- Written by Jakub Bartnik
A 35yo Male presents to the emergency with 1 day severe right flank pain that has since started becoming worse in the right lower quadrant. It came on suddenly and is much more intense at times. On exam, he is nontoxic in appearance, afebrile, and mildly tender in the right lower quadrant. You contemplate ordering a CT to rule out appendicitis, but elect to perform a renal ultrasound first.
What do you see? Yes, there is some hydronephrosis, aka ‘dro. Did you catch the stone in the sagittal pelvic clip?
Note the hyperechoic focus with posterior shadowing:
Initially missed by the ultrasound team until we used color doppler:
What is this called?
Yes! Twinkle Artifact. A property of some highly reflective objects such as calcified stones. It is dependent on machine color doppler settings and the surface of the stone, more pronounced in rough surfaces. It mimics turbulent blood flow with its multiple colors.
Here is another example of another patient’s UVJ stone with the same artifact, but less pronounced:
And this is the original patient’s stone measuring 8mm.
When you are evaluating for hydronephrosis, get in the habit of using color doppler, both on the kidneys as well as the bladder views.