Differentiation between transient ischemic attack and ischemic stroke within the first six hours after onset of symptoms by using 99mTc-ECD-SPECT

The aim of this study was to define the accuracy of 99mTc-ethyl cysteinate dimer-single photon emission computed tomography (99mTc-ECD-SPECT) in distinguishing transient ischemic attack from completed ischemic stroke at early stages after the onset of symptoms. In a prospective study we examined 82 patients within 6 hours after the onset of symptoms (neurologic deficit caused by middle cerebral artery ischemia) using both 99mTc-ECD-SPECT and computed tomography (CT). The follow-up was based on Scandinavian Stroke Scale (SSS) 24 hours and 5-7 days, as well as on CT 7 days, after the event. SPECT evaluation was performed both visually and using semiquantitative region-of-interest (ROI) analysis. According to visual SPECT analysis, on admission 59 of 82 patients had activity deficits in the symptomatic hemisphere. After 7 days, all these patients had neurologic symptoms (SSS 28 +/- 12 points), caused by a cerebral infarction as evidenced with CT. Twenty-three of 82 patients displayed no early activity deficit despite clinical symptoms. None of these patients had neurologic symptoms after 7 days (indicating transient ischemic attack or prolonged reversible ischemic neurologic deficit). In the semiquantitative SPECT analysis, all patients had abnormal count densities in the respective ROI (activity < 90% compared with the contralateral side). All patients with transient ischemia (n = 23) had count rate densities more than 70% of the respective contralateral ROI, whereas all patients with subsequent infarction (n = 59) had values < 70%. Use of 99mTc-ECD-SPECT allows transient ischemia to be distinguished from ischemic infarction using relative regional activity thresholds within the first 6 hours after onset of symptoms.     

Vitamin D-retinoid association: molecular basis and clinical applications

BACKGROUND AND PURPOSE: The role of single-photon emission CT (SPECT) in the prognosis of cerebral infarction is controversial, but most studies report that SPECT using a variety of radiopharmaceutical agents gives useful prognostic information. Only one study has questioned whether acute perfusion deficits independently add to a valid clinical prognostic score. This study was limited to middle cerebral artery territory infarcts and was negative. We present data on the prognostic utility of SPECT using 99mTc-hexamethylpropyleneamine oxime (HMPAO) in cerebral infarction, unselected by site. METHODS: Fifty consecutive unselected patients admitted to the hospital with acute cerebral infarction, of whom 10 died and 7 withdrew, had SPECT performed serially at onset and at 1 week and 3 months after stroke onset using 99mTc-HMPAO and the NOVO 810 dedicated high-resolution head tomograph. Clinical severity at presentation and outcome was measured with the Canadian Neurological Scale and the Barthel Index. Infarct volumes were measured from both the SPECT and CT scans. The data for the 43 subjects who completed the study or died were evaluated to determine the most powerful prognostic measures. Predictors were the Canadian Neurological Scale score at onset and 1 week, the Barthel Index at 1 week, the CT infarct volume typically done between 3 and 7 days after stroke onset, and the infarct volumes at the first and second SPECT. Outcome measures were the Canadian Neurological Scale score and Barthel Index score at 3 months, scored as zero for those patients who died. RESULTS: The clinical prognostic indicators correlated with the outcome measures, with coefficients between .617 and .821 (P < .0006 in all cases). The Canadian Neurological Scale score measured at 1 week was the best of these. Infarct volumes measured from SPECT correlated less well (coefficients between -.518 and -.683, P < .0019 in all cases). CT infarct volume was the poorest predictor. Although SPECT infarct volumes predicted outcome, they did so less well than clinical examination. Spontaneous infarct reperfusion did not affect outcome. CONCLUSIONS: Although the measurement of infarct volume on SPECT using 99mTc-HMPAO provides a predictor of stroke outcome, it is not a better predictor than the Canadian Neurological Scale score.     

