Early CCT signs of supratentorial brain infarction: clinico-radiological correlations

Prediction model of early biomarkers of massive cerebral infarction caused by anterior circulation occlusion: Establishment and evaluation

Objective

The purpose of this study is to establish and evaluate an early biomarker prediction model of massive cerebral infarction caused by anterior circulation occlusion.

Methods

One hundred thirty-four patients with acute cerebral infarction from January 2018 to October 2020 were selected to establish the development cohort for the internal test of the nomogram. Ninety-one patients with acute cerebral infarction hospitalized in our hospital from December 2020 to December 2021 were constituted the validation cohort for the external validation. All patients underwent baseline computed tomography (CT) scans within 12 h of onset and early imaging signs (hyperdense middle cerebral artery sign, obscuration of the lentiform nucleus, insular ribbon sign) of acute cerebral infarction were identified on CT by two neurologists. Based on follow-up CT images, patients were then divided into a massive cerebral infarction group and a non-massive cerebral infarction group. The nomogram model was constructed based on logistic regression analysis with R language. The nomogram was subsequently validated in an independent external validation cohort. Accuracy and discrimination of the prediction model were evaluated by a calibration chart, receiver operating characteristic (ROC) curve, and decision curve.

Results

The indicators, including insular ribbon sign, reperfusion therapy, National Institutes of Health Stroke Scale (NHISS) score, previous cerebral infarction, and atrial fibrillation, were entered into the prediction model through binary logistic regression analysis. The prediction model showed good predictive ability. The area under the ROC curve of the prediction model was 0.848. The specificity, sensitivity, and Youden index were 0.864, 0.733, and 0.597, respectively. This nomogram to the validation cohort also showed good discrimination (AUC = 0.940, 95% CI 0.894–0.985) and calibration.

Conclusion

Demonstrating favorable predictive efficacy and reproducibility, this study successfully established a prediction model of CT imaging signs and clinical data as early biomarkers of massive cerebral infarction caused by anterior circulation occlusion.

Intravenous thrombolysis in stroke patients with hyperdense middle cerebral artery sign

BACKGROUND AND PURPOSE

We assessed the safety and efficacy of intravenous thrombolysis (IVT) in acute stroke patients with hyperdense middle cerebral artery sign (HMCAS).

PATIENTS AND METHODS

Data from consecutive patients with acute (within 6 h of symptom onset) ischaemic stroke admitted between January 1999 and November 2007, in whom HMCAS was diagnosed on admission CT scan was retrospectively analysed. Seventy-one patients, admitted within the 3-h window, were treated with IVT, whilst further 42, admitted 3-6 h after symptom onset, were not. At 3-month clinical follow-up, outcome, mortality at 3 months and incidence of symptomatic intracranial haemorrhage were evaluated.

RESULTS

The two groups were comparable concerning age, stroke risk factors, prior antithrombotic treatment and NIHSS scores on admission. Good outcome (mRS score <or= 1) was observed in 12/71 (17%) patients who were treated with IVT and in 1/42 (2%) patients who were not (P = 0.02). IVT treatment was identified as independent predictor of good outcome (P = 0.05). Mortality was 20% in patients treated with IVT and 12% in remaining patients (P = 0.3). Symptomatic intracranial haemorrhage occurred in 1 patient of each group (2%).

CONCLUSIONS

These findings suggest that IVT in patients with HMCAS results in significantly better outcome, without significantly influencing mortality.

Early Signs of Brain Infarction at CT: Observer Reliability and Outcome after Thrombolytic Treatment—Systematic Review

PURPOSE

To review systematically all reported early computed tomographic (CT) signs in acute ischemic stroke to determine interobserver agreement and the relationship between early CT signs and patient outcome with or without thrombolysis.

MATERIALS AND METHODS

A systematic review of the literature was conducted by using Cochrane Stroke Group methodology to identify studies published between 1990 and 2003 that were performed to assess interobserver agreement about early signs of infarction on CT scans obtained within 6 hours after onset of stroke symptoms and determine the relation of early signs of infarction to clinical outcome, including any interactive effect of thrombolysis. Interobserver agreement was measured with the kappa statistic, sensitivity, and specificity. The relation of early signs to clinical outcome with or without thrombolysis was assessed with calculated odds ratios and 95% confidence intervals.

RESULTS

In 15 studies of interobserver agreement (median of 30 CT scans and six raters), the prevalence of all early infarction signs was 61% +/- 21 (standard deviation). Interobserver agreement (kappa statistics) ranged from 0.14 to 0.78 for any early infarction sign. The mean sensitivity and specificity for detection of early infarction signs with CT were 66% (range, 20%-87%) and 87% (range, 56%-100%), respectively. Experience improved detection, but knowledge of symptoms did not. In 15 studies of early infarction signs and outcome (including seven thrombolysis trials) in 3468 patients, any early infarction sign increased the risk of poor outcome (odds ratio, 3.11; 95% confidence interval: 2.77, 3.49). Two studies that sought interaction between early infarction signs and thrombolysis found no evidence that thrombolysis given in the presence of early infarction signs resulted in worse outcome than that due to early signs alone.

