Extended use of cranial CT in the evaluation of patients with stroke and transient ischaemic attacks

NIHSS score at admission can predict functional outcomes in patients with ischemic stroke undergoing carotid endarterectomy

OBJECTIVE

The aim of present study was to evaluate the prognostic impact of National Institutes of Health Stroke Scale (NIHSS) score in patients undergoing acute CEA, and to assess clinical and morphological factors that could predict worse outcomes.

METHODS

The data of 183 consecutive patients who have undergone CEA after ischemic stroke was analyzed from January 2015 to January 2021. Patients were divided into two groups using the NIHSS cut off point of 4. Functional dependence was assessed on hospital discharge and 90 days after.

RESULTS

In total, 102 patients (55.7%) had a minor stroke (Group A: NIHSS ≤ 4), whereas 81 patients (44.3%) had a moderate-major stroke (Group B: NIHSS > 4). Group A and group B showed significant differences in their intracranial anatomic features: presence of incomplete Circle of Willis (7.8% vs 17.3%; p=.05), volume of Cerebral ischemic lesion volume ≥4000 mm³ (5.9 % vs 24.7%; p=<.001), and high ASPECTS of 8 to 10 (75.5% vs 44.4%; p=<.001). The overall rate of combined perioperative stroke/myocardial infarction/death was 1.1%, with no strokes recorded during the waiting time to carotid endarterectomy (CEA). Patients in group A had a lower rate of functional dependence at discharge (4.9% vs. 35.8%; p = <.001) and at 90 days after index stroke event (2.5% vs. 19.6%; p = <.001) versus those in group B. Using multivariate binary logistic regression, admission NIHSS>4 was significantly associated with higher odds of functional dependence at discharge (OR= 7.9, 95%CI= 2.7-18.5, p = <.001) and at 90 days (OR= 10.4, 95%CI= 2.7-19.3, p = .002).

CONCLUSIONS

NIHSS>4 at admission will increase the risk of having higher mRS scores both at hospital discharge and at 90 days after index stroke event. acute CEA was safe and feasible in patients with ischemic stroke, even if they had previously undergone intravenous thrombolysis.

Predictors and Consequences of Silent Brain Infarction in Patients with Asymptomatic Carotid Stenosis

AIM

Silent brain infarction (SBI) is associated with an increased risk of stroke in patients with asymptomatic carotid stenosis (ACS), and is therefore one of the criteria for performing carotid endarterectomy (CEA). Despite an extensive literature, this issue is still a matter of debate. Aim of the present work was to evaluate incidence and predictors of SBI in patients undergoing CEA for ACS, and to investigate its possible impact on CEA outcome.

METHODS

All patients submitted to CEA in a single academic center from 2005 to 2019 were prospectively inserted into a specific database. The presence of SBI was evaluated by preoperative computed tomography (CT), considering exclusively infarctions in the carotid territories from an athero-embolic source. Preoperative characteristics were investigated as possible risk factor for SBI at the uni- and multivariate analysis. The impact of SBI on stroke occurrence after CEA was also evaluated.

RESULTS

In the designated period, over a total of 1288 ACS considered and submitted to CEA, 105 (8.2%) were associated with SBI. Male sex, hypertension, dyslipidaemia, smoking, contralateral carotid occlusion and severity of carotid stenosis were associated with SBI at the univariate analysis; preoperative statin therapy showed to be a protective factor. At the multivariate analysis, contralateral carotid occlusion and severity of stenosis were independently associated with SBI (OR: 3.16, 95%CI 1.62-6.18, P=.001; OR: 1.04, 95%CI 1.01-1.07, P=.004, respectively), with statin therapy confirmed as a protective factor (OR: 0.60, 95%CI: 0.40-0.92, P=.002). Overall post-CEA stroke rate was 0.9%, with a higher post-operative risk independently predicted by the presence of SBI (OR:4.23, 95%CI: 1.40-12.73, P=.01).

CONCLUSION

SBI is present in 8% of patients with ACS, and is significantly associated with contralateral carotid occlusion and severity of the carotid stenosis. Statin therapy reduces the occurrence of this phenomenon. The presence of SBI should be carefully considered in indication to CEA since it significantly increases the surgical risk.

Relationship between Calcification and Vulnerability of the Carotid Plaques

BACKGROUND

Carotid plaques with a high degree of calcification are usually considered at low embolic risk. However, since a precise evaluation of the extent of calcification is not possible preoperatively through duplex ultrasound and postoperatively by conventional histological examination due to the decalcification process, the relationship between the amount of calcium involvement and plaque vulnerability has not been evaluated yet. This study aims to correlate the extent of carotid plaque calcification with clinical, radiological, and histological complications.

