Congenital abnormalities
Contrast media
Stone disease, obstruction, and metabolic abnormalities
Urinary tract infection
Renal cystic disease
Solid renal neoplasms
Transitional cell carcinoma and filling defects
Urinary tract trauma/upper and lower urinary tract
Adrenal abnormalities
Vascular abnormalities
Testicular and scrotal abnormalities
Miscellaneous.