Monitoring aortic root effluent during retrograde cardioplegia delivery

Early signs of brain infarction can be detected by modern CCT technology even within the first 6 h after stroke. Little is known about the prognostic significance of early infarction signs in CCT. We prospectively evaluated clinical and CCT findings of 95 consecutive patients with an acute ischemia in the territory of the middle cerebral artery. All patients were admitted to our stroke unit within 6 h after stroke. In 55 patients CCT was performed within 3 h, and in 40 cases between 3 and 6 h. In all patients the clinical findings were assessed by the Scandinavian Stroke Scale (SSS). The disability due to stroke was evaluated after 4 weeks by use of the modified Rankin Scale. We could demonstrate the following early signs of cerebral infarction: focal hypodensity (23.2%), obscuration of basal ganglia (12.6%), focal brain swelling (22.1%), hyperdense middle cerebral artery sign (HMCA; 11.5%). In 3 patients early edema led to ventricular compression, in 1 patient to midline shift. The occurrence of early infarction signs did not depend on the etiology of ischemia but was significantly associated with a severe neurological deficit at admission and an unfavourable disability status 4 weeks after stroke. Focal brain swelling and HMCA were often followed by extensive infarction lesions on the follow-up CCT. In conclusion, early signs of hemispheric brain infarction visible on CCT scans performed within 6 h after stroke are correlated with severe stroke and an unfavourable functional outcome. However, a substantial part of our patients had a benign course of the disease in spite of early CCT pathology. Decisions on therapy in individual patients therefore should not depend on early CCT findings exclusively.     

Early clinical and radiological predictors of fatal brain swelling in ischemic stroke

BACKGROUND AND PURPOSE: Early identification of acute stroke patients at risk of fatal brain swelling is necessary to facilitate implementation of aggressive therapies. Initial clinical, laboratory, and CT characteristics that may be used as selection criteria were analyzed to determine predictors of herniation and neurological death. METHODS: Data from the placebo arm of the Lubeluzole-International-9 trial were reviewed to identify patients with fatal brain edema. Early clinical, laboratory, and radiographic parameters were evaluated in a case-control design. Initial CT scans were analyzed for early ischemic abnormalities by 2 blinded investigators. RESULTS: Twenty-three patients died from brain swelling, with minimum baseline National Institutes of Health Stroke Scale (NIHSS) scores of 20 (n=12; mean, 23.2+/-1.8) with left and 15 (n=11; mean, 17.6+/-2.2) with right hemispheric infarctions (P=0. 0001). A sample of 112 subjects with comparably severe strokes, but who did not die from brain swelling, was selected from the remaining population according to the same NIHSS scores. Among clinical and laboratory characteristics, nausea/vomiting within 24 hours after onset (odds ratio [OR], 5.1; 95% CI, 1.7 to 15.3; P=0.003) and 12-hour systolic blood pressure >/=180 mm Hg (OR, 4.2; 95% CI, 1.4 to 12.9; P=0.01) were independently associated with fatal brain swelling. Among radiographic factors, only hypodensity of >50% of the middle cerebral artery territory on initial CT scan was an independent predictor (OR, 6.1; 95% CI, 2.3 to 16.6; P=0.0004). CONCLUSIONS: Patients with baseline NIHSS score >/=20 with left or >/=15 with right hemispheric infarctions within 6 hours of symptom onset who also have nausea/vomiting or >50% middle cerebral artery territory hypodensity are at high risk for developing fatal brain swelling.     

Thrombolytic therapy in ischemic infarct

Thrombolytic therapy in acute ischemic stroke is safe and effective in a defined subgroup of stroke patients. Until now, different fibrinolytic substances including urokinase, streptokinase and recombinant tissue plasminogen activator (rt-PA) have been tested regarding safety, efficacy, dosage and economic parameters in patients suffering from both carotid and basilar artery territory strokes. Recently, two large multicenter placebo-controlled intravenous rt-PA studies were published. The results show that thrombolysis of acute carotid territory strokes (European Cooperative Acute Stroke Study) and of strokes with a deficit measurable on the NIH Stroke Scale (National Institute of Neurological Disorders and Stroke rt-PA Stroke Study) improves clinical and economic outcome parameters in patients who were treated within 6 hours of the onset of symptoms and had that no signs of extended early infarction on the initial CT-scan. The occurrence of intracranial hemorrhages is more frequent after thombolytic therapy, but the majority of bleeding complications referred to petechial or more confluent hemorrhage limited to the infarcted tissue, without clinical deterioration. However, the identification of the appropriate patients is difficult and depends on the level of clinical and diagnostic experience. In vertebrobasilar artery territory stroke, local intraarterial thrombolysis with urokinase or streptokinase is performed in most cases. Thrombolytic treatment within twelve hours of the onset of symptoms was associated with significantly better results concerning both survival and neurological recovery.     

