Computerized axial transverse tomography in cerebrovascular disease

Assessing electrocardiogram changes after ischemic stroke with artificial intelligence

OBJECTIVE

Ischemic stroke (IS) with subsequent cerebrocardiac syndrome (CCS) has a poor prognosis. We aimed to investigate electrocardiogram (ECG) changes after IS with artificial intelligence (AI).

METHODS

We collected ECGs from a healthy population and patients with IS, and then analyzed participant demographics and ECG parameters to identify abnormal features in post-IS ECGs. Next, we trained the convolutional neural network (CNN), random forest (RF) and support vector machine (SVM) models to automatically detect the changes in the ECGs; Additionally, We compared the CNN scores of good prognosis (mRS ≤ 2) and poor prognosis (mRS > 2) to assess the prognostic value of CNN model. Finally, we used gradient class activation map (Grad-CAM) to localize the key abnormalities.

RESULTS

Among the 3506 ECGs of the IS patients, 2764 ECGs (78.84%) led to an abnormal diagnosis. Then we divided ECGs in the primary cohort into three groups, normal ECGs (N-Ns), abnormal ECGs after the first ischemic stroke (A-ISs), and normal ECGs after the first ischemic stroke (N-ISs). Basic demographic and ECG parameter analyses showed that heart rate, QT interval, and P-R interval were significantly different between 673 N-ISs and 3546 N-Ns (p < 0.05). The CNN has the best performance among the three models in distinguishing A-ISs and N-Ns (AUC: 0.88, 95%CI = 0.86-0.90). The prediction scores of the A-ISs and N-ISs obtained from the all three models are statistically different from the N-Ns (p < 0.001). Futhermore, the CNN scores of the two groups (mRS > 2 and mRS ≤ 2) were significantly different (p < 0.05). Finally, Grad-CAM revealed that the V4 lead may harbor the highest probability of abnormality.

CONCLUSION

Our study showed that a high proportion of post-IS ECGs harbored abnormal changes. Our CNN model can systematically assess anomalies in and prognosticate post-IS ECGs.

Analytic Review: Ischemic Cerebrovascular Disease: Diagnosis and Management

Ischemic stroke is the most common cause of neurologic morbidity and mortality. The proper management of a stroke patient is dictated by the underlying pathophysiology. An ischemic stroke may occur as a result of restricted flow or thrombosis from atherosclerosis, artery-to-artery embolization, cardiac-to-brain embolization, or disorders of coagulation, to mention a few of the most common causes. Determining the relevant cause of stroke is made more difficult by the coexistence of many possible factors such as hypertension, atherosclerosis, and cardiac disease. Nevertheless, judgments are based on the clinical presentation, computed tomographic scans, cerebral angiograms, and results of echocardiography and electrocardiographic monitoring.

Therapy of the ischemic stroke patient is aimed primarily at preserving areas of potentially recoverable ischemic brain. This is accomplished by correcting or avoiding circumstances that can promote further impairment of ischemic brain. These include proper management of blood pressure, cardiac function, oxygenation, and fluid balance. The role of anticoagulation, hemodilution therapy, and other proposed forms of therapy is often unclear.

Abnormal levels of serum anti-elastin antibodies in patients with symptomatic carotid stenosis

BACKGROUND AND OBJECTIVE

A correlation between the levels of antibodies to alpha-elastin (alpha-AEAb) and tropoelastin (tropo-AEAb) and the corresponding peptide concentration is found in human serum in health and disease. Serum elastin peptide and anti-elastin antibodies (AEAb) levels are age-related and vary with the stages of atherosclerotic vascular damage. This study aims to determine if elastin metabolism (assessed by the ratio of tropo-AEAb to alpha-AEAb) differs in patients with symptomatic carotid stenosis versus subjects with asymptomatic stenosis.

PATIENTS AND METHODS

Alpha-AEAb and tropo-AEAb were measured by ELISA in blood sera of 65 patients with ultrasound verified high-grade symptomatic carotid stenosis (resulting in stroke 1-7 days before measurement) compared to 51 patients with asymptomatic stenosis.

RESULTS

Serum anti-alpha-elastin IgG levels are extremely increased in symptomatic versus asymptomatic carotid stenosis. The ratio of tropo-AEAb (reflecting elastin synthesis) to alpha-AEAb (a function of elastin degradation) was 3.7 in symptomatic stenosis versus 14.2 in asymptomatic stenosis (p<0.001).

CONCLUSIONS

There is a significant difference in elastin metabolism in patients with symptomatic carotid stenosis versus asymptomatic stenosis. The ratio of tropo-AEAb to alpha-AEAb as an index of elastin synthesis/degradation proves useful in investigation of atherosclerotic lesions and may represent a new immunologic marker for carotid plaque destabilization.

Predictive value of median-SSEP in early phase of stroke: a comparison in supratentorial infarction and hemorrhage

OBJECTIVE

To compare the prognostic value of median somatosensory evoked potentials (M-SSEP) changes in the early phase of supratentorial infarction and hemorrhage.

