Atherosclerotic carotid artery disease Radiomics: A systematic review with meta-analysis and radiomic quality score assessment.

BACKGROUND: Stroke, a leading global cause of mortality and neurological disability, is often associated with atherosclerotic carotid artery disease. Distinguishing between symptomatic and asymptomatic carotid artery disease is crucial for appropriate treatment decisions. Radiomics, a quantitative image analysis technique, and ML have emerged as promising tools in medical imaging, including neuroradiology. This systematic review and meta-analysis aimed to evaluate the methodological quality of studies employing radiomics for atherosclerotic carotid artery disease analysis and ML algorithms for culprit plaque identification using CT or MRI. MATERIALS AND METHODS: Pubmed, WoS and Scopus databases were searched for relevant studies published from January 2005 to May 2023. RQS assessed methodological quality of studies included in the review. QUADAS-2 assessed the risk of bias. A meta-analysis and three meta regressions were conducted on study performance based on model type, imaging modality and segmentation method. RESULTS: RQS assessed methodological quality, revealing an overall low score and consistent findings with other radiology domains. QUADAS-2 indicated an overall low risk, except for a single study with high bias. The meta-analysis demonstrated that radiomics-based ML models for predicting culprit plaques had a satisfactory performance, with an AUC of 0.85, surpassing clinical models. However, combining radiomics with clinical features yielded the highest AUC of 0.89. Meta-regression analyses confirmed these findings. MRI-based models slightly outperformed CT-based ones, but the difference was not significant. CONCLUSION: In conclusion, radiomics and ML hold promise for assessing carotid plaque vulnerability, aiding in early cerebrovascular event prediction. Combining radiomics with clinical data enhances predictive performance.

Vessel Wall Imaging Features of Spontaneous Intracranial Carotid Artery Dissection.

BACKGROUND AND OBJECTIVES: Intracranial dissection is an important cause of stroke often with nonspecific angiographic features. Vessel wall imaging (VWI) can detect dissections, but intracranial applications remain unvalidated by pathologic specimens. We sought to determine the ability of VWI to identify the rarely reported spontaneous intracranial carotid dissection (sICD) guided by postmortem validation. METHODS: VWI features of sICD, validated by postmortem specimen analysis in 1 patient, included luminal enhancement within a hypoenhancing outer wall, narrowing the mid to distal ophthalmic (C6) segment, relatively sparing the communicating (C7) segment. VWI examinations were reviewed to identify patients (1) with matching imaging features, (2) no evidence of other vasculopathies (i.e., inflammatory, intracranial atherosclerotic disease [ICAD]), and (3) adequate image quality. These sICD VWI features were compared with those in patients with known ICAD causing similar narrowing of C6 and relative sparing of C7 by a Fisher exact test accounting for multiple samples. RESULTS: Among 407 VWI examinations, 8 patients were identified with 14 sICDs, all women aged 30-56 years, 6 (75%) bilateral. All patients with sICD had risk factors of dissection (e.g., recently postpartum, fibromuscular dysplasia, and hypertension) and 3 (37.5%) had intracranial dissections elsewhere. Seven (87.5%) were diagnosed as moyamoya syndrome on initial angiography. Enhancing lesions varied from thin flap-like defects (n = 6) to thick tissue along the superolateral wall of the internal carotid artery, within the hypoenhancing outer wall. Compared with 10 intracranial carotid plaques in 8 patients with ICAD, sICD demonstrated stronger (84.6% vs 20.0%, p = 0.003-0.025) and more homogeneous (61.5% vs 0.0%, p = 0.005-0.069) enhancement and less positive remodeling (0.0% vs 60.0%, p = 0.004-0.09). T1 hyperintensity was identified in 5 sICDs in 3 patients but not identified in ICAD. Three patients with serial imaging (8- to 39.8-month maximum intervals) revealed little to no changes in stenosis, wall thickening, or enhancement. DISCUSSION: sICD is distinguishable on VWI from ICAD by enhancement characteristics, less positive remodeling, and clinical parameters. These VWI features should raise suspicion especially in young women with risk factors of dissection. Temporal stability and a lack of T1 hyperintensity should not discourage diagnosing sICD.

MRI in the Evaluation of Cryptogenic Stroke and Embolic Stroke of Undetermined Source.