Single-photon emission-computed tomography in the diagnosis of cerebrovascular diseases

BACKGROUND: SPECT-HM-PAO allows to detect the regional cerebral blood flow and total diminution of the brain perfusion still before morphological substrate evolution in CT scan, without invasive technologies. SEARCH GOAL: The authors have analyzed data obtained by SPECT-99mTc HM-PAO in the group of 46 patients suffering from cerebrovascular disorders and they have compared them with results aimed by CT scans. Both, the SPECT-99mTc HM-PAO and CT scan were performed within 48 hours or later after the onset of the stroke; some of CT scans were repeatedly performed. RESULTS: They discovered 40 positive and 6 negative SPECT-HM-PAO findings, 26 positive and 20 negative CT scans. SPECT investigation more frequently discovers circulatory failures in the clinically altered hemisphere than the CT scan does in a substrate; SPECT discloses hypoperfusion of the clinically unaltered hemisphere if silent hypoperfusion is present. The ipsilateral foci of CT substrates were significantly less frequently observed (p < 0.001) than some ipsilateral regional hypoperfusions. Not only the number, but also size and extent of hypoperfusional foci searched by SPECT are significantly higher and wider than the numbers and dimensions of substrates observed by CT (p < 0.001). CONCLUSION: CT scan diagnostic possibilities are restricted by the time factor (CT examinations performed within 48 hours since the onset of the stroke are significantly less frequently positive than those performed later-p < 0.001). SPECT examination has not such a limiting time factor (p > 0.05). MEANING: Hence SPECT-HM-PAO renders early, long lasting and wide information on the restriction of the overall and regional perfusion, independently of the fact as to whether the reduction of cerebral perfusion is, or is not going to result in ischemic necrosis and/or ischemic sclerosis. SPECT renders correlation of the perfusion disorder earlier, wider in space, and more frequently than the CT scan, and therefore it is a prerequisite to the disclosure of the mentioned silent focal blood flow reductions. (Graph 12, Fig. 3, Ref. 4.)     

99mTc-HMPAO SPECT of the brain in mild to moderate traumatic brain injury patients: compared with CT--a prospective study

Single photon emission computed tomography (SPECT) with Technetium-99m hexamethyl propylenamine oxime (Tc-99m-HMPAO) was used in 20 patients with mild to moderate traumatic brain injury (TBI) to evaluate the effects of brain trauma on regional cerebral blood flow (rCBF). SPECT scan was compared with CT scan in 16 patients. SPECT showed intraparenchymal differences in rCBF more often than lesions diagnosed with CT scans (87.5% vs. 37.5%). In five of six patients with lesions in both modalities, the area of involvement was relatively larger on SPECT scans than on CT scans. Contrecoup changes were seen in five patients on SPECT alone, two patients with CT alone and one patient had contrecoup lesions on CT and SPECT. Of the eight patients (50%) with skull fractures, seven (43.7%) had rCBF findings on SPECT scan and five (31.3%) demonstrated decrease in rCBF in brain underlying the fracture. All these patients with fractures had normal brain on CT scans. Conversely, extra-axial lesions and fractures evident on CT did not visualize on SPECT, but SPECT demonstrated associated changes in rCBF. Although there is still lack of clinical and pathological correlation, SPECT appears to be a promising method for a more sensitive evaluation of axial lesions in patients with mild to moderate TBI.     

A case of meningioma with non-accumulation of 99mTc-ECD and increased accumulation of 99mTc-HMPAO in the tumor]

99mTc-ECD SPECT and 99mTc-HMPAO SPECT with or without Matas test were performed in a 62-year-old woman with meningioma in the left anterior cranial fossa. After injection of 740 MBq 99mTc-ECD or HMPAO, 64 projection images were collected with a rotating Gamma camera. Matas test was carried out by compressing the left common carotid artery for about one minute immediately after RI injection. Although 99mTc-ECD SPECT showed non-accumulation in the tumor, 99mTc-HMPAO SPECT demonstrated increased accumulation in it. This area of increased accumulation disappeared on 99mTc-HMPAO SPECT with Matas test which causes decrease in blood flow of the tumor. These findings suggest 99mTc-ECD and 99mTc-HMPAO have a different mechanisms of accumulation in the meningioma.     