MATERIAL AND METHODS

This study includes 130 patients (mean age 62+/-11.4 years, 43 women, large middle cerebral artery territory infarction in 36 patients, restricted/lacunar in 55, massive supratentorial hemorrhage in 10, small/medium size hemorrhage in 31). M-SSEP were recorded early (0-7 days in ischemia, 0-21 days in hemorrhage) and patients stratified into groups with absent, abnormal, normal response. Clinical state was determined by the Medical Research Council (MRC) scale, Barthel Index and Rankin score and followed for at least 6 months.

RESULTS

Moderate prognostic correlation was established between N20-P25 amplitudes (r=0.34, p<0.05) and N20-P25 amplitude ratio (r=0.45, p<0.01) and Barthel Index at 6 months in patients with ischemic stroke. Moderate relationship (r=-0.34, p<0.05) exists also between N20-P25 ratio and Rankin score at 6 months in patients with small/medium size hemorrhage. In large infarctions and small/medium size cerebral hemorrhages correlations with all clinical indices of outcome are weak. In massive hemorrhage, only a weak correlation (r=-0.19, p<0.05) between amplitude ratio and Rankin score was found. The combination of initial MRC and N20-P25 amplitude ratio has 10% (in hemorrhage) to 15% (in infarction) greater prognostic value (p<0.05) than initial alone.

CONCLUSIONS

M-SSEP have independent predictive value regarding functional recovery in ischemic stroke and small/medium size cerebral hemorrhage. Combined assessment of initial MRC and M-SSEP substantially improves prognosis in acute stroke.

Early electroencephalographic findings in patients with anoxic encephalopathy after cardiopulmonary arrest and successful resusitation

This study investigated whether or not early electroencephalographic (EEG) findings and brain computed tomographic (CT) features reflect the prognosis of comatose patients for 48 h after cardiopulmonary resuscitation (CPR). EEGs and brain CT scans were collected from 21 patients within 72 h after CPR. The EEG findings were classified according to the five Hockaday grades. The Glasgow outcome scale (GOS) applied 3 months after CPR was used for prognosis. Of the nine patients with grade 1 and 2 EEGs, eight had a good outcome (five recovered satisfactorily and three remained moderately disabled). Of the eight patients with grade 4 and 5 EEGs, seven had a poor outcome (three died and four remained in a persistent vegetative state). On the other hand, there was no correlation between early CT features and prognosis except for two severe cases, one whose gray/white matter interface had disappeared and the other with relatively increased density of the thalami, brain stem and cerebellum. These findings suggest that EEG is more useful than CT scan as a diagnostic tool for anoxic encephalopathy after CPR.

[Primary intracerebral hemorrhage. Retrospective study of 72 operated cases]

We analysed 72 cases of primary intracranial hemorrhage surgically treated from 1970 to 1999. The hemorrhages were diagnosed by computerized axial tomography in 52 patients. Most hematomas were situated in the cerebral hemispheres (30 percent in thalamus-basal ganglia region and 50 percent in the subcortical matter). There were 10 patients with cerebellar hemorrhage. Hypertension (based in blood pressure recordings in the hospital and history) was found in 24 patients (33 percent). The most frequent findings were coma, intracranial hypertension and hemimotor deficit. The death rate registered was 27.7 percent; however, it was found a significant difference in the mortality index when considering the 70-79 decade (62.7 percent) and the 90-99 decade (20.7 percent). A critical analysis was made about depth hematomas, consciousness state and intracranial hypertension with herniation related to surgical procedure.

Volumetric measurements of right cerebral hemisphere infarction: use of a semiautomatic MRI segmentation technique

The applications of a new segmentation software, Anatomatic, in the evaluation of volumetric measurements of brain infarctions and the new Medimag 3D software in the evaluation of 3D image representation of infarctions are described. These programs are applied to magnetic resonance imaging. The aim of this study is to evaluate the use of these software packages in making accurate volumetric measurements in 40 patients with right cerebral infarctions, in determining the correlations between the quantitated lesions and neurological/neuropsychological dysfunctions and in creating realistic 3D views of the infarctions. Using Anatomatic, reproducible infarction volumes were achieved with ease and within a reasonably fast time. Medimag helped achieve realistic 3D representations of the infarctions. When compared, the semiautomatic segmentation proved to be much faster and yielded higher infarction volumes than the manual segmentation technique. Significantly positive correlations between the infarction volumes and neurological dysfunctions and neuropsychological deficit (neglect) helped to explain the effect of volumes on the clinical status of the patients.

Progression of mass effect after intracerebral hemorrhage

BACKGROUND AND PURPOSE

While the evolution of mass effect after cerebral infarction is well characterized, similar data regarding intracerebral hemorrhage (ICH) are scant. Our goal was to determine the time course and cause for progression of mass effect after ICH.

METHODS

Patients with spontaneous supratentorial ICH who underwent >/=2 CT scans were identified in our prospectively collected database. CT lesion size and midline shift of the pineal and septum pellucidum were retrospectively measured and correlated with clinical and CT characteristics. Causes for increased midline shift were determined by 2 independent observers.