Cryptogenic stroke refers to a stroke of undetermined etiology. It accounts for approximately one-fifth of ischemic strokes and has a higher prevalence in younger patients. Embolic stroke of undetermined source (ESUS) refers to a subgroup of patients with nonlacunar cryptogenic strokes in whom embolism is the suspected stroke mechanism. Under the classifications of cryptogenic stroke or ESUS, there is wide heterogeneity in possible stroke mechanisms. In the absence of a confirmed stroke etiology, there is no established treatment for secondary prevention of stroke in patients experiencing cryptogenic stroke or ESUS, despite several clinical trials, leaving physicians with a clinical dilemma. Both conventional and advanced MRI techniques are available in clinical practice to identify differentiating features and stroke patterns and to determine or infer the underlying etiologic cause, such as atherosclerotic plaques and cardiogenic or paradoxical embolism due to occult pelvic venous thrombi. The aim of this review is to highlight the diagnostic utility of various MRI techniques in patients with cryptogenic stroke or ESUS. Future trends in technological advancement for promoting the adoption of MRI in such a special clinical application are also discussed.

Association of Dental Infections with Intracranial Atherosclerotic Stenosis.

INTRODUCTION: Periodontal disease (PD) and dental caries are oral infections leading to tooth loss that are associated with atherosclerosis and cerebrovascular disease. We assessed the hypothesis that PD and caries are associated with asymptomatic intracranial atherosclerosis (ICAS) in the Atherosclerosis Risk in Communities (ARIC) study. METHODS: Full-mouth clinical periodontal measurements (7 indices) collected at 6 sites per tooth from 6,155 subjects from the Dental Atherosclerosis Risk in Communities Study (DARIC) without prior stroke were used to differentiate seven PD stages (Periodontal Profile Class [PPC]-I to -VII) and dental caries on coronal dental surface (DS) and dental root surface (DRS). A stratified subset underwent 3D time-of-flight MR angiogram and 3D high isotropic-resolution black blood MRI. ICAS was graded according to the criteria established by the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. We evaluated the relationship between PD stage and dental caries with asymptomatic ICAS, graded as no ICAS, <50% ICAS, and ≥50% ICAS. RESULTS: Among dentate subjects who underwent vascular imaging, 801 (70%) had no ICAS, 232 (20%) had <50% ICAS, and 112 (10%) had ≥50% ICAS. Compared to participants without gum disease (PPC-I), participants with mild-moderate tooth loss (PPC-VI), severe tooth loss (PPC-VII), and severe PD (PPC-IV) had higher odds of having <50% ICAS. Participants with extensive gingivitis (PPC-V) had significantly higher odds of having ≥50% ICAS. This association remained significant after adjusting for confounding variables: age, gender, race, hypertension, diabetes, dyslipidemia, 3-level education, and smoking status. There was no association between dental caries (DS and DRS) and ICAS <50% and ≥50%. CONCLUSION: We report significant associations between mild-moderate tooth loss, severe tooth loss, and severe PD with <50% ICAS as well as an association between extensive gingivitis and ≥50% ICAS. We did not find an association between dental caries and ICAS.

Central arterial stiffening and intracranial atherosclerosis: the atherosclerosis risk in communities neurocognitive study (ARIC-NCS): Aortic stiffness & intracranial atherosclerosis.

OBJECTIVES: Previous studies suggest an association between central arterial stiffness (CAS) and intracranial atherosclerotic disease (ICAD) among Asian participants with stroke or hypertension; this association has not been evaluated in United States populations. We assessed the cross-sectional association of CAS with ICAD presence and burden in late-life, and differences in association by age, sex, and race. MATERIALS AND METHODS: We conducted a cross-sectional analysis of 1,285 Atherosclerosis Risk in Communities Study participants [mean age 75 (standard deviation: 5) years, 38 % male, 20  % Black] at Visit 5 (2011-2013). CAS was measured as carotid-femoral pulse wave velocity (cfPWV) using the Omron VP-1000 Plus. ICAD was assessed using high-resolution vessel wall MRI and MR angiography. We evaluated associations of a 1 standard deviation (SD) cfPWV (3.02 m/s) and high vs. non-high cfPWV (≥ 13.57 m/s vs. < 13.57 m/s) with presence of plaques (yes/no) and plaque number (0, 1-2, and >2) using multivariable logistic and ordinal logistic regression models adjusted for covariates. RESULTS: Each one SD greater cfPWV was associated with higher odds of plaque presence (odds ratio (OR)=1.32, 95 % confidence interval (CI): 1.22, 1.43), and an incrementally higher odds of number of plaques (OR 1-2 vs. 0 plaques = 1.21, 95 % CI: 1.10, 1.33; OR >2 vs. 0 plaques = 1.51, 95 % CI: 1.33,1.71). Results suggested differences by race, with greater magnitude associations among Black participants. CONCLUSIONS: CAS was positively associated with ICAD presence and burden; cfPWV may be a useful subclinical vascular measure for identification of individuals who are at high risk for cerebrovascular disease.

