The options are repeat CT scan, which is expensive and the most radiation intensive (albeit very low dose for adults).
Renal sonogram is pretty good for kidney stones, especially larger ones and is totally safe. This modality can also be used to follow ureter stones that are obstructive. Bladder ultrasound can be used to folllow stones at the junction of bladder and ureter, the UVJ. Intravenous urography is the final option. Old school for sure, the IVP as it is known, is still quite good. Disadvantages are that the test is time consuming, requires IV dye that may be allergenic and nephrotoxic to some, and utilizes low dose ionizing radiation.