Management Patterns and Outcomes After Traumatic Brain Injury With Associated Blunt Cerebrovascular Injury

BACKGROUND AND OBJECTIVES

Although blunt cerebrovascular injuries (BCVIs) are relatively common in patients with traumatic brain injuries (TBIs), uncertainty remains regarding optimal management strategies to prevent neurological complications, morbidity, and mortality. Our objectives were to characterize common care patterns; assess the prevalence of adverse outcomes, including stroke, functional deficits, and death, by BCVI grade; and evaluate therapeutic approaches to treatment in patients with BCVI and TBI.

METHODS

Patients with TBI and BCVI treated at our Level I trauma center from January 2016 to December 2020 were identified. Presenting characteristics, treatment, and outcomes were captured for univariate and multivariate analyses.

RESULTS

Of 323 patients with BCVI, 145 had Biffl grade I, 91 had grade II, 49 had grade III, and 38 had grade IV injuries. Lower-grade BCVIs were more frequently managed with low-dose (81 mg) aspirin ( P < .01), although all grades were predominantly treated with high-dose (150-600 mg) aspirin ( P = .10). Patients with low-grade BCVIs had significantly fewer complications ( P < .01) and strokes ( P < .01). Most strokes occurred in the acute time frame (<24 hours), including 10/11 (90.9%) grade IV-related strokes. Higher BCVI grade portended elevated risk of stroke (grade II odds ratio [OR] 5.3, grade III OR 12.2, and grade IV OR 19.6 compared with grade I; all P < .05). The use of low- or high-dose aspirin was protective against mortality (both OR 0.1, P < .05).

CONCLUSION

In patients with TBI, BCVIs impart greater risk for stroke and other associated morbidities as their severity increases. It may prove difficult to mitigate high-grade BCVI-related stroke, considering most events occur in the acute window. The paucity of late time frame strokes suggest that current management strategies do help mitigate risks.

Extracranial carotid artery atherosclerotic plaque and APOE polymorphisms: a systematic review and meta-analysis

Introduction

Carotid atherosclerotic plaque is an important independent risk factor for stroke. Apolipoprotein E (APOE) influences cholesterol levels and certain isoforms are associated with increased carotid atherosclerosis, though the exact association between APOE and carotid plaque is uncertain. The study aimed to evaluate the association between APOE and carotid plaque.

Methods

A systematic review was performed to retrieve all studies which examined the association between carotid plaque and APOE. This study was conducted in accordance with the PRISMA guidelines. Independent readers extracted the relevant data from each study including the type of imaging assessment, plaque definition, frequency of APOE E4 carrier status and type of genotyping. Meta-analyses with an assessment of study heterogeneity and publication bias were performed. Results were presented in a forest plot and summarized using a random-effects model.

Results

After screening 838 studies, 17 studies were included for systematic review. A meta-analysis of 5 published studies showed a significant association between ε4 homozygosity and carotid plaque [odds ratio (OR), 1.53; 95% CI, 1.16, 2.02; p = .003]. Additionally, there was a significant association between patients possessing at least one ε4 allele, heterozygotes or homozygotes, and carotid plaque (OR, 1.25; 95% CI, 1.03, 1.52; p = .03). Lastly, there was no association between ε4 heterozygosity and carotid plaque (OR, 1.08; 95% CI, 0.93, 1.26; p = .30).

Conclusion

APOE ε4 allele is significantly associated with extracranial carotid atherosclerotic plaque, especially for homozygous individuals.

Extracranial Carotid Plaque Calcification and Cerebrovascular Ischemia: A Systematic Review and Meta-Analysis

BACKGROUND

Although coronary calcification quantification is an established approach for cardiovascular risk assessment, the value of quantifying carotid calcification is less clear. As a result, we performed a systematic review and meta-analysis to evaluate the association between extracranial carotid artery plaque calcification burden and ipsilateral cerebrovascular ischemic events.

METHODS

A comprehensive literature search was performed in the following databases: Ovid MEDLINE(R) 1946 to July 6, 2022; OVID Embase 1974 to July 6, 2022; and The Cochrane Library (Wiley). We performed meta-analyses including studies in which investigators performed a computed tomography assessment of calcification volume, percentage, or other total calcium burden summarizable in a single continuous imaging biomarker and determined the association of these features with the occurrence of ipsilateral stroke or transient ischemic attack.

RESULTS

Our overall meta-analysis consisted of 2239 carotid arteries and 9 studies. The presence of calcification in carotid arteries ipsilateral to ischemic stroke or in stroke patients compared with asymptomatic patients did not demonstrate a significant association with ischemic cerebrovascular events (relative risk of 0.75 [95% CI, 0.44-1.28]; P=0.29). When restricted to studies of significant carotid artery stenosis (>50%), the presence of calcification was associated with a reduced risk of ischemic stroke (relative risk of 0.56 [95% CI, 0.38-0.85]; P=0.006). When the analysis was limited to studies of patients with mainly nonstenotic plaques, there was an increased relative risk of ipsilateral ischemic stroke of 1.72 ([95% CI, 1.01-2.91]; P=0.04). Subgroup meta-analyses of total calcium burden and morphological features of calcium showed wide variability in their strength of association with ischemic stroke and demonstrated significant heterogeneity.

CONCLUSIONS

The presence of calcification in carotid plaque confers a reduced association with ipsilateral ischemic events, although these results seem to be limited among carotid arteries with higher degrees of stenosis. Adoption of carotid calcification measures in clinical decision-making will require additional studies providing more reproducible and standardized methods of calcium characterization and testing these imaging strategies in prospective studies.

Report from the society of magnetic resonance angiography: clinical applications of 7T neurovascular MR in the assessment of intracranial vascular disease

In recent years, ultra-high-field magnetic resonance imaging (MRI) applications have been rapidly increasing in both clinical research and practice. Indeed, 7-Tesla (7T) MRI allows improved depiction of smaller structures with high signal-to-noise ratio, and, therefore, may improve lesion visualization, diagnostic capabilities, and thus potentially affect treatment decision-making. Incremental evidence emerging from research over the past two decades has provided a promising prospect of 7T magnetic resonance angiography (MRA) in the evaluation of intracranial vasculature. The ultra-high resolution and excellent image quality of 7T MRA allow us to explore detailed morphological and hemodynamic information, detect subtle pathological changes in early stages, and provide new insights allowing for deeper understanding of pathological mechanisms of various cerebrovascular diseases. However, along with the benefits of ultra-high field strength, some challenges and concerns exist. Despite these, ongoing technical developments and clinical oriented research will facilitate the widespread clinical application of 7T MRA in the near future. In this review article, we summarize technical aspects, clinical applications, and recent advances of 7T MRA in the evaluation of intracranial vascular disease. The aim of this review is to provide a clinical perspective for the potential application of 7T MRA for the assessment of intracranial vascular disease, and to explore possible future research directions implementing this technique.

CGRP, Migraine, and Brain MRI in CADASIL: A Pilot Study

BACKGROUND

Migraine is associated with neuroimaging differences in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, it is unknown if migraine-related disability (MRD) or if calcitonin gene-related peptide (CGRP), a vasoactive peptide important in migraine pathology, have radiographic implications. The aims of this study were to identify whether MRD or interictal serum CGRP levels impacted neuroimaging findings for those with CADASIL.

MATERIALS AND METHODS

A cross-sectional analysis was performed. The primary outcomes were neuroimaging differences associated with MRD among those with migraine or interictal serum CGRP levels of those with and without migraine. MRD was defined by 2 migraine disability scales (Migraine Disability Assessment, Headache Impact Test-6). Retrospective brain magnetic resonance imaging was reviewed (average 1.7 ± 2.0 y before enrollment). Rank-sum and χ 2 tests were used.

RESULTS

Those with migraine (n=25, vs. n=14 without) were younger [median 49 (25 to 82) y vs. 60 (31 to 82) y, P <0.007], had fewer cerebral microbleeds (0 to 31 vs. 0 to 50, P =0.02) and less frequently had anterior temporal lobe T2 hyperintensities [68% (17/25) vs 100% (14/14), P =0.02]. MRD scale outcomes had no significant radiographic associations. Interictal serum CGRP did not differ (migraine: n=18, 27.0±9.6 pg/mL vs. no migraine: n=10, 26.8±15.7 pg/mL, P =0.965).

CONCLUSIONS

Migraine may forestall microangiopathy in CADASIL, though possibly independent of severity as measured by MRD. Interictal serum CGRP did not differ in our cohort suggesting CGRP may not be vital to migraine pathophysiology in CADASIL. Larger studies are needed to account for age differences.

