Introducing a Novel Diagnostic Modality for Thyroid Cancer: Thyroidography

This article refers to:

A New Imaging Technique for the Diagnosis of Thyroid Cancer: Thyroidography

Thyroid cancer, with an estimated 64,300 new cases and 1980 deaths in 2016, is the most common endocrine malignancy in the United States [1]. Even though thyroid cancer is associated with high overall survival, inadequate preoperative imaging can contribute to incomplete initial surgery and subsequent recurrence [2]. According to the American Thyroid Association (ATA) Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer, ultrasound is the first-line imaging modality for patients with known or suspected thyroid cancer. In addition, cross-sectional imaging, including computed tomography (CT) scan and magnetic resonance imaging (MRI), have a role in primary and nodal preoperative assessment in some patients with well-differentiated thyroid cancer. Finally, radioiodine whole body scanning has been the primary functional imaging modality for patients suspected of persistent/recurrent well-differentiated thyroid carcinoma. Newer technology utilizing radioiodine with SPECT/CT fusion significantly improves anatomic localization of disease and may be used to guide surgical intervention. However, given the slow growth rate of most thyroid cancers, the ATA Committee does not recommend the use of positron emission tomography (PET) or PET-CT prior to initial surgery for thyroid cancer [2–3].

Ultrasound is fast, cheap and reliable while providing detailed information about nodules. However, its sensitivity and specificity for diagnosing thyroid cancer is variable, ranging between 17–87% and 39–95%, respectively [4]. Additionally, low- to moderate-quality evidence suggests that individual ultrasound features are not accurate predictors of thyroid cancer. Two features, cystic content and spongiform appearance, can predict benign nodules, however this does not always apply clinically due to their infrequent occurrence [5].

Aysan et al. has introduced a novel imaging technique for diagnosing thyroid cancer—thyroidography. This modality is based on low dose X-rays that specifically reveal microcalcifications. Images are obtained from surgically excised human thyroid tissue samples using a mammography device with a neck simulator. Subsequently, an algorithm is developed to display only microcalcifications and raw images are transformed into new images (thyroidography) generated by this algorithm. Thyroidography has shown to successfully detect microcalcifications in malignant cases with significant sensitivity, positive predictive value, negative predictive value and accuracy [4].

Therefore, thyroidography is a new imaging modality that can assist providers in diagnosing thyroid cancer. The authors predict that thyroidography will not replace ultrasound, but rather, will serve as a complementary modality for diagnosing thyroid cancer [4]. Especially in the setting of carcinoma, other aspects of diseased anatomy needs to be evaluated. For example, inspection of extrathyroidal structures, namely cervical lymph nodes, is warranted after malignancy had been confirmed. Cross-sectional imaging with CT or MRI is appropriate when abnormal lymph nodes are identified at the periphery or limits of the sonographically accessible field or bulky nodal disease is incompletely imaged with ultrasonography or in the presence of evidence of extension of nodal disease into the mediastinum or deep structures of the neck (parapharyngeal and/or retropharyngeal regions) [6].

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.