Rabbit and human atherosclerotic lesions contain IgG that recognizes epitopes of oxidized LDL

In the management of major cerebral artery obstruction, cerebral perfusion reserve is key to introducing cerebral revascularization surgery. The purpose of this study was to evaluate the feasibility of assessing cerebral perfusion reserve by consecutive 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) SPECT with 5% carbon dioxide (CO2) inhalation. METHODS: The CO2 inhalation and consecutive 99mTc-HMPAO SPECT study was performed on 30 chronic ischemic cerebrovascular disease patients with unilateral major cerebral artery obstruction and on 27 patients without. CO2 reactivity was expressed as the percent increase of 99mTc-HMPAO accumulation from the baseline (%Change) and as a constant k' that was the ratio of 99mTc-HMPAO accumulation per 1 mmHg change of end-tidal CO2 tension by exponential curve fitting. RESULTS: The mean %Change and k' in the middle cerebral artery (MCA) territory on the side without an obstructive lesion or in the cerebellum ranged from 10.0% to 11.1% and from 0.98% to 1.13% per mmHg, respectively. In the MCA territory, an obstructive lesion was noted in 5.9% versus 0.54% per mmHg in the contralateral MCA territory (p < 0.01). Eleven of 30 patients with major cerebral artery obstruction revealed significant asymmetry in the k' value between bilateral MCA territories. CONCLUSION: The results showed compromised cerebral perfusion reserve in the obstructed major cerebral artery territory. The present method was proven clinically useful for evaluating cerebral perfusion reserve in patients with unilateral major cerebral artery obstruction.     

Acetazolamide challenge and technetium-99m-ECD versus iodine-123-IMP SPECT in chronic occlusive cerebrovascular disease

We compared the acetazolamide challenge test using 99mTc-ECD SPECT and 123I-IMP SPECT images in patients with chronic occlusive cerebrovascular disease. We also evaluated the usefulness of linearization correction for acetazolamide challenge test of 99mTc-ECD SPECT. METHODS: Twenty patients with unilateral chronic occlusive cerebrovascular disease (10 patients had middle cerebral arterial lesion and 10 had internal carotid lesion) were included in the study. Split-dose (a dose fractioning was 1:2), and sequential SPECT technique was used for 99mTc-ECD SPECT studies while only acetazolamide challenge test studies for 123I-IMP SPECT were performed. Permeability surface area product model (PS model) and back-diffusion model (Lassen's correction) were used for linearization correction of acetazolamide challenge with 99mTc-ECD SPECT. RESULTS: Six of 16 patients with reduced vasodilatory capacity in 123I-IMP SPECT were underestimated by 99mTc-ECD SPECT acetazolamide challenge test. Relative ECD uptake normalized by cerebellar uptake compared with IMP uptake showed a nonlinear relationship, indicating relatively less uptake in high flow range. The underestimations of limited vasodilatory capacity observed in 99mTc-ECD SPECT without linearization correction was modified by linearization algorithm. However, the effect of correction based on PS model was superior than that of Lassen's correction. The corrected 99mTc-ECD uptake ratio, based on PS model, and IMP uptake ratio demonstrated a better linear relationship than that of Lassen's correction. CONCLUSION: Technetium-99m ECD SPECT corrected based on the PS model is a better method of linearization for evaluating cerebrovascular reserve using acetazolamide challenge.     

Does arterial recanalization improve outcome in carotid territory stroke?