RESULTS

Seventy-six patients underwent 235 scans (3.1+/-1.3 per patient). Initial CT was obtained within 24 hours of ICH in 66. Twenty-five scans were repeated on day 1, 80 on days 2 through 7, 31 on days 8 through 14, and 24 >14 days after ICH. Midline shift was present on 88% of the initial scans. There were 17 instances of midline shift progression: 10 occurred early (0.2 to 1.7 days) and were associated with hematoma enlargement, and 7 occurred late (9 to 21 days) and were associated with edema progression. Progression of mass effect due to edema occurred with larger hemorrhages (P<0.05). Of 65 scans repeated for clinical deterioration, only 10 were associated with increased mass effect.

CONCLUSIONS

Progression of mass effect after ICH occurred at 2 distinct time points: within 2 days, associated with hematoma enlargement, and in the second and third weeks, associated with increase in edema. The clinical significance of later-developing edema is unclear.

The correlation of CT findings and in-hospital mortality after cerebral infarction

OBJECTIVE

To evaluate whether findings on computed tomography (CT) are useful to predict early mortality after acute cerebral infarction.

METHODS

An admission CT was performed in 98 patients with disease-onset within 7 days; CT findings were analyzed using a checking list; their influence on hospital mortality was studied by logistic regression analysis.

RESULTS

There were 29 hospital deaths. Uncal herniation and midline shift > 4 mm were strongly correlated with fatal outcome. Also associated with increased mortality: infarction of a whole hemisphere or in the distribution of internal carotid artery; massive (> 90% expected area) infarction in the territory of the anterior or posterior cerebral arteries; massive or submassive (> 50% expected area) middle cerebral artery infarction; large lesion volume (death in 9/13 patients with lesions > 50cm3); any degree of mass effect. In 68 patients with single middle cerebral artery lesions, extension of the lesion to adjacent vascular territories was also associated with a worse outcome. The number of lesions and the presence of contrast enhancement, hemorrhagic changes or cerebral atrophy did not influence outcome.

CONCLUSIONS

CT findings indicating significant mass effect and large infarcts are associated with mortality after ischemic stroke. The best combination of clinical and CT variables to estimate death risk in individual patients remains to be determined.

Decline in autopsies for deaths attributed to cerebrovascular disease

BACKGROUND AND PURPOSE

United States national autopsy rates have declined in recent years. In the present study, changes in autopsy rates for deaths due to stroke are examined and compared with changes in autopsy rates for all deaths.

METHODS

National Center for Health Statistics data on United States national autopsy rates were examined for the years 1955, 1958, and 1972-1988.

RESULTS

Since at least 1955, nonstroke deaths were more than twice as likely to be autopsied as deaths due to cerebrovascular disease. The annual autopsy frequency for all deaths, for deaths due to stroke, and for deaths due to each stroke subtype declined precipitously after 1972. Since 1982, less than 5 percent of deaths attributed to stroke have been documented by autopsy. Information obtained at autopsy was frequently ignored in the determination of cause of death on the death certificate.

CONCLUSIONS

Careful consideration of the value of autopsy for education, research, and quality assurance is urgently needed. Unless the present problems in obtaining, processing, disseminating, and using autopsy data are adequately addressed, the autopsy rate will continue to decline.

The initial impact of computed tomography on mortality attributed to brain tumor

The exponential growth in the number of computed tomography scanners in the United States between 1975 and 1977 was associated with a transient increase (11.9 and 14.4% for men and women, respectively) in annual crude mortality rates for primary malignant brain tumor from 1976 through 1978. This transient increase in mortality appears to have been an artifactual epiphenomenon associated with the introduction of a new technology.

Cost-effective investigation of patients with suspected transient ischaemic attacks

Images

TIA, RIND, minor stroke: a continuum, or different subgroups? Dutch TIA Study Group

The results of CT were studied prospectively in 606 patients with a transient ischaemic attack (TIA), 422 patients with a reversible ischaemic neurological deficit (RIND), and 1054 patients with a minor stroke, were all entered into a multi-centre clinical trial. CT scanning showed a relevant ischaemic lesion in 13% (95% confidence interval 10-16%) of TIAs, 35% (95% confidence interval 30-40%) of RINDs, and 49% (95% confidence interval 46-52%) of minor strokes (p less than 0.000001). Even within the 24 hour margin, relevant infarcts occurred more often with longer attacks, but were still found in some patients with attacks lasting less than a minute. The type and location of the infarcts were similar in the three groups. These findings suggest that the differences between TIAs, RINDs, and minor strokes are quantitative rather than qualitative.

