Fig 1. Blooming artifact. Contrast-enhanced transcranial sonography of the circle of Willis (axial scanning plane via the temporal bone window). The vessel delineation is diminished because of the strong contrast signal intensity (blooming) after IV bolus injection of the UCA. Red color-coding represents flow toward the transducer, blue color-coding flow away from it. MCA, middle cerebral artery; MCA contra, middle cerebral artery contralateral; PCA, posterior cerebral artery, PCA contra; posterior cerebral artery contralateral; ACA, anterior cerebral artery.