Association Between Spotty Calcification in Nonstenosing Extracranial Carotid Artery Plaque and Ipsilateral Ischemic Stroke

Background Small spotty calcifications in the coronary arteries are associated with an increased risk of myocardial infarction. We examined the association between spotty calcifications near the carotid bifurcations and ipsilateral ischemic stroke in patients with <50% luminal stenosis of the extracranial carotid arteries. Methods and Results We used data from the CAESAR (Cornell Acute Stroke Academic Registry), a prospective registry of all patients with acute ischemic stroke admitted to our institution. We included patients who met criteria for cryptogenic stroke and underwent computed tomography angiography and brain magnetic resonance imaging. Patients with extracranial carotid artery stenosis ≥50% and patients with posterior or bilateral anterior circulation infarcts were excluded. We examined the carotid bifurcations for spotty calcifications, defined as ≥1 contiguous regions of luminal calcification ≤3 mm along the long axis of the vessel. We also measured low-density plaque and maximum plaque thickness. The eligible cohort consisted of 117 patients with a mean age of 66.7±1.65 years with a median National Institute of Health Stroke Scale stroke at the time of arrival of 6 (range, 3-13). The number of spotty calcifications present within a low-density plaque was significantly associated with ipsilateral infarction (0.3±0.8 versus 0.1±0.4, P=0.02). Maximum plaque thickness was also significantly associated with ipsilateral infarction (1.4 mm ±1.5 versus 1.0 mm ±1.1, P=0.004). Conclusions Spotty calcifications associated with low-density plaque and maximum plaque thickness were associated with ipsilateral ischemic stroke in patients with nonstenotic carotid atherosclerosis, suggesting a role as imaging markers of high-risk plaque.

MRI Detection of Carotid Intraplaque Hemorrhage and Postintervention Cognition

BACKGROUND AND PURPOSE

Cognitive improvement has been reported after carotid revascularization and attributed to treating stenosis and correcting hypoperfusion. This study investigated the effect of carotid intraplaque hemorrhage on postintervention cognition.

MATERIALS AND METHODS

In this institutional review board-approved single-center study, consecutive patients scheduled for carotid surgery were recruited for preoperative carotid MR imaging (MPRAGE) and pre- and postintervention cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status. Pre- and postintervention scores were compared using t tests and multivariable linear regression.

RESULTS

Twenty-three participants were included, with endarterectomy performed in 20 (87%) and angioplasty/stent placement, in 3 (13%). Overall, statistically significant improvements occurred in the pre- versus postintervention mean Total Scale score (92.1 [SD, 15.5] versus 96.1 [SD, 15.8], P = .04), immediate memory index (89.4 [SD, 18.2] versus 97.7 [SD, 14.9], P < .001), and verbal index (96.1 [SD, 14.1] versus 103.0 [SD, 12.0], P = .002). Intraplaque hemorrhage (+) participants (n = 11) had no significant improvement in any category, and the attention index significantly decreased (99.4 [SD, 18.0] versus 93.5 [SD, 19.4], P = .045). Intraplaque hemorrhage (-) participants (n = 12) significantly improved in the Total Scale score (86.4 [SD, 11.8] versus 95.5 [SD, 12.4], P = .004), immediate memory index (82.3 [SD, 14.6] versus 96.2 [SD, 14.1], P = .002), delayed memory index (94.3 [SD, 14.9] versus 102.4 [SD, 8.0], P = .03), and verbal index (94.3 [SD, 13.2] versus 101.5 [SD, 107.4], P = .009). Postintervention minus preintervention scores for intraplaque hemorrhage (+) versus (-) groups showed statistically significant differences in the Total Scale score (-0.4 [SD, 6.8] versus 8.0 [SD, 8.5], P = .02), attention index (-5.9 [SD, 8.5] versus 4.3 [SD, 11.9], P = .03), and immediate memory index (4.2 [SD, 6.7] versus 12.2 [SD, 10.2], P = .04).

CONCLUSIONS

Cognitive improvement was observed after carotid intervention, and this was attributable to intraplaque hemorrhage (-) plaque. MR imaging detection of intraplaque hemorrhage status may be an important determinant of cognitive change after intervention.

Calcifying Pseudoneoplasm of the Neuraxis Presenting with Vasogenic Edema and a Perilesional Cyst

Calcifying pseudoneoplasms of the neuraxis (CAPNONs) are uncommon benign lesions that are rarely diagnosed radiographically. We report an unusual case of a left middle cerebellar peduncle CAPNON with vasogenic edema and a perilesional cyst. The patient was a 36-year-old woman with a 20-year history of left-sided hearing loss that had recently progressed. Computed tomography and magnetic resonance imaging showed a heterogenous calcified lesion with vasogenic edema and a perilesional cyst in the left middle cerebellar peduncle. Although it is a rare radiographic feature of CAPNON, vasogenic edema should be included as a possible feature of this uncommon tumefactive lesion.

The role of cross-sectional imaging of the extracranial and intracranial vasculature in embolic stroke of undetermined source

Despite an extensive workup, nearly one third of ischemic strokes are defined as Embolic Stroke of Undetermined Source (ESUS), indicating that no clear etiologic cause has been identified. Since large vessel atherosclerotic disease is a major cause of ischemic stroke, we focus on imaging of large vessel atherosclerosis to identify further sources of potential emboli which may be contributing to ESUS. For a stroke to be considered ESUS, both the extracranial and intracranial vessels must have &lt;50% stenosis. Given the recent paradigm shift in our understanding of the role of plaque vulnerability in ischemic stroke risk, we evaluate the role of imaging specific high-risk extracranial plaque features in non-stenosing plaque and their potential contributions to ESUS. Further, intracranial vessel-wall MR is another potential tool to identify non-stenosing atherosclerotic plaques which may also contribute to ESUS. In this review, we discuss the role of cross-sectional imaging of the extracranial and intracranial arteries and how imaging may potentially uncover high risk plaque features which may be contributing to ischemic strokes.

Association of Carotid Intima Media Thickening with Future Brain Region Specific Amyloid-β Burden

BACKGROUND

Carotid atherosclerosis is associated with cognitive impairment and dementia, though there is limited evidence of a direct link between carotid disease and amyloid-β (Aβ) burden.

OBJECTIVE

We studied the association of baseline and progressive carotid intima media thickness (CIMT) with Aβ on 11C-Pittsburgh Compound B (PiB) to determine if those with carotid atherosclerosis would have higher Aβ burden.

METHODS

We studied 47 participants from the Framingham Offspring cohort with carotid ultrasounds measuring CIMT at their 6th clinic examination (aged 49.5±5.7 years) and an average of 9.6 years later, and PiB imaging measuring Aβ on average 22.1 years post baseline. We used multivariate linear regression analyses to relate baseline, follow-up, mean, and progression of internal carotid artery (ICA) and common carotid artery (CCA) CIMT to Aβ in brain regions associated with Alzheimer's disease (AD) and related dementias (ADRD), adjusting for age, sex, and other vascular risk factors.

RESULTS

Participants with higher mean ICA IMT had more Aβ in the precuneus (beta±standard error [β±SE]: 0.466±0.171 mm, p = 0.01) and the frontal, lateral, and retrosplenial regions (β±SE: 0.392±0.164 mm, p = 0.022) after adjusting for age, sex, vascular risk factors, and medication use. We did not find an association between any CCA IMT measures and Aβ or progression of ICA or CCA IMT and Aβ.

CONCLUSION

Carotid atherosclerosis, as measured by ICA IMT, is associated with increased Aβ burden later in life. These findings support a link between vascular disease and AD/ADRD pathophysiology.

Comparison of Recent Practice Guidelines for the Management of Patients With Asymptomatic Carotid Stenosis

Despite the publication of several national/international guidelines, the optimal management of patients with asymptomatic carotid stenosis (AsxCS) remains controversial. This article compares 3 recently released guidelines (the 2020 German-Austrian, the 2021 European Stroke Organization [ESO], and the 2021 Society for Vascular Surgery [SVS] guidelines) vs the 2017 European Society for Vascular Surgery (ESVS) guidelines regarding the optimal management of AsxCS patients.The 2017 ESVS guidelines defined specific imaging/clinical parameters that may identify patient subgroups at high future stroke risk and recommended that carotid endarterectomy (CEA) should or carotid artery stenting (CAS) may be considered for these individuals. The 2020 German-Austrian guidelines provided similar recommendations with the 2017 ESVS Guidelines. The 2021 ESO Guidelines also recommended CEA for AsxCS patients at high risk for stroke on best medical treatment (BMT), but recommended against routine use of CAS in these patients. Finally, the SVS guidelines provided a strong recommendation for CEA+BMT vs BMT alone for low-surgical risk patients with >70% AsxCS. Thus, the ESVS, German-Austrian, and ESO guidelines concurred that all AsxCS patients should receive risk factor modification and BMT, but CEA should or CAS may also be considered for certain AsxCS patient subgroups at high risk for future ipsilateral ischemic stroke.