The value of EEG-mapping in focal cerebral lesions

In 148 patients with focal cerebral lesions the findings of EEG mapping, routine EEG and CT were compared. Regarding etiology 43 patients suffered from completed stroke (CS), 43 patients from transient ischemic attack (TIA), 33 patients had an intracerebral hemorrhage (ICH) and 29 an hemispheric tumor. In 37 patients with CS (86%) and 27 patients with TIA (63%) the EEG mapping revealed focal changes, but only in 28 patients with CS (65%) and in 11 patients (26%) with TIA using routine EEG alone. Thus the EEG mapping showed focal abnormalities significantly more often. In the remaining patient groups no significant difference in the results of EEG mapping or routine EEG could be demonstrated. Focal abnormalities corresponding to focal lesions seen in CT were obtained by means of EEG mapping in 27 patients (90%) with CS and 10 patients (77%) with TIA, but only in 17 patients (57%) with CS and 4 patients (31%) with TIA using routine EEG and in that way the EEG mapping could indicate focal lesions in CT significantly more often than routine EEG. In the remaining patient groups no significant difference in the number of focal changes corresponding to lesions in CT could be seen.

CT scanning in meningitis

Twelve paediatric cases of acute meningitis were reviewed retrospectively. Findings on CT scan were compared with the clinical course and resulting neurological sequelae. Complications detected by CT scanning include subdural effusion, empyema, hydrocephalus, cerebral atrophy, oedema and infarction. The CT scan results adequately correlated with neurological signs in most cases. Infarction was a reliable indicator of neurological sequelae. Cerebral atrophy alone, however, did not correlate well with the clinical sequelae.

Investigation of acute stroke: what is the most effective strategy?

Techniques of investigation of acute stroke syndromes have progressed rapidly in recent years, outpacing developments in effective stroke treatment. The clinician is thus faced with a variety of tests, each with different cost implications and each altering management to a greater or lesser extent. This review will concentrate on the basic tests which should be performed for all strokes (full blood count, ESR, biochemical screen, blood glucose, cholesterol, syphilis serology, chest X-ray and electrocardiogram). Additional tests may be required in selected cases: CT scan to diagnose 'non-stroke' lesions, to exclude cerebral haemorrhage if anti-haemostatic therapy is planned, and to detect strokes which may require emergency intervention (such as cerebellar stroke with hydrocephalus); echocardiography to detect cardiac sources of emboli; and in a few cases lumbar puncture and specialized haematological tests. Other tests, which are currently research tools, may be suitable for widespread use in the future including NMR, SPECT and PET scanning.

The Willis lecture: transient ischemic attacks, scientific method, and new realities

First described by Thomas Willis in 1679 and defined in the 1950s, transient ischemic attack is universally agreed to be an episode of focal neurologic deficit in a vascular distribution, sudden in onset and resolving without residual deficit in less than or equal to 24 hours. Transient ischemic attack is diagnosed by characteristic history and absence of residua on neurologic examination. After these criteria had been accepted, regional cerebral blood flow and computed cranial tomography in the 1970s, later positron emission tomography, and even more recently, magnetic resonance imaging reveal prolonged pathophysiologic and metabolic disturbances even in persons with all the definitional characteristics of transient ischemic attack. These persistent abnormalities necessitate reexamination of the validity of the concept of transient ischemic attack. Furthermore, our group suspects that transient ischemic attack is probably only a marker, and not itself the risk factor, for the cerebral infarction which frequently follows transient ischemic attack. Additionally, the surprising frequency with which cerebral infarction, unrecognized by patient or physician, is revealed using neuroimaging techniques has created a need to redefine the categories heretofore used for diagnosis and assessment of therapy and prognosis for transient ischemic attack and cerebral infarction.

The role of imaging in the management of cerebral and ocular ischaemia

The last decade has seen several major technological advances in vascular neuroradiology, the most clinically significant of which have been the facility to image the brain and the extracranial carotid bifurcation noninvasively with accuracy and safety. Another major advance has been unequivocal evidence from formal statistical overviews that antiplatelet therapy, particularly aspirin, reduces the risk of serious vascular events by about 25%. These advances have changed clinical practice such that most patients presenting with symptoms suggestive of cerebral ischaemia should now have cranial CT to exclude intracerebral hemorrhage, not only because the causes and prognosis of cerebral ischaemia differ from those of intracerebral hemorrhage, but because many patients with cerebral ischaemia should be considered for antiplatelet therapy. Besides the use of long term antiplatelet therapy and control of vascular risk factors, other acute treatment options are limited with the possible exception of anticoagulation, thrombolysis, cytoprotective agents and carotid endarterectomy. If, as seems likely, the current clinical trials show that carotid endarterectomy plus medical therapy improve upon the stroke-free survival of patients treated medically, at least in symptomatic patients with severe stenosis, the number of carotid endarterectomies performed will increase considerably because carotid bifurcation disease is the most common cause of cerebral and ocular ischemic events. It will then be even more important to be able to obtain accurate anatomical and physiological information about the extracranial and intracranial circulations with utmost safety. Duplex ultrasound is currently the noninvasive screening method of choice for carotid bifurcation disease because it is available, relatively cheap, and reasonably accurate. It not only images the vessel lumen and degree of stenosis, but also the morphology of the vessel wall and associated plaque, the relevance of which is still uncertain in the pathogenesis of cerebral and ocular ischaemia. A major limitation of duplex sonography is that it cannot reliably distinguish tight stenosis from occlusion and it does not image the proximal or distal carotid circulation. The aim of newer techniques will be to distinguish tight extracranial carotid stenosis from occlusion and to provide anatomical, physiological and pathological information about the intracranial circulation and ischemic lesions (in view of potential for thrombolytic therapy of major intracranial vessel occlusion) with safety and reproducible accuracy.

