Thyroid nodules are a common cause of concern among population, notably female, there detection increases to up to 50%, when ultrasound imaging are employed. The nodule is usually assessed by ultrasound examination in order to determine which of them can be malignant or benign. This exam is well-established as the diagnostic investigation of choice, because it is simple, safe, cost-effective and provides for reliable results.
However, an important interexaminer variability was observed in the recognition and descriptions of thyroid nodules. To narrow these gaps, guidelines have emerged such as the 2015 American Thyroid Association (ATA) and the 2017 American College of Radiology (ACR TI-RADS), which aims to standardize the reports and the propaedeutic in these cases.
ACR TI-RADS is a reporting data system for thyroid lesions, proposed to standardize the reporting results of thyroid ultrasound that can be understood by clinicians and also stratify the risk of malignancy of a lesion based on ultrasound features. In this system, each nodule was classified into a TI-RADS category (1- Bening; 2- Not suspicious; 3- Mildly suspicious; 4- Moderately suspicious; e 5- Highly Suspicious).
ATA guideline is another important way to classified nodules, on this system each nodule can be classified as Benign, Very low suspicion, Low suspicion, Intermediate suspicion, High suspicion, and in each group we will have a specific probability of malignancy.
When the nodule has suspicious radiological features the Fine needle aspiration (FNA) is required. This method is an important auxiliary tool as it allows cytological classification of these nodules according to The Bethesda System. This system classifies nodules into six groups, some of them are considered benign, indeterminate, while others are malignant and surgery is required.
The present study aims are to verify the correlation between the ATA, ACR TI-RADS classification and subjective impression with the Bethesda system obtained FNA by ultrasound-guided. Another aim is to correlation imaging criteria suggestive of malignancy with the result of cytology examination.