Table 1.

Summary: Clinical relevance of hemodynamic assessment.

Disease	Methods	Current evidence	Future research	Notes
Asymptomatic extracranial carotid stenosis	Paired flow (TCD, SPECT)	Strong association with stroke risk	Trials of revascularization versus medical therapy
Symptomatic extra and intracranial carotid occlusion	Paired flow, MTT and OEF	Strong association with stroke risk	Trials of revascularization versus medical therapy	Safer methods of revascularization needed
Symptomatic intracranial stenosis	Paired flow, OEF, quantitative flow	Strong association with stroke risk	Trials of revascularization versus medical therapy
Moyamoya disease	OEF	High prevalence of hemodynamic impairment but no prospective association with future stroke risk	Longitudinal studies of hemodynamics and stroke risk	Hemodynamic impairment may be dynamic, regionally and temporally

SPECT: single-photon emission computed tomography; MTT: mean transit time; OEF: oxygen extraction fraction.