Correlation of clinical and computed tomographic findings in stroke patients

We evaluated the correlation between clinical features and computed tomographic findings in a prospective study of 1,191 consecutive patients with acute cerebrovascular disease seen during 1 year. In the 386 patients in whom symptoms and signs initially suggested a cerebrovascular disorder, computed tomography revealed a relevant lesion in 154 (hemorrhagic in 52 [33.8%], ischemic in 102 [66.2%]) and a significant nonstroke abnormality in 14 (3.1%). Among the remaining 805 patients with symptoms and signs suggesting some central nervous system disorder other than stroke, computed tomography revealed a cerebrovascular lesion in 38 (4.7%); 35 of these lesions were ischemic. The computed tomographic findings was compatible with the final clinical diagnosis in 192 (84.2%) of the 228 patients with lesions. In the entire sample of 1,191 patients, a cerebrovascular disorder would have been missed in 38 (3.2%) without computed tomography. On the other hand, computed tomography failed to visualize a cerebrovascular lesion in 40 patients in whom such a lesion was clinically obvious. Our results emphasize that both careful neurologic assessment and a policy of early computed tomography are of crucial importance in the diagnosis of stroke and for therapeutic considerations.

Computed tomography in patients with transient ischaemic attacks: when is a transient ischaemic attack not a transient ischaemic attack but a stroke?

In a prospective community-based study, 184 patients with transient ischaemic attacks (TIAs) were identified from a study population of about 105,000 between 1981 and 1986. Computed tomography (CT) was attempted in all those with cerebral ischaemic attacks (n = 152, 83%); patients with amaurosis fugax only (n = 32, 27%) were not scanned routinely. Scans were obtained in 120 (79%) of those with cerebral attacks and 12 (38%) of those with amaurosis fugax. The scans were reported by a neuroradiologist who was blinded to the patients' clinical features. Of 120 (27%:95% confidence interval 19-35) scans in patients with cerebral attacks, 32 showed a focal area of hypodensity or cortical loss, but in only 14 (12%:95% confidence interval 6-18) was this in an area of the brain appropriate to the patients' symptoms. There were no significant differences in the clinical features, the duration of attacks or the prognosis (i.e., risk of death, stroke or myocardial infarction) of patients with and without ischaemic lesions on CT. It is concluded that patients with clinically definite TIAs who have a presumed ischaemic and appropriately sited lesion on CT should not be re-classified as having had a stroke.

Measurements of acute cerebral infarction: lesion size by computed tomography

As part of a prospective therapy study of 65 patients with acute, nonhemorrhagic, cerebral infarction, computed tomographic scans of the head were obtained at admission, 7-10 days, and 3 months. The scans were analyzed for the presence, site, size, and volume measurement of the infarction. At 7-10 days, the mean infarction volume as measured by computed tomography was 55 cm3 or about 4 x 4 x 3.5 cm (range = 0-507 cm3). At 3 months, the mean infarction volume decreased by 25% to 41 cm3. For the 26 scans showing infarction at the time of admission, the mean lesion volume was 33 cm3 at admission, 51 cm3 at 7-10 days, and 49 cm3 at 3 months. With lesion size at 7-10 days expressed as percentage of total brain volume, the mean infarction size was only 5%. Of the 49 patients with lesions revealed by computed tomography at 7-10 days, 20 had an infarction of 1% or less of total brain volume, while only six had an infarction of 20% or more of total brain volume. The lesion volumes as measured by the 7-10-day computed tomography correlated with the neurologic examination scores on admission (Spearman's rank-order correlation = 0.78) and with the scores at 1 week (Spearman's rank-order correlation = 0.79).

Cerebral infarction in patients with transient ischemic attacks

Cranial computed tomography of 284 patients with transient ischemic attacks (TIAs) and without previous stroke was evaluated. The sample population included patients with carotid and/or vertebrobasilar TIAs. Computed tomography revealed cerebral infarction in 34 patients, including 5 with multiple infarctions. The lesion location was consistent with TIA symptoms in 16 patients. In another 16 patients, however, the lesion location did not correspond to the TIA symptoms; these lesions were attributed to previous silent infarctions. Two patients with multiple infarctions had both symptomatic and asymptomatic lesions. Age and carotid stenosis were each significantly related to an increased chance of detecting cerebral infarction (either symptomatic or asymptomatic). No significant relationship between race, gender, hypertension, diabetes, cardiac disease, or smoking and the incidence of infarction was found by either univariate or multivariate analyses.

