Applying TI-RADS in Thyroid Sonography: Clearing Away the Fog

Out of every 100 adults living in North America, 4 to 7 will have a palpable thyroid nodule and 19 to 67 will have a non-palpable nodule demonstrated by ultrasound (US). Despite a 2.4X increase in detection of thyroid cancer over the last 30 years, the 5-year mortality rate has been stable at around 2% since 2005. This could be due to many factors, but one apparent significant contributor is the over-diagnosis of malignant nodules, likely based on better detection rates from US imaging. It has been estimated that more than half of papillary thyroid cancer nodules (the most common type of thyroid cancer) would not have resulted in clinical symptoms during the life-time of the patient if left alone. With US now able to detect cysts as small as 1mm, and solid nodules in the range of 2-3 mm, physicians are left with a difficult decision in determining which nodules require a fine-needle aspiration (FNA) and which are better left alone. To aid with this difficult decision, standardized evidenced based guidelines were developed by various groups and organizations. Of these, thyroid image reporting and data system (TI-RADS) and American Thyroid Association (ATA) 2015 guidelines are the most commonly used in our institution (The Ottawa Hospital). While these efforts to create a standardized system are helpful in determining which nodules require FNA, the basis of these decisions has to come from high-quality imaging technique. However, a retrospective study at our institution found that there was large discrepancy in imaging technique used by technologists when imaging the thyroid. We suggest, at any point of thyroid imaging (pre, during and post FNA) a standardized technique be used in assessment. Providing all necessary imaging data will allow radiologists to produce a sufficiently detailed report, synthesize the findings, and ensure the best management plan possible for each patient. Future work by technologist associations may help establish more robust imaging standards for this patient population.