HMPAO SPECT or SPECT/CT Brain Single-photon-emission computed tomography (SPECT) studies can be used to assess perfusion in patients with moyamoya and can be augmented with acetazolamide challenge to assess perfusion instability and vascular reserve. Perfusion imaging is also used to assess functional improvement after treatment [39]. Arteriography Cervicocerebral Catheter angiography is required for definitive diagnosis of moyamoya and is typically obtained as part of a preoperative assessment prior to surgical revascularization or following revascularization to assess the development of surgically created collaterals. US Duplex Doppler Transcranial Head US does not typically play a role in the management of children with moyamoya. Variant 4: Child. Known or suspected cervicocranial arterial dissection based on clinical or imaging findings. Next imaging study. Cervicocranial artery dissection occurs in 2.5/100,000 children per year and is up to 4 times more common in children than in adults [50-52]. Purely intracranial dissections are also more common in children than adults [50]. Patients with cervical artery dissection can present with headache, neck pain, or ischemic infarction due to emboli, whereas patients with intracranial artery dissection can present with ischemic infarction, subarachnoid hemorrhage (SAH), or symptoms due to local mass effect [50,52]. A history of antecedent trauma may or may not be present. CT Head CT can show areas of infarction or SAH although the sensitivity of CT is less than that of MRI with DWI for demonstrating acute infarction [43]. A crescent-shaped hyperattenuating area in a cranial or cervical artery is consistent with an intramural hematoma and is highly suggestive of dissection [52]. CTA Head and Neck CTA can demonstrate vessel narrowing, pseudoaneurysm, or an intimal flap in dissection [50,52]. MRI Head and Neck MRI is the preferred study for the demonstration of infarction due to cervicocranial arterial dissection [50,52,53].
Cerebrovascular Disease Child PCAs. HMPAO SPECT or SPECT/CT Brain Single-photon-emission computed tomography (SPECT) studies can be used to assess perfusion in patients with moyamoya and can be augmented with acetazolamide challenge to assess perfusion instability and vascular reserve. Perfusion imaging is also used to assess functional improvement after treatment [39]. Arteriography Cervicocerebral Catheter angiography is required for definitive diagnosis of moyamoya and is typically obtained as part of a preoperative assessment prior to surgical revascularization or following revascularization to assess the development of surgically created collaterals. US Duplex Doppler Transcranial Head US does not typically play a role in the management of children with moyamoya. Variant 4: Child. Known or suspected cervicocranial arterial dissection based on clinical or imaging findings. Next imaging study. Cervicocranial artery dissection occurs in 2.5/100,000 children per year and is up to 4 times more common in children than in adults [50-52]. Purely intracranial dissections are also more common in children than adults [50]. Patients with cervical artery dissection can present with headache, neck pain, or ischemic infarction due to emboli, whereas patients with intracranial artery dissection can present with ischemic infarction, subarachnoid hemorrhage (SAH), or symptoms due to local mass effect [50,52]. A history of antecedent trauma may or may not be present. CT Head CT can show areas of infarction or SAH although the sensitivity of CT is less than that of MRI with DWI for demonstrating acute infarction [43]. A crescent-shaped hyperattenuating area in a cranial or cervical artery is consistent with an intramural hematoma and is highly suggestive of dissection [52]. CTA Head and Neck CTA can demonstrate vessel narrowing, pseudoaneurysm, or an intimal flap in dissection [50,52]. MRI Head and Neck MRI is the preferred study for the demonstration of infarction due to cervicocranial arterial dissection [50,52,53].