BACKGROUND AND PURPOSE: We sought to determine whether early (< 8 hours) or delayed (8 to 24 hours) recanalization after stroke may be an independent variable in the improvement of clinical outcome in patients with occlusion of the middle cerebral artery. METHODS: We prospectively studied 77 patients by combined Scandinavian Stroke Scale score at admission, repeated computed tomography and angiography before and after thrombolytic treatment at < 8 hours after stroke onset, and transcranial Doppler ultrasound 24 hours later. We tested an association between clinical and neuroradiological baseline characteristics, recanalization, and outcome as assessed by the modified Rankin Scale 4 weeks after stroke and determined the effect of recanalization on mortality and good outcome (Rankin Scale grades 0 to 3) by multiple logistic regression analyses. RESULTS: Recanalization rates at 8 and 24 hours after stroke correlated with sites of occlusion (middle cerebral artery branch, 73% and 73%, trunk, 27% and 38%, respectively; intracranial internal carotid artery bifurcation, 14% and 14%; P = .002), collaterals (good, 43% and 51%, respectively; scarce, 17% and 19%, respectively; P = .01), and Scandinavian Stroke Scale score at admission (P = .002). Six of 6 patients with delayed recanalization had good outcomes. Recanalization at < 8 hours after symptom onset had no independent predictive value for good outcome (P = .69). Recanalization at 24 hours increased the proportion of good outcomes from 23% to 75% in a subgroup of patients. Recanalization did not independently affect mortality (P > .15). CONCLUSIONS: Even if delayed, arterial recanalization may improve clinical outcome in a subgroup of patients with middle cerebral artery occlusion.     

Asymptomatic cerebral infarctions in patients with ischemic stroke

We studied 383 consecutive patients with stroke and ischemic lesions on CT scan for the presence of symptomatic cerebral infarction (SCI) and asymptomatic cerebral infarction (ACI). We evaluated risk factors as well as volume, site and number of the lesions. ACIs occurred in 34% of the cases (130/383); 88% of ACIs were lacunes and internal borderzone infarctions, with a volume of less than 2 ml. Larger infarctions were asymptomatic in 27 patients (20.8%); 114 (68.7%) out of 166 patients with two or more SCIs (68.7%) had one or more ACIs. Infarctions in the lateral middle cerebral artery (MCA) territory were SCIs, in the medial MCA territory ACIs. Independent risk factors for ACI were age above 70 years and smoking; cardioembolism prevailed in SCI, small vessel disease in ACI; high levels of disability prevailed in SCIs.     

Rat bone marrow-derived mast cells co-cultured with 3T3 fibroblasts in the absence of T-cell derived cytokines require stem cell factor for their survival and maintain their mucosal mast cell-like phenotype

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7%) and statistically similar specificity (63.8 and 81.8%, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100%) was statistically superior to CT (69%). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.     

Failure to identify cerebral infarct mechanisms from topography of vascular territory lesions

PURPOSE: Our purpose was to determine whether topographic patterns of ischemic damage seen on brain imaging studies are useful for evaluating different mechanisms of infarction and for distinguishing embolic from hemodynamic disorders. METHODS: Early CT scans were reviewed to identify brain infarctions in the middle cerebral artery territory in 800 patients with either significant obstructive lesions of the internal carotid artery (70% stenosis, n = 17; occlusion, n = 85) or nonvalvular atrial fibrillation (n = 186) as the only identified source of stroke. Ninety-nine CT studies were considered suitable for entry into the final analysis. The scans were digitized and superimposed on postmortem brain sections by matching algorithms to display the variability of the cerebrovascular territories. RESULTS: Cortical borderzone-type infarctions were rare and evenly distributed among patients with cardiac sources of embolism (3.2%) and severe carotid obstructions (3.6%). In contrast, subcortical borderzone infarcts occurred significantly more often in patients with carotid obstructive disease (36% versus 16%). However, on computerized segmentation analysis, the topography of infarction was the same in both groups. CONCLUSION: The current concept that stroke mechanisms can be inferred from interpretation of stroke patterns on brain scans is heavily confounded by the variability in intracranial arterial territory distributions. Since individual arterial territories cannot be identified in vivo, interpretation of stroke topography is invalidated. In particular, the cortical wedge-type of borderzone infarction, said to result from hemodynamic compromise in low-flow perfusion territories, is an ambiguous observation and may be seen in patients with cerebral embolism and hemodynamic compromise due to severe carotid disease.     

Persisting perfusion defect in transient ischemic attacks: a new clinically useful subgroup?