METHODS

Symptomatic and asymptomatic consecutive patients submitted to carotid endarterectomy between January to December 2014 were included in the study. The amount of carotid calcification was assessed at preoperative computed tomography (CT) through measurement of thickness and circumferential calcium extension and graded from 1 to 8 accordingly (Babiarz classification). Patients were then categorized into 2 groups (low-level group: grade 1-5; high-level group: grade 6-8) and correlated with clinical characteristics and ipsilateral cerebral ischemic lesions at CT. Vulnerability of the plaque was assessed histologically according with American Heart Association (AHA) Classification. Results were overall blindly correlated.

RESULTS

One hundred five patients (81% male; age: 73 ± 8 years) were enrolled in the study. Forty (38%) were symptomatic and 43 (40%) had an ipsilateral focal lesion at preoperative cerebral CT. Thirty-six (38%) patients had high-level carotid calcification degree at CT scan. At histological analysis, 56 (56%) plaques were considered complicated (AHA type VI). Patients with high-level and low-level carotid calcification had similar epidemiological risk factors, preoperative neurological symptoms, and histological complications (17% vs. 15%, P = 0.76 and 50% vs. 55%, P = 0.62, respectively). The high-level calcification group showed a significantly higher incidence of ipsilateral cerebral lesions at preoperative CT (56% vs. 32%, P = 0.01).

CONCLUSIONS

A high level of calcification of the carotid plaque is not necessarily associated with lower vulnerability: the incidence of preoperative neurological symptoms and histological complications is similar in patients with and without extensive carotid plaque calcification. Cerebral ischemic lesions may be even more frequent in the presence of highly calcified plaques.

Basal Cerebral Computed Tomography as Diagnostic Tool to Improve Patient Selection in Asymptomatic Carotid Artery Stenosis

One-hundred patients were included to evaluate the role of cerebral computed tomography (CT) to improve patient selection in asymptomatic internal carotid stenosis. Symptomatic patients were assigned to group A, asymptomatic patients to group B. A cerebral CT pattern A was observed in groups A and B in 60% and 20%, respectively ( P < .0001). Between A and B groups, type 6 plaques were found, respectively, in 26.7% and 7.5% of patients ( P = .01); a type 5 in 51.7% and 45% ( P = .32) of patients; and a type 4 in 21.7% and 47.5% of patients, respectively ( P = .006). Within B group, the association of CT pattern A and histological plaque level 4, 5, and 6 was, respectively, 25% ( P = .15), 50% ( P = .53), and 25% ( P = .16). In group B, a 7-fold risk increase in CT pattern A was found in patients with level 6 plaque. In asymptomatic patients with high-risk plaque, a basal cerebral CT scan can be used as diagnostic tool to improve patient selection for intervention.

Striatal Hypodensities, Not White Matter Hypodensities on CT, Are Associated with Late-Onset Depression in Alzheimer's Disease

This study examined whether there were neuroanatomical differences evident on CT scans of individuals with dementia who differed on depression history. Neuroanatomical variables consisted of visual ratings of frontal lobe deep white matter, subcortical white matter, and subcortical gray matter hypodensities in the CT scans of 182 individuals from the Study of Dementia in Swedish Twins who were diagnosed with dementia and had information on depression history. Compared to individuals with Alzheimer's disease and no depression, individuals with Alzheimer's disease and late-onset depression (first depressive episode at age 60 or over) had a greater number of striatal hypodensities (gray matter hypodensities in the caudate nucleus and lentiform nucleus). There were no significant differences in frontal lobe deep white matter or subcortical white matter. These findings suggest that late-onset depression may be a process that is distinct from the neurodegenerative changes caused by Alzheimer's disease.

Silent cerebral events in asymptomatic carotid stenosis

BACKGROUND

Approximately 20% of strokes are attributable to carotid stenosis. However, the number of asymptomatic patients needed to prevent one stroke or death with endarterectomy is high at 17 to 32. There is a clear need to identify asymptomatic individuals at high risk of developing future ischemic events to improve the cost-effectiveness of surgery. Our aim was to examine the evidence for subclinical microembolization and silent brain infarction in the prediction of stroke in asymptomatic carotid stenosis using transcranial Doppler (TCD), computed tomography (CT), and magnetic resonance imaging (MRI).

METHODS

The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Articles regarding humans between 1966 and 2010 were identified through systematic searches of Pubmed, MEDLINE, and EMBASE electronic databases using a predetermined search algorithm.

