CT Head CT is less sensitive than MRI for demonstrating acute infarctions but can be useful in evaluating rare instances of intracranial hemorrhage in moyamoya [43]. CTA Head CTA, including multiphase CTA, is an alternative to MRA and catheter angiography in the initial diagnosis and follow-up of children with moyamoya. MRI Head Proposed screening guidelines for moyamoya include diagnostic imaging using MRI/MRA in at-risk populations, particularly if there are symptoms of cerebral ischemia. Screening of first-degree relatives of patients with moyamoya is probably not warranted in the absence of symptoms or unless multiple family members are already known to be affected. T2-weighted fluid-attenuated inversion-recovery imaging may show high signal in the sulci (ivy sign), indicative of slow flow in affected vascular territories. A similar appearance may be evident on T1- weighted contrast-enhanced studies. SWI may be used to demonstrate microhemorrhage that has been reported in up to 52% of patients [44]. Arteriopathy can also be further evaluated with the technique of vessel-wall imaging [15,45]. MRA Head MRA is an alternative to CTA in the initial and follow-up imaging evaluation of children with moyamoya and is the preferred noninvasive vascular imaging modality. MRA is typically performed together with brain MRI to evaluate both the cerebral vasculature and the brain parenchyma. CT Head Perfusion The use of perfusion CT, including xenon-enhanced CT, in children with moyamoya is feasible but requires repetitive imaging of the brain [28]. MR Head Perfusion MR cerebral blood flow evaluation includes perfusion-weighted MR, either using arterial spin-labeling techniques without IV contrast or dynamic susceptibility contrast techniques with IV contrast. Perfusion imaging is also used to assess functional improvement after treatment [39,46-49].
Cerebrovascular Disease Child PCAs. CT Head CT is less sensitive than MRI for demonstrating acute infarctions but can be useful in evaluating rare instances of intracranial hemorrhage in moyamoya [43]. CTA Head CTA, including multiphase CTA, is an alternative to MRA and catheter angiography in the initial diagnosis and follow-up of children with moyamoya. MRI Head Proposed screening guidelines for moyamoya include diagnostic imaging using MRI/MRA in at-risk populations, particularly if there are symptoms of cerebral ischemia. Screening of first-degree relatives of patients with moyamoya is probably not warranted in the absence of symptoms or unless multiple family members are already known to be affected. T2-weighted fluid-attenuated inversion-recovery imaging may show high signal in the sulci (ivy sign), indicative of slow flow in affected vascular territories. A similar appearance may be evident on T1- weighted contrast-enhanced studies. SWI may be used to demonstrate microhemorrhage that has been reported in up to 52% of patients [44]. Arteriopathy can also be further evaluated with the technique of vessel-wall imaging [15,45]. MRA Head MRA is an alternative to CTA in the initial and follow-up imaging evaluation of children with moyamoya and is the preferred noninvasive vascular imaging modality. MRA is typically performed together with brain MRI to evaluate both the cerebral vasculature and the brain parenchyma. CT Head Perfusion The use of perfusion CT, including xenon-enhanced CT, in children with moyamoya is feasible but requires repetitive imaging of the brain [28]. MR Head Perfusion MR cerebral blood flow evaluation includes perfusion-weighted MR, either using arterial spin-labeling techniques without IV contrast or dynamic susceptibility contrast techniques with IV contrast. Perfusion imaging is also used to assess functional improvement after treatment [39,46-49].