"Color Doppler energy" (or "power Doppler"), a new color Doppler ultrasound technique that is independent of flow direction and very sensitive to movement, was assessed for its use in the identification of intracranial aneurysms in patients with recent subarachnoid hemorrhage immediately prior to using cerebral angiography. Features that identified aneurysms using this technique included the appearance of abnormal color where no normal artery was expected, abnormal bulging of an artery, and greater "expansibility" of the aneurysm in comparison to an adjacent normal vessel. In this exploratory study, 30 of 33 aneurysms were correctly identified in 35 patients with a good bone window. Color Doppler energy is considerably more sensitive to intracranial blood flow than conventional color Doppler imaging. Color Doppler energy is a useful research tool; if these preliminary results are verified in larger series, in addition to examination for vasospasm, the technique could be used for identification and follow up of aneurysms.