A prospective study of the effect of nonionic contrast media on thyroid function

Abstract

To observe the effect of iodine in nonionic contrast media on thyroid function, we measured free thyroxine (FT4) and thyroid stimulating hormone (TSH) following nonionic contrast radiography in 73 patients (49 males; 24 females) aged 50 to 84 years, mean 65.7 years. FT4 was significantly (p < 0.01) raised above baseline at 8 weeks but not 4 weeks following contrast injection (mean +/- standard deviation, 17.1 +/- 5.9 and 14.3 +/- 4.0 vs 13.3 +/- 2.7 pmol/L at baseline); however, TSH was significantly (p < 0.03) depressed at both 4 and 8 weeks (1.09 +/- 0.68 and 1.21 +/- 1.56 vs 1.40 +/- 0.90 mIU/L). T3 did not change significantly. FT4 rose by more than 20% in 15/73 and TSH fell by more than..