US Duplex Doppler Transcranial Transcranial Doppler may be useful, both in the detection of microembolic events and in the detection of intracranial vascular pathology. However, this is typically not an initial imaging test in the setting of stroke due to the poor anatomical delineation of US and potential consequences of delayed treatment in the setting of LVO [39]. Variant 4: Adult. Recent ischemic infarct; greater than 24 hours. Initial imaging. This variant addresses cases of clinically suspected recent ischemic infarct, although beyond the established and extended stroke windows, that is, >24 hours after symptom onset. Whereas some observational studies suggest benefit [65], no large RCTs have demonstrated the benefit of EVT for LVO strokes after the 24 hour mark. Given the lack of supporting evidence for the usefulness for EVT beyond 24 hours, the urgency of exclusion of stroke due to LVO is largely abated and the workup of a new stroke becomes less urgent. At this stage, imaging is more focused on stroke follow-up and treatment of complications, rehabilitation planning, and secondary prevention [13]. Cerebrovascular Diseases-Stroke Arteriography Cervicocerebral Cerebral angiography has the highest spatial resolution and temporal resolution of any vascular study and may detect underlying etiologies in patients presenting with stroke in a delayed fashion beyond 24 hours, which may not be detectable by other modalities, and can potentially help guide management. The usefulness of revascularization for intracranial LVO beyond 24 hours has not been demonstrated by RCT, which reduces the urgency of diagnosis [65]. Moreover, the urgency of diagnosis of many other stroke etiologies detected only by arteriography in the setting of delayed presentation is less well defined beyond 24 hours. Cerebral angiography is typically reserved for diagnoses not excluded by less invasive modalities and even then is of uncertain specificity and sensitivity [66].
Cerebrovascular Diseases Stroke and Stroke Related Conditions PCAs. US Duplex Doppler Transcranial Transcranial Doppler may be useful, both in the detection of microembolic events and in the detection of intracranial vascular pathology. However, this is typically not an initial imaging test in the setting of stroke due to the poor anatomical delineation of US and potential consequences of delayed treatment in the setting of LVO [39]. Variant 4: Adult. Recent ischemic infarct; greater than 24 hours. Initial imaging. This variant addresses cases of clinically suspected recent ischemic infarct, although beyond the established and extended stroke windows, that is, >24 hours after symptom onset. Whereas some observational studies suggest benefit [65], no large RCTs have demonstrated the benefit of EVT for LVO strokes after the 24 hour mark. Given the lack of supporting evidence for the usefulness for EVT beyond 24 hours, the urgency of exclusion of stroke due to LVO is largely abated and the workup of a new stroke becomes less urgent. At this stage, imaging is more focused on stroke follow-up and treatment of complications, rehabilitation planning, and secondary prevention [13]. Cerebrovascular Diseases-Stroke Arteriography Cervicocerebral Cerebral angiography has the highest spatial resolution and temporal resolution of any vascular study and may detect underlying etiologies in patients presenting with stroke in a delayed fashion beyond 24 hours, which may not be detectable by other modalities, and can potentially help guide management. The usefulness of revascularization for intracranial LVO beyond 24 hours has not been demonstrated by RCT, which reduces the urgency of diagnosis [65]. Moreover, the urgency of diagnosis of many other stroke etiologies detected only by arteriography in the setting of delayed presentation is less well defined beyond 24 hours. Cerebral angiography is typically reserved for diagnoses not excluded by less invasive modalities and even then is of uncertain specificity and sensitivity [66].