Question special

In patients with chronic kidney disease or those who are at risk of developing kidney injury while hospitalized, what are ways you optimize patients prior to receiving an intravenous contrast load? Is there a GFR range whereby it may be considered safe to receive a relatively small contrast load (e.g., CT chest with contrast) but ill advised for the patient to receive a larger contrast load like in cardiac catheterization? Are there any tools available to help predict which patients are most at risk for developing contrast induced nephropathy?