RESULTS

Fifty-eight full text articles met the inclusion criteria. A median of 28% of microemboli positive patients experienced a stroke or transient ischemic attack during follow-up compared with 2% of microemboli negative patients (P = .001). The same was true for the end point of stroke alone with a median of 10% of microemboli positive patients experiencing a stroke vs 1% of microemboli negative patients (P = .004). A specific pattern of silent CT infarctions was related to future stroke risk (odds ratio [OR] = 4.6; confidence interval [CI] = 3.0-7.2; P < .0001). There are no prospective MRI studies linking silent infarction and stroke risk.

CONCLUSIONS

There is level 1 evidence for the use of TCD to detect microembolization as a risk stratification tool. However, this technique requires further investigation as a stroke prevention tool and would be complemented by improvements in carotid plaque imaging.

Texture Analysis of Ultrasonic Images of Symptomatic Carotid Plaques can Identify Those Plaques Associated with Ipsilateral Embolic Brain Infarction

OBJECTIVES

The aim of our study was to determine the association between objective, computerised texture analysis of carotid plaque ultrasonic images and embolic CT-brain infarction in patients presenting with hemispheric neurological symptoms.

DESIGN

Cross-sectional study in patients with 50%-99% (ECST) carotid stenosis.

PATIENTS AND METHODS

Carotid plaque ultrasonic images (n=54, 26 with TIAs and 28 with stroke) obtained during carotid ultrasound were normalised and standardised for resolution and subsequently assessed visually for the presence of discrete echogenic or juxtaluminal echolucent components and overall echogenicity (plaque type). Using computer software, 51 histogram/textural features of the plaque outlines were calculated. Factor analysis was subsequently applied to eliminate redundant variables. Small cortical, large cortical and discrete subcortical infarcts on CT-brain scan were considered as being embolic.

RESULTS

Twenty-five cases (46%) had embolic infarcts. On logistic regression, grey-scale median (GSM), a measure of echolucency, spatial grey level dependence matrices (SGLDM) correlation and SGLDM information measure of correlation-1, measures of homogeneity were significant (p<0.05), but not grey level runlength statistics (RUNL) Run Percentage (RP), stenosis severity, type of symptoms or echolucent juxtaluminal components. Using ROC curves methodology, SGLDM information measure of correlation-1 improved the value of GSM in distinguishing embolic from non-embolic CT-brain infarction.

CONCLUSION

Computerised texture analysis of ultrasonic images of symptomatic carotid plaques can identify those that are associated with brain infarction, improving the results achieved by GSM alone. This methodology could be applied to prospective natural history studies of symptomatic patients not operated on or randomised trials of patients undergoing carotid angioplasty and stenting in order to identify high-risk subgroups for cerebral infarction.

Patterns of brain computed tomography infarction and carotid plaque echogenicity

PURPOSE

It was suggested that in the absence of cardioembolism the discrete subcortical and cortical infarctions on brain computed tomography (CT) are most likely associated with carotid atheroma, whereas the hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions are most likely associated with other pathologic conditions. The aim of this study was to determine the ultrasonic characteristics of carotid plaques and the degree of stenosis that were associated with the different brain CT infarction patterns and normal CT (pattern A, discrete subcortical and cortical infarctions; pattern B, hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions).

METHODS

Four hundred nineteen carotid plaques (315 patients), producing 50% to 99% stenosis on duplex scanning, were studied. These plaques were imaged on duplex scanning, captured, digitized, and normalized (standardized) in a computer. Subsequently, their gray scale median (GSM) was evaluated to distinguish quantitatively the hypoechoic (low GSM) from the hyperechoic (high GSM) plaques. The brain CT infarction patterns of A, B, or normal CT on the ipsilateral hemisphere were noted.

RESULTS

The pattern A brain CT infarction was associated with carotid plaques having median GSM of 11 and median degree of stenosis of 80%, as contrasted with pattern B (median GSM, 28.5; median degree of stenosis, 75%) or normal CT (median GSM, 22; median degree of stenosis, 75%) (Kruskal-Wallis test, P <.001 for the GSM and P =.002 for the degree of stenosis). In the logistic regression analysis only the GSM and not the degree of stenosis distinguished the plaques associated with the three CT patterns.

CONCLUSIONS

The pattern A brain CT infarction was associated with hypoechoic plaques suggesting an involvement of extracranial carotid artery embolization, whereas the pattern B was associated with hyperechoic plaques suggesting an involvement of other mechanisms (hemodynamic, intracranial small and large vessel disease).

Correlates of embolic events detected by means of transcranial Doppler in patients with carotid atheroma

PURPOSE

This study identified in patients with carotid plaques the associations of emboli detected by means of transcranial Doppler (TCD) with cerebrovascular symptoms, brain computed tomography (CT) infarction patterns, and the attributes of plaques (echodensity, degree of stenosis).