BACKGROUND AND PURPOSE: Cerebral infarction and prolonged regional hypoperfusion have been described in patients with transient ischemic attacks (TIAs). The aim of this study was to compare the sensitivity of single-photon emission CT (SPECT) with that of brain CT and to evaluate the clinical significance of differentiation of TIA patients with or without focal hypoperfusion. METHODS: From a hospital-based population, we studied the SPECT and CT findings in 76 consecutive patients, without a stroke history, who presented with TIA in the carotid artery territory. The recorded variables were the time of SPECT, imaging (<36 or > or = 36 hours), clinical presentation, history of previous TIA(s), duration of the presenting attack (<2 or > or = 2 hours), vascular risk factors, and etiology. We used both visual and semiquantitative analyses for the SPECT evaluation. Acetazolamide challenge was not performed. RESULTS: The overall SPECT sensitivity was 36% (27/76). When brain CT and SPECT were performed in the same patients, the SPECT sensitivity was significantly higher than that of CT (19/59 [32%] versus 8/59 [14%]; P=.007). The SPECT sensitivity was not dependent on the time of investigation, duration of attacks, history of TIA(s), or the clinical presentation. The vascular risk and etiologic factors were not significantly different between the patients with or without prolonged focal hypoperfusion. Logistic regression did not identify any variable to discriminate the two groups. CONCLUSIONS: Despite its better sensitivity compared with CT, SPECT performed without the acetazolamide test provides no additional clinically useful information on the vascular risk factors and etiology in TIA patients.     

Repeated application of carvone-induced bacteria to enhance biodegradation of polychlorinated biphenyls in soil

OBJECTIVE: To determine the correlation between metabolite concentrations and clinical outcome during the acute or subacute phase of ischemic stroke by using single-voxel localized proton magnetic resonance spectroscopy (1H-MRS). SETTING: A university hospital neurologic department. PATIENTS AND METHODS: Combined single-voxel 1H-MRS and magnetic resonance imaging were performed on 26 patients with a recent ischemic stroke (on 8 patients during the first 24 hours after the stroke and on 18 during the first week). For all patients, the signals from N-acetylaspartate, choline-containing compounds, and creatine-phosphocreatine were compared with those on the contralateral side as peak area ratios. The data for 1H-MRS were related to scores on the Scandinavian Stroke Scale and the Barthel Index at a 6-month clinical follow-up. RESULTS: The signals from N-acetylaspartate, choline-containing compounds, and creatine-phosphocreatine were significantly reduced in all infarcted areas (P<.001, P<.001, and P=.003, respectively, Wilcoxon signed rank test). A lactate signal was present in 19 patients. The statistical analysis showed a significant positive correlation between N-acetylaspartate signals and Scandinavian Stroke Scale scores and between reduction of N-acetylaspartate signals and Barthel Index scores (Spearman rank correlation test). Patients in whom lactate was present had Scandinavian Stroke Scale scores significantly lower than patients in the group without lactate (Mann-Whitney U test). CONCLUSION: Single-voxel 1H-MRS performed during the acute or subacute phase of ischemic stroke may provide prognostic information.     

Effects of injection rates of contrast material on arterial phase hepatic CT

PURPOSE: The aim of our study was twofold: to determine the frequency and magnitude of perfusion defect in stroke patients who qualify for rtPA therapy within 3 hours of stroke onset and to determine the ability of rtPA to improve perfusion by 24 hours. SUBJECTS AND METHODS: Patients with suspected hemispheric stroke who fulfilled entry criteria into the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Study and also had pretreatment injection of (99m)Tc-HMPAO, with single-photon emission computed tomography (SPECT) performed using a triple-head camera at baseline and 24 hours, were included. RESULTS: All 12 patients who qualified for rtPA therapy had perfusion defects on baseline SPECT (SPECT graded scale [SGS] score range, 16 to 79). Mean+/-SD perfusion defect was comparable in rtPA (n=4)versus placebo (n=5) groups (SGS score, 36+/-18 versus 39+/-12; NS) despite earlier injection time in the rtPA group (98+/-24 versus 141+/-21 minutes; P=.02). Total SPECT scanning time was 20 to 25 minutes. At 24 hours, reperfusion was greater in rtPA patients compared with the placebo group (SGS score, 7+/-9 versus 29+/-17; P=.05), with relative improvement in the region-of-interest scores of 87+/-16% after rtPA compared with 28+/-30% with placebo (P=.01). CONCLUSIONS: A substantial perfusion defect exists in stroke patients with larger hemispheric infarcts who meet NINDS criteria for rtPA therapy, and rtPA is better able than placebo to rectify this defect. SPECT is feasible for clinical trials and should be evaluated as a substituted end point in stroke therapeutic trials.     

