Ultrasound of a nonobstructing stone

Longitudinal ultrasound image of the right kidney showing an echogenic stone (A; arrowhead) with posterior acoustic shadowing (A; dashed arrows). Twinkle artifact (B; arrows) on the color Doppler image is also helpful to confirm a stone. A noncontrast computed tomography (CT) scan obtained on the same day also shows the stone on transverse (C) and coronal (D) reconstructions.