Arterial Tortuosity: An Imaging Biomarker of Childhood Stroke Pathogenesis?

Association between cervicocerebral artery dissection and tortuosity - a review on quantitative and qualitative assessment

Cervicocerebral artery dissection stands out as a significant contributor to ischemic stroke in young adults. Several studies have shown that arterial tortuosity is associated with dissection. We searched Pubmed and Embase to identify studies on the association between arterial tortuosity and cervicocerebral artery dissection, and to perform a review on the epidemiology of cervicocerebral artery tortuosity and dissection, pathophysiology, measurement of vessels tortuosity, strength of association between tortuosity and dissection, clinical manifestation and management strategies. The prevalence of tortuosity in dissected cervical arteries was reported to be around 22%-65% while it is only around 8%-22% in non-dissected arteries. In tortuous cervical arteries elastin and tunica media degradation, increased wall stiffness, changes in hemodynamics as well as arterial wall inflammation might be associated with dissection. Arterial tortuosity index and vertebrobasilar artery deviation is used to measure the level of vessel tortuosity. Studies have shown an independent association between these two measurements and cervicocerebral artery dissection. Different anatomical variants of tortuosity such as loops, coils and kinks may have a different level of association with cervicocerebral artery dissection. Symptomatic patients with extracranial cervical artery dissection are often treated with anticoagulant or antiplatelet agents, while patients with intracranial arterial dissection were often treated with antiplatelets only due to concerns of developing subarachnoid hemorrhage. Patients with recurrent ischemia, compromised cerebral blood flow or contraindications for antithrombotic agents are usually treated with open surgery or endovascular technique. Those with subarachnoid hemorrhage and intracranial artery dissection are often managed with surgical intervention due to high risk of re-hemorrhage.

Association of Morphology of Lenticulostriate Arteries and Proximal Plaque Characteristics With Single Subcortical Infarction: A Whole-Brain High-Resolution Vessel Wall Imaging Study

BACKGROUND

We aimed to investigate the association of characteristics of lenticulostriate artery (LSA) morphology and parental atheromatous disease (PAD) with single subcortical infarction (SSI) and to explore whether the LSA morphology is correlated with proximal plaque features in asymptomatic PAD.

METHODS AND RESULTS

Patients with acute SSI were prospectively enrolled and classified as large- and small-SSI groups. The clinical data and imaging features of LSA morphology (branches, length, dilation, and tortuosity) and middle cerebral artery plaques (normalized wall index, remodeling index, enhancement degree, and hyperintense plaques) were evaluated. Logistic regression was performed to determine the association of large SSIs with morphologic features of LSAs and plaques. The Spearman correlation between the morphologic characteristics of LSAs and plaque features in asymptomatic PAD was analyzed. Of the 121 patients recruited with symptomatic PAD, 102 had coexisting asymptomatic contralateral PAD. The mean length of LSAs (odds ratio, 0.84 [95% CI, 0.73-0.95]; P=0.007), mean tortuosity of LSAs (odds ratio, 1.13 [95% CI, 1.05-1.22]; P=0.002), dilated LSAs (odds ratio, 22.59 [95% CI, 2.46-207.74]; P=0.006), and normalized wall index (odds ratio, 1.08 [95% CI, 1.01-1.15]; P=0.022) were significantly associated with large SSIs. Moreover, the normalized wall index was negatively correlated with the mean length of LSAs (r=-0.348, P<0.001), and the remodeling index was negatively correlated with the mean tortuosity of LSAs (r=-0.348, P<0.001) in asymptomatic PAD.

CONCLUSIONS

Our findings suggest that mean length of LSAs, mean tortuosity of LSAs, dilated LSAs, and normalized wall index are associated with large SSIs. Moreover, plaque features in asymptomatic PAD are correlated with morphologic features of LSAs.

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.

