Thyroid ultrasonography as a tool for detecting thyroid autoimmune diseases and predicting thyroid dsfunction in apparently healthy subjects.
In order to establish its usefulness for the diagnosis and follow-up of thyroid autoimmune diseases, thyroid ultrasonography together with free T4 (FT4), free T3 (FT3), TSH, antibodies (Tg Ab) and thyroperoxidase antibodies (TPO Ab) were performed and re-evaluated during a 3-yr follow-up in 482 apparently healthy subjects, living in a borderline iodine-sufficient urban area. Thyroid dysfunction was found in 7 out of 12 (58.3%) subjects with circulating thyroid autoantibodies, who also had thyroid hypoechogenicity (2 had overt and 3 subclinical hypothyroidism at booking; 2 developed subclinical hypothyroidism during the follow-up), and in none of the 12 subjects with normal thyroid echostructure (chi2=7.26, p=0.007). Thyroid dysfunction was found in 4 out of 29 (13.7%) subjects with negative Tg and/or TPO Ab who also had thyroid hypoechogenicity (1 had Graves' disease at booking, 1 developed Graves' disease and 2 subclinical hypothyroidism during the follow-up), and in none of the 429 with normal thyroid echostructure (chi2=82.03, p<0.0001). Although positive TPO and/or Tg Ab were more frequent (24/482, 5%) in subjects with thyroid dysfunction (7/11) than in those who remained euthyroid during the study (17/471, chi2=69.66, p<0.0001), thyroid hypoechogenicity had a higher sensitivity than the positivity of thyroid autoantibody tests (100 vs 63.3%) for diagnosing or predicting thyroid dysfunction.


CONCLUSIONS
1) thyroid ultrasonography is a useful tool to detect thyroid autoimmune disease in apparently healthy subjects; 2) present and future thyroid dysfunction is more readily predicted by a hypoechogenic pattern at thyroid ultrasound than by the occurrence of serum thyroid autoantibodies.
Rago
T
T
Department of Endocrinology and Metabolism, University of Pisa, Italy.
Chiovato
L
L
Grasso
L
L
Pinchera
A
A
Vitti
P
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013954:Thyroglobulin / Q000276:immunology; D013959:Thyroid Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000276:immunology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013963:Thyroid Hormones / Q000276:immunology; D014463:Ultrasonography
D001323:Autoantibodies; D013963:Thyroid Hormones; D013954:Thyroglobulin; D007453:Iodide Peroxidase