CONCLUSION

Further work is required to determine which signs are most reliably detected, whether scoring systems help to improve detection, and whether any early infarction sign should influence decisions concerning thrombolysis.

Perfusion harmonic imaging in acute middle cerebral artery infarction

Initial reports indicate that cerebral perfusion deficits in acute ischemic stroke might be detectable by means of transcranial harmonic imaging after an ultrasound contrast agent (UCA) bolus injection. Twenty-four patients with acute middle cerebral artery (MCA) infarction were investigated twice with perfusion harmonic imaging (PHI) after Levovist (Schering, Berlin, Germany) bolus injection no longer than 12 h after symptom onset. The findings were compared with those of cranial computed tomography (CCT). All 24 patients suffered from acute ischemic stroke of the MCA territory (median National Institutes of Health Stroke Scale score: 15 points). Corresponding to the area of infarction in follow-up CCT, a marked contrast deficit was visualized in 19 of 24 patients by initial PHI, which had a sensitivity and specificity of 86.4% and 96.2%, respectively, for predicting the occurrence and localization of a definite infarction in the midthalamic plane. The area of hypoperfusion in the initial PHI investigation correlated with the definite area of infarction in follow-up CCT (r=0.66, p<0.01). When time-intensity curves of both hemispheres were compared, the areas under the curve were significantly less in the symptomatic brain regions (p=0.01). With PHI and UCA bolus injection, it is possible to assess cerebral perfusion deficits that correlate with the definite area of infarction in acute ischemic stroke patients.

Visible infarction on computed tomography is an independent predictor of poor functional outcome after stroke, and not of haemorrhagic transformation

OBJECTIVES

To examine a very large dataset to provide a robust answer to the question of whether visible infarction on computed tomography was (a) an independent predictor of functional outcome at all times up to 48 hours after stroke, and (b) independently associated with haemorrhagic transformation, with or without antithrombotic treatment.

METHODS

The study assessed associations between visible infarction, time to randomisation, baseline neurological deficit, stroke syndrome, allocated aspirin or heparin treatment, recurrent haemorrhagic stroke, early death and six month functional outcome in the International Stroke Trial.

RESULTS

Of 12 550 patients, 6267 (50%) had visible infarction up to 48 hours after stroke. The prevalence of visible infarction increased with increasing time from onset and extent of the stroke syndrome. Visible infarction was independently associated with increased death within 14 days (odds ratio (OR) 1.17, 95% CI 1.02 to 1.35), and of death or dependency at six months (OR 1.42, 95% CI 1.31 to 1.55), an absolute increase of 13%, or 130 per 1000 more dead or dependent patients with visible infarction than without it. There was no significant independent relation between visible infarction and fatal or non-fatal haemorrhagic transformation, or interaction between visible infarction and aspirin or heparin treatment allocation with six month functional outcome.

CONCLUSIONS

Visible infarction on computed tomography up to 48 hours after stroke is an independent adverse prognostic sign.

Ultrasonographic prediction of patients' outcome in hyperacute ischemic stroke

OBJECTIVE

We examined whether carotid ultrasonographic (US) findings in hyperacute ischemic stroke are useful to predict patients' outcome.

METHODS

We studied 73 consecutive patients with carotid stroke using both computed tomography (CT) and duplex carotid ultrasonography within 6 h of stroke onset. We evaluated early CT findings defined as obscuration of the lentiform nucleus, loss of the insular ribbon and/or cortical effacement, and US findings indicating internal carotid artery (ICA) or middle cerebral artery trunk occlusion. The National Institute of Health Stroke Scale (NIHSS) at admission and modified Rankin scale on day 30 were assessed.

RESULTS

According to multiple logistic regression analysis, positive US findings (P = 0.0045, odds ratio, 11.1) provided the best predictor of modified Rankin scale score > or =3 compared with a baseline NIHSS> or =16 (P = 0.036, odds ratio, 7.9) and early CT findings (P = 0.18).

CONCLUSION

US findings of hyperacute stroke may provide a better predictor of patients' outcome.

Computed tomographic and transcranial Doppler sonographic findings in acute and subacute phases of middle cerebral artery strokes

PURPOSE

The aim of this study was to compare the sensitivities of visual and densitometric analyses of CT scans and transcranial Doppler sonograms (TCD) in detecting early changes in acute stroke.

METHODS

CT and TCD were each performed twice in 12 patients; first in the acute phase (within 28 hours of stroke onset), then in the subacute phase (mean +/- standard deviation, 6 +/- 3 days after onset) of a stroke. Hypodensity on the CT scans was evaluated visually, and the optical density of both the stroke region and the corresponding region on the unaffected side was measured. Measurement of flow parameters in the middle cerebral artery was carried out with TCD before or shortly (within 4 hours) after CT scanning.

RESULTS

In the acute phase, blood flow velocities were significantly lower on the affected side than they were on the unaffected side (means, 42 +/- 13 and 55 +/- 25 cm/second, respectively; p = 0.012). Marked asymmetry in flow velocity was found in 3 of the 4 patients who had normal CT scans in the acute phase. The asymmetry in flow velocity disappeared by the sixth day after the stroke. The resistance index did not correlate with the final infarct size.

