title: The crescent sign and hydronephrosis.
mesh_terms: D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging*; D007223:Infant; D007668:Kidney / Q000002:abnormalities*; D008297:Male; D014518:Ureterocele / Q000000981:diagnostic imaging; D001745:Urinary Bladder Diseases / Q000000981:diagnostic imaging; D014567:Urography