Carotid Plaque-RADS: A Novel Stroke Risk Classification System.

BACKGROUND: Carotid artery atherosclerosis is highly prevalent in the general population and is a well-established risk factor for acute ischemic stroke. Although the morphological characteristics of vulnerable plaques are well recognized, there is a lack of consensus in reporting and interpreting carotid plaque features. OBJECTIVES: The aim of this paper is to establish a consistent and comprehensive approach for imaging and reporting carotid plaque by introducing the Plaque-RADS (Reporting and Data System) score. METHODS: A panel of experts recognized the necessity to develop a classification system for carotid plaque and its defining characteristics. Using a multimodality analysis approach, the Plaque-RADS categories were established through consensus, drawing on existing published reports. RESULTS: The authors present a universal classification that is applicable to both researchers and clinicians. The Plaque-RADS score offers a morphological assessment in addition to the prevailing quantitative parameter of "stenosis." The Plaque-RADS score spans from grade 1 (indicating complete absence of plaque) to grade 4 (representing complicated plaque). Accompanying visual examples are included to facilitate a clear understanding of the Plaque-RADS categories. CONCLUSIONS: Plaque-RADS is a standardized and reliable system of reporting carotid plaque composition and morphology via different imaging modalities, such as ultrasound, computed tomography, and magnetic resonance imaging. This scoring system has the potential to help in the precise identification of patients who may benefit from exclusive medical intervention and those who require alternative treatments, thereby enhancing patient care. A standardized lexicon and structured reporting promise to enhance communication between radiologists, referring clinicians, and scientists.

Detection of Dolichoectasia and Atherosclerosis by Automated MRA Tortuosity Metrics in a Population-Based Study.

BACKGROUND: Intracranial vessel tortuosity is a key component of dolichoectasia and has been associated with atherosclerosis and adverse neurologic outcomes. However, the evaluation of tortuosity is mainly a descriptive assessment. PURPOSE: To compare the performance of three automated tortuosity metrics (angle metric [AM], distance metric [DM], and distance-to-axis metric [DTA]) for detection of dolichoectasia and presence of segment-specific plaques. STUDY TYPE: Observational, cross-sectional metric assessment. POPULATION: 1899 adults from the general population; mean age = 76 years, female = 59%, and black = 29%. FIELD STRENGTH/SEQUENCE: 3-T, three-dimensional (3D) time-of-flight MRA and 3D vessel wall MRI. ASSESSMENT: Tortuosity metrics and mean luminal area were quantified for designated segments of the internal carotid artery, middle cerebral artery, anterior cerebral artery, posterior cerebral artery, vertebral artery, and entire length of basilar artery (BA). Qualitative interpretations of BA dolichoectasia were assessed based on Smoker's visual criteria. STATISTICAL TESTS: Descriptive statistics (2-sample t-tests, Pearson chi-square tests) for group comparisons. Receiver operating characteristics area under the curve (AUC) for detection of BA dolichoectasia or segment-specific plaque. Model inputs included 1) tortuosity metrics, 2) mean luminal area, and 3) demographics (age, race, and sex). RESULTS: Qualitative dolichoectasia was identified in 336 (18%) participants, and atherosclerotic plaques were detected in 192 (10%) participants. AM-, DM-, and DTA-calculated tortuosity were good individual discriminators of basilar dolichoectasia (AUCs: 0.76, 0.74, and 0.75, respectively), with model performance improving with the mean lumen area: (AUCs: 0.88, 0.87, and 0.87, respectively). Combined characteristics (tortuosity and mean luminal area) identified plaques with better performance in the anterior (AUCs ranging from 0.66 to 0.78) than posterior (AUCs ranging from 0.54 to 0.65) circulation, with all models improving by the addition of demographics (AUCs ranging from 0.62 to 0.84). DATA CONCLUSION: Quantitative vessel tortuosity metrics yield good diagnostic accuracy for the detection of dolichoectasia. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies.