Carotid Artery Stiffness: Imaging Techniques and Impact on Cerebrovascular Disease

Arterial stiffness is an important measure of vascular aging and atherosclerosis. Though it is measured in many well-known epidemiologic cohort studies, arterial stiffness is often overlooked in routine clinical practice for a number of reasons including difficulties in measurement, variations in definition, and uncertainties surrounding treatment. Central arterial stiffness, a surrogate for aortic stiffness, is the most commonly measured marker of arterial stiffness. In addition to central stiffness, there are also a number of ultrasound based techniques to measure local vascular stiffness, including carotid stiffness. There is evidence that both local carotid stiffness and central arterial stiffness measures are associated with multiple cerebrovascular processes, including stroke and cognitive dysfunction. Mechanistic explanations supporting this association include increased flow load experienced by the cerebral microvasculature leading to cerebral parenchymal damage. In this article, we review definitions of carotid artery stiffness measures and pathophysiologic mechanisms underpinning its association with plaque development and downstream cerebral pathology. We will review the evidence surrounding the association of carotid stiffness measures with downstream manifestations including stroke, cerebral small vessel disease detected on brain MR such as white matter hyperintensities and covert brain infarctions, brain atrophy, and cognitive dysfunction. With consistent definitions, measurement methods, and further scientific support, carotid stiffness may have potential as an imaging-based risk factor for stroke and cognitive decline.

Association between Extracranial Carotid Artery Plaque and Cognitive Dysfunction: A Systematic Review and Meta-Analysis

BACKGROUND

Extracranial carotid atherosclerosis has been variably associated with dementia. Prior studies have focused on the association of carotid intima media thickness or carotid stenosis; however, there is evidence that carotid plaque may contribute to dementia, perhaps via microembolic phenomena.

OBJECTIVES

We sought to evaluate the role of carotid plaque in contributing to cognitive impairment by performing a systematic review and meta-analysis to summarize the association between extracranial carotid plaque and cognitive dysfunction and dementia.

METHODS

We performed a comprehensive literature search evaluating the association of extracranial carotid plaque with cognition. We included studies measuring carotid plaque on ultrasound, computed tomography, or MR and also evaluated cognition through neuropsychological testing. Meta-analyses with assessment of study heterogeneity and publication bias were performed. Results were presented in a forest plot and summarized using a random-effects model.

RESULTS

After screening 1,674 studies, we included 40 for systematic review and 16 and 7 studies for two meta-analyses with a total of 19,029 and 27,325 patients, respectively. We found a positive relationship between the presence of extracranial carotid plaque and cognitive dysfunction with a pooled random-effects odds ratio (OR) of 1.83 (95% CI, 1.50, 2.24) and a pooled random-effects hazard ratio (HR) of 1.47 (95% CI, 1.15, 1.89), respectively. A sensitivity analysis of only longitudinal studies found a persistent positive association. Measures of heterogeneity showed moderate heterogeneity in each meta-analysis, respectively (I-squared statistic = 57% and 70%).

CONCLUSION

The presence of extracranial carotid plaque is significantly associated with cognitive dysfunction and dementia in both cross-sectional and longitudinal analyses. After further confirmation, our results support carotid plaque being a potentially modifiable risk factor in the development of dementia.

Optimal management of asymptomatic carotid stenosis in 2021: the jury is still out. An International, multispecialty, expert review and position statement

OBJECTIVES

The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic.

MATERIALS AND METHODS

A literature review was performed with a focus on data from recent studies.

RESULTS

Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients <75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses.

CONCLUSIONS

Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

Asymptomatic Carotid Disease and Cognitive Impairment: What Is the Evidence?

The development of cognitive dysfunction and dementia is a complex, multifactorial process. One of the contributors to various types of cognitive dysfunction is carotid atherosclerosis which can frequently be seen in asymptomatic individuals. There are a number of different manifestations of asymptomatic carotid atherosclerosis including arterial stiffness, carotid intima-media thickening, flow-limiting stenosis, and complex, atherosclerotic plaque. Each of these forms of atherosclerosis may contribute to cerebral parenchymal damage, contributing to cognitive dysfunction. In this review article, we will discuss each of these forms of carotid atherosclerosis, present the potential mechanistic underpinnings behind an association, and then review the scientific evidence supporting potential associations to cognitive dysfunction and dementia.

Carotid Compliance and Parahippocampal and Hippocampal Volume over a 20-Year Period

Introduction

We evaluated the association between carotid compliance, a measure of arterial stiffness, to parahippocampal volume (PHV) and hippocampal volume (HV) over 20 years later in the Atherosclerosis Risk in the Community study.

Methods

We included participants with common carotid compliance measurements at visit 1 (1987–1989) and volumetric brain MRI at visit 5 (2011–2013). The primary outcomes are pooled bilateral PHV and HV. We performed linear regression models adjusting for age, sex, vascular risk factors, and total brain volume.

Results

Of the 614 participants, higher compliance was correlated with higher PHV (R = 0.218[0.144–0.291], p < 0.001) and HV (R = 0.181 [0.105–0.255, p < 0.001]). The association was linear and significant after adjusting for confounders. At follow-up MRI, 30 patients with dementia had lower PHV and HV than patients without dementia (p < 0.001 and p < 0.001, respectively).

Conclusion

Carotid compliance is associated with higher PHV and HV when measured 20 years later, further supporting the link between arterial stiffness and cognitive decline.

Differentiation of symptomatic and asymptomatic carotid intraplaque hemorrhage using 3D high-resolution diffusion-weighted stack of stars imaging

Ischemic events related to carotid disease are far more strongly associated with plaque instability than stenosis. 3D high-resolution diffusion-weighted (DW) imaging can provide quantitative diffusion measurements on carotid atherosclerosis and may improve detection of vulnerable intraplaque hemorrhage (IPH). The 3D DW-stack of stars (SOS) sequence was implemented with 3D SOS acquisition combined with DW preparation. After simulation of signals created from 3D DW-SOS, phantom studies were performed. Three healthy subjects and 20 patients with carotid disease were recruited. Apparent diffusion coefficient (ADC) values were statistically analyzed on three subgroups by using a two-group comparison Wilcoxon-Mann-Whitney U test with p values less than 0.05: symptomatic versus asymptomatic; IPH-positive versus IPH-negative; and IPH-positive symptomatic versus asymptomatic plaques to determine the relationship with plaque vulnerability. ADC values calculated by 3D DW-SOS provided values similar to those calculated from other techniques. Mean ADC of symptomatic plaque was significantly lower than asymptomatic plaque (0.68 ± 0.18 vs. 0.98 ± 0.16 x 10^-3  mm² /s, p < 0.001). ADC was also significantly lower in IPH-positive versus IPH-negative plaque (0.68 ± 0.13 vs. 1.04 ± 0.11 x 10^-3  mm² /s, p < 0.001). Additionally, ADC was significantly lower in symptomatic versus asymptomatic IPH-positive plaque (0.57 ± 0.09 vs. 0.75 ± 0.11 x 10^-3  mm² /s, p < 0.001). Our results provide strong evidence that ADC measurements from 3D DW-SOS correlate with the symptomatic status of extracranial internal carotid artery plaque. Further, ADC improved discrimination of symptomatic plaque in IPH. These data suggest that diffusion characteristics may improve detection of destabilized plaque leading to elevated stroke risk.

Optimal Management of Asymptomatic Carotid Stenosis in 2021: The Jury is Still Out. An International, Multispecialty, Expert Review and Position Statement

OBJECTIVES

The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic.

MATERIALS AND METHODS

A literature review was performed with a focus on data from recent studies.

RESULTS

Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients < 75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses.

CONCLUSIONS

Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

MR Perfusion in the Evaluation of Mechanical Thrombectomy Candidacy

ABSTRACT

Stroke is a leading cause of disability and mortality, and the incidence of ischemic stroke is projected to continue to rise in coming decades. These projections emphasize the need for improved imaging techniques for accurate diagnosis allowing effective treatments for ischemic stroke. Ischemic stroke is commonly evaluated with computed tomography (CT) or magnetic resonance imaging (MRI). Noncontrast CT is typically used within 4.5 hours of symptom onset to identify candidates for thrombolysis. Beyond this time window, thrombolytic therapy may lead to poor outcomes if patients are not optimally selected using appropriate imaging. MRI provides an accurate method for the earliest identification of core infarct, and MR perfusion can identify salvageable hypoperfused penumbra. The prognostic value for a better outcome in these patients lies in the ability to distinguish between core infarct and salvageable brain at risk-the ischemic penumbra-which is a function of the degree of ischemia and time. Many centers underutilize MRI for acute evaluation of ischemic stroke. This review will illustrate how perfusion-diffusion mismatch calculated from diffusion-weighted MRI and MR perfusion is a reliable approach for patient selection for stroke therapy and can be performed in timeframes that are comparable to CT-based algorithms while providing potentially superior diagnostic information.