Newer Updates in Pediatric Vascular Diseases

Pediatric neurovascular pathology directly involves or is in close proximity to the central nervous system (CNS). These vascular pathologies can occur in isolation or in association with broader syndromes. While some vascular pathologies are unique to the pediatric population, the full spectrum of adult neurovascular lesions can also affect children however, may present differently both clinically and on diagnostic imaging. Non-invasive (Ultrasound, CT, MRI) imaging plays a critical role in the diagnosis, treatment planning, and follow-up of vascular lesions involving the CNS. The modality can be chosen based on the age of the child, urgency of diagnosis, and local availability. Each modality has sensitivities and specificities which vary based on the location and imaging findings of a specific neurovascular pathology. In addition to non-invasive options, digital subtraction angiography (DSA) may be used as both a diagnostic and therapeutic imaging method for pediatric vascular lesions of the central nervous system. The diagnosis and management of pediatric cerebrovascular disease requires the close collaboration between pediatricians and pediatric specialists including neuroradiologists, neurologists, neurosurgeons, cardiologists, neurointerventionalists, and anesthesiologists among others. A detailed understanding of imaging findings, natural history, and treatment options is essential to guide and monitor imaging and treatment. The goal of this review is to provide the reader with an overview on pediatric neurovascular pathologies, provide examples of pathognomonic imaging findings, and present a brief review of endovascular treatment options, if applicable.

Incidence, kinetics, and risk factors for intra- and extracranial cerebral arteriopathies in a newborn sickle cell disease cohort early assessed by transcranial and cervical color Doppler ultrasound

The risk of stroke in children with sickle cell disease (SCD) is detected by abnormal intracranial arterial time-averaged mean of maximum velocities (TAMVs ≥200 cm/s). Recently, extracranial internal carotid artery (eICA) arteriopathy has been reported, and a cross-sectional study showed that eICA-TAMVs ≥160 cm/s are significantly associated with eICA kinkings and stenosis. The cumulative incidence of and predictive risk factors for intracranial arteriopathy are well described in sickle cell anemia (SCA=SS/Sβ0) but are lacking for SC/Sβ+ children, as is the cumulative incidence of eICA arteriopathy. We report a prospective longitudinal cohort study including 493 children with SCD (398 SCA, 95 SC/Sβ+), all assessed by transcranial and cervical color Doppler ultrasound. Cerebral MRI/MRA data were available in 375 children with SCD and neck MRA in 365 children. eICA kinkings were defined as eICA tortuosities on neck MRA, with an internal acute angle between the two adjacent segments <90°. The median follow-up was 10.6 years. The cumulative incidence of kinkings was significantly lower in SC/Sβ+ children than in children with SCA, and no SC/Sβ+ child developed intra- or extracranial stenotic arteriopathy. The 10-year KM estimate of cumulative incidence (95% CI) for eICA-TAMVs ≥160 cm/s revealed its development in the 2nd year of life in children with SCA, reaching a plateau of 17.4% (13.2–21.6%) by about 10 years of age, while the plateau for eICA stenosis was 12.3% (8.3–16.3%). eICA assessment identified 13.5% (9.3–17.7%) patients at risk of stroke who were not detected by transcranial color Doppler ultrasound. We also show, for the first time, that in addition to a congenital origin, eICA kinkings sin patients with SCD can develop progressively with aging as a function of eICA-TAMVs, themselves related to anemia severity. Ongoing hydroxyurea treatment was significantly associated with a lower risk of abnormal intracranial arteriopathy and eICA kinkings. After adjustment with hydroxyurea, baseline low hemoglobin, high reticulocyte, and WBC counts remained independent risk factors for intracranial arteriopathy, while low hemoglobin and SEN β-haplotype number were independent risk factors for extracranial arteriopathy. The association between extracranial arteriopathy and SEN β-haplotype number suggested a genetic link between the ethnic origin and incidence of eICA kinkings. This prospective cohort study shows the importance of systematically assessing the eICA and of recording biological parameters during the 2nd year of life before any intensive therapy to predict the risk of cerebral arteriopathy and treat patients with severe baseline anemia.

