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

Area of Science:

• Endocrinology
• Radiology
• Thyroid Function

Background:

• Iodine-containing contrast media are widely used in radiographic procedures.
• The impact of iodine load from nonionic contrast media on thyroid function, particularly in older populations, requires further investigation.

Purpose of the Study:

• To evaluate the effects of nonionic contrast radiography on thyroid hormone levels, specifically free thyroxine (FT4) and thyroid stimulating hormone (TSH).

Main Methods:

• Prospective study involving 73 patients (aged 50-84 years) undergoing nonionic contrast radiography.
• Measurement of serum FT4 and TSH levels at baseline, 4 weeks, and 8 weeks post-contrast administration.

Main Results:

• A significant increase in FT4 was observed at 8 weeks post-injection (p < 0.01), while TSH levels were significantly depressed at both 4 and 8 weeks (p < 0.03).
• More than 20% increase in FT4 occurred in 15/73 patients, and more than 20% decrease in TSH in 41/73 patients.
• Two patients developed hyperthyroidism, and other thyroid function abnormalities were noted in four patients.

Conclusions:

• Nonionic contrast media containing iodine can induce transient thyroid dysfunction, characterized by elevated FT4 and suppressed TSH, in older adults.
• While overt hyperthyroidism is uncommon, a significant trend towards thyroid stimulation exists post-iodine exposure.
• The findings suggest a potential link between patient age and the observed thyroid function alterations.