Management of patients with asymptomatic carotid stenosis may need to be individualized: a multidisciplinary call for action. Republication of J Stroke 2021;23:202-212

The optimal management of patients with asymptomatic carotid stenosis (ACS) is the subject of extensive debate. According to the 2017 European Society for Vascular Surgery guidelines, carotid endarterectomy should (Class IIa; Level of Evidence: B) or carotid artery stenting may be considered (Class IIb; Level of Evidence: B) in the presence of one or more clinical/imaging characteristics that may be associated with an increased risk of late ipsilateral stroke (e.g. silent embolic infarcts on brain computed tomography/magnetic resonance imaging, progression in the severity of ACS, a history of contralateral transient ischemic attack/stroke, microemboli detection on transcranial Doppler, etc.), provided documented perioperative stroke/death rates are <3% and the patient's life expectancy is >5 years. Besides these clinical/imaging characteristics, there are additional individual, ethnic/racial or social factors that should probably be evaluated in the decision process regarding the optimal management of these patients, such as individual patient needs/patient choice, patient compliance with best medical treatment, patient sex, culture, race/ethnicity, age and comorbidities, as well as improvements in imaging/operative techniques/outcomes. The present multispecialty position paper will present the rationale why the management of patients with ACS may need to be individualized.

Management of Patients with Asymptomatic Carotid Stenosis May Need to Be Individualized: A Multidisciplinary Call for Action

The optimal management of patients with asymptomatic carotid stenosis (ACS) is the subject of extensive debate. According to the 2017 European Society for Vascular Surgery guidelines, carotid endarterectomy should (Class IIa; Level of Evidence: B) or carotid artery stenting may be considered (Class IIb; Level of Evidence: B) in the presence of one or more clinical/imaging characteristics that may be associated with an increased risk of late ipsilateral stroke (e.g., silent embolic infarcts on brain computed tomography/magnetic resonance imaging, progression in the severity of ACS, a history of contralateral transient ischemic attack/stroke, microemboli detection on transcranial Doppler, etc.), provided documented perioperative stroke/death rates are <3% and the patient’s life expectancy is >5 years. Besides these clinical/imaging characteristics, there are additional individual, ethnic/racial or social factors that should probably be evaluated in the decision process regarding the optimal management of these patients, such as individual patient needs/patient choice, patient compliance with best medical treatment, patient sex, culture, race/ethnicity, age and comorbidities, as well as improvements in imaging/operative techniques/outcomes. The present multispecialty position paper will present the rationale why the management of patients with ACS may need to be individualized.

Extracranial Vascular Disease: Carotid Stenosis and Plaque Imaging

Carotid atherosclerosis is an important contributor to ischemic stroke. When imaging carotid atherosclerosis, it is essential to describe both the degree of luminal stenosis and specific plaque characteristics because both are risk factors for cerebrovascular ischemia. Carotid atherosclerosis can be accurately assessed using multiple imaging techniques, including ultrasonography, computed tomography angiography, and magnetic resonance angiography. By understanding the underlying histopathology, the specific plaque characteristics on each of these imaging modalities can be appreciated. This article briefly describes some of the most commonly encountered plaque features, including plaque calcification, intraplaque hemorrhage, lipid-rich necrotic core, and plaque ulceration.

Using Ultrasound and Inflammation to Improve Prediction of Ischemic Stroke: A Secondary Analysis of the Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

Current ischemic stroke risk prediction is primarily based on clinical factors, rather than imaging or laboratory markers. We examined the relationship between baseline ultrasound and inflammation measurements and subsequent primary ischemic stroke risk.

METHODS

In this secondary analysis of the Multi-Ethnic Study of Atherosclerosis (MESA), the primary outcome is the incident ischemic stroke during follow-up. The predictor variables are 9 carotid ultrasound-derived measurements and 6 serum inflammation measurements from the baseline study visit. We fit Cox regression models to the outcome of ischemic stroke. The baseline model included patient age, hypertension, diabetes, total cholesterol, smoking, and systolic blood pressure. Goodness-of-fit statistics were assessed to compare the baseline model to a model with ultrasound and inflammation predictor variables that remained significant when added to the baseline model.

RESULTS

We included 5,918 participants. The primary outcome of ischemic stroke was seen in 105 patients with a mean follow-up time of 7.7 years. In the Cox models, we found that carotid distensibility (CD), carotid stenosis (CS), and serum interleukin-6 (IL-6) were associated with incident stroke. Adding tertiles of CD, IL-6, and categories of CS to a baseline model that included traditional clinical vascular risk factors resulted in a better model fit than traditional risk factors alone as indicated by goodness-of-fit statistics.

CONCLUSIONS

In a multiethnic cohort of patients without cerebrovascular disease at baseline, we found that CD, CS, and IL-6 helped predict the occurrence of primary ischemic stroke. Future research could evaluate if these basic ultrasound and serum measurements have implications for primary prevention efforts or clinical trial inclusion criteria.

Optimal Carotid Plaque Features on Computed Tomography Angiography Associated With Ischemic Stroke

Background Stenosis has historically been the major factor used to determine carotid stroke sources. Recent evidence suggests that specific plaque features detected on imaging may be more highly associated with ischemic stroke than stenosis. We sought to determine computed tomography angiography (CTA) imaging features of carotid plaque that optimally discriminate ipsilateral stroke sources. Methods and Results In this institutional review board-approved retrospective cross-sectional study, 494 ipsilateral carotid CTA-brain magnetic resonance imaging pairs were available for analysis after excluding patients with alternative stroke sources. Carotid CTA and clinical markers were recorded, a multivariable Poisson regression model was fitted, and backward elimination was performed with a 2-sided threshold of P<0.10. Discriminatory value was determined using receiver operating characteristic analysis, area under the curve, and bootstrap validation. The final CTA carotid-source stroke prediction model included intraluminal thrombus (prevalence ratio, 2.8 [P<0.001]; 95% CI, 1.6-4.9), maximum soft plaque thickness (prevalence ratio, 1.2 [P<0.001]; 95% CI, 1.1-1.4), and the rim sign (prevalence ratio, 2.0 [P=0.007]; 95% CI, 1.2-3.3). The final discriminatory value (area under the curve=78.3%) was higher than intraluminal thrombus (56.4%, P<0.001), maximum soft plaque thickness (76.4%, P=0.007), or rim sign alone (69.9%, P=0.001). Furthermore, NASCET (North American Symptomatic Carotid Endarterectomy Trial) stenosis categories (cutoffs of 50% and 70%) had lower stroke discrimination (area under the curve=67.4%, P<0.001). Conclusions Optimal discrimination of ipsilateral carotid sources of stroke requires information on intraluminal thrombus, maximum soft plaque thickness, and the rim sign. These results argue against the sole use of carotid stenosis to determine stroke sources on CTA, and instead suggest these alternative markers may better diagnose vulnerable carotid plaque and guide treatment decisions.

Rabbit models of intracranial atherosclerotic disease for pathological validation of vessel wall MRI

INTRODUCTION

Vessel wall magnetic resonance imaging can improve the evaluation of intracranial atherosclerotic disease. However, pathological validation is needed to improve vessel wall magnetic resonance imaging techniques. Human pathology samples are not practical for such analysis, so an animal model is therefore needed.

MATERIALS AND METHODS

Watanabe heritable hyperlipidemic rabbits and apolipoprotein E knockout rabbits were evaluated against New Zealand white wild-type rabbits. Evaluation of intracranial arteries was performed with vessel wall magnetic resonance imaging and pathological analysis, rating the presence and severity of disease in each segment. Two-tailed t-tests were performed to compare disease occurrence and severity prevalence among rabbit subtypes. Sensitivity and specificity were calculated to assess the diagnostic accuracy of vessel wall magnetic resonance imaging.

RESULTS

Seventeen rabbits (five Watanabe heritable hyperlipidemic, four apolipoprotein E knockout and eight New Zealand white) were analysed for a total of 51 artery segments. Eleven segments (five Watanabe heritable hyperlipidemic and six apolipoprotein E knockout) demonstrated intracranial atherosclerotic disease on pathology. Disease model animals had lesions more frequently than New Zealand white animals (P<0.001). The sensitivity and specificity of vessel wall magnetic resonance imaging for the detection of intracranial atherosclerotic disease were 68.8% and 95.2%, respectively. When excluding mild cases to assess vessel wall magnetic resonance imaging accuracy for detecting moderate to severe intracranial atherosclerotic disease lesions, sensitivity improved to 100% with unchanged specificity.

CONCLUSION

Intracranial atherosclerotic disease can be reliably produced and detected using 3T vessel wall magnetic resonance imaging-compatible Watanabe heritable hyperlipidemic and ApoE rabbit models. Further analysis is needed to characterize better the development and progression of the disease to correlate tissue-validated animal findings with those in human vessel wall magnetic resonance imaging studies.

Associations between the size and location of myocardial infarction and cerebral infarction

BACKGROUND

Myocardial infarction (MI) is a known cause of cerebral infarction. We assessed whether the size and location of MI is associated with the risk of cerebral infarction.