Novel imaging markers for altered cerebrovascular morphology in aging, stroke, and Alzheimer's disease

BACKGROUND AND PURPOSE

Altered brain vasculature is a key phenomenon in several neurologic disorders. This paper presents a quantitative assessment of the anatomical variations in the Circle of Willis (CoW) and vascular morphology in healthy aging, acute ischemic stroke (AIS) and Alzheimer's Disease (AD).

METHODS

We used our novel automatic method to segment and extract geometric features of the cerebral vasculature from MR angiography scans of 175 healthy subjects, which were used to create a probabilistic atlas of cerebrovasculature and to study normal aging and intersubject variations in CoW anatomy. Subsequently, we quantified and analyzed vascular alterations in 45AIS and 50 AD patients, two prominent cerebrovascular and neurodegenerative disorders.

RESULTS

In the sampled cohort, we determined that the CoW is fully formed in only 35% of healthy adults and found significantly (p < .05) increased tortuosity and fractality, with increasing age and also with disease in both AIS and AD. We also found significantly lower vessel length, volume, and number of branches in AIS patients, as expected. The AD cerebral vessels exhibited significantly smaller diameter and more complex branching patterns, compared to age-matched healthy adults. These changes were significantly heightened (p < .05) among healthy, early onset mild AD, and moderate/severe dementia groups.

CONCLUSION

Although our study does not include longitudinal data due to paucity of such datasets, the specific geometric features and quantitative comparisons demonstrate the potential for using vascular morphology as a noninvasive imaging biomarker for neurologic disorders.

Arterial tortuosity syndrome causing recurrent transient ischemic attacks in young adult: a case report

BACKGROUND

Arterial Tortuosity Syndrome (ATS) is a rare autosomal recessive disorder characterized by elongated and tortuous arteries. Although ATS showed a significant clinical and pathophysiological overlap with other syndromes involving connective tissues, only few cases of cerebrovascular events related to this syndrome have been described so far.

CASE PRESENTATION

We report the case of a 33-years-old male diagnosed with ATS since childhood, that experienced three sudden episodes of expressive aphasia and right hemiparesis with spontaneous resolution. He was treated with recombinant tissue plasminogen activator (r-TPA) at a dosage of 0.9 mg/kg with a complete recovery. Brain Magnetic Resonance Imaging (MRI) showed the absence of acute ischemic lesions and the patient was diagnosed with recurrent transient ischemic attacks (TIA). Intracranial and supra-aortic trunks Magnetic Resonance Angiography (MRA) and Angio-CT scan of the thoracic and abdominal aorta showed marked vessel tortuosity without stenosis. To our knowledge, this is the first reported case of an ATS patient with TIA in young age that was treated with intravenous thrombolysis with recombinant plasminogen activator.

CONCLUSION

Our report strengthens the relationship between ATS and juvenile cerebrovascular events, suggesting that an extensive study of body vessels in order to detect potential stenoses or occlusions in these cases is needed. The greater predisposition to cerebrovascular events in ATS could benefit from a more aggressive primary and secondary prevention therapy.

Quantitative Assessment of the Intracranial Vasculature of Infants and Adults Using iCafe (Intracranial Artery Feature Extraction)

Comprehensive quantification of intracranial artery features may help to assess and understand regional variations of blood supply during early brain development and aging. We analyzed vasculature features of 27 healthy infants during natural sleep, 13 infants at 7-months (7.3 ± 1.0 month), and 14 infants at 12-months (11.7 ± 0.4 month), and 13 older healthy, awake adults (62.8 ± 8.7 years) to investigate age-related vascular differences as a preliminary study of vascular changes associated with brain development. 3D time-of-flight (TOF) magnetic resonance angiography (MRA) acquisitions were processed in iCafe, a technique to quantify arterial features (http://icafe.clatfd.cn), to characterize intracranial vasculature. Overall, adult subjects were found to have increased ACA length, tortuosity, and vasculature density compared to both 7-month-old and 12-month-old infants, as well as MCA length compared to 7-month-old infants. No brain laterality differences were observed for any vascular measures in either infant or adult age groups. Reduced skull and brain sharpness, indicative of increased head motion and brain/vascular pulsation, respectively, were observed in infants but not correlated with length, tortuosity, or vasculature density measures. Quantitative analysis of TOF MRA using iCafe may provide an objective approach for systematic study of infant brain vascular development and for clinical assessment of adult and pediatric brain vascular diseases.

