Imaging of urachal anomalies

Urachal anomalies are classified into four types depending on the level of persistence of the embryonic urachal remnants between the urinary bladder and the umbilicus: patent urachus, umbilical-urachal sinus, urachal cyst, and vesico-urachal diverticulum. Due to the increasing use of cross-sectional imaging, urachal anomalies are frequently detected as incidental findings. Imaging plays a pivotal role in the initial diagnosis, evaluation of complications, treatment follow-up, and long-term surveillance of patients with urachal anomalies. Different urachal anomalies demonstrate characteristic imaging features that aid in a timely diagnosis and guide treatment. A patent urachus is visualized as an elongated tubular structure between the umbilicus and the urinary bladder. While umbilical-urachal sinus appears as focal dilatation at the umbilical end of the urachal remnant, the vesico-urachal diverticulum presents as a focal outpouching of the urinary bladder at anterosuperior aspect. Urachal cysts are identified as midline fluid-filled sacs most frequently located near the dome of the urinary bladder. Untreated urachal anomalies could progress into potential complications, including infection and malignancy. Knowledge regarding imaging features of urachal anomalies helps in timely diagnosis, treatment, follow-up, and early detection of complications.