Background and Purpose-Initial reports indicate that transcranial harmonic imaging after ultrasound contrast agent bolus injection (BHI) can detect cerebral perfusion deficits in acute ischemic stroke. We evaluated parametric images of the bolus washout kinetics. Methods-Twenty-three patients with acute internal carotid artery infarction were investigated with perfusion harmonic imaging after SonoVue bolus injection Յ40 hour after the onset of symptoms. The findings were compared with those of cranial computed tomography (CCT) and clinical course 4 months after stroke. Results-Images of pixel-wise peak intensity (PPI) and time to peak intensity could be calculated for all patients. Spearman rank correlations of rϭ0.772 (PϽ0.001) and rϭ0.572 (Pϭ0.008) between area of PPI signal decrease and area of infarction in the follow-up CCT as well as outcome after 4 months were obtained, respectively. Conclusions-In the early phase of acute ischemic stroke, BHI after SonoVue bolus injection is a useful ultrasound tool for analyzing cerebral perfusion deficits at the patient's bedside. BHI data correlate with the definite area of infarction and outcome after 4 months. Key Words: ultrasonography Ⅲ stroke Ⅲ contrast media I n patients with acute cerebral ischemia, brain perfusion can be analyzed by several diagnostic methods, such as computed tomography (CT), magnetic resonance tomography, single-photon emission computed tomography, and positron emission tomography. Ultrasound, as a less time-consuming, inexpensive, and well-tolerated bedside method for critically ill patients, has been introduced for the evaluation of brain perfusion. 1-4 By using transcranial harmonic imaging, it is possible to track an ultrasound contrast agent bolus within the human cerebral microcirculation. This technology is called bolus perfusion harmonic imaging (BHI). Initial reports have indicated that this harmonic imaging technique may be useful in assessing pathologic brain perfusion. [5][6][7][8][9] The purpose of our study was to evaluate the diagnostic and prognostic potential of this new imaging tool after processing of the image loops in patients with acute ischemic stroke. Subjects and Methods PatientsInclusion criteria were as follows: acute onset of sensorimotor hemiparesis, neglect or incomplete aphasia Յ40 hours before the initial investigation, and early stroke signs on cranial computed tomography (CCT) (focal hypoattenuation or focal brain swelling in the territory of the internal carotid artery, obscuration of basal ganglia, or hyperdense middle cerebral artery sign 10 ), as well as a sufficient acoustic bone window for conventional transcranial colorcoded sonography (TCCS). Exclusion criteria were as follows: intracranial hemorrhage detected by CCT and complete aphasia, pregnancy, and severe cardiac, pulmonary, or renal disease. All patients gave informed consent.By using the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Score (mRS), the clinical status of the patients was assessed before the investigat...