Cerebrovascular Disease Progression in Patients With ACTA2 Arg179 Pathogenic Variants

OBJECTIVE

To establish progression of imaging biomarkers of stroke, arterial steno-occlusive disease, and white matter injury in patients with smooth muscle dysfunction syndrome caused by mutations in the ACTA2 gene, we analyzed 113 cerebral MRI scans from a retrospective cohort of 27 patients with ACTA2 Arg179 pathogenic variants.

METHODS

Systematic quantifications of arterial ischemic strokes and white matter lesions were performed on baseline and follow-up scans using planimetric methods. Critical stenosis and arterial vessel diameters were quantified applying manual and semiautomated methods to cerebral magnetic resonance angiograms. We then assessed correlations between arterial abnormalities and parenchymal injury.

RESULTS

We found characteristic patterns of acute white matter ischemic injury and progressive internal carotid artery stenosis during infancy. Longitudinal analysis of patients older than 1.2 years showed stable white matter hyperintensities but increased number of cystic-like lesions over time. Progressive narrowing of the terminal internal carotid artery occurred in 80% of patients and correlated with the number of critical stenoses in cerebral arteries and arterial ischemic infarctions. Arterial ischemic strokes occurred in same territories affected by critical stenosis.

CONCLUSIONS

We found characteristic, early, and progressive cerebrovascular abnormalities in patients with ACTA2 Arg179 pathogenic variants. Our longitudinal data suggest that while steno-occlusive disease progresses over time and is associated with arterial ischemic infarctions and cystic-like white matter lesions, white matter hyperintensities can remain stable over long periods. The evaluated metrics will enable diagnosis in early infancy and be used to monitor disease progression, guide timing of stroke preventive interventions, and assess response to current and future therapies.

Association between Extracranial Carotid Artery Tortuosity and Clinical Outcomes in Anterior Circulation Acute Ischemic Stroke without Undergoing Endovascular Treatment

BACKGROUND

Extracranial carotid artery (ECA) tortuosity may influences successful recanalization rates of mechanical thrombectomy in acute ischemic stroke (AIS), yet the relationship between ECA tortuosity and the prognosis of patients with anterior circulation AIS who cannot undergo endovascular treatment remains uncertain. We hypothesized that increased tortuosity of the ECA leads to unfavorable outcomes in such patients.

METHODS

Patients with anterior circulation AIS who underwent computed tomography angiography of the head and neck in our hospital between March 2018 and November 2018 were retrospectively analyzed. The tortuosity of the bilateral ECA was measured, and functional outcomes were evaluated by a modified Rankin Scale (mRS) at 90 days. Multivariate logistic regression models were used to determine the association between ECA tortuosity and outcomes of patients.

RESULTS

A total of 203 patients were enrolled in our study, including 140 patients (68.97%) with favorable outcomes (mRS, 0-2) and 63 patients (31.03%) with unfavorable outcomes (mRS, 3-6). After adjusting for age, atrial fibrillation, stroke territory, and posthospital antithrombotics/statins therapy in multivariate logistic regression model I, ECA tortuosity (odds ratio, 1.052; 95% confidence interval, 1.010-1.096; P = .015) was an independent risk of unfavorable outcomes in enrolled patients. In the other 2 models (II and III) which adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, and with or without posthospital medication, ECA tortuosity was also showed independent relationship to unfavorable outcomes. The optimal cutoff was 12.5 to predict the unfavorable outcomes in a receiver operating characteristic curve.

CONCLUSIONS

Our study demonstrated that the ECA tortuosity is an independent predictor of unfavorable outcomes for anterior circulation AIS patients who without undergoing endovascular treatment after hospital admission. ECA tortuosity values greater than 12.5 may indicate an unfavorable outcome.

