Most infarctions are due to vasculopathy involving the supraclinoid portion of the internal carotid artery or branches of the circle of Willis and occurring in a watershed distribution. Clinically silent infarctions are known to occur in 17% of children with SCD [84]. The National Heart Lung and Blood institute recommends that children with SCD between 2 and 16 years of age undergo transcranial Doppler US screening every 6 months. The treatment of acute stroke symptoms in children with SCD is transfusion. CT Head CT is relatively insensitive compared with MRI for the demonstration of infarction and is typically only used in the acute setting if MRI is unavailable or to document hemorrhage or evaluate for mass effect [26]. CTA Head CTA is not used in routine neurovascular screening in children with SCD. CTA can be used in children with contraindication to MRA. MRI Head MRI can show T2 prolongation in watershed vascular territories or cortex in patients with SCD. MRA Head MRA is the study of choice to screen for vessel stenosis in children with SCD with elevated transcranial Doppler US velocities in the intracranial vessels [39,44]. Although MRA can accurately show vessel stenosis, it is susceptible to false-positive results when long echo times are used or when severe anemia is present, resulting in turbulent blood flow and localized artefactual signal loss resembling focal stenosis [26,84,85]. Although gadolinium-enhanced MRA can be used, it is generally not required and is often avoided because of concerns that it may potentiate hemolysis in patients with SCD [26]. MRI of the brain without IV contrast is typically performed during the same examination as the MRA to assess the brain parenchyma for ischemic injury. Arteriography Cervicocerebral Catheter angiography is generally not indicated except in uncommon circumstances, including preoperative assessment for revascularization for moyamoya syndrome and suspected aneurysm complicating SCD [26].
Cerebrovascular Disease Child PCAs. Most infarctions are due to vasculopathy involving the supraclinoid portion of the internal carotid artery or branches of the circle of Willis and occurring in a watershed distribution. Clinically silent infarctions are known to occur in 17% of children with SCD [84]. The National Heart Lung and Blood institute recommends that children with SCD between 2 and 16 years of age undergo transcranial Doppler US screening every 6 months. The treatment of acute stroke symptoms in children with SCD is transfusion. CT Head CT is relatively insensitive compared with MRI for the demonstration of infarction and is typically only used in the acute setting if MRI is unavailable or to document hemorrhage or evaluate for mass effect [26]. CTA Head CTA is not used in routine neurovascular screening in children with SCD. CTA can be used in children with contraindication to MRA. MRI Head MRI can show T2 prolongation in watershed vascular territories or cortex in patients with SCD. MRA Head MRA is the study of choice to screen for vessel stenosis in children with SCD with elevated transcranial Doppler US velocities in the intracranial vessels [39,44]. Although MRA can accurately show vessel stenosis, it is susceptible to false-positive results when long echo times are used or when severe anemia is present, resulting in turbulent blood flow and localized artefactual signal loss resembling focal stenosis [26,84,85]. Although gadolinium-enhanced MRA can be used, it is generally not required and is often avoided because of concerns that it may potentiate hemolysis in patients with SCD [26]. MRI of the brain without IV contrast is typically performed during the same examination as the MRA to assess the brain parenchyma for ischemic injury. Arteriography Cervicocerebral Catheter angiography is generally not indicated except in uncommon circumstances, including preoperative assessment for revascularization for moyamoya syndrome and suspected aneurysm complicating SCD [26].