Thyroid Ultrasound Versus Antithyroid Peroxidase Antibody Determination: A Cohort Study of Four Hundred Fifty-One Subjects

Abstract

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.

Low concordance between positive antibodies to thyroperoxidase and thyroid ultrasound autoimmune pattern in pregnant women

“…In fact, there are two ways to explain the low prevalence of ultrasound autoimmune pattern in TPOAbpositive pregnant women: a low sensitivity of TUS or a low specificity of TPOAb-positivity. However, several previous studies have shown a good sensitivity of TUS for the diagnosis of early stages of Hashimoto's thyroiditis and subclinical hypothyroidism in non-pregnant subjects [14,15,16,18]. Similarly, the specificity of TPOAb in common population is high and was nearly 100 % for histological findings of Hashimoto's thyroiditis [19,20].…”

“…According to Dvorakova et al [15] decreased thyroid echogenicity can be an early indicator of serious thyropathies before laboratory dysfunction and clinical symptoms appear. In the study of Raber et al there was 85-96 % positive predictive value for TPOA-positive patients and 91 % negative predictive value for TPOAb-negative subjects [16]. Hypoechogenicity in TUS in postpartum thyroiditis had a prognostic significance for development of thyroid dysfunction [17].…”

A hypoechoic pattern of the thyroid at ultrasound does not indicate autoimmune thyroid diseases in patients with morbid obesity

“…Over the last decade, ultrasound (US) scans proved to be a valuable tool for the diagnostic work-up of thyroid diseases (1)(2)(3)(4)(5)(6)(7)(8). Besides estimation of thyroid volume and identification of non-palpable thyroid nodules (9), US scans are able to characterize the echographic structure of thyroid tissue (10).…”

“…In autoimmune thyroid diseases (AITDs), however, both lymphocytic infiltration and disruption of normal tissue architecture cause a reduction in thyroid echogenicity (1,4,6,10,11). Thyroid hypoechogenicity is currently viewed as an early sign of thyroid autoimmunity, which may be present even when the thyroid disorder is not suspected from a clinical point of view (4,6,7,12,13). Rapid improvements in US equipment and the use of standardized computerized algorithms have permitted an objective and quantitative measurement of tissue echogenicity in thyroid diseases (11)(12)(13), as well as in other pathological conditions (14,15).…”

Função tireoidiana subclínica e aspectos ultra-sonográficos em mulheres submetidas a rastreamento de função tireoideana em local de trabalho

“…Grande parte dos casos persistentes de doença subclínica da tireóide persistente evolui para doença clínica 2 . Estudos recentes indicam que a ultra-sonografia da tireóide e a dosagem de anti-TPO são os melhores métodos para identificar indivíduos com chances de desenvolver doença clínica da tireóide 43,[45][46][47] . Os resultados deste estudo são consistentes com os dados desses outros autores [49][50][51][52] , que mostraram a importância das alterações ultra-sonográficas no diagnóstico da doença tireoidiana autoimune.…”