Premature newborn now 1 month old with decreased urine output who had an umbilical arterial catheter placed at birth

US of thrombus in aorta caused by umbilical arterial catheter
Coronal grayscale US of the aorta centered at the level of the kidneys (above) shows a round echogenic object within the aorta at the level of the origin of the renal arteries. Coronal color doppler US of the aorta (below) shows good blood flow around the object and into the renal arteries which was confirmed on spectral doppler US.

The diagnosis was non-occlusive thrombus of the aorta secondary to past umbilical arterial catheterization.