BACKGROUND AND PURPOSE: Brain arterial diameters are markers of cerebrovascular disease. Demographic and anatomical factors may influence arterial diameters. We hypothesize that age, sex, height, total cranial volume (TCV), and persistent fetal posterior cerebral artery (fPCA) correlate with brain arterial diameters across populations. METHODS: Participants had a time-of-flight MRA from nine international cohorts. Arterial diameters of the cavernous internal carotid arteries (ICA), middle cerebral arteries (MCA), and basilar artery (BA) were measured using LAVA software. Regression models assessed the association between exposures and brain arterial diameters. RESULTS: We included 6,518 participants (mean age: 70 ± 9 years; 41% men). Unilateral fPCA was present in 13.2% and bilateral in 3.2%. Larger ICA, MCA, and BA diameters correlated with older age (Weighted average [WA] per 10 years: 0.18 mm, 0.11 mm, and 0.12 mm), male sex (WA: 0.24 mm, 0.13 mm, and 0.21 mm), and TCV (WA: for one TCV standard deviation: 0.24 mm, 0.29 mm, and 0.18 mm). Unilateral and bilateral fPCAs showed a positive correlation with ICA diameters (WA: 0.39 mm and 0.73 mm) and negative correlation with BA diameters (WA: -0.88 mm and -1.73 mm). Regression models including age, sex, TCV, and fPCA explained on average 15%, 13%, and 25% of the ICA, MCA, and BA diameter interindividual variation, respectively. Using height instead of TCV as a surrogate of head size decreased the R-squared by 3% on average. CONCLUSION: Brain arterial diameters correlated with age, sex, TCV, and fPCA. These factors should be considered when defining abnormal diameter cutoffs across populations.

Chromosome 10q24.32 Variants Associate With Brain Arterial Diameters in Diverse Populations: A Genome-Wide Association Study.

BACKGROUND: Brain arterial diameters (BADs) are novel imaging biomarkers of cerebrovascular disease, cognitive decline, and dementia. Traditional vascular risk factors have been associated with BADs, but whether there may be genetic determinants of BADs is unknown. METHODS AND RESULTS: The authors studied 4150 participants from 6 geographically diverse population-based cohorts (40% European, 14% African, 22% Hispanic, 24% Asian ancestries). Brain arterial diameters for 13 segments were measured and averaged to obtain a global measure of BADs as well as the posterior and anterior circulations. A genome-wide association study revealed 14 variants at one locus associated with global BAD at genome-wide significance (P<5×10-8) (top single-nucleotide polymorphism, rs7921574; ß=0.06 [P=1.54×10-8]). This locus mapped to an intron of CNNM2. A trans-ancestry genome-wide association study meta-analysis identified 2 more loci at NT5C2 (rs10748839; P=2.54×10-8) and AS3MT (rs10786721; P=4.97×10-8), associated with global BAD. In addition, 2 single-nucleotide polymorphisms colocalized with expression of CNNM2 (rs7897654; ß=0.12 [P=6.17×10-7]) and AL356608.1 (rs10786719; ß=-0.17 [P=6.60×10-6]) in brain tissue. For the posterior BAD, 2 variants at one locus mapped to an intron of TCF25 were identified (top single-nucleotide polymorphism, rs35994878; ß=0.11 [P=2.94×10-8]). For the anterior BAD, one locus at ADAP1 was identified in trans-ancestry genome-wide association analysis (rs34217249; P=3.11×10-8). CONCLUSIONS: The current study reveals 3 novel risk loci (CNNM2, NT5C2, and AS3MT) associated with BADs. These findings may help elucidate the mechanism by which BADs may influence cerebrovascular health.

A Novel Window Into Human Vascular Remodeling and Diagnosing Carotid Flow Impairment: The Petro-Occipital Venous Plexus.

