Thyroid ultrasound versus antithyroid peroxidase antibody determination: a cohort study of four hundred fifty-one subjects.
Autoimmune thyroiditis is mirrored by a hypoechoic ultrasound pattern. We determined diagnostic precision of thyroid sonography compared to that of anti-thyroid peroxidase antibody (TPOAb) concentration. Ambulatory patients with unknown thyroid status (n = 451; 407 female, ages 44 +/- 16 years; 45 male, ages 50 +/- 14 years) excluding those with suspected hyperthyroidism or on drugs known to cause hypothyroidism were recruited consecutively. Subjects were recruited from a specialized thyroid outpatient unit with higher frequencies of thyroid disorders than in the general population. Before determination of thyroid function and TPOAb concentration thyroid volume (normal values: women < 12 mL, men < 14 mL) and echogenicity (grade 1 = normal: similar to submandibular gland, hyperechoic to neck muscles; grade 2: hypoechoic to submandibular gland, hyperechoic to neck muscles, grade 3: iso-/hypoechoic to neck muscles) were determined. Positive predictive value of grade 3 pattern for detection of autoimmune thyroiditis was 94% (with overt hypothyroidism) and 96% (with any degree of hypothyroidism), that of grade 2 or 3 85% and 87%, respectively. Negative predictive value of grade 1 pattern for detection of euthyroid TPOAb negative subjects was 91%. Goiter was present in 31% and 21% of TPOAb postive and negative subjects, respectively, while 11% and 15% had an atrophic thyroid gland (p = not significant [n.s.]). Given a high intraobserver and interobserver agreement abnormal thyroid ultrasound patterns were highly indicative of autoimmune thyroiditis and allowed the detection of thyroid dysfunction with 96% probability.
Raber
Wolfgang
W
Division of Endocrinology & Metabolism, Department of Medicine III, University of Vienna, Vienna, Austria. wolfgang.raber@univie.ac.at
Gessl
Alois
A
Nowotny
Peter
P
Vierhapper
Heinrich
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging / Q000276:immunology; D007037:Hypothyroidism / Q000000981:diagnostic imaging / Q000276:immunology; D007453:Iodide Peroxidase / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D013967:Thyroiditis, Autoimmune / Q000000981:diagnostic imaging* / Q000276:immunology; D014463:Ultrasonography
D001323:Autoantibodies; C056626:thyroid microsomal antibodies; D007453:Iodide Peroxidase