CX3CR1-CCR2-dependent monocyte-microglial signaling modulates neurovascular leakage and acute injury in a mouse model of childhood stroke

Stroke is among the top 10 causes of death in children. The developmental stage of the brain is central to stroke pathophysiology. The incidence of childhood arterial ischemic stroke (CAIS) is lower than of perinatal arterial ischemic stroke but the rate of recurrence is strikingly high. Vascular inflammation is seen as major contributor to CAIS but the mechanisms that govern structural-functional basis of vascular abnormalities remain poorly understood. To identify the contribution of immune-neurovascular interactions to CAIS, we established stroke model in postnatal day 21 (P21) mice. We demonstrate acute functional deficits and histological injury and chronic MRI-identifiable injury, brain atrophy and marked derangements in the vascular network. In contrast to negligible albumin leakage and neutrophil infiltration following acute perinatal stroke, CAIS leads to significantly increased albumin leakage and neutrophil infiltration in injured regions of wild type mice and mice with functional CX3CR1-CCR2 receptors. In mice with dysfunctional CX3CR1-CCR2 signaling, extravascular albumin leakage is significantly attenuated, infiltration of injurious Ccr2⁺-monocytes essentially aborted, accumulation of Ly6G+ neutrophils reduced and acute injury attenuated. Unique identifiers of microglia and monocytes revealed phenotypic changes in each cell subtype of the monocyte lineage after CAIS. Taken together, CX3CR1-CCR2-dependent microglia-monocyte signaling contributes to cerebrovascular leakage, inflammation and CAIS injury.

Cervicocerebral quantitative arterial tortuosity: a biomarker of arteriopathy in children with intracranial aneurysms

OBJECTIVE

Although intracranial arterial aneurysms (IAAs) of childhood are usually idiopathic, it is possible that underlying arteriopathy escapes detection when using conventional diagnostic tools. Quantitative arterial tortuosity (QAT) has been studied as a biomarker of arteriopathy. The authors analyzed cervicocerebral QAT in children with idiopathic IAAs to assess the possibility of arteriopathy.

METHODS

Cases were identified by text-string searches of imaging reports spanning the period January 1993 through June 2017. QAT of cervicocerebral arterial segments was measured from cross-sectional studies using image-processing software. Other imaging and clinical data were confirmed by retrospective electronic record review. Children with idiopathic IAAs and positive case controls, with congenital arteriopathy differentiated according to aneurysm status (with and without an aneurysm), were compared to each other and to healthy controls without vascular risk factors.

RESULTS

Cervicocerebral QAT was measured in 314 children: 24 with idiopathic IAAs, 163 with congenital arteriopathy (including 14 arteriopathic IAAs), and 127 healthy controls. QAT of all vertebrobasilar segments was larger in children with IAAs (idiopathic and arteriopathic forms) (p < 0.05). In children with congenital arteriopathy without an aneurysm, QAT was decreased for the distal cervical vertebral arteries and increased for the supraspinal vertebral artery relative to healthy children. QAT of specific cervicocerebral segments correlated with IAA size and rupture status.

CONCLUSIONS

Cervicocerebral QAT is a biomarker of arteriopathy in children with IAA, even in the absence of other disease markers. Additional findings suggest a correlation of cervicocerebral QAT with IAA size and rupture status and with the presence of IAA in children with congenital arteriopathy.

Craniocervical Arterial Dissection in Children: Pathophysiology and Management

BACKGROUND

Craniocervical arterial dissection is a commonly reported arteriopathy associated with stroke in children. It is characterized by a high stroke recurrence rate and variable outcomes. Here we review the pathophysiology, clinical presentation, and diagnostic neuroimaging approaches that are helpful in accurate diagnosis and follow-up of children with arterial dissection.

METHODS

MEDLINE searches (2000 to 2018) for articles that contained patients aged less than 18 years with craniocervical arterial dissection was performed, with the goal of analyzing their presenting features, pathophysiological mechanisms, and imaging characteristics and interventions.