Prediction of intracerebral hemorrhage survival

The Pilot Stroke Data Bank obtained information on 94 patients with intracerebral hemorrhage. These data were used to identify factors predictive of 30-day outcome from among 85 demographic, historical, clinical, and laboratory variables generally available to clinicians on the day of admission. The 9 univariate factors statistically associated with outcome were Glasgow Coma Scale score, systolic blood pressure, pulse pressure, horizontal and vertical gaze palsies, severity of weakness, presence of brainstem-cerebellar deficits, interval stroke course, and parenchymal hemorrhage size. Beginning with these factors, a step-down variable selection procedure was used to derive a logistic regression model, containing only Glasgow Coma Scale score, pulse pressure, and hemorrhage size, that could be used to categorize correctly 92% of the patients as alive or dead at 30 days after onset.

Discrepancies between CT and EEG findings after acute cerebrovascular disease

Combined EEG and brain CT examinations were performed in 33 patients during the 1st and 2nd week after stroke. CT was abnormal in 17 patients (51%) and EEG was abnormal in 24 patients (72%). In 17 patients CT and EEG showed conflicting results; in 5 patients with normal EEG findings CT was pathological, and 12 patients had normal CT but pathological EEG findings. In this latter group, there were 5 particularly interesting cases with normal CT and a prominent unilateral EEG abnormality. Recently patients with this combination of findings have been described where further investigations disclosed internal carotid occlusion, which could be treated surgically. It is suggested that EEG should be more extensively used when CT findings are negative after stroke, and if a major unilateral EEG abnormality is encountered in such cases, further investigations with angiography should be considered in order to exclude surgically treatable internal carotid occlusion.

Computed tomography in reversible ischaemic attacks: clinical and prognostic correlations in a prospective study

Two hundred and nineteen patients admitted with reversible atherothrombotic ischaemic attacks were prospectively evaluated by computed tomography. Of these patients, 122 were diagnosed as suffering from transient ischaemic attacks, 58 from reversible ischaemic neurological deficits and 39 from reversible ischaemic neurological deficits with incomplete resolution. In 133 cases the ischaemic event affected the carotid system, in 63 the vertebrobasilar system and in 23 cases the system could not be determined. Brain infarctions were observed in 64 patients (29.2%), cerebral atrophy in 96 (44.4%) and dilatation of a ventricle in 17 (7.8%). The frequency of brain infarction was related to the duration of the neurological deficit, being 20.5% in those with transient ischaemic attacks, 37.9% in those with reversible ischaemic neurological deficits and 43.6% in patients with reversible ischaemic neurological deficits with incomplete resolution (P = 0.005). Ischaemic lesions were closely correlated with abnormalities on supra-aortic trunk angiography or Doppler ultrasonography. During an average follow-up period of 21 months, a higher percentage of recurrence was found in those patients with CT infarctions, but the difference was not significant.

Clinico-epidemiologic study of stroke in Akita, Japan

An analysis was performed of 2,168 consecutive stroke patients who were examined by computed tomography and entered into a hospital-based stroke registry in Akita Prefecture, Japan. The occurrence of cerebral hemorrhage, cerebral infarction, and subarachnoid hemorrhage was 30, 55, and 14%, respectively. Age-specific rates of subarachnoid hemorrhage were higher in women than men; other types of stroke showed a preponderance in men. Total strokes increased in the winter; this seasonal difference was confined to cerebral hemorrhage. Putaminal hemorrhages predominated in the younger age groups; thalamic hemorrhage and cerebellar hemorrhage were predominant in the older age groups. The increased accuracy of the diagnosis of stroke subtypes by the use of computed tomography in this study is in contrast to other community-based epidemiologic studies that have relied solely on clinical diagnosis. This increased accuracy is seen to be the reason that new ratios of stroke subtype incidence have been identified.

Tissue damage at computed tomography following resolution of intracerebral hematomas

Tissue damage as sequelae after spontaneous intracerebral hemorrhage in eight consecutive patients was investigated with computed tomography performed 3 days, 2 weeks and 6 months after the stroke. The presence of contrast enhancement after 2 weeks, hypodense areas after 6 months, and atrophy of adjacent structures were considered to be markers of irreversible tissue damage. Except for a narrow zone in the periphery of the hematoma (ring blush) contrast enhancement was not observed, neither in the hematoma nor in areas where resolution had taken place. After 6 months the site of the hematomas was not identifiable in 3 patients, and 4 patients had small 'lacunar' hypodense lesions. Only one patient had a more extensive hypodense area 6 months after the hemorrhage. The most prominent sequelae after intracerebral hematoma were atrophy of adjacent structures (i.e. atrophy of basal ganglia, thalamus and ventricular enlargement) which were seen in all patients even though irreversible de loco damage in the hematoma area was sparse or absent.

