The role of imaging studies for evaluation of stroke in children

Childhood stroke

Stroke is an important cause of neurological morbidity in children; most survivors have permanent neurological deficits that affect the remainder of their life. Stroke in childhood, the focus of this Primer, is distinguished from perinatal stroke, defined as stroke before 29 days of age, because of its unique pathogenesis reflecting the maternal-fetal unit. Although approximately 15% of strokes in adults are haemorrhagic, half of incident strokes in children are haemorrhagic and half are ischaemic. The causes of childhood stroke are distinct from those in adults. Urgent brain imaging is essential to confirm the stroke diagnosis and guide decisions about hyperacute therapies. Secondary stroke prevention strongly depends on the underlying aetiology. While the past decade has seen substantial advances in paediatric stroke research, the quality of evidence for interventions, such as the rapid reperfusion therapies that have revolutionized arterial ischaemic stroke care in adults, remains low. Substantial time delays in diagnosis and treatment continue to challenge best possible care. Effective primary stroke prevention strategies in children with sickle cell disease represent a major success, yet barriers to implementation persist. The multidisciplinary members of the International Pediatric Stroke Organization are coordinating global efforts to tackle these challenges and improve the outcomes in children with cerebrovascular disease.

ACR Appropriateness Criteria® Cerebrovascular Disease-Child

Stroke is an uncommon but an important and under-recognized cause of morbidity and mortality in children. Strokes may be due to either brain ischemia or intracranial hemorrhage. Common symptoms of pediatric acute stroke include headache, vomiting, focal weakness, numbness, visual disturbance, seizures, and altered consciousness. Most children presenting with an acute neurologic deficit do not have an acute stroke, but have symptoms due to stroke mimics which include complicated migraine, seizures with postictal paralysis, and Bell palsy. Because of frequency of stroke mimics, in children and the common lack of specificity in symptoms, the diagnosis of a true stroke may be delayed. There are a relatively large number of potential causes of stroke mimic and true stroke. Consequently, imaging plays a critical role in the assessment of children with possible stroke and especially in children who present with acute onset of stroke symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A child with atypically subtle clinical presentation of acute arterial ischaemic stroke in the middle cerebral artery

Arterial ischaemic stroke in the paediatric population is considered a rare disease, and its diagnosis is often delayed due to the subtlety and variability of clinical symptoms, especially in younger patients. The clinical presentation and imaging features of ischaemic stroke in the paediatric population are variable depending on the underlying cause, affected artery and patient’s age. Literally, acute occlusion of the middle cerebral artery shows significant clinical signs and symptoms, and riotous imaging findings due to the size of the territory. Here, we present a case of a 15-year-old boy who unusually had subtle and intermittent clinical symptoms in spite of a complete acute occlusion in his right middle cerebral artery.

Imaging of Pediatric Stroke

Despite being as common as brain tumors in children, lack of awareness of pediatric stroke presents unique challenges, both in terms of diagnosis and management. Due to diverse and overlapping risk factors, as well as variable clinical presentations, the diagnosis can be either missed or frequently delayed. Early recognition and treatment of pediatric stroke is however critical in optimizing long-term functional outcomes, reducing morbidity and mortality, and preventing recurrent stroke. Neuroimaging plays a vital role in achieving this goal. The advancements in imaging over the last two decades have allowed for multiple modality options for suspected stroke with more accurate diagnosis, as well as quicker turnaround time in imaging diagnosis, especially at primary stroke centers. However, with the multiple imaging possibilities, referring physicians can be overwhelmed with the best option for each clinical situation and what the literature recommends. Here the authors review the etiology of pediatric stroke in the settings of arterial ischemia, hemorrhage, and cerebral sinovenous thrombosis (CSVT), with emphasis on the best diagnostic tools available, including advanced imaging techniques.

Patient and Process Factors Associated With Type of First Neuroimaging and Delayed Diagnosis in Childhood Arterial Ischemic Stroke

OBJECTIVES

In-hospital factors contribute more to delayed diagnosis of childhood arterial ischemic stroke (AIS) than prehospital factors. We aimed to explore process and patient factors associated with type of and timing to neuroimaging in childhood AIS in the emergency department (ED).

METHODS

This was a retrospective hospital registry-based study of children with AIS, presenting to an Australian tertiary pediatric ED between January 2003 and December 2012. Neuroimaging data and timelines of care were also collected from referring hospitals for transferred patients.