RESULTS

Sixteen articles met the study criteria and reported 182 cases of craniocervical arterial dissection, 68% male, average age 8.6 years. Dissection was associated with head and neck trauma in 56% of the cases and frequently involved the posterior (61%) and extracranial locations (64%); the vertebral artery was the most commonly involved artery (60%). The most common clinical presentation was hemiparesis (80/160, 50%), followed by headache (64/164, 39%). Magnetic resonance imaging was the preferred neuroimaging method, followed by cerebral catheter angiography as a gold standard definitive neurovascular imaging modality when the initial vascular imaging revealed nondiagnostic findings.

CONCLUSIONS

The diagnosis of arterial dissection requires a high index of suspicion and consideration for detailed neurovascular imaging, including both the cranial and cervical regions. Neurovascular imaging challenges, especially visualization of arterial abnormalities, highlight the importance of appropriate and timely use of specific neurovascular imaging techniques. Magnetic resonance imaging appears to be the preferred neurovascular imaging modality in children with arterial dissection and may obviate the need for invasive cerebral catheter angiography.

Clinical Variability in Two Macedonian Families with Arterial Tortuosity Syndrome

Arterial tortuosity syndrome (ATS) is a rare autosomal recessive disorder caused by mutations in the solute carrier family 2 member 10 (SLC2A10) gene encoding a glucose/ascorbic acid transporter. The clinical features of ATS are mild-to-severe tortuosity of the large and medium arteries throughout the body, accompanied by dysmorphisms and joint laxity. Vascular changes in different parts of the body lead to stenosis and/or aneurysms requiring difficult surgical procedures. Here we present two new patients with ATS from two unrelated families. Patient 1 presented at 10 years of age with headache and typical physical appearance, delicate skeleton, large visible pulsation of the carotid arteries in the neck, and joint laxity. On computed tomography (CT) angiography she had severe tortuosity of the aortal branches and cerebral arteries, but no significant tortuosity of the pulmonary arteries. Two cousins of the girl carried the same homozygous c.254T>C, p.(Leu85Pro) mutation in SLC2A10, however, they additionally had a severe involvement of the pulmonary vessels. Patient 2 was a 9-year-old girl diagnosed with severe tortuosity and stenosis of the pulmonary arteries and progressive myocardiopathy. Her physical appearance was very similar to Patient 1, except that she also had growth retardation. After long-term follow-up by cardiologists, she underwent cardiac surgery abroad, with an unfavorable outcome. Homozygosity for the c.685C>T, p.(Arg229*) mutation in the SLC2A10 gene was detected. Consanguinity was disclosed within both families. Our findings confirm the intrafamilial phenotype variability of ATS. A novel finding is the severe tortuosity of cerebral arteries causing migraine that has not been described before in a child with ATS.

Two-dimensional speckle-tracking echocardiographic evaluation of the longitudinal deformation of the left ventricular myocardium in patients with severe coronary artery tortuosity

PURPOSE

Coronary artery tortuosity (CAT) is an anatomical condition in which epicardial coronary arteries have abnormal curves or spiral courses. Although correlated with higher rates of positive stress test, its effects on the myocardial function remain to be clearly defined.

METHODS

We included in this cross-sectional study and evaluated with 2D speckle-tracking echocardiography 40 consecutive patients admitted to our hospital for selective coronary angiography which showed severe CAT without significant epicardial coronary artery stenosis, and 40 consecutive subjects matched for age, hypertension, and diabetes in whom selective coronary angiography showed neither CAT nor significant epicardial coronary artery stenosis.

RESULTS

Systolic strain, strain rate, and early and late diastolic strain rates were not significantly different between the 2 groups, even after adjustment for potential confounding variables.

CONCLUSION

The 2D speckle-tracking echocardiography-derived indices of longitudinal deformation of the left ventricular myocardium were not significantly different between the patients with severe CAT and controls.