CONCLUSIONS

In some patients, the use of TCD in acute stroke may show alterations that reflect tissue damage that is undetectable on CT. Therefore, CT and TCD should be considered complementary diagnostic tools in the acute phase of stroke.

Mechanical ventilation in patients with hemispheric ischemic stroke

OBJECTIVE

Whether stroke patients should be ventilated mechanically is still a contentious issue, because their outcome is very poor. We wanted to investigate how often mechanical ventilation is indicated in patients with hemispheric ischemic stroke as well as the outcome of these patients and the factors by which outcome is influenced.

DESIGN

Prospective case series.

SETTING

University hospital, neurocritical care unit.

SUBJECTS

Subjects were 218 patients who met the following inclusion criteria: age 18-85 yrs, acute hemispheric ischemic infarction, clinical examination, and computed tomography within 6 hrs after the onset of symptoms.

INTERVENTIONS

Mechanical ventilation was instituted with one or more of the following conditions: deterioration of consciousness with the inability to protect the airway; PaO2 of <60; P(CO2) of >60 mm Hg; breath rate of >40 breaths/min; and left heart insufficiency with definitive or impending pulmonary edema.

MEASUREMENTS AND MAIN RESULTS

Mechanical ventilation was indicated for 52 (24%) of the 218 patients: in 47 (90%) patients because of deterioration of consciousness, and in five (10%) patients because of heart insufficiency and/or pneumonia. In a logistic regression model, the history of hypertension and a size of infarction exceeding two thirds of the middle cerebral artery territory were independent variables for the application of mechanical ventilation. After 3 months, 42 (81%) of these 52 patients had died. The most common cause of death was fatal midbrain herniation caused by complete middle cerebral artery infarction. Patients who survived had a good-to-fair outcome.

CONCLUSIONS

New therapeutic strategies (e.g., hemicraniectomy) must be developed to reduce mortality and improve the outcome for this subgroup of ischemic stroke patients. Mechanical ventilation is and will remain a crucial element within such new concepts.

Predictors of stroke outcome

Recent literature has identified many of the important factors helpful in predicting outcome even at the very acute stage of stroke. Demographic factors, risk factors, clinical exam findings, clinical scales laboratory tests, and neuroimaging all provide important information that can assist the clinician in predicting outcome. Specific factors seem to influence the effect of stroke treatments such as thrombolysis. Consideration of these factors is important when treatment decisions such as thrombolysis are being contemplated. New techniques such as eco-planar MR Imaging are now being developed that seem extremely accurate in predicting outcome. These techniques represent the "crystal ball" of predicting stroke outcome.

Computed tomography findings in the first few hours of ischemic stroke: implications for the clinician

In order to evaluate the clinical usefulness of emergency computed tomography (CT) in acute ischemic stroke, we assessed whether CT findings within the first few hours of stroke onset reliably predict type, site and size of the index infarction, and risk of death or disability. For this reason we reviewed clinical and CT findings in a cohort of unselected consecutive patients referred to the stroke unit of a large urban hospital because of a presumed ischemic stroke in the anterior circulation (AC), and submitted to CT within 5 h from onset. Out of 158 total patients, emergency CT revealed parenchymal changes compatible with AC focal ischemia in 77 (49%) and a hyperdense middle cerebral artery (MCA) in 41 (26%). Parenchymal changes and hyperdense MCA predicted an AC territorial infarction respectively in 97% of cases (95% C.I. 93% to 100%) and in 95% of cases (95% C.I. 88% to 100%). Site and size of early changes coincided with those of final lesions in 79% of patients with cortical changes and in 95% of patients with cortico-subcortical changes, but only in 37% of patients with initial subcortical changes, the remainder of whom developed a cortico-subcortical infarction. At logistic regression parenchymal changes were the only independent predictor of an AC territorial infarction. Negative predictive power, however, was only 40% (95% C. I. 29% to 51%) for parenchymal changes, and 35% for hyperdense MCA (95% C.I. 26% to 44%). The odds for death or disability at 1 month associated with parenchymal changes were thrice as high as with negative CT, even after adjustment for clinical severity on admission. These results indicate that CT scan adds significantly to the prediction of outcome made on clinical grounds. The frequent development of a territorial infarction in patients with initially negative CT and the subsequent recruitment of the cortex in those initially exhibiting only subcortical changes suggest that the transition from ischemia to infarction often occurs after the first five h following stroke.

Imaging developing brain infarction

Continued advances in neuroimaging technology have made it practical to image multiple aspects of evolving brain infarction during the potential window period of therapeutic opportunity in stroke. Recent methodologic developments include computed tomography angiography and perfusion, and the description of quantitative parameters for magnetic resonance blood oxygen level-dependent perfusion imaging. In pathophysiologic studies, metabolism and function in the ischemic focus and the peri-infarct tissue have been further characterized. Clinical studies have focused on the applications of computed tomography and magnetic resonance imaging for prethrombolysis patient selection. These methods have an important role in the evaluation and development of new pharmaceutical agents and will be increasingly used in clinical practice as new therapies become available.