**3.2 Risk patients**

High-risk patients have a history of CKD 4 and 5 (glomerular filtration rate (GFR) < 30 ml/min), dialysis, and with reduced renal function who have had or are awaiting liver transplantation. The lower risk includes patients with CKD 3 (GFR 30–59 ml/min) and children under 1 year, because of their immature renal function [22]. Younger children and elderly persons are not affected by NSF because their immune system is immature [23]. Although the pathogenesis is not revealed, the immune system might have a key role in inducing NSF.

No cases of NSF have been reported in patients with GFR greater than 60 ml/ min. The role of various possible cofactors in the pathogenesis of NSF is not proven.

Pregnant patients. In the absence of specific information, it seems wise to manage pregnant patients, regardless of their renal function, in the same way as children aged under 1 year to protect the fetus.

In the use of GBCAs, serum creatinine should be measured before gadolinium contrast media administration for all patients.