Recent developments and new frontiers in childhood arterial ischemic stroke

This review will discuss important developments in childhood arterial ischemic stroke over the past decade, focusing on improved understanding of the causes, consequences, and targets for intervention. Risk factors for childhood arterial ischemic stroke are different to adults. Infections, particularly herpes group viruses, are important precipitants for stroke. Non-atherosclerotic arteriopathies are the most common cause of childhood arterial ischemic stroke and an important predictor of recurrent events. Recent advances include the identification of serum biomarkers for inflammation and endothelial injury, and imaging biomarkers to monitor for vascular progression. Multicenter trials of immunotherapies in focal cerebral arteriopathies are currently in development. Recognition of clinical and radiological phenotypic patterns has facilitated the discovery of multisystem disorders associated with arterial ischemic stroke including ACTA2 arteriopathy and adenosine deaminase 2 deficiency. Identification of these Mendelian disorders provide insights into genetic mechanisms of disease and have implications for medical and surgical management. In contrast to adults, there are long diagnostic delays in childhood arterial ischemic stroke. Refinement of pediatric Code Stroke protocols and clinical decision support tools are essential to improve diagnostic certainty and improve access to reperfusion therapies. Children do not recover better than adults following arterial ischemic stroke, with more than half of survivors having long-term impairments. The physical, cognitive, and behavioral consequences of childhood arterial ischemic stroke are increasingly reported but further research is required to understand their impact on participation, quality of life, psychosocial, and family functioning. Longitudinal studies and the use of advanced imaging techniques, to understand neurobiological correlates of functional reorganization, are essential to developing targeted intervention strategies to facilitate recovery.

Quantitative Arterial Tortuosity Suggests Arteriopathy in Children With Cryptogenic Stroke

BACKGROUND AND PURPOSE

Quantitative arterial tortuosity (QAT) is a ratio of vessel length between 2 points to the shortest linear distance between same points. QAT has been reported as an imaging biomarker of arteriopathy in pediatric arterial ischemic stroke (AIS) because of dissection and transient cerebral arteriopathy. We sought to determine whether QAT abnormalities are present in other subtypes of pediatric AIS.

METHODS

Children with AIS-absent conventional biomarkers of arteriopathy and case-controls who underwent magnetic resonance angiography were classified by stroke mechanism. The primary study population consisted of cryptogenic AIS cases. AIS with bow hunter physiology and cardiogenic emboli were also evaluated. AIS because of nontraumatic dissection served as positive controls. Patients without vascular risk factors served as negative controls. Segmental QAT of cervicocerebral arteries were measured using automated image processing and differences between groups analyzed.

RESULTS

In negative controls, QAT showed significant age-related variability for most arterial segments. Positive controls showed significantly increased QAT of the distal extracranial vertebral arteries (VAs) and decreased QAT of the intracranial VA relative to negative controls. Cryptogenic stroke and bow hunter physiology cases were similar to positive controls showing increased QAT of the distal extracranial VA and decreased QAT of the intracranial VA relative to negative controls. Cardioembolic stroke cases were similar to negative controls showing decreased QAT of the distal extracranial VA and increased QAT of the intracranial VA relative to positive controls.

CONCLUSIONS

Pediatric cryptogenic stroke is frequently associated with cervicocerebral arteriopathies expressing altered QAT. QAT may be a diagnostic biomarker of arteriopathy in pediatric AIS.

Harnessing Neuroimaging Capability in Pediatric Stroke: Proceedings of the Stroke Imaging Laboratory for Children Workshop

On June 5, 2015 the International Pediatric Stroke Study and the Stroke Imaging Laboratory for Children cohosted a unique workshop focused on developing neuroimaging research in pediatric stroke. Pediatric neurologists, neuroradiologists, interventional neuroradiologists, physicists, nurse practitioners, neuropsychologists, and imaging research scientists from around the world attended this one-day meeting. Our objectives were to (1) establish a group of experts to collaborate in advancing pediatric neuroimaging for stroke, (2) develop consensus clinical and research magnetic resonance imaging protocols for pediatric stroke patients, and (3) develop imaging-based research strategies in pediatric ischemic stroke. This article provides a summary of the meeting proceedings focusing on identified challenges and solutions and outcomes from the meeting. Further details on the workshop contents and outcomes are provided in three additional articles in the current issue of Pediatric Neurology.