CT in hemispheric ischaemic attacks

Mass Effect and Atrophy after Stroke

Cerebral edema, resolution of edema, and subsequent development of cerebral atrophy were studied prospectively in 83 patients with ischemic stroke with CT 3 days, 2 weeks, and 6 months post-stroke. Nineteen patients had large (diameter > 3 cm), 25 medium sized (diameter ≥ 1.5 ≤ 3 cm), and 15 lacunar infarcts (diameter < 1.5 cm). In 24 patients no infarcts were seen. Changes of Evans' ratio (ER), septum-caudate distance (S/C), and width of widest cortical sulci (SuW) were taken as markers of mass effect/atrophy. These parameters were within normal limits in most cases. However, when all CT scans performed in each patient were compared, changes of ER, S/C, and SuW became apparent as evidence of mass effect and subsequent atrophy development. Mass effect occurred in 81 percent and atrophy in 58 percent of patients with large infarcts. In patients with medium sized infarcts, mass effect occurred in 38 percent and atrophy in 45 percent.

Focal Cerebral Infarction in Newborn: Description of Three Cases

We observed 3 full-term newborns with focal ischemic injury of the middle cerebral artery (MCA), in which diagnosis of MCA stroke was suspected by US and confirmed by CT scan and MRI. A four-year follow-up was carried out to study the effect of neonatal stroke on neurodevelopmental outcome. All children had a history of pre-perinatal risk factors: neonatal cerebral infarction in term infants, in fact, has many possible causes, including bacterial meningitis, inherited or acquired coagulopathies, trauma and hypoxia-ischemia. The prognosis of neonatal MCA infarction depends on early diagnosis, on the CNS plasticity mechanism and, finally, on medical therapy and neuropsychological rehabilitation.

[Emergency heart valve replacement after acute cerebral embolism during florid endocarditis]

BACKGROUND

The indication for urgent cardiac surgical interventions in patients with active infective endocarditis has to be considered carefully following thromboembolic events, because of the high recurrence rate of such complications. In the case of brain embolisms the prognostic benefit of urgent surgery has been discussed controversially as effective anticoagulation during open heart surgery may result in secondary cerebral hemorrhages.

PATIENTS AND METHODS

Between 1978 and 1993 infective endocarditis (IE) was proven in 288 consecutive and prospectively followed patients (131 females, 157 males; mean age 53.6 +/- 8.7 [9 to 81] years). To analyze potential benefits and risks of an urgent surgical intervention early after embolic cerebral infarction, cumulated survival rates were calculated for patients with and without surgical intervention with special reference to incremental risk factors and the timing of surgery.

RESULTS

In 50 patients (17.4%) the clinical course was complicated by one, and in 58 patients (20.2%) by recurrent embolic events. In 80% the first embolism occurred within 33 days following the first manifestation of typical signs and symptoms of IE. 80% of recurrent events were observed within 32 days following the initial embolism. 71% of all embolic events were cerebral. In patients with cerebral embolism corroborated by computed tomography (CCT), the clinical course was complicated by intracranial hemorrhage in 12.5% while it was only 1.5% for patients without cerebral embolism. Because of a lack of therapeutic alternatives, 22 of 49 patients with recurrent embolic events, of which at least one was cerebral, underwent urgent cardiac surgery within 4 to 366 hours after the first cerebral manifestation. The cumulated survival rate of patients operated within 72 hours after the initial cerebral embolism was significantly more favorable (p < or = 0.000) than for unoperated patients or those who were operated after more than 8 days.

CONCLUSION

An embolic event during IE carries a more than 50% risk of recurrence. In patients with short duration of signs and symptoms of IE and postembolic echocardiographic demonstration of persistent vegetations the probability is > 80%. At least for those patients urgent surgical intervention to remove the source of infection and embolic hazard seems to be beneficial. Surgical intervention using the heart-lung-machine should be performed within 72 hours. Such early timing results in a significant lower rate of secondary cerebral hemorrhages (p < or = 0.00) than a postponed operation. To exclude early reperfusion hemorrhage due to spontaneous thrombus fragmentation, CCT should be repeated directly preoperatively.

