This document discusses various filling defects that can occur in the ureter as seen on clinical imaging. It includes examples of nonopaque ureteral calculi, blood clots, renal vein thrombosis, transitional cell carcinoma, ureteritis cystica, ureteral tuberculosis, and malacoplakia - each presenting with different characteristic imaging patterns within the ureter. Accompanying images and descriptions help distinguish these conditions based on features like stippling, papillary contours, strictures, dilatations, beading, or thickening of the ureter.