Strokes among black people in Harare, Zimbabwe: results of computed tomography and associated risk factors

Computed tomography was performed and risk factors evaluated in 100 consecutive adult patients presenting to the two teaching hospitals in Harare with a clinical diagnosis of stroke. The mean age of the patients was 52; only 28 were 65 or older. Non-stroke lesions were found in seven patients and were predicted by a recent history of convulsions (p less than 0.0001). Five lesions (four subdural haematomas and one cerebral cysticercosis) were remediable. Hypertension was present in 27 (93%) of the 29 patients with cerebral haemorrhage and in 49 (53%) of the 93 patients with stroke lesions. In 22 (45%) of these patients the hypertension had not been diagnosed, and another 22 had defaulted from treatment. All 13 patients who died before computed tomography had hypertension, and over half showed evidence of haemorrhagic stroke. There was a cardiac source for all 12 cases of cerebral embolism. In eight of the 100 patients cerebral infarction was attributed to neurosyphilis. None of the patients had clinical evidence of atherosclerosis. Smoking and oral contraceptives did not seem important risk factors for stroke. Detection and control of hypertension remain the most important measures needed to reduce the incidence of and mortality from stroke in Zimbabwe.

The role of cranial computed tomography in carotid surgery

In patients who present with TIA, RIND, or CVA, the cranial CT scan can rule out other etiologies for neurologic symptoms. In addition to the clinical presentation, the CT scan allows further stratification of patients being considered for carotid endarterectomy. We propose that patients be classified as TIA (+), TIA (-), RIND (+), or CVA (-). The CT scan has defined a new subgroup of patients, TIA (+) and RIND (+)--the Silent Cerebral Infarction. Patients who are categorized as TIA (+), RIND (+), and CVA (+) (cerebral infarction on CT or by history) are at increased risk for intraoperative ischemia and postoperative neurologic deficit. As such, they should be selectively shunted based on intraoperative EEG monitoring or routinely shunted. There is a strong association between ulcerative plaque at the carotid bifurcation and cerebral infarction on CT. The CT scan is a critical diagnostic procedure in evaluating the patient with an acute neurologic event. Patients with negative CT scans are candidates for early operation. Carotid endarterectomy should generally be delayed for 4 to 6 weeks in patients with positive CT scans.

Carotid endarterectomy in patients with actively changing neurological deficits--correlations with CT brain scans

The place of carotid endarterectomy in patients with actively changing neurological deficits (ACND) is yet to be defined. This is a study of 15 patients with ACND who underwent carotid endarterectomy. All patients had demonstrable neurological deficits at the time of surgery. However no patient had severe devastating symptomatology or decreased levels of consciousness. Eight patients (Group I) were classified as stroke-in-evolution (SIE) according to Millikan. Seven other patients (Group II) were also unstable with deficits of recent onset but did not demonstrate a classical progressive or stepwise deterioration. Average internal carotid stenosis was 80% (range 50-90%). In each of the Group I patients CT scans of the brain demonstrated cerebral infarction in the area appropriate to the deficit. CT scans were performed in four of the Group II patients, two of whom showed cerebral infarction while two were normal. Seven of the eight Group I patients improved after surgery while one progressed to a completed stroke. Six of the seven Group II patients improved following surgery while one died on the third postoperative day. These results suggest an improved outlook with surgery when compared either with the natural history of SIE or with the results when anticoagulants alone are used.

Value of computed tomography in patients with stroke: Oxfordshire Community Stroke Project

The usefulness of computed tomography (CT) was assessed in 325 consecutive patients with a "clinically definite first stroke" from a community stroke register. CT detected five "non-stroke" lesions (two cerebral gliomas, one cerebral metastasis, and two subdural haematomas), a frequency of 1.5%. Five patients were identified with cerebellar haemorrhage, but only one survived long enough to have a CT scan. CT was useful in excluding intracranial haemorrhage as the cause of the stroke in four patients receiving anticoagulants and seven receiving antiplatelet treatment; it showed intracranial haemorrhage in one patient taking aspirin. Forty six patients were in atrial fibrillation at the time of their stroke; four had intracranial haemorrhages and three had haemorrhagic cerebral infarcts. Nineteen patients with presumed ischaemic minor stroke were considered suitable for carotid endarterectomy; CT showed small haemorrhages in two. The CT scan provides very useful information in a minority (up to 28%) of patients with first stroke, who can be selected on quite simple criteria: (a) doubt (usually because of an inadequate history) whether the patient has stroke or a treatable intracranial lesion; (b) the possibility of cerebellar haemorrhage or infarction; (c) the exclusion of intracranial haemorrhage in patients who either are already taking or likely to need antihaemostatic drugs or are being considered for carotid endarterectomy; (d) if the patient deteriorates in a fashion atypical of stroke.

Clinical-CT correlations in TIA, RIND, and strokes with minimum residuum

An approach to the controversy of the physiopathology and classification of ischemic stroke is attempted in this study. The computed tomographies (CT) of 88 patients with transient ischemic attacks (TIA), 46 with reversible ischemic neurologic deficits (RIND) and 70 with ischemic strokes with minimum residuum (SMR) are analysed. The incidence of focal ischemic lesions on CT is 25% in TIA and RIND and 35% in SMR, when the study was performed after the first 24 hours. The incidence of cerebral infarction was much lower when the CT was performed within the first 24 hours after the clinical event. No significant differences in size or location of the infarction were found between the different groups. Deep infarctions were smaller than superficial ones. TIA duration correlated neither with the incidence of CT abnormalities nor with the size of the lesions. No correlation was found between doppler or oculoplethysmography abnormalities, clinical groups and CT findings. In reference to the structural lesions that underlie the clinical syndromes, TIA, RIND and SMR should not be considered as different groups.