RESULTS

Seventy-one AIS episodes and 19 transient ischemic attacks were recorded. The majority (56%) were initially seen at a referring hospital. Patients underwent computed tomography (CT) as first scan more frequently than magnetic resonance imaging (MRI) as first scan (61% vs. 32%) at both the referring and the tertiary hospitals. Time to first scan as CT was significantly shorter compared with MRI (median = 1.5 hours vs. 10.9 hours, p < 0.001). MRI was performed more often at the tertiary hospital (92.5% vs. 26%, p = 0.001). Median time to performance of diagnostic MRI was 15.1 hours (interquartile range = 7.1-23.5), with no significant difference between patients first presenting to a referring hospital and those directly accessing the tertiary center. Patient characteristics including age, past medical history, conscious state, focal symptoms, and signs on arrival were not associated with the type of first neuroimaging or time to diagnostic MRI. Patients presenting during weekends were less likely to receive an MRI as first scan (odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.1-0.8), while time to MRI was significantly longer for children presenting after hours (5 pm-8 am; median = 17.6 hours vs. 8.4 hours, p = 0.026). MRI overall and as first scan was associated with a higher use of sedation than CT (OR = 6.5, 95% CI = 1.3-32.9; and OR = 3.9, 95% CI = 1.3-11.8), particularly for children younger than 5 years of age (OR = 12.5, 95% CI = 3-52.4).

CONCLUSIONS

Strategies to improve rapid diagnosis of pediatric stroke should include shared regional hospital networks protocols to optimize local imaging strategies and where possible rapid transfer to the tertiary center. Future priorities should include development of pediatric ED physician decision support tools to differentiate stroke from mimics and the development and implementation of rapid ED imaging stroke protocols to improve access to confirmatory MRI scanning.

Management of pediatric central nervous system emergencies: a review for general radiologists

TEACHING OBJECTIVES

To review the most common and most important diseases and disorders of the central nervous system (CNS) in pediatric emergencies, discussing the indications for different imaging tests in each context.

DISCUSSION

In pediatric patients, acute neurologic symptoms (seizures, deteriorating level of consciousness, focal neurologic deficits, etc.) can appear in diverse clinical situations (trauma, child abuse, meningoencephalitis, ischemia…). It is important to decide on the most appropriate neuroimaging diagnostic algorithm for each situation and age group, as well as to know the signs of the most typical lesions that help us in the etiological differential diagnosis. Pediatric patients' increased vulnerability to ionizing radiation and the possible need for sedation in studies that require more time are factors that should be taken into account when indicating an imaging test. It is essential to weigh the risks and benefits for the patient and to avoid unnecessary studies.

Cerebral sinovenous thrombosis (CSVT) in children: what the pediatric radiologists need to know

Cerebral sinovenous thrombosis (CSVT) is a relatively uncommon and potentially life-threatening condition in childhood, occurring in various clinical settings. Nowadays, however, it is increasingly diagnosed as related to many causes, likely due to greater clinical awareness and improvement of neuroradiologic techniques. The prompt diagnosis is an important goal to significantly reduce the risk of acute complications and long-term sequelae. The purpose of this narrative overview is to provide a useful educational tool in daily clinical practice for radiologists with a broad perspective of CSVT including a discussion of more common potential pitfalls related to misinterpretation of images in children. This paper will also review the normal venous anatomy, its variants, risk factors that contribute to cause CSVT (neonates with their specific causes of CSVT are not included in this review) and the practical imaging feature of cerebral sinovenous thrombosis on MRI and CT. Finally, a brief overview of frequent and severe CSVT conditions in children with key points in imaging is shown.

West Virginia University pediatric stroke registry: clinical description and risk factors identification in patients from a rural area

PURPOSE

To develop an institutional pediatric stroke database at West Virginia University to support the classification and description of clinical and radiographic characteristics of pediatric stroke in children living in rural areas.

METHODS

A custom-made database was developed using Microsoft Access to include specific query forms for data retrieval. Data were collected retrospectively from electronic medical record of pediatric patients with ischemic and hemorrhagic stroke, with emphasis on clinical presentation, risk factors, and neuroimaging studies between 2000 and 2012.

RESULTS

In the children group, vasculitis and hypercoagulable disorders were identified less frequently than reported. In the neonate group, only extremely sick, symptomatic patents were acutely diagnosed with stroke.

CONCLUSION

Patients with the most common risk factors for stroke (cardiac disease) were overrepresented. This suggests that in children receiving medical attention in rural areas less common risk factors for stroke might not be identified, increasing the risk recurrence. Increased index of suspicion is needed about pediatric stroke in rural areas, and early transfer to a tertiary care center for identification of risk factors is mandatory.