The ‘ring of fire’ Foley balloon
Previously, we talked about the utility of ‘twinkling sign or artifact’ in detection of kidney stones. Interestingly, balloon of the Foley catheter can also twinkle on color Doppler appearing like a ‘ring of fire’. Apart from being a fun-fact, this may be helpful to make sure the Foley Balloon is in the bladder when the presence of debris/ blood clots obscures the view. In this example, the patient had a Foley in place but the echogenic material (clots) in the bladder was blocking it leading to impaired drainage (= that’s why there is urine [anechoic thing] surrounding the Foley balloon). Interestingly, the ring of fire is prominent when the focal zone (hourglass icon) is set at the level of the balloon. If you place it above the balloon, the artifact loses prominence or may even disappear.