The Sonographic Features of the Thyroid Gland After Treatment with Radioiodine Therapy in Patients with Graves' Disease

Association of autoimmune thyroid disease with type 1 diabetes mellitus and its ultrasonic diagnosis and management

As a common hyperglycemic disease, type 1 diabetes mellitus (T1DM) is a complicated disorder that requires a lifelong insulin supply due to the immune-mediated destruction of pancreatic β cells. Although it is an organ-specific autoimmune disorder, T1DM is often associated with multiple other autoimmune disorders. The most prevalent concomitant autoimmune disorder occurring in T1DM is autoimmune thyroid disease (AITD), which mainly exhibits two extremes of phenotypes: hyperthyroidism [Graves' disease (GD)] and hypo-thyroidism [Hashimoto's thyroiditis, (HT)]. However, the presence of comorbid AITD may negatively affect metabolic management in T1DM patients and thereby may increase the risk for potential diabetes-related complications. Thus, routine screening of thyroid function has been recommended when T1DM is diagnosed. Here, first, we summarize current knowledge regarding the etiology and pathogenesis mechanisms of both diseases. Subsequently, an updated review of the association between T1DM and AITD is offered. Finally, we provide a relatively detailed review focusing on the application of thyroid ultrasonography in diagnosing and managing HT and GD, suggesting its critical role in the timely and accurate diagnosis of AITD in T1DM.

Ultrasound Assessment of Autonomous Thyroid Nodules before and after Radioiodine Therapy Using Thyroid Imaging Reporting and Data System (TIRADS)

The Thyroid Imaging and Reporting System (TIRADS) allows a sonographic assessment of the malignancy risk of thyroid nodules (TNs). To date, there is a lack of systematic data about the change in ultrasound (US) features after therapeutic interventions. The aim of this study was to characterize the changes in autonomously functioning thyroid nodules (AFTNs) after radioiodine therapy (RIT) by using TIRADS. We retrospectively assessed data from 68 patients with AFTNs treated with RIT between 2016 and 2018 who had available first and second follow-up US imaging. Before RIT, 69.1% of the AFTNs were classified as low-risk TNs when applying Kwak TIRADS (EU-TIRADS 52.9%), 22.1% were intermediate-risk TNs (EU-TIRADS 19.1%), and 8.8% were high-risk TNs (EU-TIRADS 27.9%). Twelve months after RIT, 22.1% of the AFTNs showed features of high-risk TNs according to Kwak TIRADS (EU-TIRADS 45.6%). The proportion of intermediate TNs also increased to 36.8% (EU-TIRADS 29.4%), and 41.2% were low-risk TNs (EU-TIRADS 25%). A significant percentage of AFTNs presented with features suspicious for malignancy according to TIRADS before RIT, and this number increased significantly after therapy. Therefore, before thyroid US, thorough anamnesis regarding prior radioiodine treatment is necessary to prevent unneeded diagnostic procedures.

The Role of Nuclear Medicine in the Clinical Management of Benign Thyroid Disorders, Part 1: Hyperthyroidism

Benign thyroid disorders, especially hyper- and hypothyroidism, are the most prevalent endocrine disorders. The most common etiologies of hyperthyroidism are autoimmune hyperthyroidism (Graves disease, GD), toxic multinodular goiter (TMNG), and toxic thyroid adenoma (TA). Less common etiologies include destructive thyroiditis (e.g., amiodarone-induced thyroid dysfunction) and factitious hyperthyroidism. GD is caused by autoantibodies against the thyroid-stimulating hormone (TSH) receptor. TMNG and TA are caused by a somatic activating gain-of-function mutation. Typical laboratory findings in patients with hyperthyroidism are low TSH, elevated free-thyroxine and free-triiodothyronine levels, and TSH-receptor autoantibodies in patients with GD. Ultrasound imaging is used to determine the size and vascularity of the thyroid gland and the location, size, number, and characteristics of thyroid nodules. Combined with lab tests, these features constitute the first-line diagnostic approach to distinguishing different forms of hyperthyroidism. Thyroid scintigraphy with either radioiodine or ^99mTc-pertechnetate is useful to characterize different forms of hyperthyroidism and provides information for planning radioiodine therapy. There are specific scintigraphic patterns for GD, TMNG, TA, and destructive thyroiditis. Scintigraphy with ^99mTc-sestamibi allows differentiation of type 1 from type 2 amiodarone-induced hyperthyroidism. The radioiodine uptake test provides information for planning radioiodine therapy of hyperthyroidism. Hyperthyroidism can be treated with oral antithyroid drugs, surgical thyroidectomy, or ¹³¹I-iodide. Radioiodine therapy is generally considered after failure of treatment with antithyroid drugs, or when surgery is contraindicated or refused by the patient. In patients with TA or TMNG, the goal of radioiodine therapy is to achieve euthyroid status. In GD, the goal of radioiodine therapy is to induce hypothyroidism, a status that is readily treatable with oral thyroid hormone replacement therapy. Dosimetric estimates based on the thyroid volume to be treated and on radioiodine uptake should guide selection of the ¹³¹I-activity to be administered. Early side effects of radioiodine therapy (typically mild pain in the thyroid) can be handled by nonsteroidal antiinflammatory drugs. Delayed side effects after radioiodine therapy for hyperthyroidism are hypothyroidism and a minimal risk of radiation-induced malignancies.