The usefulness of conventional and echo colour Doppler sonography in the differential diagnosis of toxic multinodular goitres

Abstract

OBJECTIVE: To assess the potential role of conventional sonography and colour flow Doppler (CFD) sonography (CFDS) in the differential diagnosis of toxic multinodular goitres. SUBJECTS AND METHODS: We investigated 55 patients with untreated hyperthyroidism (24 with typical toxic diffuse goitre of Graves' disease (Group A); 26 with multinodular goitre (Group B); and five with single toxic adenoma (Group C); 22 euthyroid subjects (12 with non-toxic multinodular goitre (Group D) and ten normal subjects (Group E)) were included as controls. In all cases free thyroxine, free tri-iodothyronine, TSH, TSH receptor antibodies (TRAb), anti-thyroperoxidase antibody, anti-thyroglobulin antibodies and anti-thyroid microsomal antibodies were determined and a [(99m)Tc]pertechnetate thyroid scan was performed. RESULTS: Patients with toxic multinodular goitre displayed two different CFDS patterns: 18 patients (Group B-1) had nodules with normal vascularity surrounded by diffuse parenchymal hypoechogenicity with markedly increased CFD signal and maximal peak systolic velocity (PSV) (a pattern similar to Group A patients with Graves' disease); eight patients (Group B-2) had increased intra- and perinodular CFD signal and PSV with normal extranodular vascularity (a pattern similar to that found in Group C patients with single toxic adenoma). Patients of Group B-1 showed a proportion of clinically evident thyroid ophthalmopathy, positive TRAb and other thyroid autoantibodies similar to that observed in Group A patients, while no evidence of thyroid autoimmunity was found in Group B-2. Sixteen out of 18 (89%) patients from Group B-1 displayed a scintiscan pattern of diffuse uneven radionuclide distribution, while seven out of eight (87.5%) of those from Group B-2 had localized uptake in multiple discrete nodules. Taken together, these data strongly suggest that Group B-1 mostly represents patients with the multinodular variant of Graves' disease, while Group B-2 represents patients with non-autoimmune toxic multinodular goitre. CONCLUSIONS: This study shows that combined conventional sonography and CFDS may easily distinguish nodular variants of Graves' disease from non-autoimmune forms of toxic multinodular goitre and confirms the clinical usefulness of this technique in the first-line evaluation of hyperthyroid patients.