METHODS

Eighty carotid plaques (in 59 patients), producing 50% to 99% stenosis, were imaged on duplex scanning and analyzed echomorphologically in a computer with the gray scale median (GSM). The GSM facilitated the quantitative distinction of dark (low GSM) from bright (high GSM) plaques. Stenosis was assessed with duplex scanning. Emboli were counted on TCD in the ipsilateral middle cerebral artery for half an hour. The brain CT infarction patterns (pattern A: discrete subcortical and cortical; pattern B: hemodynamic, diffuse white matter lesions, basal ganglia infarctions, lacunes) and normal CT and cerebrovascular symptoms on the ipsilateral hemisphere were noted.

RESULTS

Emboli were more frequent in symptomatic (median count, 3) than asymptomatic (median count, 0) hemispheres (Mann-Whitney U test, P =.031) and in hemispheres with pattern A infarction (median count, 3.5) than in hemispheres with pattern B infarction or normal CT (median count, 0; Kruskal-Wallis test, P =.047). The increased embolic count was associated with decreased GSM (Spearman correlation, P =.045, r = -0.22), but not with high degrees of stenosis (Spearman correlation, P =.44, r = 0.086).

CONCLUSION

Emboli were more frequent in symptomatic than asymptomatic hemispheres and in CT pattern A harboring hemispheres than in CT pattern B or normal hemispheres. They were more frequent in the presence of low-plaque echodensity, but not in the presence of a high degree of stenosis. These data support the embolic nature of cerebrovascular symptomatology and CT pattern A infarctions.

Stroke: pathogenesis, investigations, and prognosis--Part II of III

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part I the epidemiology, clinical picture, and risk factors were discussed, while part III will consist of the management and rehabilitation). In the present part (II) the pathogenetic and pathophysiologic aspects of stroke are described. Regarding the investigations apart from the history and clinical examination and general investigations, the following specialized investigations and their role are discussed in detail: Computed tomography (CT), magnetic resonance imaging (MRI), xenon-blood-flow, positron emission tomography (PET), cerebral angiography, magnetic resonance angiography (MRA), ultrasonography, transcranial Doppler (TCD), echocardiography, Holter monitoring, and biopsies. In addition, taking into account the information from the above-cited modalities a prognosis for the final outcome is presented.

Patterns of cerebrovascular symptomatology associated with carotid atheroma

The aim of this study was to identify ultrasonic tissue characteristics and stenosis of carotid plaques that correspond to amaurosis fugax, hemispheric transient ischaemic attack, and stroke. At total of 146 symptomatic carotid plaques (136 patients) associated with amaurosis fugax, hemispheric transient ischaemic attack, stroke, and having 50-99% stenosis on duplex, were studied. These plaques were imaged on duplex, captured in a computer and their grey scale median was evaluated to distinguish the dark (low grey scale median) from the bright (high grey scale median) plaques. Stenosis was assessed on duplex. The amaurosis fugax group corresponded to carotid plaques with low grey scale median and severe stenosis, as contrasted with the other two groups (hemispheric transient ischaemic attack and stroke) (P < 0.05). These results suggested that amaurosis fugax was dependent only on the instability of carotid plaques, whereas hemispheric transient ischaemic attack and stroke were both dependent on carotid plaques and other pathogenetic factors.

Reproducibility of computer-quantified carotid plaque echogenicity: can we overcome the subjectivity?

BACKGROUND AND PURPOSE

We sought to assess the reproducibility, interobserver variability, and application to clinical studies of a new method for the quantitative assessment of carotid plaque echogenicity.

METHODS

Carotid plaques were scanned with the use of ultrasound, and their images were stored in a computer. They were normalized by assigning certain gray values to blood and adventitia, and the gray scale median (GSM) was used to quantify their echogenicity. The variability between storage media, between degrees of magnification, and between probes was assessed. The method was applied to 232 asymptomatic carotid plaques causing 60% to 99% stenosis in relation to the presence of ipsilateral CT-demonstrated brain infarcts. In all parts of the study the plaque GSM was measured before and after normalization to evaluate its effect. Interobserver agreement for the scanning process was assessed.

RESULTS

The GSM mean difference before and after normalization for variability studies of storage media, degrees of magnification, and probes was -14.5 and -0.12, 2.24 and 1.68, and -8.3 and -0.7, respectively. The median GSM of plaques associated with ipsilateral nonlacunar silent CT-demonstrated brain infarcts was 14, and that of plaques that were not so associated was 30 (P:=0.003). The interobserver GSM difference was -0.05 (95% CI, -1.7 to 1.6).

CONCLUSIONS

Our method decreases the variability between storage media and between probes but not the variability between degrees of magnification. It separates echomorphologically the carotid plaques associated with silent nonlacunar CT-demonstrated brain infarcts from plaques that are not so associated.