MR enhancing brain lesions in methanol intoxication

Methanol intoxication can cause necrosis of the putamen and subcortical white matter that is evident on neuroimaging. We report a 47-year-old man with significant methanol intoxication who had enhancing lesions in the caudate nuclei, putamina, hypothalamus, and subcortical white matter by MRI. This case demonstrates that contrast enhancement of brain lesions can be observed after methanol poisoning.

Late seizures following a first symptomatic brain infarct are related to large infarcts involving the posterior area around the lateral sulcus

Controversies exist concerning factors that contribute to the occurrence of epileptic seizures after stroke. Therefore, we studied prospectively the occurrence of seizures in 322 patients with a first-ever CT-confirmed symptomatic territorial brain infarct involving the cortex. We also studied potential risk factors for seizures, and gave special attention to cortical infarct location. Fifty-four patients developed post-stroke seizures. We distinguished between early- and late-onset seizures, occurring within two weeks following stroke-onset, or later than two weeks, respectively. We found that patients of 65 years or older with a cardioembolic brain infarct involving the middle temporal or post-central gyrus, had an almost eight times increased risk of early-onset seizures, whereas patients with a large brain infarct involving the supramarginal or superior temporal gyrus, had a five times increased risk of late-onset seizures. We conclude that risk factors and epileptogenic cortical areas for post brain infarct seizures can be identified, which however, differ between early- and late-onset seizures. These two seizure types may also differ in terms of seizure mechanism. Our findings may influence the decision on prophylactic treatment with antiepileptic drugs in stroke patients.

Supratentorial brain infarcts in adult-onset seizures; the Maastricht Epilepsy Case Register

We studied the frequency of supratentorial brain infarction as the cause of late-onset epilepsy in 680 patients with a first seizure after the age of 20, registered on an epilepsy register: 65 (10%) had seizures following a symptomatic supratentorial brain infarct. Brain infarction as the presumed cause of epilepsy was related to age at first seizure. A first seizure occurred within one year after brain infarction in 62%, and later than two years in 19%. Eight of 14 patients (57%) with an early seizure (< or = 2 weeks), and 28 of 41 patients (68%) with a first seizure later than two weeks post-stroke had seizure recurrences despite anti-epileptic treatment. Of 38 patients who underwent computed tomography head scan (CT), 32 (84%) had a cortical infarct, whereas six (16%) had one or more lacunar infarcts. This may indicate that lacunar infarction may be associated with post-stroke epilepsy. Using a detailed topographic brain atlas to localize the cortical infarcts, no 'specific epileptogenic' gyri could be identified. What factors predict future epilepsy in stroke patients need to be studied in prospective series of well-defined stroke subgroups.

Computed tomography in prognostic stroke evaluation

BACKGROUND AND PURPOSE

Computed tomography is now routinely used in many hospitals to investigate cerebrovascular disease. The purpose of our prospective study was to determine whether cranial computed tomography in connection with neurological assessment was useful in prognostic evaluation of survival after acute stroke.

METHODS

Two-hundred forty-five consecutive stroke patients were included in the project during a 1-year period. Each had a detailed neurological assessment 24-72 hours after stroke onset and underwent cranial computed tomography without intravenous contrast injection within the first week after admission. The lesions were divided according to neuroanatomic regions. In the statistical analyses we used a multiple logistic regression model with survival/death as the binary variable.

RESULTS

Computed tomography showed 76% of the patients had infarcts, 11% had hemorrhages, and 13% had no acute lesion. Forty-three patients had more than one acute lesion, and 57 had one or more old infarctions. The temporal, parietal, and frontal regions and the basal ganglia were most often affected.

CONCLUSIONS

We conclude that age, level of consciousness, and involvement of the temporal lobe on computed tomography were factors of prognostic significance regarding survival in the acute phase.

