Ultrasonic quantification of cerebral perfusion in acute anterior circulation occlusive stroke—A comparative challenge of the refill- and the bolus-kinetics approach

PURPOSE: To prospectively evaluate the potential of semi-quantitative evaluation of cerebral perfusion in acute ischemic stroke by comparing two established ultrasound approaches. MATERIALS AND METHODS: Consecutive inclusion of patients with acute occlusion of middle cerebral artery (MCA) confirmed by either magnetic resonance imaging (MRI) or computed tomography (CT) perfusion imaging qualifying for interventional therapy. Comparison of bilateral high mechanical index (MI) bolus-kinetics (HighMiB) and unilateral low MI refill-kinetics (LowMiR) performed before specific treatment. RESULTS: In 16/31 patients HighMiB was eligible, in 8/31 patients LowMiR was eligible. In six out of these eight patients both HighMiB and LowMiR were eligible for direct comparison. In MR/CT perfusion imaging of the 16 patients eligible for HighMiB, 29/48 cortical regions of interest (ROIs) (60%) displayed hypoperfusion or ischemia, areas inadequately accessible by LowMiR. These ROIs made up 49% of the 59 ROIs displaying hypoperfusion or ischemia, altogether. Matching of parameters in normal and impaired ROIs between LowMiR and MRI/CT perfusion imaging was significantly poorer than in HighMiB. CONCLUSION: LowMiR using refill-kinetics potentially has the advantage of real time imaging and better resolution. The diagnostic impact, however, proves inferior to HighMiB both with respect to imaging quality and semi-quantitative evaluation.