In the anterosuperior wall of the bladder, at the site of sonographic finding of concern, there is a non enhancing soft density that measures 10 mm craniocaudal x 12mm AP 13 mm transverse. On the delayed images, this soft tissue density is positioned anterior to contrast that has layered dependently in the bladder. accordingly it cannot be determined whether it fills with contrast, although this is suspected since it had appearance of a diverticulum on the sonographic images. From this density in anterosuperior wall of the bladder, a thin band of tissue extends cephalad to the umbilicus. these findings are consistent with a persistent urachal remnant. No cyst or enchaning mass is seen. Please tell me what this means?