Neonatal cerebral infarction: symptoms, CT findings and prognosis

In a retrospective multi-center study, we investigated eighteen infants with unilateral cerebral infarctions confirmed by computed tomography (CT) scans. The initial symptoms were observed in all the patients between 0 and 3 days of age. Convulsions or apneic attacks were the initial symptoms in all but one. Only 4 patients had complicated obstetric histories and none showed polycythemia or electrolyte abnormalities. All of the initial CT scans revealed unilaterally localized hypodense areas. In 10, the initial CT scans were performed within 24 hours after the clinical onset. In 16, the lesions were within the territory of the middle cerebral artery, 9 of which also involved the cortico-spinal tract (CST). In the remaining 2 patients, the lesions were located within the territory of the posterior cerebral artery. None of the 9 patients without CST involvement developed hemiplegia, whereas 5 (56%) of the 9 with CST involvement had hemiplegia, which is a fairly low incidence compared with that in adult cases. This difference was thought to be related to neonatal brain plasticity.

Cerebrovascular disease in Saudi Arabia

We studied the pattern and outcome of strokes in 200 Saudi patients. Cerebral infarction constituted 87% of strokes, subarachnoid hemorrhage 4.5%, cerebral hemorrhage 6.5%, and venous infarction 2%. The vessel most commonly involved was part or all of the middle cerebral artery, constituting 52% (90) of the 174 arterial infarcts. Lacunar infarcts were seen in 21% (37) of the patients with arterial infarcts. Among all 200 patients, 8% died and 8% had secondary generalized seizures. Hypertension occurred in 41% of the 174 patients with arterial infarcts and 62% of the 13 with cerebral hemorrhages. The highest incidence of hypertension as a risk factor was among those with lacunar infarcts (81%), ganglionic cerebral hemorrhages (80%), and infarcts of deep branches of the middle cerebral artery (57%). Embolic infarcts due to rheumatic heart disease constituted 11% of all arterial infarcts. We conclude that our pattern of strokes is similar to that of the west rather than that of the Japanese, but with less frequent arteriovenous malformations and aneurysms.

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.

99mTc-hexamethylpropylene amine oxime SPECT and X-ray CT in acute cerebral ischaemia

Early diagnosis of acute cerebral ischaemia is still unsatisfactory, because X-ray computed tomography (CT) does not reveal the site and extent of hypoperfusion within the first 24 h. Single photon emission computed tomography (SPECT) using 99mTc-hexamethylpropylene amine oxime (HMPAO) may offer earlier information, since the distribution of HMPAO follows the actual cerebral perfusion pattern. We therefore investigated 53 patients suffering from acute cerebral ischaemia (10 with transient ischaemic attacks, 9 with prolonged ischaemic reversible neurological deficits, 34 with completed stroke). SPECT and CT examinations were performed on days 1, 3, and 14. On day 1, SPECT revealed hypoperfused areas in 42 patients, whereas CT showed hypodensities only in 5. The sensitivity of SPECT was higher in cortical compared with subcortical ischaemia. In patients suffering from reversible neurological deficits SPECT normalized in the follow-up, corresponding to clinical improvement. In completed stroke, SPECT demonstrated variable perfusion patterns with hypo-, normo-, and hypoperfused areas on day 3 and especially on day 14. In contrast to CT, HMPAO SPECT leads to early diagnosis of cerebral ischaemia, in particular within the cerebral cortex.

SPET brain imaging with 201 diethyldithiocarbamate in acute ischaemic stroke

Thirty-five patients with acute ischaemic stroke were studied within 24 h after hospital admission with thallium 201 diethyldithiocarbamate single photon emission tomography (201Tl-DDC SPET) and X-ray computed tomography (CT). 201Tl-DDC is a non-redistributing agent that allows postponed imaging after early administration and early therapeutic intervention. In 16 patients both investigations were performed within 24 h after stroke onset. The sensitivity of SPET was 94% and of CT 81% in the first 24 h, when hypodensity and obliteration of sulci were used as CT reading criteria. When only hypodensity was used as a criterion, the sensitivity of CT was 50% in this group. Sensitivity of CT compared with SPET became increasingly better in patients with older infarcts (1-18 days). In two-thirds of patients, the lesion demonstrated on SPET was larger than that on CT, and this was especially so with older infarcts. Crossed cerebellar diaschisis occurred in 69% of patients. The high sensitivity of 201Tl-DDC SPET in the first 24 h after ischaemic stroke and the favourable properties of this radiopharmaceutical make it a method of interest in the assessment of initial perfusion defects in early experimental stroke therapies.

