 Perinatal stroke (<6 months of age), although the most common acute stroke in children (20 to 62.5/100,000 live births), will not be discussed in this topic. As in many cases, the diagnosis is retrospective when the child presents later in life with new onset seizure, asymmetric motor function, or failure of developmental milestones [8]. The majority of perinatal stroke is likely to be caused by thromboembolism from the placenta through a patent foramen ovale or fetal heart defect [8]. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org and 25% presented outside of the therapeutic window [2]. The study was closed by the NIH for lack of patient accrual [2]. To date, there is insufficient information about acute pediatric stroke to confirm the appropriate window for initiation of thrombolytic therapy in children [12]. A window of 24 hours from stroke onset to initiation of treatment is used in this clinical scenario. This treatment is considered in children >2 years of age [13]. The risk of symptomatic hemorrhage into an ischemic infarction in adults treated with IV tissue-type plasminogen activator is 6.4% and is unknown in children [2]. Recently, interest in the use of intra-arterial treatment for stroke in children has developed because of the documented success of this type of therapy in adults. However, currently, no systematic study of such therapy in children has been performed, and only case reports exist [14]. Adult studies have shown good results with mechanical thrombectomy up to 6 hours or longer on a case-by-case basis from acute stroke symptom onset [15].
Cerebrovascular Disease Child PCAs.  Perinatal stroke (<6 months of age), although the most common acute stroke in children (20 to 62.5/100,000 live births), will not be discussed in this topic. As in many cases, the diagnosis is retrospective when the child presents later in life with new onset seizure, asymmetric motor function, or failure of developmental milestones [8]. The majority of perinatal stroke is likely to be caused by thromboembolism from the placenta through a patent foramen ovale or fetal heart defect [8]. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org and 25% presented outside of the therapeutic window [2]. The study was closed by the NIH for lack of patient accrual [2]. To date, there is insufficient information about acute pediatric stroke to confirm the appropriate window for initiation of thrombolytic therapy in children [12]. A window of 24 hours from stroke onset to initiation of treatment is used in this clinical scenario. This treatment is considered in children >2 years of age [13]. The risk of symptomatic hemorrhage into an ischemic infarction in adults treated with IV tissue-type plasminogen activator is 6.4% and is unknown in children [2]. Recently, interest in the use of intra-arterial treatment for stroke in children has developed because of the documented success of this type of therapy in adults. However, currently, no systematic study of such therapy in children has been performed, and only case reports exist [14]. Adult studies have shown good results with mechanical thrombectomy up to 6 hours or longer on a case-by-case basis from acute stroke symptom onset [15].