Background Adaptive arterial remodeling caused by flow reduction from downstream stenosis has been demonstrated in animal studies. The authors sought to determine whether inward remodeling from downstream stenosis also occurs in humans and is detectable by ex vacuo expansion of the Rektorzik venous plexus (RVP) surrounding the petrous internal carotid artery. Methods and Results The authors analyzed 214 intracranial magnetic resonance imaging examinations that included contrast-enhanced vessel wall imaging. RVP symmetry was qualitatively assessed on vessel wall imaging. RVP thickness (RVPT) was measured on the thicker side if asymmetric or randomly assigned side if symmetric. Maximum stenosis (M1 or intracranial internal carotid artery) was measured. Posterior communicating artery and A1 diameters (>1.0 mm and 1.5 mm, respectively) defined adequate collateral outflow when proximal to the stenosis. Seventy-two patients had stenosis downstream from RVPT measurements. For those without adequate outflow (38 of 72), 95.0% with RVPT ≥1.0 mm had ≥50% stenosis compared with only 5.6% with RVPT <1.0 mm. For these 72 patients, higher RVPT (RVPT ≥1.0 mm versus <1.0 mm) and absent adequate outflow were associated with greater downstream stenosis (P<0.001) using multivariate regression. For patients with downstream stenosis without adequate outflow, asymmetric RVP thickening was associated with greater ipsilateral stenosis (P<0.001, all had ≥46% stenosis) when stenosis was unilateral and greater differences in stenosis between sides (P=0.005) when stenosis was bilateral. Conclusions Inward internal carotid artery remodeling measured by RVPT or RVP asymmetry occurs as downstream stenosis approaches 50%, unless flow is preserved through a sufficiently sized posterior communicating artery or A1, and may serve as a functional measure of substantial flow reduction from downstream stenosis.

Association of leisure-time physical activity and sedentary behavior with carotid atherosclerosis morphology: The ARIC carotid-MRI study.

Objective: We evaluated the prospective association of midlife leisure-time physical activity (LTPA) and sedentary behavior (SB), and their temporal patterns, with MRI-measured carotid atherosclerotic morphology. Methods: Participants enrolled in the Carotid MRI substudy (2004-2006) of the Atherosclerosis Risk in Communities (ARIC) Study and with self-reported assessments of LTPA and SB at visits 1 (1987-1989) and 3 (1993-1995) were included in this study. LTPA was ascertained using the ARIC/Baecke physical activity questionnaire and categorized according to the American Heart Association's metric of poor, intermediate, or ideal physical activity. SB, measured as TV viewing frequency, was categorized as high, medium, and low. We used multivariable adjusted linear and logistic regression models to examine the associations between midlife (visit 3 only) and persistent (visit 1 to 3) LTPA and TV viewing with carotid artery plaque burden and components. Results: Among the 1,582 (mean age: 59 years, 43% male, 18% Black) participants, 45.7%, 21.7%, and 32.6% reported ideal, intermediate, or poor LTPA, respectively. High TV viewing was reported in 33.8% of participants, with 46.4% and 19.8% reporting medium or low TV viewing, respectively. Compared to poor LTPA, ideal LTPA in midlife was not associated with total wall volume (ß=0.01, 95% CI: -0.01, 0.03), maximum carotid wall thickness (ß=0.06, 95% CI: -0.08, 0.21), normalized wall index (ß=-0.01, 95% CI: -0.03, 0.01), or maximum stenosis (ß=-0.11, 95% CI: -1.98, 1.76). Low or middle, compared to high, TV viewing was also not associated with carotid artery measures of plaque burden. Compared to poor LTPA or high TV viewing, ideal LTPA (odds ratio (OR): 0.82, 95% CI: 0.55, 1.23) and low TV viewing (OR=0.90, 95% CI: 0.56, 1.44) was not associated with odds of lipid core presence, respectively. Conclusion: Overall, this study does not provide strong evidence for an association between LTPA and SB with carotid plaque measures.

Chromosome 10q24.32 Variants Associate with Brain Arterial Diameters in Diverse Populations: A Genome-Wide Association Study.