Brain damage after open heart surgery in patients with acute cardioembolic stroke

We evaluated 14 patients with acute cardiogenic embolism who underwent open heart surgery soon after the onset to determine the cerebral and cardiac factors that influence neurologic outcome. The mean interval from onset of cerebral embolism to surgery was 5.3 (range 1-16) days. Five of the 14 patients had vegetations from infective endocarditis (including prosthetic valve endocarditis) as embolic sources, eight had intracardiac thrombi, and one had atrial myxoma. The diagnosed site of infarction before surgery was based on computed tomographic and/or angiographic findings. Of the 14 patients, four had infarcts due to major artery occlusion, seven due to cortical branch occlusion, and two due to perforating artery occlusion; one patient presented with a transient ischemic attack without computed tomographic abnormalities. Ten patients (71%) showed no clinical aggravation after open heart surgery; however, two patients died of massive cerebral hemorrhage, one died of deterioration of brain edema, and another became comatose from midbrain hemorrhage immediately after surgery. The four patients with clinical aggravation comprised three with septic embolism and one with aseptic occlusion of a major artery. From these results, infective endocarditis and a large infarct appear to be possible aggravating factors when patients with recent cerebral embolism undergo open heart surgery.

Significance of cerebral CT in neurological practice

The significance of cerebral CT in neurological diagnostic practice was analysed in this prospective study on 1191 consecutive patients investigated during a one-year period. CT abnormalities were detected in 601 cases (51%), local hemispheral lesions (22%) generalized atrophy (19%) and infratentorial lesions (5%) being the most common findings. In the cases which had presented at referral to CT with clinical indices suggesting cerebral pathology the CT was abnormal in 71% (379 of 537) while the percentage was 34 (222 of 654) in the cases in which CT was performed for exclusion criteria. The clinical diagnostic reviewed by CT accuracy was 88% in cerebral tumours, 69% in cerebral infarction and from 83% to 94% in various intracranial hemorrhages but only 51% in cerebral atrophy which was the most common CT finding without clinical correlates. Apart from atrophy, CT revealed other pathology than clinically suggested in 147 cases (e.g. cerebral infarct in 58, hemorrhage in 16, tumour in 8 and diverse abnormalities in 54 cases). Contrast medium enhancement (used in 45% of the scans) provided more information when compared with the plain scan in 16% (86 of 537), no more than 3 lesions (0.6% of the enhanced scans; 2 meningeomas and one vascular malformation) being visible with enhancement only.

Herpes zoster ophthalmicus and ipsilateral infarction in the territory of the anterior choroidal artery

We report a further case of retarded contralateral hemiplegia syndrome after herpes zoster ophthalmicus in which the motor deficit was caused by an ischemic infarction in the territory supplied by the anterior choroidal artery. We discuss the clinical and physiopathogenetic features of the case and consider the computed tomographic and neurological patterns of anterior choroidal infarction.

Computed tomographic changes in juvenile hemiplegia

A retrospective analysis of the computer tomographic scans (CT) in 68 patients with juvenile hemiplegia was done. There was predominance of males (60%) over females, as well as left-sided lesions (57%). The CT findings were normal in 15% with atrophic changes in 34%, low attenuation areas of fluid density in 46% and 2.9% (two cases) with tumours. Typical areas of infarction following vascular injuries could be identified in 15% of cases. Six out of 8 calcifications were associated with tuberculoma of the brain. It is noted that cystic changes are the end-results of most infarctions, infections and other diseases within the brain. Therefore, CT as a diagnostic tool is efficacious in determining the anatomical site of lesion, but incapable of elucidating the aetiological basis of such a lesion.