METHODS AND RESULTS

We performed a cross-sectional study of adults who underwent both brain MRI and delayed-enhancement cardiac MRI (DE-CMR) within 365 days of each other at Weill Cornell Medicine between 2014 and 2017 and had evidence of MI on DE-CMR. We used multiple logistic regression to evaluate associations between MI size and any cerebral infarction, apical MI location and any cerebral infarction, and MI size/location and cortical versus subcortical cerebral infarction. Models were adjusted for demographics, and the total number of vascular risk factors. Among 234 patients who underwent both DE-CMR and brain MRI within 365 days, 76 had evidence for MI on DE-CMR. Among these 76 patients, 51 (67.1%) had evidence of cerebral infarction. The size of MI (global MI burden) was not associated with any cerebral infarction (OR per 5% increase in MI size, 1.12; 95% CI, 0.85-1.47), but was associated with cortical cerebral infarction (OR per 5% increase in MI size, 1.30; 95% CI, 1.00.-1.68). Similarly, apical MI location was not associated with any cerebral infarction (OR 2.63, 95% CI, 0.78-8.87), but was associated with cortical cerebral infarction (OR, 3.67; 95% CI, 1.19-11.33).

CONCLUSION

Among patients with MI on cardiac MRI, both size and apical location of MI were associated with cortical cerebral infarction. Our results may help stratify cardioembolic risk and inform antithrombotic treatment algorithms among patients with MI.

Carotid artery plaque characteristics: current reporting practices on CT angiography

PURPOSE

Extracranial ICA imaging has largely focused on the degree of luminal stenosis, but recent advances suggest specific plaque features are crucial in stroke risk assessment. We evaluated the current state of reporting carotid plaque features on neck CTAs at an academic institution.

METHODS

In this retrospective observational study, we included neck CTAs performed on patients over age 50 with any reported carotid plaque. We evaluated reports for mention of the following: degree of luminal stenosis, soft plaque, calcified plaque, plaque thickness, quantification of soft and calcified plaque, plaque ulceration, and increased risk associated with specific features. We used Fisher's exact test to compare how often each feature was mentioned.

RESULTS

We included a total of 651 reports from unique patients (mean age, 68.1 ± 13.3 years). A total of 639 reports (98.1%) explicitly mentioned degree of stenosis per NASCET criteria. Specific plaque features were less frequently characterized: soft plaque in 116 (17.8%); calcified plaque in 166 (25.5%); quantification of the amount of soft plaque and calcified plaque in 24 (3.7%) and 16 (2.5%) reports, respectively; plaque thickness in 12 (1.8%); plaque ulceration in 476 (73.1%); and increased risk associated with plaque in 2 (0.3%). Degree of stenosis was statistically more likely to be mentioned than any other plaque feature (p < 0.001).

CONCLUSION

Currently, nearly all reports mention the degree of luminal stenosis on neck CTAs while a significant minority mention specific plaque features. Despite mounting evidence of the importance of carotid plaque features in stroke risk assessment, radiology reports do not routinely report these findings.

Brain imaging biomarkers of carotid artery disease

Extracranial carotid artery atherosclerotic disease is a major contributor to ischemic stroke. Carotid atherosclerotic disease can present with a spectrum of findings ranging from mild carotid intima-media thickness to high-risk vulnerable carotid plaque features and carotid stenosis. Before leading to clinically overt stroke or transient ischemic attack, there may be other markers of downstream ischemia secondary to carotid atherosclerotic disease. In this review article, we will review some of the imaging findings that may be seen downstream to carotid artery disease on various imaging modalities, including hemodynamic and perfusional abnormalities which may be seen on CT, MR, or using other advanced imaging techniques, white matter hyperintensities on brain imaging, silent or covert brain infarctions, cerebral microbleeds, and regional and generalized cerebral volume loss. Many of these imaging findings are seen routinely on brain magnetic resonance imaging in patients without overt clinical symptoms. Despite frequently being asymptomatic, many of these imaging findings are also strongly associated with increased risk of future stroke, cognitive impairment, and even mortality. We will review the existing evidence underpinning the associations between these frequently encountered imaging findings and carotid artery atherosclerotic disease. Future validation of these imaging findings could lead to them being powerful biomarkers of cerebrovascular health.

The progression of carotid atherosclerosis and imaging markers of dementia

INTRODUCTION

We studied the association of carotid intima-media thickness (CIMT) with hippocampal volume (HV) in community dwelling individuals, testing the hypothesis that persons with carotid atherosclerosis progression would have lower HV.

METHODS

We studied 1376 Framingham Offspring participants with two carotid ultrasounds and brain magnetic resonance imaging (MRIs). We used multivariable linear regression analyses to relate CIMT progression and HV and total brain volume. Regression models were adjusted for demographics and vascular risk factors, time interval between imaging examinations, and baseline CIMT. We assessed effect modification by hypertension treatment (HRx).

RESULTS

Participants with higher ICA IMT progression had significantly lower HV after adjustment for vascular risk factors and baseline IMT (standardized beta ± standard error: -0.067 ± 0.027, P = .01). We observed weaker association between ICA IMT change and HV among subjects treated for hypertension (β = -0.047, P = .19 vs β = -0.096, P = .026).

DISCUSSION

Cumulative vascular risk factor exposure, reflected by CIMT progression, may increase the risk of neurodegeneration.

Carotid Vessel Wall Imaging on CTA

Vessel wall imaging has been increasingly used to characterize plaque beyond luminal narrowing to identify patients who may be at the highest risk of cerebrovascular ischemia. Although detailed plaque information can be obtained from many imaging modalities, CTA is particularly appealing for carotid plaque imaging due to its relatively low cost, wide availability, operator independence, and ability to discern high-risk features. The present Review Article describes the current understanding of plaque characteristics on CTA by describing commonly encountered plaque features, including calcified and soft plaque, surface irregularities, neovascularization, and inflammation. The goal of this Review Article was to provide a more robust understanding of clinically relevant plaque features detectable on routine CTA of the carotid arteries.

Abstract TMP93: Carotid Stiffness and Parahippocampal Volume Over a 20-Year Period: A Secondary Analysis of the ARIC Study

Introduction: Arterial stiffness is associated with dementia, however, the relationship between carotid stiffness and parahippocampal volume (PHV) is less established. Decreased PHV is a validated early biomarker of Alzheimer’s disease.

Hypothesis: Carotid artery stiffness will be associated with lower PHV on MRI performed over 20 years later in the Atherosclerosis Risk in the Community (ARIC) study.

Methods: We included ARIC patients with common carotid stiffness measurements on ultrasound at Visit 1 (1987-1989) and volumetric brain MRI at Visit 5 (2011-2013). The primary outcome is pooled bilateral PHV in mL.

Results: We included 664 participants with a mean (SD) age of 75.7 (5.4) at the follow-up MRI (42% female). The mean (SD) PHV was 3.9 (0.6) mL. Carotid stiffness was correlated with lower PHV (R=-0.142, p <0.001) and compliance was correlated with higher PHV (R =0.220, p<0.001) (Table 1). The associations were linear (Figure 1) and significant after adjusting for confounders (Table 2). At the follow-up MRI, 32 patients had an adjudicated diagnosis of dementia and lower PHV than patients without dementia (4.0 vs. 3.4 mL, p<0.001), further validating the significance of PHV in this cohort.

Conclusion: Carotid stiffness is associated with decreased PHV when measured 20 years later, further supporting the link between large artery atherosclerosis and cognitive decline.

Reclassification of Ischemic Stroke Etiological Subtypes on the Basis of High-Risk Nonstenosing Carotid Plaque

Background and Purpose- Carotid artery plaque with <50% luminal stenosis may be an underappreciated stroke mechanism. We assessed how many stroke causes might be reclassified after accounting for nonstenosing plaques with high-risk features. Methods- We included patients enrolled in the Cornell Acute Stroke Academic Registry from 2011 to 2015 who had anterior circulation infarction, magnetic resonance imaging of the brain, and magnetic resonance angiography of the neck. High-risk plaque was identified by intraplaque hemorrhage ascertained from routine neck magnetic resonance angiography studies using validated methods. Infarct location was determined from diffusion-weighted imaging. Intraplaque hemorrhage and infarct location were assessed separately in a blinded fashion by a neuroradiologist. We used the McNemar test for matched data to compare the prevalence of intraplaque hemorrhage ipsilateral versus contralateral to brain infarction. We reclassified stroke subtypes by including large-artery atherosclerosis as a cause if there was intraplaque hemorrhage ipsilateral to brain infarction, regardless of the degree of stenosis. Results- Among the 1721 acute ischemic stroke patients registered in the Cornell Acute Stroke Academic Registry from 2011 to 2015, 579 were eligible for this analysis. High-risk plaque was more common ipsilateral versus contralateral to brain infarction in large-artery atherosclerotic (risk ratio [RR], 3.7 [95% CI, 2.2-6.1]), cryptogenic (RR, 2.1 [95% CI, 1.4-3.1]), and cardioembolic strokes (RR, 1.7 [95% CI, 1.1-2.4]). There were nonsignificant ipsilateral-contralateral differences in high-risk plaque among lacunar strokes (RR, 1.2 [95% CI, 0.4-3.5]) and strokes of other determined cause (RR, 1.5 [95% CI, 0.7-3.3]). After accounting for ipsilateral high-risk plaque, 88 (15.2%) patients were reclassified: 38 (22.6%) cardioembolic to multiple potential etiologies, 6 (8.5%) lacunar to multiple, 3 (15.8%) other determined cause to multiple, and 41 (20.8%) cryptogenic to large-artery atherosclerosis. Conclusions- High-risk carotid plaque was more prevalent ipsilateral to brain infarction across several ischemic stroke subtypes. Accounting for such plaques may reclassify the etiologies of up to 15% of cases in our sample.