Cerebral infarction with transient signs (CITS): do TIAs correspond to small deep infarcts in internal carotid artery occlusion?

Among 75 patients in whom internal carotid artery (ICA) occlusion was discovered on angiography, 5 presented with transient ischemic attacks (TIAs) without suffering a stroke. Although neurological examination was normal, all had evidence for one (in one instance two) hypodense lesion suggesting infarction contralateral to the neurological dysfunction on computed tomography (CT). These infarcts were small and deeply located, being indistinguishable from lacunes in most cases. We suggest that cerebral infarction with transient signs ( CITS ) may be a usual finding in patients with ICA occlusion who suffer isolated TIAs. In these cases, CITS may correspond to incomplete cerebral necrosis related to a well-developed collateral supply, or to recurrent ischemia in the region of an old "silent" infarct. CITS should be differentiated from TIAs, which may be diagnosed only in absence of visible structural lesion.

CT and cerebral ischemic infarcts. Correlations between morphological and clinical-prognostic findings

A total of 66 patients with supratentorial ischemic infarct underwent serial CT scans in order to study the relationship between CT images and clinical evolution of the infarct. Little information of prognostic value is given by CT in patients with slight neurological deficits, whereas it enables factors with a negative influence on the prognosis to be identified in patients with moderate to severe deficits.

Positron CT imaging using a high resolution PCT device (Positologica-I), 11CO, 13NH3, and 18FDG in clinical evaluation of cerebrovascular diseases

Positron computed tomography (PCT) was performed in 3 normal volunteers and 21 patients with cerebrovascular diseases using a high resolution PCT device 'Positologica-I' and three tracers 11CO, 13NH3, and 18FDG. Relatively early lesions showed various accumulation patterns, and metabolism and perfusion mismatches were clearly shown by this measurement. One type of mismatch is luxury perfusion which had a slight increase of blood volume. Another type of uncoupling is misery perfusion. Remote effects of ischemic lesions also appeared on PCT with 18FDG and 13NH3. From our clinical results, the PCT method with a high resolution device and radiopharmaceuticals such as 11CO, 13NH3, and 18FDG is very useful in the assessment of cerebrovascular diseases and in defining circulatory dysfunction in man.

Brain and plasma proteins in spinal fluid as markers for brain damage and severity of stroke

Forty well-defined acute stroke patients were investigated for some cerebro-spinal fluid (CSF) markers of cerebral damage. Myelin-basic protein (MBP), tau-fraction, albumin, IgG and transferrin were analyzed on two early occasions after onset of clinical symptoms. Patients with transitory ischaemic attack (TIA) had normal values for MBP both at first and second lumbar puncture. Patients with cerebral infarction and haemorrhage had mean MBP concentrations higher than normal at both lumbar punctures. In cerebral infarction there was a significant increase in MBP from the first to the second lumbar puncture. Patients with intracerebral haemorrhage showed the highest mean MBP values and MBP was markedly elevated already at the first lumbar puncture, suggesting different mechanisms of destruction of nervous tissue in cerebral infarction and bleeding. The amount of MBP was also significantly correlated to the visibility of the cerebral lesion at CT-scan and to the short-term outcome of the patients. The tau-fraction, indicating damage to grey matter, was higher than normal in the majority of patients with cerebral infarction and TIA. The concentration of MBP increases with the extent of brain lesion and a high value indicates a poor short-term prognosis for the patient. This study shows that the brain specific MBP in CSF is a useful marker of cerebral damage in acute cerebrovascular disease.

Algorithms in the management of cerebrovascular disease

We present a diagnostic approach to the various clinical presentations of patients with cerebrovascular disease. It involves grouping the patients into five categories: (1) asymptomatic, (2) transient neurologic episodes, (3) unstable neurologic deficits, (4) prolonged neurologic deficits and (5) completed stroke. An algorithm is given for each category and an approach to management is outlined. The algorithms are clinically validated by reviewing the results of 185 reconstructive operations performed on patients with manifestations of cerebrovascular disease who were managed following the algorithms.

Evaluation of peripartum strokes by computed tomography

Eleven women with peripartum strokes were evaluated by cranial computed tomography (CT). The interval between childbirth and the onset of symptoms varied from 1 day to 22 days. Computed tomography scans were done within 7 days of the onset of symptoms in six cases and in the remaining five cases on the 8th, 12th, 12th, 12th and 20th day, respectively. All CT scans were abnormal, 10 showing evidence of arterial infarction by low-attenuation lesions and only one of sino-venous occlusion shown by a high-attenuating haematoma.