was designed to describe disturbances of cerebral autoregulation during the timecourse of experimental SAH (eSAH) in rats. A second aim of the study was to relate the results to a reported timecourse of angiographic vasospasm in the same animal model. Previous studies have shown that the timecourse of angiographically visible vasospasm in eSAH is biphasic with maximal spasm at 10 min and 2 days after induction of eSAH. At 5 days, the vasospasms have resolved. CBF was measured using a 133-Xenon intracarotid injection method which allowed serial measurements of mean hemispheric CBF during controlled manipulations of arterial blood pressure. In this way, an autoregulation curve could be constructed. The present study shows that autoregulation is severely disturbed or even totally absent at 2 and 5 days after eSAH. Thus there seems to be no direct correlation between presence of angiographic vasospasm and impairment of autoregulation, or that the impairment of autoregulation is more protracted than the presence of cerebral vasospasm, presuming a correlation exist.

Cerebral blood flow and plasma volume during hyperglycemia in the conscious rat

Cerebral blood flow (CBF) and cerebral plasma volume (CPV) were measured under steady-state hyperglycemic conditions in the hemispheres and brainstem-cerebellum of conscious rats. There groups of hyperglycemic animals each having a different level of plasma glucose concentration, 25, 33.3, 44.4 mmol/l, and a normoglycemic control group were studied. CBF was not affected at the hyperglycemic levels of 25 and 33.3 mmol/l. Mean hemispheric and brainstem-cerebellum CBF values appeared lower than in controls at the highest glycemic level although the differences were not statistically significant. CPV was found to be unchanged at the hyperglycemic level of 25 mmol/l, while it was found to be increased in the hemispheres of the animals whose plasma glucose concentration had been elevated to 33.3 and 44.4 mmol/l. The results of the study do not support the claim that hyperglycemia may enhance ischemic brain injury by reducing CBF.

Xenon-enhanced Computed Tomographic Measurement of Cerebral Blood Flow in Patients with Chronic Subdural Hematomas

Abstract We compared clinical symptoms with extent of brain shift on computed tomographic (CT) scans and quantitative and three-dimensional measurements of cerebral blood flow (CBF) on xenon-enhanced CT scans in 10 patients with chronic subdural hematomas. Five patients had only headache and minimal or no brain shift on a CT scan. The other five had hemiparesis and/or mental disturbance in addition to headache and moderate or severe brain shift on a CT scan. The mean hemispheric CBF decreased about 7% in patients with headache and about 35% in patients with hemiparesis and/or mental disturbance. It decreased also on the side without the hematoma. The CBF reduction was always more pronounced in the putamen and thalamus than in the cortex. On the contrary, the cortex CBF was mostly preserved or even elevated in both groups of patients. We speculate that CBF reduction in patients with a chronic subdural hematoma occurs initially in central cerebral areas like the basal ganglia and thalamus, and then extends to the entire hemisphere including the cortex as brain compression and displacement progress. Central cerebral area involvement might be more responsible for clinical symptoms than the cortex.

Xenon-enhanced computed tomographic measurement of cerebral blood flow in patients with chronic subdural hematomas

We compared clinical symptoms with extent of brain shift on computed tomographic (CT) scans and quantitative and three-dimensional measurements of cerebral blood flow (CBF) on xenon-enhanced CT scans in 10 patients with chronic subdural hematomas. Five patients had only headache and minimal or no brain shift on a CT scan. The other five had hemiparesis and/or mental disturbance in addition to headache and moderate or severe brain shift on a CT scan. The mean hemispheric CBF decreased about 7% in patients with headache and about 35% in patients with hemiparesis and/or mental disturbance. It decreased also on the side without the hematoma. The CBF reduction was always more pronounced in the putamen and thalamus than in the cortex. On the contrary, the cortex CBF was mostly preserved or even elevated in both groups of patients. We speculate that CBF reduction in patients with a chronic subdural hematoma occurs initially in central cerebral areas like the basal ganglia and thalamus, and then extends to the entire hemisphere including the cortex as brain compression and displacement progress. Central cerebral area involvement might be more responsible for clinical symptoms than the cortex.

Regional Cerebral Blood Flow in Patients with Affective Disorders

Regional cerebral blood flow at rest was measured in 38 patients with major depressive disorders and 16 controls by SPECT with inhalation of xenon-133. All subjects had been withdrawn from medication. The mean hemispheric cerebral blood flow was not statistically different between the controls and the different subgroups of depressed patients defined either by biological markers or clinical characteristics. However, the predominantly cortical blood flow, measured on the outer cerebral rim of the third tomographic slice, was significantly lower on the left hemisphere in bipolar patients when compared with normals and unipolar patients. The same lateralisation was observed in patients with an endogenous depression according to the Newcastle scale.

Hemodynamic Evaluation of Vascular Reconstructive Surgery for Childhood Moyamoya Disease Using Single Photon Emission Computed Tomography

To evaluate the efficacy of vascular reconstructive surgery for childhood moyamoya disease, the cerebral blood flow (CBF) in 31 hemispheres of 16 patients was examined by single photon emission computed tomography (SPECT) using the 133Xe inhalation method. Results were divided into two groups; 17 hemispheres with superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis [A(+) group] and 14 hemispheres without anastomosis [A(-) group]. The mean hemispheric CBF (mCBF) and regional CBF (rCBF) in the frontal, temporal, occipital, and basal ganglia regions were calculated. Pre- and postoperative SPECT on the 10 hemispheres of the A(+) group showed an increase in mCBF in 6 hemispheres, the disappearance of the low perfusion area (LPA) in all 5 hemispheres where LPA was present before surgery, and an improvement in rCBF distribution (an increase in rCBF in the frontal and temporal lobes and a decrease in the basal ganglia). This suggests that vascular reconstruction is greatly effective in treating this disease. A comparison between the A(+) group and the A(-) group by postoperative SPECT, as well as the clinical outcomes and the postoperative findings of electroencephalography and angiography, revealed that the A(+) group was superior to the A(-) group in the frequency of LPA (12% and 43%, respectively) and rCBF in the frontal region where STA-MCA anastomosis was usually performed. These results indicate that STA-MCA anastomosis with indirect synangiosis is the most effective treatment of childhood moyamoya disease.

Cerebral Blood Flow in Patients with Putaminal Hemorrhage after Stereotactic Aspiration or Conservative Treatment

Changes in cerebral blood flow (CBF) were measured and compared in 40 patients with putaminal hemorrhage who underwent either stereotactic hematoma aspiration or conservative treatment. There were no statistically significant differences in mean CBF or hemispheric CBF between the two treatment groups. Although there are claims of the superiority of surgery from the standpoint of integrated cortical function following mild putaminal hemorrhage, the results of this investigation indicate that conservative therapy is adequate in such cases, based on improvement in CBF.