Associations Between Features of Nonstenosing Carotid Plaque on Computed Tomographic Angiography and Ischemic Stroke Subtypes

Background

Thromboembolism from nonstenosing carotid plaques may be an underrecognized cause of embolic strokes of undetermined source (ESUS). We evaluated the association between features of nonstenosing atherosclerotic plaque on computed tomographic angiography and ESUS.

Methods and Results

We identified consecutive acute ischemic stroke patients from 2011 to 2015 who had unilateral anterior territory infarction on brain magnetic resonance imaging and a neck computed tomographic angiography. We included ESUS cases and as controls, cardioembolic strokes. Patients with ≥50% internal carotid artery atherosclerotic stenosis ipsilateral to the stroke were excluded from this analysis. Reviewers blinded to infarct location and stroke cause retrospectively evaluated computed tomographic angiography studies for specific plaque features including thickness of the total, soft, and calcified plaque; presence of ulceration; and perivascular fat attenuation. Paired t tests and McNemar's test for paired data were used to compare plaque features ipsilateral versus contralateral to the side of infarction. Ninety‐one patients with ESUS or cardioembolic stroke were included in this study. Total plaque thickness was greater on the infarcted side (2.1±2.0 mm) than the contralateral side (1.2±1.5 mm) (P=0.006) among ESUS cases, but not among cardioembolic cases (1.9±1.6 mm versus 1.8±1.6 mm) (P=0.32).

Conclusions

Among ESUS cases, total plaque thickness was greater ipsilateral to the side of infarction than on the contralateral, stroke‐free side. No such side‐to‐side differences were apparent in cardioembolic strokes. Our findings suggest that nonstenosing large‐artery atherosclerotic plaques represent one underlying mechanism of ESUS.

Association Between Carotid Artery Perivascular Fat Density and Cerebrovascular Ischemic Events

Background Studies have shown that pericoronary artery inflammation can be accurately detected via increased attenuation on computed tomography. Our purpose was to evaluate the association between pericarotid inflammation, measured by density of carotid perivascular fat on computed tomography angiography, with stroke and transient ischemic attack. Methods and Results We screened computed tomography angiography examinations for patients with unilateral internal carotid artery ( ICA ) stenosis ≥50% to 99%. A blinded neuroradiologist placed regions-of-interest in the pericarotid fat on the slice showing maximal stenosis. Two-sample t tests were performed to assess between-subject differences in mean Hounsfield Units in carotid perivascular fat between symptomatic and asymptomatic patients. Paired t tests were used to assess within-subject differences in mean Hounsfield Units between stenotic versus nonstenotic ICA s in a given patient. We included 94 patients, including 42 symptomatic and 52 asymptomatic patients. In the between-subject analysis of stenotic ICA s, we found symptomatic patients had higher mean pericarotid fat density compared with asymptomatic patients (-66.2±19.2 versus -77.1±20.4, P=0.009). When comparing nonstenotic ICA s, there was no significant difference between pericarotid fat density in symptomatic compared with asymptomatic patients (-81.0±13.3 versus -85.3±18.0: P=0.198). Within-subject comparison showed statistically significant increased density in stenotic ICA versus nonstenotic ICA with mean Hounsfield Units difference of 11.1 ( P<0.0001). Conclusions We found increased density, a surrogate marker for perivascular inflammation, in the fat surrounding ICA s ipsilateral to stroke or transient ischemic attack compared with asymptomatic ICA s. Our findings suggest that inflammation associated with culprit carotid plaques extends beyond the vessel lumen and can be identified using simple methods on computed tomography angiography imaging.

Cost Effectiveness of Assessing Ultrasound Plaque Characteristics to Risk Stratify Asymptomatic Patients With Carotid Stenosis

Background

Imaging may play an important role in identifying high‐risk plaques in patients who have carotid disease and who could benefit from surgical revascularization. We sought to evaluate the cost effectiveness of a decision‐making rule based on the ultrasound imaging assessment of plaque echolucency in patients with asymptomatic carotid stenosis.

Methods and Results

We used a decision‐analytic model to project lifetime quality‐adjusted life years and costs for 5 stroke prevention strategies: (1) medical therapy only; (2) revascularization if both plaque echolucency and stenosis progression to >90% are present; (3) revascularization only if plaque echolucency is present; (4) revascularization only if stenosis progression >90% is present; or (5) either plaque echolucency or stenosis progression is present. Risks of clinical events, costs, and quality‐of‐life values were estimated based on published sources and the analysis was conducted from a healthcare system perspective for asymptomatic patients with 70% to 89% carotid stenosis at presentation. Patients who did not undergo revascularization had the highest stroke events (17.6%) and lowest life‐years (8.45), while those who underwent revascularization on the basis of either presence of plaque echolucency on ultrasound or progression of carotid stenosis had the lowest stroke events (12.0%) and longest life‐years (14.41). The either plaque echolucency or progression‐based revascularization group had an incremental cost‐effectiveness ratio of $110 000/quality‐adjusted life years compared with the plaque echolucency‐based strategy, which had an incremental cost‐effectiveness ratio of $29 000/quality‐adjusted life years compared with the joint echolucency and progression‐based strategy.

Conclusions

Plaque echolucency on ultrasound can be a cost‐effective tool to identify patients with asymptomatic carotid artery stenosis most likely to benefit from carotid endarterectomy.

Carotid Plaque Positron Emission Tomography Imaging and Cerebral Ischemic Disease

Background and Purpose- The clinical utility of positron emission tomography (PET) imaging in evaluating carotid artery plaque vulnerability remains unclear. Two tracers of recent interest for carotid plaque imaging are ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹⁸F-sodium fluoride (¹⁸F-NaF). We performed a systematic review and meta-analysis evaluating the association between carotid artery ¹⁸F-FDG or ¹⁸F-NaF uptake and recent or future cerebral ischemic events. Methods- A systematic review of Ovid MEDLINE, Ovid EMBASE, and the Cochrane library was conducted from inception to December 2017 for articles evaluating PET tracer uptake in recently symptomatic versus asymptomatic carotid arteries, and articles evaluating carotid uptake in relation to future ischemic events. Cerebral ischemic events were defined as ipsilateral strokes, transient ischemic attacks, or amaurosis fugax. We quantitatively pooled studies by a random-effects model when 3 or more studies were amenable for analysis. We assessed the standardized mean difference between tracer uptake in the symptomatic versus asymptomatic carotid artery using Cohen's d metric. Results- After screening 4144 unique articles, 13 prospective cohort studies assessing carotid artery ¹⁸F-FDG uptake in patients with recent cerebral ischemia were eligible for review. Eleven cohorts of 290 subjects scanned with ¹⁸F-FDG were eligible for meta-analysis. We found that carotid arteries ipsilateral to recent ischemic events had significantly higher ¹⁸F-FDG uptake than asymptomatic arteries (Cohen's d =0.492; CI=0.130-0.855; P=0.008) as well as significant heterogeneity (Cochran's Q =31.5; P=0.0005; I²=68.3%). Meta-regression was not performed due to the limited number of studies in the analysis. Only 2 studies investigating ¹⁸F-NaF PET imaging, and another 2 articles investigating ischemic event recurrence were found. Conclusions- Recent ipsilateral cerebral ischemia may be associated with increased carotid ¹⁸F-FDG uptake on PET imaging regardless of degree of carotid stenosis, although significant heterogeneity was found, and these results should be interpreted with caution. Emerging evidence suggests a similar association may be present with ¹⁸F-NaF plaque uptake. More studies are warranted to provide definitive conclusions on the utility of ¹⁸F-FDG or ¹⁸F-NaF in carotid plaque evaluation before investigating carotid PET as a diagnostic tool for cerebral ischemic events.