Safety of anticoagulation after hemorrhagic infarction

Cerebral hemorrhagic infarction visualized on CT, secondary to embolic stroke in an anticoagulated individual, is usually associated with clinically stable or improving neurologic signs; fear of transforming the hemorrhagic infarction into a hematoma, however, usually prompts cessation of anticoagulation until the blood has cleared on CT, despite the recognized risk of recurrent embolism during this non-anticoagulated period. We now report our experience with 12 patients with hemorrhagic infarction who remained anticoagulated. Eleven men and one woman, ages 33 to 77, developed hemorrhagic infarction while on heparin, warfarin, or both, for prevention of recurrent embolism. Patients were either continued on uninterrupted anticoagulation from stroke onset (n = 6), or anticoagulation was withheld for several days and then resumed (n = 4), or it was withheld for 5 and 14 days (n = 2) after stroke onset and then continued uninterrupted despite the CT appearance of hemorrhagic infarction. Eleven patients had a definite cardioembolic source for stroke (atrial fibrillation, seven; ventricular thrombus, two; and ventricular dyskinesia, two). One patient had carotid occlusion with local intra-arterial embolism. Hemorrhagic infarcts varied in size and were located in the middle cerebral artery territory in 11 patients and posterior cerebral artery territory in one. All patients remained clinically stable or improved on anticoagulation. Serial CTs showed fading hemorrhagic areas. When the risk of recurrent embolism is high, anticoagulation may be safely used in some patients with hemorrhagic infarction.     

Intra-individual differences between technetium-99m-HMPAO and technetium-99m-ECD in the normal medial temporal lobe

Regional distributions of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) and 99mTc-ethyl cysteinate dimer (99mTc-ECD) were compared in the normal brain. METHODS: Six paid, healthy volunteers (mean age 26 yr) had high-resolution neuroperfusion SPECT using both 99mTc-HMPAO and 99mTc-ECD on separate days. RESULTS: Regional distribution of the two tracers differed. Technetium-99m-HMPAO accumulated more in the thalamus, frontal lobe, temporal lobe and cerebellum than 99mTc-ECD, which accumulated more in the occipital and parietal lobes. There was a considerable difference in the accumulation of the two tracers in the medial temporal lobe. The percent accumulations of 99mTc-HMPAO and 99mTc-ECD in the medial temporal lobe compared with the mean global cerebral cortical accumulation were 93.9% +/- 2.4% and 83.1% +/- 4.1% (mean +/- s.d.), respectively. CONCLUSION: The results suggest that 99mTc-HMPAO and 99mTc-ECD require specific and separate criteria for diagnosing temporal lobe pathologies, such as dementia and temporal lobe epilepsy.     

Pattern of admissions of patients with apoplexy. Time connection between symptom onset and admission and relation to medical and social factors. The Copenhagen Stroke Study

The purpose of the study was to study admission delay in patients with stroke, and to analyze the influence of demographic, medical, and pathophysiological factors on admission delay. The study was prospective and consecutive and included 1197 unselected patients admitted with acute stroke from a well-defined catchment area in Copenhagen. Only 35% were admitted within the first six hours from stroke onset, and 50% of the patients were admitted later than 14 hours from stroke onset. Living alone (OR 1.75, 95% CI 1.3 to 2.3) and retired working status (OR 1.6, 95% CI 1.01 to 1.54) delayed admission. A well-functioning social network thus seems important to early admission. The milder the stroke, the higher was the risk of delayed admission (OR 1.25 per 10 points increase in stroke severity (Scandinavian Neurological Stroke Scale on admission), 95% CI 1.06 to 2.54. Other factors such as age, sex, diabetes, hypertension, ischaemic heart disease, other comorbidity, previous stroke, headache, aphasia, apraxia, anosognosia, neglect, lowered consciousness, mental status, and type of stroke had no independent influence on admission time. However, a history of TIA increased the chance of early admission by odds 1.64 (95% CI 1.01 to 2.54), indicating that an increase in public awareness and knowledge may reduce delay and save precious time.