Novel Imaging Techniques in the Management of Thyroid Nodules and Autoimmune Thyroid Disease

Thyroid nodular disease due to its high incidence, oscillating from about 10 to about 70% of the adult population, constitute a major socioeconomic problem. Introduction of high-resolution thyroid ultrasonography together with its wide accessibility and low cost, has dramatically increased the detection rate of thyroid lesions. Meanwhile, the estimated risk of malignancy is relatively low, within the range from less than 3 to about 10%. These indicate a great need for novel diagnostic tools, which will allow a credible differentiation between the suspected nodules, which require surgical treatment from benign lesions, which may be managed conservatively. Ideally this technique should be cheap, easy to perform and non-invasive. Introduction of novel ultrasound-based techniques such as Doppler examination, contrast-enhanced ultrasonography, 3D ultrasonography and sonoelastography have further increased the diagnostic potential of non-invasive techniques. A great technological advancement is observed especially if sonoelastography is concerned; i.e. Shear Wave Elastography (SWE) is thought to be more objective, reliable and reproducible than older variants of elastography, requiring complicated compressive maneuvers. However, novel imaging techniques are not limitation-free, and therefore fine-needle aspiration biopsy is still an irreplaceable gold standard in the diagnostics of thyroid nodules.

The ultrasound features are being classified into different scales used for assessment of malignancy risk of thyroid nodules (i.e. novel EU-TIRADS classification introduced by ETA in 2017), which practical utility is still under study. Nuclear medicine based imaging has also proved to be useful in this setting. Following wider use of PET-CT, a problem of incidentally diagnosed increased focal thyroid uptake has emerged. A progress has also been made in scintigraphic examinations. Especially fusion techniques have found to be particularly useful, like SPECT-ultrasound fusion or PET-ultrasound fusion in the detection of malignant thyroid lesions. Finally, ultrasound-based methods have moved from the field of diagnostics into therapy, when High-Intensity Focused Ultrasound (HIFU) has been developed. Although still not widely available, this technique is considered cost-effective and attractive alternative for thyroid surgery or radioiodine therapy, in case of large symptomatic thyroid nodules. Some authors report potential use of this modality i.e. in hyperparathyroidism or Graves’ disease. However, its real effectiveness and safety is still to be determined before firm recommendations on the use can be made. Novel ultrasound techniques has also been demonstrated to be useful as additional techniques in the diagnostics, monitoring and differentiation of different types of thyroiditis as well in the assessment of lymph nodes suspected for metastatic disease.

The goal of this Research Topic is to present reports on the use of novel ultrasound-based and radioisotope methods of thyroid imaging as well as studies assessing the usefulness of novel risk classifications of thyroid lesions in the diagnostics, monitoring and therapy of thyroid nodules and autoimmune thyroid disease.

The scope of the issue would cover articles presenting comprehensive and critical evaluation of the usefulness of novel thyroid imaging techniques in a clinical setting. Original research studies are preferred, but also expert reviews or clinical case reports (but only of exceptional value) might be accepted.