Abstract WP404: Cost-Effectiveness of Plaque Echolucency on Ultrasound as a Stroke Risk Stratification Tool in Asymptomatic Carotid Artery Stenosis

Imaging may play an important role in identifying high-risk plaques in patient with carotid disease who could benefit from surgical revascularization. We sought to evaluate the cost-effectiveness of a decision-making rule based on the ultrasound (US) imaging assessment of plaque echolucency (PE) in patients with asymptomatic carotid stenosis. We developed a decision-analytic model to project lifetime quality-adjusted life years (QALYs) and costs for five stroke prevention strategies: 1) medical therapy only; 2) revascularization if both PE and stenosis progression to >90% is present; 3) revascularization only if PE is present; 4) revascularization only if stenosis progression >90% is present; or 5) either PE or stenosis progression is present. Risks of clinical events, costs, and quality-of-life values were estimated based on published sources and the analysis was conducted from a health care system perspective for asymptomatic patients with 70-89% carotid stenosis at presentation. Patients who did not undergo revascularization had the highest stroke events (16.9%) and lowest life-years, while those who underwent revascularization on the basis of either presence of PE on US or progression of carotid stenosis had the lowest stroke events (10.0%) and longest life-years (13.67). The either PE or progression-based revascularization group had an incremental cost effectiveness ratio of $43,000/QALY compared with those with revascularization based on having both PE and stenosis progression. Plaque echolucency on US can be a cost-effective tool to identify patients with asymptomatic carotid artery stenosis most likely to benefit from carotid endarterectomy.

Abstract TMP115: Carotid Atherosclerosis Progression and Hippocampal Volume

Background: Carotid atherosclerosis is a known risk factor for stroke and dementia. Carotid atherosclerosis may play a role in neurodegeneration and be a potential target for treatment and preventive efforts for stroke and dementia in asymptomatic individuals. We studied the association of carotid intima media thickness (CIMT) with hippocampal volume (HV) in community-dwelling individuals, and hypothesize that persons with carotid atherosclerosis progression would have a lower HV.

Methods: We studied 1,376 Framingham Offspring participants (age 67±8.7 years; 53% women) with two carotid ultrasound measurements (1995-1998 and 2005-2008) and brain MRI scans at or near the second ultrasound, who were stroke, dementia, or other neurological illnesses-free at MRI. We used multivariable linear regression analyses to relate annualized carotid IMT change at internal [ICA] and common carotid [CCA] to HV volume (as a percentage of total cranial volume). Models were adjusted for age, sex, time interval between second carotid duplex and MRI, systolic blood pressure, hypertension treatment (HRx), diabetes, total cholesterol level, smoking, cardiovascular disease and baseline CIMT. We additionally assessed effect modification by HRx and statin use.

Results: Mean (±SD) carotid IMT change per year was 0.064±0.082mm in ICA and 0.008±0.008 mm in CCA. Participants with higher ICA IMT progression had significantly lower HV after adjustment for vascular risk factors and baseline IMT (β±SE [standardized beta±standard error]: -0.067±0.027, p= 0.01), but not CCA IMT progression (β±SE: 0.01± 0.0276 p= 0.72). In subgroup analyses, we observed weaker association between ICA IMT change and HV among subjects with HRx (β = -0.047, p=0.19 vs. β =-0.096, p=0.026 in untreated individuals), but HRx by IMT change interaction was not statistically significant (p-interaction=0.39). Effects were similar in statin subgroups and statistically non-significant for CCA IMT progression.

Conclusions: Cumulative vascular risk factor exposure, as reflected by ICA IMT progression, are associated with neurodegeneration represented by lower hippocampal volumes. Such changes occur prior to onset of clinical dementia, suggesting that carotid IMT may be a target for preventive efforts.

Effect of Clinical History on Interpretation of Computed Tomography for Acute Stroke

Objective

We assessed whether providing detailed clinical information alongside computed tomography (CT) images improves their interpretation for acute stroke.

Methods

Using the prospective Cornell AcutE Stroke Academic Registry, we randomly selected 100 patients who underwent noncontrast head CT within 6 hours of transient ischemic attack or minor acute ischemic stroke and underwent magnetic resonance imaging (MRI) within 6 hours of the CT. Three radiologist investigators evaluated each of the 100 CT studies twice, once with and once without accompanying information on medical history, signs, and symptoms. In random sequence, each study was interpreted in one condition (ie, with or without detailed accompanying information) and then after a 4-week washout period, in the opposite condition. Using MRI diffusion-weighted imaging (DWI) as the reference standard, we classified CT interpretations as correct (true positives or negatives) or incorrect (false positives or negatives). We used logistic regression with sandwich estimators to compare the proportion of correct interpretations.

Results

In patients with DWI-defined infarcts, acute ischemia was called on 20% of CTs with detailed history and 18% without history. In patients without infarcts, the absence of ischemia was called on 77% of CTs with history and 77% without history. The proportion of correct interpretations of CTs accompanied by detailed clinical history (49%) did not differ significantly from those without history (47%; odds ratio: 1.1; 95% confidence interval: 0.8-1.4).

Conclusions

Reported findings on head CT for evaluation of suspected acute ischemic stroke were similar regardless of whether detailed clinical history was provided.

Angiographic Blush after Mechanical Thrombectomy is Associated with Hemorrhagic Transformation of Ischemic Stroke

BACKGROUND AND PURPOSE

Risk factors for hemorrhagic transformation of ischemic stroke after mechanical thrombectomy (MT) are not well established. We conducted a study to determine if prominent angiographic cerebral vascularity following recanalization with thrombectomy (angiographic blush) is associated with hemorrhagic transformation.

METHODS

Using the Cornell AcutE Stroke Academic Registry, we identified stroke patients who had thrombectomy and achieved recanalization of anterior circulation large-vessel occlusion between 2012 and 2015. The exposure variable was presence of angiographic blush after recanalization, defined as capillary blush with or without early venous drainage. The primary outcome was volume of hemorrhagic transformation on brain imaging after thrombectomy, as determined by semiautomated volumetric analysis on computed tomography or magnetic resonance imaging among those adjudicated to have hemorrhagic conversion by neuroradiology investigators blinded to angiography results. Using a doubly robust estimator with propensity scores and outcome regression adjusting for demographics and known risk factors for hemorrhagic transformation, we evaluated whether angiographic blush after recanalization is associated with an increased volume of hemorrhagic transformation.

RESULTS

Among 48 eligible patients, 31 (64.6%) had angiographic blush and 26 (54.2%) had radiographic hemorrhagic transformation (mean volume, 7.6 ml). Patients with angiographic blush averaged lower thrombolysis in cerebral infarction scores and more often received intravenous thrombolysis. In adjusted analysis, angiographic blush was associated with an increased volume of hemorrhagic transformation: mean volume, 10.3ml (95% CI, 3.7-16.9 ml) with blush versus 1.8ml (95% Confidence Interval (CII = Confidence Interval), 0.1-3.4 ml) without (P = .01).

CONCLUSIONS

Presence of angiographic blush after MT was independently associated with the volume of hemorrhagic transformation.

Abstract TP60: Effect of Clinical History in Radiologist Interpretation of Computed Tomography for Acute Stroke

Introduction: Computed tomography (CT) is widely used for suspected acute ischemic stroke. Radiologists often interpret these scans with limited information and may benefit from more complete knowledge of the clinical situation.

Hypothesis: Providing detailed clinical information improves the interpretation of CTs for acute stroke.

Methods: In the prospective Cornell AcutE Stroke Academic Registry (CAESAR), we randomly selected 100 patients who underwent noncontrast head CT within 6 hours of transient ischemic attack (TIA) or minor acute ischemic stroke (National Institutes of Health Stroke Scale score ≤3) and underwent magnetic resonance imaging (MRI) within 6 hours of the CT. Three radiologists each twice evaluated CT studies both with and without accompanying information on the patient’s medical history, neurological deficit, and symptom time course. In random sequence, each study was interpreted by each radiologist in one condition (i.e., with or without detailed accompanying information), and then after a 4-week washout period, the same study was interpreted again by each radiologist in the opposite condition. Using MRI diffusion weighted imaging (DWI) as the reference standard for brain infarction, we classified CT interpretations as correct (true positives or true negatives) or incorrect (false positives or false negatives). McNemar’s test was used to compare the proportion of correct interpretations in the condition with detailed clinical information versus the condition without detailed information.

Results: In patients with DWI-defined infarcts, acute ischemia was correctly called on 20% (95% confidence interval [CI], 14-27%) of CTs with detailed history versus 18% (95% CI, 12-25%) without history. In patients without infarcts, the absence of acute ischemia was correctly called on 77% (95% CI, 70-84%) of CTs with history and 77% (95% CI, 69-83%) without history. The proportion of correct interpretations of CTs accompanied by detailed clinical history (49% [95% CI, 43-54%]) did not differ significantly from those without history (47% [95% CI, 42-53%]) ( P = 0.67).

Conclusions: Reported findings on head CT for evaluation of suspected acute ischemic stroke were similar regardless of whether detailed clinical history was provided.