Background: Brain arterial diameters are novel imaging biomarkers of cerebrovascular disease, cognitive decline and dementia. Traditional vascular risk factors have been associated with brain arterial diameters but whether there may be genetic determinants of brain arterial diameters is unknown. Results: We studied 4150 participants from six geographically diverse population-based cohorts (40% European, 14% African, 22% Hispanic, 24% Asian ancestries). We measured brain arterial diameters for 13 segments and averaged them to obtain a global measure of brain arterial diameters as well as the posterior and anterior circulations. A genome-wide association study (GWAS) revealed 14 variants at one locus associated with global brain arterial diameter at genome-wide significance (P<5×10-8) (top SNP, rs7921574; ß =0.06, P=1.54×10-8). This locus mapped to an intron of CNNM2. A trans-ancestry GWAS meta-analysis identified two more loci at NT5C2 (rs10748839; P=2.54×10-8) and at AS3MT (rs10786721; P=4.97×10-8), associated with global brain arterial diameter. In addition, two SNPs co-localized with expression of CNNM2 (rs7897654, ß=0.12, P=6.17×10-7) and AL356608.1 (rs10786719, ß =-0.17, P=6.60×10-6) in brain tissue. For the posterior brain arterial diameter, two variants at one locus mapped to an intron of TCF25 were identified (top SNP, rs35994878; ß =0.11, P=2.94×10-8). For the anterior brain arterial diameter, one locus at ADAP1 was identified in trans-ancestry genome-wide association analysis (rs34217249; P=3.11×10-8). Conclusion: Our study reveals three novel risk loci (CNNM2, NT5C2 and AS3MT) associated with brain arterial diameters. Our finding may elucidate the mechanisms by which brain arterial diameters influence the risk of stroke and dementia.

International Union of Angiology (IUA) consensus paper on imaging strategies in atherosclerotic carotid artery imaging: From basic strategies to advanced approaches.

Cardiovascular disease (CVD) is the leading cause of mortality and disability in developed countries. According to WHO, an estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Of these deaths, 85% were due to major adverse cardiac and cerebral events. Early detection and care for individuals at high risk could save lives, alleviate suffering, and diminish economic burden associated with these diseases. Carotid artery disease is not only a well-established risk factor for ischemic stroke, contributing to 10%-20% of strokes or transient ischemic attacks (TIAs), but it is also a surrogate marker of generalized atherosclerosis and a predictor of cardiovascular events. In addition to diligent history, physical examination, and laboratory detection of metabolic abnormalities leading to vascular changes, imaging of carotid arteries adds very important information in assessing stroke and overall cardiovascular risk. Spanning from carotid intima-media thickness (IMT) measurements in arteriopathy to plaque burden, morphology and biology in more advanced disease, imaging of carotid arteries could help not only in stroke prevention but also in ameliorating cardiovascular events in other territories (e.g. in the coronary arteries). While ultrasound is the most widely available and affordable imaging methods, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), their combination and other more sophisticated methods have introduced novel concepts in detection of carotid plaque characteristics and risk assessment of stroke and other cardiovascular events. However, in addition to robust progress in usage of these methods, all of them have limitations which should be taken into account. The main purpose of this consensus document is to discuss pros but also cons in clinical, epidemiological and research use of all these techniques.

Initial Diagnostic Evaluation of the Child With Suspected Arterial Ischemic Stroke.

ABSTRACT: Numerous factors make the initial diagnostic evaluation of children with suspected arterial ischemic stroke (AIS) a relatively unsettling challenge, even for the experienced stroke specialist. The low frequency of pediatric AIS, diversity of unique age-oriented stroke phenotypes, and unconventional approaches required for diagnosis and treatment all contribute difficulty to the process. This review aims to outline important features that differentiate pediatric AIS from adult AIS and provide practical strategies that will assist the stroke specialist with diagnostic decision making in the initial phase of care.

Definitive Diagnostic Evaluation of the Child With Arterial Ischemic Stroke and Approaches to Secondary Stroke Prevention.

ABSTRACT: In children with arterial ischemic stroke (AIS), the definitive diagnosis of stroke subtype and confirmation of stroke etiology is necessary to mitigate stroke morbidity and prevent recurrent stroke. The common causes of AIS in children are sharply differentiated from the common causes of adult AIS. A comprehensive, structured diagnostic approach will identify the etiology of stroke in most children. Adequate diagnostic evaluation relies on advanced brain imaging and vascular imaging studies. A variety of medical and surgical secondary stroke prevention strategies directed at the underlying cause of stroke are available. This review aims to outline strategies for definitive diagnosis and secondary stroke prevention in children with AIS, emphasizing the critical role of neuroimaging.

Reperfusion Therapies for Children With Arterial Ischemic Stroke.