Abstract WP24: Angiographic Blush After Mechanical Thrombectomy is Associated With Hemorrhagic Conversion of Ischemic Stroke

Introduction: Risk factors for hemorrhagic transformation of ischemic stroke after mechanical thrombectomy are not well established.

Hypothesis: Prominent cerebral tissue vascularity on angiography after recanalization with thrombectomy (angiographic blush) is associated with hemorrhagic transformation.

Methods: Among patients in the Cornell AcutE Stroke Academic Registry (CAESAR), we identified those who underwent stent-retriever-based thrombectomy for anterior circulation occlusion between 2012 and 2015. The presence of hemorrhagic transformation and angiographic blush were determined by neuroradiologists and neurointerventionalists. We identified angiographic blush as hypervascularity with or without early venous drainage. Hemorrhagic transformation was defined using CT or MRI studies performed within 7 days of thrombectomy. Our primary outcome was the volume of hemorrhagic transformation, determined using 3D-Slicer software. Our secondary outcome was the presence of any hemorrhagic transformation. Using a doubly robust estimator, we analyzed whether the presence of angiographic blush after recanalization was associated with an increased volume of hemorrhagic transformation after adjustment for demographics and previously published risk factors for hemorrhagic transformation.

Results: Among 48 eligible patients (median age, 68 years; median NIHSS score, 18), 31 (64.6%) had angiographic blush and 26 (54.2%) had hemorrhagic transformation (mean volume, 7.6 cc). Patients with angiographic blush had lower TICI scores and had more often received alteplase. After adjustment for demographics and risk factors for hemorrhagic transformation, the presence of angiographic blush was significantly associated with an increased volume of hemorrhagic transformation: mean volume, 10.3 (95% CI, 3.7-16.9) cc with any blush versus 1.8 (95% CI, 0.1-3.4) cc without any blush (p=0.01). Angiographic blush was nonsignificantly associated with the presence of any hemorrhagic transformation (odds ratio, 1.5; 95% CI, 0.9-2.5).

Conclusions: In a single-center study, we found that the presence of angiographic blush after mechanical thrombectomy was independently associated with an increased volume of hemorrhagic transformation.

Abstract TP191: Association Between Myocardial Infarction and Brain Infarction on Magnetic Resonance Imaging

Introduction: The relationship between myocardial infarction and brain infarction remains incompletely understood. Magnetic resonance imaging (MRI) offers excellent characterization of infarction in both the heart and brain.

Methods: We performed a retrospective cross-sectional study at our hospital to evaluate the association between myocardial infarction and brain infarction as detected on MRI. We identified all adult patients who underwent both cardiac MRI and brain MRI within 6 months of each other during the period 2014-2017. Myocardial infarction was identified by the presence of myocardial scar on delayed enhancement cardiac MRI. A neuroradiologist investigator reviewed all brain MRI studies to characterize acute and chronic infarcts. In secondary analyses, we evaluated the association between myocardial infarction and cortical versus subcortical brain infarction. The chi-square test was use to compare categorical variables.

Results: We identified 211 adults who underwent cardiac MRI and brain MRI within 6 months of each other. Myocardial infarction was present in 66 (31.3%) of cardiac MRIs. Brain infarction was present in 112 (53.1%) of brain MRIs, 61 (28.9%) of which were cortical infarcts, 33 (15.6%) subcortical, and 18 (8.5%) posterior fossa. Myocardial infarction was more common in patients with brain infarction (41.1%; 95% confidence interval [CI], 31.9-50.8%) than in patients without brain infarction (20.2%; 95% CI, 12.8-29.5%) ( P = 0.001). In secondary analyses, myocardial infarction was most common in patients with cortical brain infarcts (50.8%; 95% CI, 37.7-63.9%), less common in patients with only subcortical infarcts (27.3%; 95% CI, 13.3-45.5%), and least common in those with no brain infarcts ( P value for comparison among groups, < 0.001).

Conclusions: We found an association between myocardial infarction and brain infarction on MRI. The association was strongest between myocardial infarcts and cortical brain infarcts.

Association between Carotid Plaque Features on CTA and Cerebrovascular Ischemia: A Systematic Review and Meta-Analysis

BACKGROUND

CTA is a widely available imaging examination that may allow the evaluation of high-risk carotid plaque features.

PURPOSE

Our aim was to evaluate the association between specific carotid plaque features on CTA and ipsilateral cerebrovascular ischemia.

DATA SOURCES

We performed a systematic review of Ovid MEDLINE, Ovid Embase, Scopus, and the Cochrane Library from inception to March 2016 for articles that evaluated the relationship between CTA-detected carotid plaque features and ischemic events, defined as ipsilateral ischemic stroke or transient ischemic attack.

STUDY SELECTION

Sixteen studies were ultimately included after screening 12,557.

DATA ANALYSIS

Two readers recorded data from each study and assessed the study quality with all disagreements resolved by a third reader. A random-effects OR was used to evaluate the association between cerebrovascular ischemia and each of the evaluated plaque features.

DATA SYNTHESIS

We found significant positive relationships with cerebrovascular ischemia for the presence of soft plaque (OR, 2.9; 95% CI, 1.4-6.0), plaque ulceration (OR, 2.2; 95% CI, 1.4-3.4), and increased common carotid artery wall thickness (OR, 6.2; 95% CI, 2.5-15.6). We found a significant negative relationship between calcified plaque and ipsilateral ischemia (OR, 0.5; 95% CI, 0.4-0.7).

LIMITATIONS

We found heterogeneity in the existing literature secondary to lack of standardized plaque features and clinical definitions.

CONCLUSIONS

Soft plaque, plaque ulceration, and increased common carotid artery wall thickness on CTA are associated with ipsilateral cerebrovascular ischemia, while calcified plaque is negatively associated with downstream ischemic events.

Association between Intracranial Atherosclerotic Calcium Burden and Angiographic Luminal Stenosis Measurements

BACKGROUND AND PURPOSE

Calcification of the intracranial vasculature is an independent risk factor for stroke. The relationship between luminal stenosis and calcium burden in the intracranial circulation is incompletely understood. We evaluated the relationship between atherosclerotic calcification and luminal stenosis in the intracranial ICAs.

MATERIALS AND METHODS

Using a prospective stroke registry, we identified patients who had both NCCT and CTA or MRA examinations as part of a diagnostic evaluation for ischemic stroke. We used NCCTs to qualitatively (modified Woodcock Visual Score) and quantitatively (Agatston-Janowitz Calcium Score) measure ICA calcium burden and used angiography to measure arterial stenosis. We calculated correlation coefficients between the degree of narrowing and calcium burden measures.

RESULTS

In 470 unique carotid arteries (235 patients), 372 (79.1%) had atherosclerotic calcification detectable on CT compared with 160 (34%) with measurable arterial stenosis on CTA or MRA (P < .001). We found a weak linear correlation between qualitative (R = 0.48) and quantitative (R = 0.42) measures of calcium burden and the degree of luminal stenosis (P < .001 for both). Of 310 ICAs with 0% luminal stenosis, 216 (69.7%) had measurable calcium scores.

CONCLUSIONS

There is a weak correlation between intracranial atherosclerotic calcium scores and luminal narrowing, which may be explained by the greater sensitivity of CT than angiography in detecting the presence of measurable atherosclerotic disease. Future studies are warranted to evaluate the relationship between stenosis and calcium burden in predicting stroke risk.

Neutrophil-Lymphocyte Ratio and Perihematomal Edema Growth in Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Although preclinical studies have shown inflammation to mediate perihematomal edema (PHE) after intracerebral hemorrhage, clinical data are lacking. Leukocyte count, often used to gauge serum inflammation, has been correlated with poor outcome but its relationship with PHE remains unknown. Our aim was to test the hypothesis that leukocyte count is associated with PHE growth.

METHODS

We included patients with intracerebral hemorrhage admitted to a tertiary-care stroke center between 2011 and 2015. The primary outcome was absolute PHE growth during 24 hours, calculated using semiautomated planimetry. Linear regression models were constructed to study the relationship between absolute and differential leukocyte counts (monocyte count and neutrophil-lymphocyte ratio) and 24-hour PHE growth.

RESULTS

A total of 153 patients were included. Median hematoma and PHE volumes at baseline were 14.4 (interquartile range, 6.3-36.3) and 14.0 (interquartile range, 5.9-27.8), respectively. In linear regression analysis adjusted for demographics and intracerebral hemorrhage characteristics, absolute leukocyte count was not associated with PHE growth (β, 0.07; standard error, 0.15; P=0.09). In secondary analyses, neutrophil-lymphocyte ratio was correlated with PHE growth (β, 0.22; standard error, 0.08; P=0.005).

CONCLUSIONS

Higher neutrophil-lymphocyte ratio is independently associated with PHE growth. This suggests that PHE growth can be predicted using differential leukocyte counts on admission.