ABSTRACT: Modern hyperacute reperfusion therapies including intravenous thrombolysis and mechanical thrombectomy have transformed the management of arterial ischemic stroke (AIS) in adults. Multiple randomized clinical trials have demonstrated that these therapies enable remarkable improvements in clinical outcome for properly selected patients with AIS. Because pediatric patients were excluded from predicate clinical trials, there is a conspicuous lack of data to guide selection of therapies and inform age-adjusted and pathology-oriented treatment modifications for children. Specifically, technical guidance concerning treatment eligibility, drug dosing, and device implementation is lacking. This review aims to outline important features that differentiate pediatric AIS from adult AIS and provide practical strategies that will assist the stroke specialist with therapeutic decision making.

Understanding the Clinical Implications of Intracranial Arterial Calcification Using Brain CT and Vessel Wall Imaging.

Background and Purpose: Intracranial arterial calcification (IAC) has been the focus of much attention by clinicians and researchers as an indicator of intracranial atherosclerosis, but correlations of IAC patterns (intimal or medial) with the presence of atherosclerotic plaques and plaque stability are still a matter of debate. Our study aimed to assess the associations of IAC patterns identified on computed tomography (CT) with the presence of plaque detected on vessel wall magnetic resonance imaging and plaque stability. Materials and Methods: Patients with stroke or transient ischemic attack and intracranial artery stenosis were recruited. IAC was detected and localized (intima or media) on non-contrast CT images. Intracranial atherosclerotic plaques were identified using vessel wall magnetic resonance imaging and matched to corresponding CT images. Associations between IAC patterns and culprit atherosclerotic plaques were assessed by using multivariate regression. Results: Seventy-five patients (mean age, 63.4 ± 11.6 years; males, 46) were included. Two hundred and twenty-one segments with IAC were identified on CT in 66 patients, including 86 (38.9%) predominantly intimal calcifications and 135 (61.1%) predominantly medial calcifications. A total of 72.0% of intimal calcifications coexisted with atherosclerotic plaques, whereas only 10.2% of medial calcifications coexisted with plaques. Intimal calcification was more commonly shown in non-culprit plaques than culprit plaques (25.9 vs. 9.4%, P = 0.008). The multivariate mixed logistic regression adjusted for the degree of stenosis showed that intimal calcification was significantly associated with non-culprit plaques (OR, 2.971; 95% CI, 1.036-8.517; P = 0.043). Conclusion: Our findings suggest that intimal calcification may indicate the existence of a stable form of atherosclerotic plaque, but plaques can exist in the absence of intimal calcification especially in the middle cerebral artery.

Vascular Involvement in Neurosarcoidosis: Early Experiences From Intracranial Vessel Wall Imaging.

BACKGROUND AND OBJECTIVES: Cerebrovascular manifestations in neurosarcoidosis (NS) were previously considered rare but are being increasingly recognized. We report our preliminary experience in patients with NS who underwent high-resolution vessel wall imaging (VWI). METHODS: A total of 13 consecutive patients with NS underwent VWI. Images were analyzed by 2 neuroradiologists in consensus. The assessment included segment-wise evaluation of larger- and medium-sized vessels (internal carotid artery, M1-M3 middle cerebral artery; A1-A3 anterior cerebral artery; V4 segments of vertebral arteries; basilar artery; and P1-P3 posterior cerebral artery), lenticulostriate perforator vessels, and medullary and deep cerebral veins. Cortical veins were not assessed due to flow-related artifacts. Brain biopsy findings were available in 6 cases and were also reviewed. RESULTS: Mean patient age was 54.9 years (33-71 years) with an M:F of 8:5. Mean duration between initial diagnosis and VWI study was 18 months. Overall, 9/13 (69%) patients had vascular abnormalities. Circumferential large vessel enhancement was seen in 3/13 (23%) patients, whereas perforator vessel involvement was seen in 6/13 (46%) patients. Medullary and deep vein involvement was also seen in 6/13 patients. In addition, 7/13 (54%) patients had microhemorrhages in susceptibility-weighted imaging, and 4/13 (31%) had chronic infarcts. On biopsy, 5/6 cases showed perivascular granulomas with vessel wall involvement in all 5 cases. DISCUSSION: Our preliminary findings suggest that involvement of intracranial vascular structures may be a common finding in patients with NS and should be routinely looked for. These findings appear concordant with previously reported autopsy literature and need to be validated on a larger scale.